HomeMy WebLinkAboutResolution No. 4814 COUNCIL RESOLUTION NO, 4814
A RESOLUTION APPROVING THE EUGENE-
SPRINGFIELD METRO AREA MULTI-HAZARD
MITIGATION PLAN,
PASSED: 7/0
REJECTED:
OPPOSED:
ABSENT: Nathanson
CONSIDERED: November 8, 2004
RESOLUTION NO, 4814
A RESOLUTION APPROVING THE EUGENE-SPRiNGFIELD
METRO AREA MULTI-HAZARD MITIGATION PLAN,
The City Council of the City of Eugene finds that:
A. The adoption of a multi-hazard mitigation plan is required as a condition
for communities to remain eligible for future Federal Emergency Management
Agency (FEMA) mitigation grant funds.
B. The Cities of Eugene and Springfield have jointly prepared the Eugene-
Springfield Metro Area Multi-Hazard Mitigation Plan in order to meet FEMA's
funding requirement, a copy of which is attached as Exhibit A and incorporated
herein by reference.
C. The City Council has reviewed and considered the Eugene-Springfield
Metro Area Multi-Hazard Mitigation Plan.
D. The mitigation strategies and action items identified in the plan will be
implemented only when funding sources have been identified and projects have
been prioritized as outlined in the plan.
NOW, THEREFORE,
BE IT RESOLVED BY THE CITY COUNCIL OF THE CITY OF EUGENE,
a Municipal Corporation of the State of Oregon, as follows:
Section 1. Based on the above findings, which are hereby adopted, the
Eugene-Springfield Metro Area Multi-Hazard Mitigation Plan attached as Exhibit
A is approved as the official Multi-Hazard Mitigation Plan for the City of Eugene.
Section 2. This Resolution shall become effective immediately upon its
adoption.
The foregoing Resolution adopted the 8th day of November, 2004.
City Recorder
Resolution
Multi-Hazard Mitigation Plan
for the
EUGENE~SPRINGFIELD
Metropolitan Area
Public Review Draft
October 13, 2004
October 28, 20~4
Mr. Dennis S~grist
State Hazard M~tiganon Officer
Oregon Emergency Management
P,O Box 14370
Salem, Orcgon 97509-5062
Dear Mn Sigrist:
As requested, the Regi. on has completed a pre-adoption review of the MultbHazard Mitigation
Plan for the Eugene/Springfield Metropolitan Area. The plan succcsslSally contains the requn'cd
criteria, excluding 7he adoption, as outhued in 44 CFR Pan 20t, The plan review v, orksbcet is
enclosed, This letter serves as the Region's comrninnenl to approve the plan for the cities of Eugene
and Springfield upon the condinon adoption documents are received w~thin 60 days by each of thc
juns&ct~ons.
The U.S. Depa/tment of Homctand Security's Federal Emergency Management Agency ~,FEMA)
well not approve d~e plan until ~t is adopted The jansd~crions are nor eligible tbr mmgation project
grams until formal approx, al by FEMA,
Please contact me at 425.48Z47O0 v, ~th an5 questions.
Smcerel~,
Sharon Loper
PDM Pro,ram and Mitigation Plans Manager
Enclosure
Snow Storm ~]ctnua~3, 2004
S~tow Si'otto 2004
3-lood 1996
Hazard Mitigation Plan prepared by:
Kenneth A. Goettel
Goettel & Assocmtes Inc.
1732 Arena Drive
Davis, CA 95616
(530) 750-0440
Numerous staff from the City of Eugene, City of Springfield, Lane County, and other local
and state agencies provided invaluable input to and assistance with the development of this
Hazard Mitigation Plan, including:
Chuck Solin
Emergency Program Manager
City of Eugene
Ke-vin M. S. Rack
Emergency Management
City of Spnngfield
Bill Clingman
GIS Specialist
Lane County of Governments
Cover Photo City of Eugene, Windstorm Damage, February 7, 2002
l~side Cover City of Eugene, Snow Storm, January 2004
City of Eugene, Flood 1996
EXECUTIVE SUMMARY
This Multi-Hazed Mitigation Plan ~br the Eugene and Sphngfield metropolitan area covers
each of the major natural and anthropogenic hazards that pose risks to the c~tizens, buildings,
and infi'astructure within the metro area. The primary objectives of this mitigation plan are to
reduce the negative impacts of future disasters on the community, i.e., to save lives, mimmize
injuries, damage to buildings and infrastructure (particularly critical facihties), and reduce
economic loss. The intent and purpose of the plan is to educate and infon-n public officials
and residents, increase awareness of the risks posed by hazards, and to facilitate reduction of
risk by encouraging implementation of hazard mitigation projects; however, this mitigation
plan is a planning document, not a regulatory document; therefore, it does not regulate
development or land use.
All communities in the United States must adopt FEMA-approved hazard mitigation plans in
order to remain eligible for future FEMA pre- or post-disaster hazard mitigation grant
programs. This mitigation plan meets FEMA's plalming requirements by addressing hazards,
walnerability, and risk. Hazard means the f~equency and severity of disaster events.
Vulnerability means the value, importance, and fragility of braidings and inlYastructure. Risk
means the threat to people, buildings and infrastructure, taking Into account the probabilities of
disaster events.
This document is a DRAFT. Review comments, suggestions, coi'rections and additions are
encouraged from all interested parties. Please send comments to: Chuck Solin, City of Eugene
Emergency Program Manager at chuck r solin(~ci eugene~or us
This Hazard Mitigation Plan contains the following main sections:
Overview and Context
Chapter 1: introduction
Chapter 2: Commmzity Profile
Chapter 3: Commumty Lnvolvement and Public Process
Chapter 4: Mitigation Goals, Strategies and Action items
Chapter 5: Plan Adoption, Implementation, and Maintenance
Hazards
Chapter 6: Floods
Chapter 7: Winter Storms
Chapter 8: Landslides
Chapter 9: Wildland/Urban Interface Fires
Chapter 10: Eal~rhquakes
Chapter 11: Volcanic Hazards
Chapter 12: Dam Safety
Chapter 13: Disruption of Utility and Transportation Systems
Chapter 14: HAZMAT Incidents
Chapter 15: Te~'onsm
Appendix
Example Mitigation Projects
Floods
Earthquakes
Hazard Mitigation Plan
TABLE OF CONTENTS
1. INTRODUCTION ............................................................................................ 1-1
1.1 What is a Hazard Mitigation Plan? ............................................................................ 1-1
1.2 Why is Mitigation Planning Important? .................................................................... 1-1
1.3 The Eugene/Springfield Metro Area Mitigation Plan ................................................ 1-2
1.4 Key Concepts and Definitions ................................................................................... 1-3
1.5 The Mitigation Process .............................................................................................. t-7
1.6 The Role of Benefit-Cost Analysis in Mitigation Planning ....................................... 1-9
1.7 Principles of Benefit-Cost Analysis ......................................................................... 1-10
1.6 Hazard Synopsis ....................................................................................................... 1-14
2.0 COMMUNITY PROFILE: EUGENE/SPRINGFIELD
METROPOLITAN AREA ............................................................................ 2-1
2.1 Population and Demographics ................................................................................... 2-1
2.2 Employment and Economics ..................................................................................... 2-2
2.3 Geography and Climate ............................................................................................. 2-3
2.4 Land and Development .............................................................................................. 2-4
2.5 Housing in the Eugene/Springfield Metro Area ........................................................ 2-4
3.0 PUBLIC PROCESS and COMMUNITY INVOLVEMENT .................... 3-1
3.1 Community involvement ........................................................................................... 3-1
3.2 Previous Mitigation Activities ................................................................................... 3-1
3.3 Planning Process ........................................................................................................ 3-1
Public Review Draft: October 12, 2004
Hazard Mitigation Plan
4,0 PLAN GOALS~ MITIGATION STRATEGIES & ACTION
iTEMS ............................................................................................................. 4-1
4.1 Mitigation Plan Objectives ........................................................................................
4.2 Multi-Hazard Mitigation Strategies and Action Items ............................................... 4-2
4.3 Hazard Specific Mitigation Strategies and Action items ........................................... 4-2
4.3.1 Flooding Within FEMA-Mapped Flood Plains ...................................................... 4-2
4.3.2 Flooding Outside of FEMA-Mapped Flood Plains ..................................... 4-3
4.3.3 Winter Storms ............................................................................................. 4-3
4.3.4 kandslides ................................................................................................... 4-3
4.3.5 Wildland/Urban Interface Fires .................................................................. 4-3
4.3.6 Earthquakes ................................................................................................. 4-4
4.3.7 Volcanic Hazards ........................................................................................ 4-4
4.3.8 Dam Safety .................................................................................................. 4-4
4.3.9 Disrupt/on of Utility and Transportation Systems ...................................... 4-4
4.3.10 Hazmat Incidents ...................................................................................... 4-4
4.3.1 1 Terrorism ................................................................................................... 4-5
4.4 The Role of Benefit-Cost Analysis in ln-~plementing Mitigation Measures
5,0 MITIGATION PLAN ADOPTION~ MAINTENANCE AND
IMPLEMENTATION .................................................................................... 5-1
5.1 Plan Adoption ............................................................................................................ 5-1
5.2 Plan Implementation .................................................................................................. 5-1
5.3 Plan Maintenance .......................................................................................................
6.0 FLOOD HAZARDS ....................................................................................... 6-1
6.1 Historical Floods in the Eugene/Springfield Metro Area .......................................... 6-1
6.2 The 1996 Flood .......................................................................................................... 6-1
ii Pubhc Rewew Draft: October 12, 2004
6.3 Flood Hazards and Flood Risk: Within Mapped Floodplains .................................. 6-2
6.3.1 Overview .....................................................................................................
6.3.2 Flood Hazard Data ...................................................................................... 6-3
6.3.3 Interpreting Flood Hazard Data for Mapped Floodplains ........................... 6-7
6.3.4 Caveats for the Eugene Springfield Flood Insurance Study ....................... 6-8
6.4 Flood Hazards and Flood Risk: Outside of Mapped Floodplains ............................. 6-9
6.5 Inventory Exposed to Flood Hazards in the Eugene/Spnngfield Area .................... 6-11
6.6 Flood Insurance Data for the Eugene/Springfield Area ........................................... 6-13
6.7 Estimating Flood Losses and Flood Risk ................................................................. 6-13
6.8 Common Flood Mitigation Projects and Action Items ............................................ 6-14
7~0 WINTER STORMS ....................................................................................... 7-1
7.1 Overview .................................................................................................................... 7-1
7.2 Winter Storms Hazard Assessment .............................................................................
7.2.1 Rain Hazard Data ........................................................................................ 7-2
7.2.2 Wind Hazard Data ........................................................................................ 7-5
7.2.3 Historical Winter Storm Data ...................................................................... 7-8
7.3 Winter Stmrn Risk Assessment ................................................................................. 7-9
7.4 Mitigation of Winter Storm Impacts ........................................................................ 7-10
8.0 LANDSLIDES ................................................................................................ 8-1
8.1 Landslide Overview and Definitions
8.2 Landslide Hazard Assessment ....................................................................................
8.3 Landslide Risk Assessment ......................................................................................... 8-9
8.4 Mitigation of Landslide Risk ................................................................................... 8-10
Pubhc Review Draft. October 12, 2004
Hazard Mitigation Plan
9.0 WILDLAND/URBAN INTERFACE FIRES
9.1 Fire Primer ................................................................................................................. 9-1
9.1.1 Structure Fires ............................................................................................. 9-1
9.1.2 Wildland Fires ............................................................................................. 9-5
9.1.3 Wildland/Urban Interface Fires .................................................................. 9-8
9.2 Measures of the Level of Fire Hazard ........................................................................ 9-9
9.3 Historical Data for Wildland Fires in Oregon .......................................................... 9-11
9.4 Urban/Wildland Interface Fire Hazards for Eugene/Springfield ............................. 9-12
9.5 Mitigation Strategies ................................................................................................ 9-16
EARTHQUAKES
10.1 Earthquake Printer ................................................................................................. 10- t
10.2 Seismic Hazards for Lane County and Eugene/Springfield
10.3 Other Aspects of Seismic Hazards in Lane County ............................................... 10-8
10.3.1 Sod Effkcts .............................................................................................. 10-8
10.3.2 Landslides ............................................................................................... 10-9
10.3.3 Dam Failures ........................................................................................... 10-9
10.3.4 Tsunamis and Seiches ............................................................................. 10-9
10.4 Risk Assessment for Scenario Earthquakes ......................................................... 10-10
10.4.1 M$.5 Cascadia Subducfion Zone Interface Earthquake ........................ 10-11
10.4.2 M7.5 Cascadia Subduction Zone Intraplate Earthquake ....................... 10-12
10.5 Earthquake Risk Assessment: Technical Guidance ............................................ 10-13
10.5.1 Level Two Risk Assessment .................................................................. 10-14
10.5.2 Level Three Risk Assessment ................................................................ 10-14
10.6 Other Earthquake Loss Estimates for Eugene/Springfield .................................. 10-16
10.6.1 Probable Maximum Loss Study of City Buildings in Eugene .................10-16
10.6.2 DOGAMI Study of 200 Buildings ........................................................... 10-16
10.6.3 Windshield Survey and General Comments ............................................ 10-16
10.7 Earthquake Hazard Mitigation Projects: General Examples ............................... 10-17
Public Review Draft' October 12, 2004
Hazard Mitigation Plan
VOLCANIC HAZARDS ...........................................................................
11.1 Overview ................................................................................................................ 11- l
11.2 Volcanic Hazard Types .......................................................................................... 11-2
11.3 Volcanic Hazards for the Eugene/Springfield Metro Area .................................... 11-3
11.4 Mitigation of Volcanic Hazards ............................................................................. 11-7
12.0 DAM SAFETY ........................................................................................... 12-1
12.1 Overview old'Dams ................................................................................................. 12-1
12.2 Dam Primer ............................................................................................................ 12-2
12.2.1 Dam Nomenclature and Types of Dams ................................................. 12-2
12.2.2 Dam Failure Modes ................................................................................. 12-3
12.3 Oregon Dam Data .................................................................................................. 12-4
12.4 Dam Failure Hazard Assessment: Eugene/Springfield MeVro Area ...................... 12-5
12.5 Risk Assessment (Preliminary) .............................................................................. t 2-7
12.5.1 Flood Damage to Dams .......................................................................... 12-7
12.5.2 Earthquake Dmnage to Dams .................................................................. 12-7
12.5.3 Loss Estimates (Preliminary) .................................................................. 12-8
12.6 Mitigation Strategies .............................................................................................. 12-9
References ....................................................................................................................... 12-10
13.0 DISRUPTION OF UTILITY AND TRANSPORTATION
SYSTEMS .................................................................................. 13-1
13.1 Transportation Systems .......................................................................................... 13-1
13.2 Utility Systems - Overview .................................................................................... 13-3
13.3 Potable Water Systems .......................................................................................... 13-5
Pubhc Review Draft: October 12, 2004
Hazard Mitigation Plan
13.4 Wastewater Systems .............................................................................................. 13-5
13.5 Natural Gas Systems .............................................................................................. 13-6
13.6 Telecommunications Systems ................................................................................ 13-6
13.7 Electric Power Systems .......................................................................................... 13-7
14.0 HAZARADOUS MATERIALS ................................................ 14-1
14.1 Introduction ........................................................................................................... 14-1
14.2 Effects of Hazardous Materials on Humans .......................................................... 14-2
t4.3 Classification Systems and Emergency Response Protocols ................................. 14-3
14.4 Statutory and Regulatory Context .......................................................................... 14-5
14.5 Fixed Site Hazardous Materials Locations ............................................................ 14-7
14.6 Hazardous Materials Transport: Truck, Rail and Pipelines .................................. 14-8
14.6.1 Overview and Truck Shipments ................................................................. 14-8
14.6.2 Rail Shipments ......................................................................................... 14-10
14.6.3 Pipelines ................................................................................................... 14-10
14.7 Potential Impacts of Hazardous Material Incidents ............................................. 14-12
14.8 Summary and Mitigation Strategies ..................................................................... 14-13
14.8.1 Plapming and Response ......................................................................... 14-13
14.8.2 Mitigation Measures ............................................................................ 14-15
14.8.2.1 Physical Safety Measures .................................................................. 14-15
14.8.2.2 Standard Operating Procedures ......................................................... 14-15
14.8.2.3 Mitigation and Emergency Response Planning ................................. 14-16
t 4.8.2.4 Drinking Water Protection Planning .................................................. 14-16
References .................................................................................................................... 14-17
15.0 TERRORISM ............................................................................. 15-1
15.1 Overview ................................................................................................................ 15-1
15.2 Threat Spectrum ..................................................................................................... 15-1
Pubhc Rewew Draft: October 12~ 2004
Hazard Mitigation Plan
15.3 Mitigation Actions ................................................................................................. 15-2
Pubhc Rewew Draft: October 12, 2004
Hazard Mitigation Plan
APPENDIX: MITIGATION PROJECT EXAMPLES ................. A-1
A. 1 Flood Mitigation Projects, Springfield .................................................................. A. 1-1
A.2 Earthquake Mitigation Project, Eugene City Hall ................................................ A.2-1
Public Review Draft: October 12, 2004
1.0 iNTRODUCTION
1.1 What is a Hazard Mitigation Plan?
The Eugene/Springfield Metro Area and surrounding areas are subject to a wide
range of natural and anthropogenic (human-caused) hazards, including: floods, winter
storms, landslides, wildand/urban interface fires, earthquakes, dam failures,
hazardous matedai spills, and many others. Some of these hazard events, such as
winter storms, happen to some extent every year. Others, such as earthquakes, may
significantly affect the Eugene/Springfield Metro Area only once every few hundred
years. The effect of potential future hazard events on the Eugene/Springfield Metro
Area may be minor - a few inches of water in a street - or it may be major - with
damages and economic losses reaching millions of dollars.
The effects of major disasters on communities can be devastating: the total damages,
economic losses, casualties, disruption, hardships and suffering are often far greater
than the physical damages alone. Furthermore, recovery from major disasters often
takes many years and some heavily affected communities may never fully recover.
Completely eliminating the risk of future disasters in the Eugene/Springfield Metro
Area is neither technologically possible nor economically feasible. However,
substantially reducing the negative consequences of future disasters Ls achievable
with the implementation of a pragmatic Hazard Mitigation Plan.
Mitigation simply means actions that reduce the potential for negative consequences
from future disasters. That is, mitigation actions reduce future damages, losses and
casualties.
The Eugene/Springfield Metro Area mitigation plan has several key elements.
1. Each hazard that may significantly affect the Eugene/Springfield
Metro Area is reviewed to determine the probability (frequency) and
severity of likely hazard events.
2. The vulnerability of the Eugene/Springfield Metro Area to each
hazard is evaluated to determine the likely extent of physical
damages, casualties, and economic consequences.
3. A range of mitigation alternatives are evaluated to identify those with
the greatest potential to reduce future damages and losses in the
Eugene/Springfield Metro Area, to protect facilities deemed critical to
the community's well being, and that are desirable from the
community's political and economic perspectives.
1.2 Why is I~litigation Planning Important for the Eugene/Springfield
Metro Area?
Effective mitigation planning will help the residents of the Eugene/Springfield Metro
Area deal with natural and anthropogenic hazards realistically and rationally. That is,
to help identify specific locations in the Eugene/Springfield Metro Area where the level
Public Review Draft August 6, 2004 1-1
of risk from one or more hazards may be unacceptably high and then to find cost
effective ways to reduce such risk. Mitigation planning strikes a pragmatic middle
ground between unwisely ignoring the potential for major hazard events on one hand
and unnecessarily overreacting to the potential for disasters on the other hand.
Furthermore, the Federal Emergency Management Agency (FEMA) now requires
each local government entity to adopt a multi-hazard mitigation plan to remain eligible
for future pre- or post-disaster FEMA mitigation funding. Thus, an important objective
in developing this plan is to maintain eligibility for FEMA funding and to enhance the
Eugene/Springfield Metro Area's ability to attract future FEMA mitigation funding.
The Plan is specifically designed to help the Eugene/Springfield Metro Area gather the
data necessary to compete successfully for future FEMA funding of mitigation
projects. FEMA requires that all FEMA-funded hazard mitigation projects must be
"cost-effective" (i.e., the benefits of a project must exceed the costs). Benefit-cost
analysis is thus an important component of mitigation planning, not only to meet
FEMA requirements, but also to help evaluate and prioritize potential hazard
mitigation projects in the Eugene/Springfield Metro Area, regardless of whether
funding is from FEMA, state or local government or from private sources.
1.3 The Eugene/Springfield Metro Area Mitigation Plan
This Eugene/Springfield Metro Area Mitigation Plan is built is upon a quantitative
assessment of each of the major hazards that may significantly affect the
Eugene/Springfield Metro Area, including their frequency, severity, and geographic
areas most likely to be affected. The hazards addressed include: floods, severe
winter storms, wildland/urban interface fires, landslides, dam failures, earthquakes
and others. The Eugene/Springfield Metro Area Mitigation Plan covers the cities of
Eugene and Springfield and immediate surrounding areas. The geographic areas
covered by available hazard data often do not correspond exactly to political
boundaries. Thus, the plan covers approximately, but not exactly, the areas
encompassed by the Urban Growth Boundary and the Eugene/Springfield Metro
Planning Area Boundary.
The Eugene/Springfield Metro Area Mitigation plan also includes a quantitative
assessment of the vulnerability of buildings, infrastructure, and people to each of
these hazards. That is, the plan includes an evaluation of the likely magnitude of the
effects of future disasters on the Eugene/Springfield Metro Area.
These reviews of the hazards and the vulnerability of the Eugene/Springfield Metro
Area to these hazards are the foundation of the mitigation plan. From these
assessments, specific locations where buildings, infrastructure, and/or people may be
at high risk are identified. These high risk situations then become priorities for future
mitigation actions to reduce the negative consequences of future disasters on the
Eugene/Springfield Metro Area.
The Eugene/Springfield Metro Area Mitigation Plan deals with hazards realistically and
rationally and also strikes a balance between suggested physical mitigation measures
to eliminate or reduce the negative consequences of future of disasters and planning
Public Review Draft August 6, 2004 1-2
measures which better prepare the community to respond to and recover from
disasters for which physica~ mitigation measures are not possible or not economically
feasible.
1.4 Key Concepts and Definitions
The central concept of mitigation planning is that mitigation reduces risk. Risk is
defined as the threat to people and the built environment posed by the hazards being
considered. That is, risk is the potential for damages, losses and casualties arising
from the impact of hazards on the built environment. The essence of mitigation
planning is to identify high risk locations/situations in the Eugene/Springfield Metro
Area and to evaluate ways to mitigate (reduce) the effects of future disasters on these
high risk locations/situations.
The level of risk at a given location, building or facility depends on the combination of
hazard and exposure as shown in Figure 1.1 below.
Figure 1.1
Hazard and Exposure Combine to Produce Risk
HAZARD EXPOSURE RiSK
Frequency Value and Threat to the
and Severity + Vulnerability of = Community:
of Hazard Events Inventory Peopie, Buildings
and Infrastructure
Risk is generally expressed in dollars (estimates of potential damages and other
economic losses) and in terms of casualties (numbers of deaths and injuries).
There are four key concepts that govern hazard mitigation planning: hazard,
exposure, risk and mitigation. Each of these key concepts is addressed in turn.
HAZARD refers to natural or anthropogenic events that may cause damages, losses
or casualties (e.g., floods, winter storms, landslides, earthquakes, hazardous matedal
spills, etc.). Hazards are characterized by their frequency and severity and by the
geographic area affected. Each hazard is characterized differently, with appropriate
parameters for the specific hazard. For example, floods may be characterized by the
frequency of flooding, along with flood depth and flood velocity. Winter storms may be
characterized by the amount of rainfall in a 24-hour period, by the wind speed, or by
the amount of snow or ice associated with a storm. Earthquakes may be
characterized by the severity and duration of ground motions and so on.
A hazard event, by itself, may not result in any negative effects on a community~ For
example, a flood-prone five-acre parcel may typically experience several shallow
floods per year, with several feet of water expected in a 50-year flood event.
However, if the parcel is wet~ands, with no structures or infrastructure, then there is no
risk. That is, there is no threat to people or the built environment and the frequent
Public Review Draft August 6, 2004 1-3
flooding of this parcel does not have any negative effects on the community. Indeed,
in this case, the very frequent flooding (i.e., the high hazard) may be beneficial
environmentally by providing wildlife habitat, recreational opportunities, and so on.
Figure 1,2
Hazard Alone Does Not Produce Risk
HAZARD,,, .
The important point here is that hazards do not necessarily produce risk to people and
property, unless there is vulnerable inventory exposed to the hazard. Risk to people,
buildings or infrastructure results only when hazards are combined with exposure.
EXPOSURE is the quantity, value and vulnerability of the built environment (inventory
of people, buildings and infrastructure) in a particular location subject to one or more
hazards. Inventory is described by the number, size, type, use, and occupancy of
buildings and by the infrastructure present. Infrastructure includes roads and other
transportation systems, utilities (potable water, wastewater, natural gas, and electric
power), telecommunications systems and so on.
Inventory varies markedly in its importance to a community and thus varies markedly
in its importance for hazard mitigation planning. Some types of facilities, "critica~
facilities," are especially important to a community, particularly during disaster
situations. Examples of critical facilities include police and fire stations, hospitals,
schools, emergency shelters, 911 centers, and other important buildings. Critical
facilities may also include infrastructure elements that are important links or nodes in
providing service to large numbers of people such as a potable water source, an
electric power substation and so on. "Links" are elements such as water pipes,
electric power lines, telephone cables that connect portions of a utility or
transportation system. "Nodes" are locations with important functions, such as
pumping plants, substations, or switching offices.
For hazard mitigation planning, inventory must be characterized not only by the
quantity and value of buildings or infrastructure present but also by its vulnerability to
each hazard under evaluation. For example, a given facility may or may not be
particularly vulnerable to flood damages or earthquake damages, depending on the
Public Review Draft August 6, 2004 1-4
details of its design and construction. Depending on the hazard, different engineering
measures of the vulnerability of buildings and infrastructure are used.
Figure 1.3
Exposure (Quantity, Value and Vulnerability of Inventory)
RISK is the threat to people and the built environment - the potential for damages,
losses and casualties arising from hazards. Risk, which results only. from the
combination of Hazard and Exposure as discussed above, is illustrated schematically
in Figure 1.4 below.
Figure 1.4
Risk Results from the Combination of Hazard and Exposure
Public Review Draft August 6, 2004 1-5
Risk is the potentiai for future damages, losses or casualties. A disaster event
happens when a hazard event is combined with vulnerable inventory (that is when
hazard event strikes vulnerable inventory exposed to the hazard). The highest risk in
a community occurs in high hazard areas (frequent and/or severe hazard events) with
large inventories of vulnerable buildings or infrastructure.
However, high risk can also occur with only moderately high hazard, if there is a large
inventory of highly vulnerable inventory exposed to the hazard. For example, seismic
hazard is lower in Oregon than in the seismically active areas of California. However,
for some buildings, seismic risk in Oregon may be comparable to or even higher than
seismic risk in California, because some of the building inventory in Oregon is much
more vulnerable to earthquake damages. Conversely, a high hazard area can have
relatively Iow risk if the inventory is resistant to damages (e.g., elevated to protect
against flooding or strengthened to minimize earthquake damages).
i~tlTIGATION means actions to reduce the risk due to hazards. Mitigation actions
reduce the potential for damages, losses, and casualties in future disaster events.
Repair of buildings or infrastructure damaged in a disaster is not mitigation because
repair simply restores a facility to its pre-disaster condition and does not reduce the
potential for future damages, losses, or casualties. Hazard mitigation projects may be
initiated proactively - before a disaster, or after a disaster has already occurred. In
either case, the objective of mitigation is always is to reduce future damages, losses
or casualties.
A few of the most common types of mitigation projects are shown below in Table 1.5
Table 1.5
Common l~itigation Projects
Hazard Mitigation Project
Flood Build or ~mprove levees or flood walls
Improve channels for flood control
Improve drainage systems and culvert capacities
Create detenbon ponds for storage
Relocate, elevate or floodproof flood-prone structures
Acquire and demolish h~ghly flood-prone structures
Winter Storms Add emergency generators for critical facihbes
Improve redundancy of utility systems
Trim trees to reduce failures of utility lines
Earthquakes Upgrade seismic performance of buildings
Upgrade seismic performance of ~nfrastructure
Landslides Remediate shde conditions
Relocate ublity hnes or structures
Wildland/Urban Interface Fires Increase fire safe construction practices
Vegetation (fuel Icad) control
General Enhance emergency planmng and mutual aid
Expand pubhc education programs
Public Review Draft August 6, 2004 1-6
The mitigation project list above is not comprehensive and mitigation projects can
encompass a broad range of other actions to reduce future damages, ~osses, and
casualties.
1.5 The Mitigation Process
The key element for all hazard mitigation projects is that they reduce risk. The
benefits of a mitigation project are the reduction in risk (i.e., the avoided damages,
~osses, and casualties attributable to the mitigation project). In other words, benefits
are simply the difference in expected damages, losses, and casualties before
mitigation (asqs conditions) and after mitigation. These important concepts are
illustrated below in Figure
Figure 1,6
Mitigation Projects Reduce Risk
RISK
BEFORE
I~ITIGATION
BENEFITS
OF
I~ITIGATION
REDUCTION
RISK IN RISK
AFTER
MITIGATION
Quantifying the benefits of a proposed mitigation project is an essential step in hazard
mitigation planning and implementation. Only by quantifying benefits is it possible to
compare the benefits and costs of mitigation to determine whether or not a particular
project is worth doing (i.e., is economically feasible). Real world mitigation planning
almost always involves choosing between a range of possible alternatives, often with
varying costs and varying effectiveness in reducing risk.
Quantitative risk assessment is centrally important to hazard mitigation planning.
When the level of risk is high, the expected levels of damages and losses are likely to
be unacceptable and mitigation actions have a high priority. Thus, the greater the
risk, the greater the urgency of undertaking mitigation.
Conversely, when risk is moderate both the urgency and the benefits of undertaking
mitigation are reduced. It is neither technologically possible nor economically feasible
to eliminate risk completely. Therefore, when levels of risk are Iow' and/or the cost of
mitigation is high relative to the level of risk, the risk may be deemed acceptable (or at
least tolerable). Therefore, proposed mitigation projects that address Iow levels of risk
Public Review Draft August 6, 2004 1-7
or where the cost of the mitigation project is large relative to the level of risk are
generally poor candidates for implementation.
The overall mitigation planning process is outlined in Figure 1.7 below.
Figure 1.7
The Mitigation Planning Process
Mitigation Planning Flowchart
Risk Assessment
Quantify the Threat
to the Built Environment
Is Level of Risk
Acceptable?
Risk Acceptable? Risk 'Not Acceptable?
Mitigation Not Necessary Mitigation Desired
!
Identify Mitigation Alternatives
Find Solutions to Risk
!
Prioritize Mitigation Alternatives
Benefit-Cost Analysis
and related tools
!
Obtain Funding
Implement Mitigation Measures
Reduce Risk
The flow chart above outlines the major steps in Hazard Mitigation Planning and
Implementation for the Eugene/Springfield Metro Area.
The first steps are quantitative evaluation of the hazards (frequency and severity)
affecting the Eugene/Springfield Metro Area and of the inventory (people, buildings,
and infrastructure) exposed to these hazards. Together these hazard and exposure
data determine the level of risk for specific locations, buildings or facilities in the
Eugene/Springfield Metro Area.
Public Review Draft August 6, 2004 1-8
The next key step is to determine whether or not the level of risk posed by each of the
hazards affecting the Eugene/Springfield Metro Area is acceptable or to~erabie. Only
the residents of the Eugene/Springfield Metro Area can make this determination. If
the tevel of risk ks deemed acceptable or at least tolerable, then mitigation actions are
not necessary or at least not a high priority.
On the other hand, if the teve~ of risk is deemed not acceptable or tolerable, then
mitigation actions are desired. In this case, the mitigation planning process moves on
to more detailed evaluation of specific mitigation alternatives, pdodtization, funding
and implementation of mitigation measures. As with the determination of whether or
not the level of risk posed by each hazard is acceptable or not, decisions about which
mitigation projects to undertake can be made only by the residents of the Eugene/
Springfield Metro Area.
For reference, a more detailed discussion of the overall mitigation planning process,
including each step in the planning process flow chart shown above in Figure 1.5, is
given in Chapter 2 of the Regional A~l Hazard Mitigation Master Plan for Benton, Lane
and Linn Counties (in both the Phase One and Phase Two reports). Further, more
detailed information for flood mitigation projects is given in Annex I of the Phase One
Plan: Flood Hazard Mitigation Planning Template for Loca~ Governments.
1.6 The Role of Benefit-Cost Analysis in IVlitigation Planning
Communities, such as the Eugene/Springfield Metro Area that are considering
whether or not to undertake mitigation projects must answer questions that don't
always have obvious answers, such as:
What is the nature of the hazard problem?
How frequent and how severe are hazard events?
Do we want to undertake mitigation measures?
What mitigation measures are feasible, appropriate, and affordable?
How do we prioritize between competing mitigation projects?
Are our mitigation projects likely to be eligible for FEMA funding?
Benefit-cost analysis is a powerful tool that can help communities provide solid,
defensible answers to these difficult socio-political-economic-engineedng questions.
Benefit-cost analysis is required for a~l l=EMA-funded mitigation projects, under
both pre-disaster and post-disaster mitigation programs. Thus, communities
seeking FEMA funding must understand benefit-cost analysis. However,
regardless of whether or not FEMA funding is involved, benefit-cost analysis provides
a sound basis for evaluating and prioritizing possible mitigation projects for any natural
hazard.
Public Review Draft August 6, 2004 1-9
Benefit-cost analysis software, technical manuals and a wide range of guidance
documents are available from FEMA at no cost to communities. A Benefit-Cost
Analysis Toolkit CD which contains all of the FEMA benefit-cost materials is available
from FEMA. The publication What is a Benefit? Draft Guidance for Benefit~Cost
Analysis is particularly recommended as a general reference for benefit-cost analysis
of hazard mitigation projects. This publication includes categories of benefits to count
for mitigation projects for various types of buildings, critical facilities, and infrastructure
and has simple, standard methods to quantity the full range of benefits for most types
of mitigation projects.
t.7 Principles of Benefit-Cost Analysis
Benefit-cost analysis is the tool that provides answers to a central question for hazard
mitigation projects: "is it worth it?" If hazard mitigation were free, individuals and
communities would undertake mitigation with robust enthusiasm and the risks from
hazards would soon be greatly reduced. Unfortunately, mitigation is not free, but often
rather expensive. For a given situation, is the investment in mitigation justified? Is
the owner (public or private) better off economically to accept the risk or invest now in
mitigation to reduce future damages? These are hard questions to answer! Benefit-
cost analysis can help a community answer these difficult questions.
In the complicated real world of mitigation projects, there are many factors which
determine whether or not a mitigation project is worth doing or which of two or more
mitigation projects should have the highest priority. Consider a town which has two
flood prone neighborhoods and each neighborhood desires a mitigation project. The
two neighborhoods have different numbers of houses, different value of houses,
different frequencies and severity of flooding. The first neighborhood proposes storm
water drainage improvements at a cost of $3.0 million. The second neighborhood
wants to elevate houses at a cost of $3.0 million. Which of these projects should be
completed? Both? One or the Other? Neither? Which project should be completed
first if there is only funding for one? Are there alternative mitigation projects which are
more sensible or more cost-effective than the proposed projects?
Such complex socio-politicakeconomic-engineering questions are heady impossible to
answer without completing the type of quantitative flood risk assessment and benefit-
cost analysis discussed below.
in determining whether or not a given mitigation project is worth doing, the level of risk
exposure without mitigation is critical. Consider a hypothetical $1,000,000 mitigation
project. Whether or not the project is worth doing depends on the level of risk before
mitigation and on the effectiveness of the project in reducing risk. For example, if the
before mitigation risk is low (a subdivision street has a few inches of water on the
street every couple of years or a soccer field in a city park floods every five years or
so) the answer is different than if the before mitigation risk is high (100 or more
houses are expected to have flooding above the first floor every 10 years or a critical
facility is expected to be shut down because of flood damages once every five years).
All well-designed mitigation projects reduce risk (badly designed projects can increase
risk or simply transfer risk from one community to another). However, just because a
Public Review Draft August 6, 2004 1-10
mitigation project reduces risk does not make it a good project. A $1,000,000 project
that avoids an average of $100 per year in flood damages is not worth doing, while the
same project that avoids an average of $200,000 per year in flood damages i_ss worth
doing.
The principles of benefit-cost analysis are briefly summarized here. The benefits of a
hazard mitigation project are the reduction in future damages and losses, that is, the
avoided damages and losses that are attributable to a mitigation project. To conduct
benefit-cost analysis of a specific mitigation project the risk of damages and losses
must be evaluated twice: before mitigation and after mitigation, with the benefits being
the difference. The benefits of a hazard mitigation project are thus simply
avoided future damages and tosses.
Because the benefits of a hazard mitigation project accrue in the future, it is
impossible to know exactly what they will be. For example, we do not know when
future floods or other natural hazards will occur or how severe they will be. We do
know, however, the probability of future floods or other natural hazards (if we have
appropriate hazard data). Therefore, the benefits of mitigation projects must be
evaluated probabilistically and expressed as the difference between annualized
damages before and after mitigation. The following simplified example illustrates the
principles of benefit-cost analysis; more details are given in the examples in the
Appendices.
To illustrate the principles of benefit-cost analysis, we consider a hypothetical single
family house in the town of Acorn, with the house located on the banks of Squirrel
Creek. The house is a one story struture, about 1500 square feet on a post
foundation, with a replacement value of $60/square foot (total $90,000). We have
flood hazard data for Squirrel Creek (stream discharge and flood elevation data) and
elevation data for the first floor of the house. Therefore, we can calculate the annual
probability of flooding in one-foot increments, as shown below.
Table 1,8
Damages Before Mitigation
Flood Depth Annual Probability Scenario Damages and Annualized Flood
(feet) of Flooding Losses Per Flood Event Damages and Losses
0 0 2050 $6,400 $1,312
1 0 1234 $14,300 $I ,765
2 0 0867 $24,500 $2,124
3 0.0223 $28,900 $673
4 0 0098 $32,100 $315
5 0.0036 $36,300 $123
Total Expected Annual (Annualized) Damages and Losses $6,312
Flood depths shown above in Table 1.8 are in one foot increments of water depth
above the lowest floor elevation. Thus, a "3" foot flood means all floods between 2.5
feet and 3.5 feet of water depth above the floor. We note that a "0" foot flood has, on
Public Review Draft August 6, 2004 1~t 1
average, damages because this flood depth means water plus or minus 6" of the floor;
even if the flood level is a few inches below the first floor, there may be damage to
flooring and other building elements because of wicking of water.
The Scenario (per flood event) damages and losses include expected damages to the
building, content, and displacement costs if occupants have to move to temporary
quarters while flood damage is repaired.
The Annualized (expected annual) damages and losses are calculated as the product
of the flood probability times the scenario damages. For example, a 4 foot flood has
slightly less than a 1% chance per year of occurring. If it does occur, we expect about
$32,100 in damages and losses. Averaged over a long time, 4 foot floods are thus
expected to cause an average of about $315 per year in flood damages. Note that
the smaller floods, which cause less damage per flood event, actually cause higher
average annual damages because the probability of smaller floods is so much higher
than that for larger floods. With these data, the house is expected to average $6312
per year in flood damages. This expected annual or "annualized" damage estimate
does not mean that the house has this much damage every year. Rather, in most
years there will be no floods, but over time the cumulative damages and losses from a
mix of relatively frequent smaller floods and less frequent larger floods is calculated to
average $6312 per year.
The calculated results in Table t.8 are the flood risk assessment for this house for the
as-is, before mitigation situation. The table shows the expected levels of damages
and losses for scenario floods of various depths and also the annualized damages
and losses.
The risk assessment shown in Table 1.8 shows a high flood risk, with frequent severe
flooding which the owner deems unacceptable. Therefore he explores mitigation
alternatives to reduce the risk: the example below is to elevate the house 4 feet.
Table 1.9
Damages After I~itigation
Flood Depth Annual Probability Scenario Damages and Annualized Flood
(feet) of Flooding Losses Per Flood Event Damages and Losses
0 0 2050 $0 $0
I 0 1234 $0 $0
2 0.0867 $0 $0
3 0.0223 $0 $0
4 0.0098 $6,400 $63
5 0.0036 $14,300 $49
$112
By elevating the house 4 feet, the owner has reduced his expected annual (annualized)
damages from $6312 to $112 (98% reduction) and greatly reduced the probability or
Public Review Draft August 6, 2004 1-12
frequency of flooding affecting his house. The annualized benefits are the difference in
the annualized damages and losses before and after mitigation or $6312 - $112 = $6200.
is this mitigation project worth doing? Common sense says yes, because the flood
risk appears high: the annualized damages before mitigation are high ($6,312). To
answer this question more quantitatively, we complete our benefit-cost analysis of this
project. One key factor is the cost of mitigation. A mitigation project that is worth doing
at one cost may not be worth doing at a higher cost. Let's assume that the elevation
costs $20,000. This $20,000 cost occurs once, up front, in the year that the elevation
project is completed.
The benefits, however, accrue statistically over the lifetime of the mitigation project.
Following FEMA convention, we assume that a residential mitigation project has a
useful lifetime of 30 years. Money (benefits) received in the future has less value than
money received today because of the time value of money. To take the time value of
money into account, we need to do what is known as a "present value calculations"
We compare the present value of the anticipated stream of benefits over 30 years in
the future to the up-front out-of-pocket cost of the mitigation project.
A present value calculation depends on the lifetime of the mitigation project and on
what is known as the discount rate. The discount rate may be viewed simply as the
interest rate you might earn on the cost of the project if you didn't spend the money on
the mitigation projecL Let's assume that this mitigation project is to be funded by
FEMA, which uses a 7% discount rate to evaluate hazard mitigation projects. With a
30-year lifetime and a 7% discount rate, the "present value coefficient" which is the
value today of $1.00 per year in benefits over the lifetime of the mitigation project is
12.41. That is, each $1.00 per year in benefits over 30 years is worth $12.41 now.
The benefit-cost results are now as follows.
Table 1.10
Benefit-Cost Results
Annualized Benefits $6,200
Present Value Coefficient 12.41
Net Present Value of Future Benefits $76,942
Mitigation Project Cost $20,000
Benefit-Cost Ratio 3.85
These results indicate a beneflt-cost ratio of 3.85. Thus, in FEMA's terms the
mitigation project is cost-effective and eligible for FEMA funding. Taking into account
the time value of money, which is essential for a correct economic calculation, results
in lower benefits than if we simply multiplied the annual benefits times the 30 year
project useful lifetime. Economically, simply multiplying the annual benefits times the
lifetime would ignore the time value of money and thus gives an incorrect, spurious
resulL
The above discussion of benefit-cost analysis of a flood hazard mitigation project is
intended to illustrate the basic concepts. Very similar principles apply to mitigation
Public Review Draft August 6, 2004 1-13
projects for earthquakes or any other natural hazards. The role of benefit-cost analysis
in prioritizing and implementing mitigation projects in the Eugene/Springfield Metro
Rea is addressed in Chapter 4 (Plan Goals, Mitigation Strategies and Action Items).
More detailed example evaluations of flood and earthquake mitigation projects the
Eugene/Springfield Metro Area are given in the Appendices.
1.8 Hazard Synopsis
To set the overall context of hazard mitigation planning, we briefly review the major
hazards that significantly affect the Eugene/Springfield Metro Area. Some hazards
affect the entire area, while other hazards have only localized potential consequences.
The Eugene/Springfield Metro Area has several areas of flood plains mapped by
FEMA. These include areas along the Mohawk River, the McKenzie River, the
Willamette River (including the Middle Fork and Coast Fork), as well as areas along
creeks, including Amazon Creek, and several smaller creeks. In addition, other
portions of the Eugene/Springfield Metro Area, outside of the mapped floodplains, are
also subject to significant, repetitive flooding from local storm water drainage.
The entire Eugene/Springfield Metro Area region is subject to the effects of winter
storms, including wind, rain, snow and ice, as well as secondary effects such as
power outages.
Portions of the hilly areas of the Eugene/Springfield Metro Area, especially the hills in
southern portions of Eugene and Springfield are subject to landslides or mudslides,
which may affect buildings, roads, and utilities.
Much of the Eugene/Springfield Metro Area region is subject to some level or risk from
major wildland/urban interface fires. However, residential areas near the edge of the
Eugene/Springfield Metro Area, especially those bordering or impinging into forested
areas have much higher levels of risk from wildland/urban interface fires.
The entire Eugene/Springfield Metro Area region is subject to the affects of
earthquakes, including not only major earthquakes on the Cascadia Subduction Zone
off the Oregon coast, but also smaller crustal earthquakes within Oregon.
The entire Eugene/Springfield Metro Area region is subject, to volcanic hazards from
eruptions in the Cascades. The most likely effects are only minor ash falls, with
perhaps some minor flooding from lahars into the McKenzie River far upstream from
the Eugene/Springfield Metro Area. However, major volcanic events could affect the
water supply because of ash falls into the McKenzie River watershed.
Large portions of land along the Willamette and McKenzie Rivers, including highly
populated areas, are in the inundation areas from dam failures. While dam failures
are highly unlikely, the consequences of failure would be high.
The entire Eugene/Springfield Metro Area region is subject to disruption of utility and
transportation systems from winter storms and other natural hazards, as well as from
anthropogenic causes.
Public Review Draft August 6, 2004 1-14
Anthropogenic hazards, such as hazardous materia~ releases, are possible nearby or
downwind from fixed site concentrations (e.g., industrial sites) as well as along
transportation corridors from truck or railroad accidents.
Terrorist incidents or other deliberate malevolent actions by vandals, disturbed
individuals, employees or members of organized groups could affect the
Eugene/Springfield Metro Area
In summary, there are many hazards which affect all or large portions of the
Eugene/Springfield Metro Area.
The remaining chapters of this mitigation plan include the following.
Chapter 2 provides a brief community profile for the Eugene/Springfield Metro Area.
Chapter 3 documents the community involvement and public process involved in
developing this mitigation plan.
Chapter 4 outlines the mitigation plan goals, mitigation strategies, and action items.
Chapter 5 documents the formal process of plan adoption, implementation, and
maintenance.
Chapters 6 through 15 cover each of the major hazards addressed in this mitigation
plan, including: floods, winter storms, landslides, wildland/urban interface fires,
earthquakes, volcanic hazards, dam safety,, disruption of utility and transportation
systems, hazmat incidents, and terrorism.
The Appendix includes example mitigation projects for flood and earthquake hazards.
Public Review Draft August 6, 2004 1-15
2.0 Community Profile: Eugene/Springfield Metropolitan Area
2.1 Population and Demographics
The Eugene/Springfield Metro Area is located in the Southern Willamette Valley at the
confluence of the Willamette and McKenzie Rivers, between the Coast Range and the
Cascades. The Southern Willamette Valley has been populated by a series of native
peoples for thousands of years. The most recent Native American inhabitants of the
Southern Willamette Valley were collectively called Kalapuya. Archeological evidence
indicates that the Kalapuya lived in the area for several centuries. The first European
settlers in the area arrived in Eugene and Springfield in 1846 and 1849, respectively.
Eugene and Springfield were incorporated as cities in 1862 and 1885.
The Eugene/Springfield Metro Area is the second largest in Oregon. 2003 population
estimates for the cities of Eugene and Springfield are 143,395 and 54,720,
respectively. These 2003 estimates are about 4% higher than 2000.
2000 Census data are available for the cities of Eugene and Springfield, for Lane
County and for the Eugene-Springfield Metropolitan Statistical Area (MSA), as defined
by the Census Bureau. The Eugene-Springfield MSA includes all of Lane County.
Table
Population Demographics (:2000 Census Data)
Demographic Data I Lane County I Eugene I Springfield
Age
Under 5 years 5.8% 5 3% 8.2%
Under 18 years 22.9% 20.6% 26 8%
18 years and over 77.1% 79.4% 73.2%
18 years to 65 years 63.8% 67.3% 62.8%
65 years and over 13.3% 12.1% 10.4%
Ethnicity of Households
White 92.8% 90.5% 92.6
Black or African Amenan 0.7% 1.1% 0.6
American Indian and Alaska Native 0 9% 0 8% 1.1
Asian 1.8% 3 3% 0.8
Native Hawadn and Pacific Islander 0.1% 0.2% 0.2
Other or two or more races 3.7% 4.2% 4.6
Hispanic or Latlno (of any race) 3.0% 3.4% 4 4
Language Spoken at Home
English only 92.1% 90.0% 92,1
Language other than English 7.9% 10.0% 7.9
Speak Enghsh less than very well 2.9% 3.7% 3 2
Spanish 4.1% 3.7% 5 2
Other Indo-European languages 1 9% 2.4% 1 7
Asian and Pacific Island languages 1.6% 2 8% 0~9
The Age and Ethnicity categories in Table 2.1 above intentionally include overlapping
subsets of categories for planning purposes. For emergency planning purposes,
children, elderly adults, and people whose primary language is not English are
Public Review Draft August 6, 2004 2-1
generally considered special needs populations. Based on these 2000 census data,
the Eugene/SpdngfieM Metro Area has a substantial population of children and e~dedy
adults, along with about 8% of the population whose primary language is not English.
As shown in Table 2-1 above, about 23% of the population are children ~ess than 18
years old, while about 13% are adults over 65 years old.
There are relatively minor differences in some data categories between the entire
metropolitan area, the cities of Eugene and Springfield, and in areas outside of city
limits but within Lane County or the metropolitan statistica~ area used by the Census.
For example, Springfield has a higher percentage of Spanish speaking residents and
a lower percentage of Asian speaking residents than does Eugene. However, these
differences are probably not large enough to be significant for most emergency
planning purposes.
The Census website (www.census.gov) has a vast amount of other economic and
demographic data for Lane County, the Eugene/Springfield Metro Area and the cities
of Eugene and Springfield. See the website for additional demographic data,
including school enrollment, educational levels, disability status, and many other
categories of demographic data.
2,2 Employment and Economics
in the earliest years, the economy of the Eugene/Springfield Metro Area was largely
agrarian; wheat was the first commercial crop. Industrialization began in the 1850s
with the construction of the millrace to provide water power for flour mills, lumber mills,
and later for woolen mills. The Willamette River was the major transportation artery
for the region. In the 1870s, development accelerated when the railroad from
California reached Eugene. Through the mid-20th century, the lumber industry was a
very important segment of the local economy. However, by the 1990s, the lumber
industry had declined in importance, with economic growth in new sectors, including
the high-tech sector. The major employment categories in the Eugene/Springfield
Metro Area are government (Federal, State, County, and the Cities), education, wood
products, and the high-tech sector.
Education has been a major segment of the regional economy since the founding of
the University of Oregon in 1872. Over the next century, several private co~leges and
Lane Community College have added to the importance of the education sector to the
economy of the Eugene/Springfield metropolitan area.
Selected economic data for Lane County from the 2000 Census are summarized
below in Table
Public Review Draft August 6, 2004 2-2
Table 2,2
Selected Economic Data
Demographic Data Lane County
Population 16 years and older 258,327
In labor force 64 3%
Employed 60 2%
Unemployed 4.1%
Not ~n labor force 35 7%
Commuting to work
Drove alone 71 6%
Carpooled 12 2%
Public transportation 3.3%
Walked 4.2%
Other means (includes bicycles) 3 7%
Worked at home 5.1%
Incomes and poverty levels
Median household income $36,942
Median family income $45,111
Families below poverty level 9.0%
w~th children under 18 years 14 8%
with children under 5 years 20 1%
The Census website (www.census.gov) has a vast amount of other economic/
demographic data for the Eugene/Springfield Metro Area and for the cities of Eugene
and Springfield. See the website for additional economic/demographic data, including
employment breakdowns by occupation and industry, and detailed income data.
2.3 Geography and Climate
The Eugene/Springfield Metro Area is located near the southern end of the Willamette
Valley, at the confluence of the Willamette and McKenzie Rivers, between the Coast
Range and the Cascades. The Region 2050 profile (Lane Council of Governments,
2000) noted poetically that the Eugene/Springfield area "offers a diversity of
landscapes: broad valleys dotted with wetlands, rivers, lakes, and creeks lined with
riparian vegetation, buttes, forests, mountains, foothills, parks and farms?'
In addition to the Willamette and McKenzie Rivers, there are numerous creeks running
through the area and several large lakes nearby (mostly reservoirs on the maior
rivers). Recreational opportunities abound, not only on the rivers and lakes, but also
in the large nearby areas of foothills and mountains.
The climate for the Eugene/Springfield Metro Area is moderate. Mean daily
temperatures range from highs of about 82 degrees and lows of about 51 de9rees in
July and August to highs of about 46 degrees and lows of about 34 or 35 degrees in
December and January.
The average annual rainfall is about 46 inches. Average monthly precipitation varies
from about 7 to 8 inches in November through January to about 0.4 inch in July.
Average annual snowfall is only about 6.0 inches.
Public Review Draft August 6, 2004 2-3
2.4 Land and Development
The Cities of Eugene and Springfield share a metropolitan Urban Growth Boundary
(UGB) for planning purposes. For reference, we note that the Metro Plan Boundary is
very similar to, but slightly more extensive than the Urban Growth Boundary
Data on current land uses in the Eugene/Springfield Metro Area are summarized
below in Table 2.3 (from Region 2050 reports for Eugene and Springfield, LCOG,
2000).
Table 2.3
Land Use
Eugene-Springfield Eugene Springfield
Demographic Data UGB UGB UBG
UGB area (acres) 49,010 35,215 13,795
UGB area (square miles) 76.6 55.0 21.6
Area within city limits 73% 75% 67%
Area outside city limits 27% 25% 33%
Undeveloped land 29% 26% 36%
Developed land 71% 74% 64%
Residential 40% 42% 35%
Commercial 8% 9% 6%
Government, education 4% 4% 3%
Parks 7% 9% 3%
Industrial 8% 6% 13%
Roads and other 4% 4% 4%
Overall, for the Eugene-Springfield UGB, about 73% of the area is within city limits
and 27% outside of city limits. About 71% of the total area is developed, with 29%
undeveloped. Of the developed land, the predominant land use is residential, with
commercial, industrial and parks being the next largest land use categories.
2.5 Housing in the Eugene/Springfield [rvletro Area.
The 2000 Census and the Region 2050 reports both contain data on housing in the
Eugene/Springfield Metro Area. These data are summarized in Table 2.4 below.
Housing unit data are from the 2000 Census; housing units by type are from the
Region 2050 reports and thus are not available for Lane County as a whole.
Public Review Draft August 6, 2004 2-4
Table 2.4
Housing Data
Demographic Data Lane County~ Eugene Springfield
Total housing units 138,946 61,444 21,500
Occupied umts 130,453 58,110 20,514
Vacant units 8,493 3,334 986
Vacany percentage 6.1% 5 4% 4 6%
Owner-occupied units 62.3% 51 8% 53 6%
Renter-occupied units 37.7% 48 2% 46.4%
Housing Umts by Type
Single-family detached n/a 58% 61%
MultPfamdy n/a 38% 31%
Manufactured homes in parks n/a 4% 8%
~ or equivalently, the Census Bureau's Eugene-Spnngfield Metropohtan
Statsbcal Area (MSA).
For the Cities of Eugene and Springfield, the total housing unit data show a high
proportion of renter-occupied units. This high proportion reflects the high percentage
of students in the area and other economic factors. The percentage of renter-
occupied housing units for the entire Eugene/Springfield Metro area is substantially
lower, reflecting a much higher percentage of owner-occupied housing units in the
portions of the area outside of the city limits of Eugene and Springfield.
Public Review Draft August 6, 2004 2-5
3,0 Community ~nvolvernent and Public Process
3.1 Community involvement in the Eugene/Springfield Metro Area Mitigation
P~anning
The Cities of Eugene and Springfield recognize that community involvement is an
essential step in developing a mitigation plan, and both Cities have involved their
local communities in the mitigation planning process to help ensure the final plan
reflects the values and needs of our residents, as well as building the support base
necessary to implement the Plan. Citizen involvement has provided valuable
historical knowledge about the community and has enhanced (he completeness and
accuracy of the Plan. The Cities understand that area businesses and service
providers also have key information, and their involvement has also been essential
to the success of the planning process.
3,2 Previous Mitigation Activities
Alt City regulated development within the Special Flood Hazard areas, including fill,
needs an approved permit from the City. Generally this approval process is a part of
the building permit, but it may also be a separate floodplain development permit.
The Cities are working to reduce the risk of flood damages by actively enforcing
floodplain management regulations, alerting the community to flooding risks, and
providing information on how to protect property in the event of a flood. The Cities of
Eugene and Springfield have participated in the National Flood Insurance Program
since t985.
Both Cities provide regular maintenance of channels, ditches and catch basins to
prevent the accumulation of sediments and vegetation that obstruct flows and can
lead to flooding. The annual fall leaf recycling and collection program reduces the
chance of obstructed storm water collection systems. Infilling of drainage courses is
prohibited without approval, and a permit is required for most grading and fill work.
3.3 Planning Process
To ensure that the Eugene/Springfield Natural Hazard Mitigation Plan has been
prepared and reviewed by the key stakeholders within the community, the following
process has been utilized.
1. Mitigation planning began in earnest after the 1996 flooding throughout
western Oregon, including the Eugene/Springfield Metro Area. A Regional
Emergency Management Coordinating Council (REMCC) was established,
including representatives from Lane County and Eugene/Springfield, as well
as Benton, Lincoln, and Linn Counties. Planning efforts through this effort
continued through 2002, with numerous public meetings for local
organizations and residents. Results of this planning process include a three
Public Rewew Draft October 11, 2004
volume Regional Ali-Hazard Mitigation Plan that was prepared and adopted
by each of the counties, including Lane County.
The establishment of a Natural Hazards Mitigation Technical Advisory
Committee beginning in December 2003.
a. Recruitment of new members was accomplished through direct
mailing of invitations and personal contacts.
b. Use of the Disaster Operations Task Team in Eugene and the
Emergency Management Committee in Springfield. Each of these
committees has representatives from Police, Fire/EMS, Public Works
and the Planning/Development Departments.
c. These committees meet monthly, and updates and changes to the
Plan have been provided to the committees on an ongoing basis.
3. In December of 2003, a public meeting was held to discuss natural hazard
mitigation planning.
a. Notification of this meeting was issued by invitation to a list of
individual stakeholders, which included local utility companies, real
estate and development interests, Army Corps of Engineers, American
Red Cross, Williams Northwest Pipeline, Rainbow Water District, Lane
Council of Governments, Eugene Water and Electric Board and staff
from the Cities of Eugene and Springfield.
b. The agenda for the meeting included
i. An overview of hazard planning, presented by Kenneth Goettel
of Goettel & Associates Inc.,
ii. Identification of problems caused by natural hazards in the
Eugene/Springfield Metro Area, and
iii. Potential solutions to the identified problems.
c. The meeting was attended by 15 of the various representatives invited
to the meeting.
4. Final review and comments from City staff and Utility Boards.
a. Two meetings were held--June 14, 2004 and July 14, 2004-with staff
from the Cities of Eugene and Springfield. Also present was staff from
Springfield Utility Board (SUB) and Eugene Water and Electric Board
(EWEB).
Pubhc Review Draft October 11,2004 3~2
b. Focus of the meetings was to elicit comments and changes necessary
for Chapter 4 "Plan Goals, Mitigation Strategies and Action Items".
Those items were then incorporated into the final draft issued for
public review and comment.
5. A series of public meetings to review the final draft of the Plan were held in
Eugene and Springfield on September 13 and September 16, 2004.
a. Notification of this meeting included the same stakeholders from the
December 2003 meeting plus the following:
i. City residents
ii. Local businesses
iii. Planning commissions
6. The Draft Plan was made available on the City of Eugene web site, and
comments on the Plan were incorporated into the final draft submitted to
Oregon Emergency Management and FEMA for review.
Continued public involvement will be maintained through the internet. On the
City of Eugene's homepage (http:flwww.ci.eugene.or.us), open the drop-
down box labeled "Services" and select "Emergency Information" to go to the
City of Eugene Emergency Information Center web page
(www.ci.eugene.or.us/HRRS/EMRGNCYCTR.htm). Information and updates
on the Mitigation Plan are available on this web page, in addition to other
links to emergency information resources.
Public Rewew Draft October 11,2004 3-3
4,0 Plan Goals, Mitigation Strategies and Action items
4.1 Mitigation Plan Objectives
The overal~ purpose of the Eugene/Springfield Metro Area Hazard Mitigation Plan is to
reduce the negative impacts of future natural or anthropogenic disasters on the
community. That is, the purpose is to minimize the potential for deaths, injuries,
damages, and economic ~osses and disruption. Completely eliminating the risk of
future disasters in the Eugene/Springfield Metro Area is neither technologically
possible nor economically feasible. However, substantially reducing the negative
impacts of future disasters is achievable with the implementation of a pragmatic
Hazard Mitigation Plan.
The primary objectives of this Hazard Mitigation Plan are:
1. Save lives and reduce injuries
2~ Minimize damage to buildings and infrastructure, especially to critical
facilities,
3. Minimize economic losses,
4. Decrease disruption of public services, businesses, schools, and families,
5. Protect the environment,
6. Foster public/private partnerships, and
7. Strengthen the social fabric and economic welFbein9 of the
Eugene/Springfield Metro Area.
The Eugene/Springfield Metro Area has prepared this Hazard Mitigation Plan with
these important benefits in mind. Community involvement in both planning and
implementing Hazard Mitigation steps in the Eugene/Springfield Metro Area is
essential for the success of this long term effort. This Mitigation Plan is intended to be
a catalyst to motivate the public sector, the business community, and the public into
giving of their time, energy and resources to implement the mitigation actions deemed
most important for the Eugene/Springfield Metro Area.
In addition, adoption of this Hazard Mitigation Plan will help the Eugene/Springfield
Metro Area meet regulatory requirements, including:
8. FEMA's (Federal Emergency Management Agency) mitigation planning
requirements so that the Eugene/Springfield Metro Area remains eligible for
pre- and post-disaster mitigation funding from FEMA,
9. FEMA's Flood Insurance Program's Community Rating System guidelines,
to help minimize future flood insurance rates in the Eugene/Springfield
Metro Area,
10. Oregon Emergency Management's mitigation planning evaluation criteria,
and
11. Oregon's Goal 7 natural hazard planning guidelines.
Meeting these regulatory requirements is an essential step to facilitate implementation
of mitigation measures and in making progress towards achieving the primary
objectives summarized above.
Public Review Draft: October 12, 2004 4-1
4.2 Mu~ti-Hazard ~itigation Strategies and Action items
There are some mitigation strategies and action items which apply to all of the
hazards that pose risks to the Eugene/Springfield Metro Area.
1. Develop categories of buildings and infrastructure at risk from most likely
hazards and prioritize mitigation projects to reduce the level of risk.
2. Identify and pursue funding opportunities to develop and implement specific
mitigation projects in the Eugene/Springfield Metro Area, including
a. FEMA pre-disaster and post-disaster mitigation programs,
b. Other Federal government programs, and
c. State, Lane County and the Eugene/Springfield Metro Area
resources.
3. Develop incentives for businesses and residents to pursue hazard
mitigation projects.
4. Strengthen emergency preparedness and response capabilities by
incorporating the hazard and risk information in the mitigation plan into
emergency planning.
5. Consider the information, objectives, mitigation strategies and action items
when updating documents and programs.
6. Continue to meet FEMA's Community Rating System requirements for
lower flood insurance rates.
7. Enhance awareness of hazards by:
a. Maintaining the Mitigation Committee on an ongoing basis,
b. Encouraging public/private partnerships in mitigation actions,
c. Continuing education and outreach efforts.
8. Update Eugene and Springfield Emergency Operations Plans.
Establishing Project Priorities
The Eugene/Springfield Metro Area Mitigation Plan has been developed to encourage
all City departments to include natural hazard mitigation planning and project
implementation in their normal day-to-day operations. By implementing plan activities
through existing programs and resources, the cost of mitigation is often a small portion
of the overall cost of a project's design or program. For example, when critical
buildings, such as fire stations, have needed remodeling, for a variety of reasons,
seismic upgrades have often been incorporated into the remodeling project. The
cities of Eugene and Springfield will evaluate these opportunities and establish their
own unique priorities to accomplish mitigation activities where existing funds and
resources are available and there is community interest in implementing those
measures. If no federal funding is used in these situations, the priodtization process
Public Review Draft: October 12, 2004 4-2
will be somewhat less formal and not tied to a strict benefit-cost model, but will still
need to meet all the requirements for capital improvement projects, including public
review, and receiving budget approval.
When federal funding is available for hazard mitigation, there are usually requirements
that establish a rigorous benefit-cost analysis as a predominate criterion in
establishing project priorities. Projects to reduce or eliminate damage to infrastructure
that has been damaged repeatedly by the same hazard in the same area can also be
singled-out as a high priority for hazard mitigation. Critical infrastructure facilities such
as police and fire stations, emergency operations centers and primary transportation
corridors that provide significant service benefits to a large population are also high
priority mitigation opportunities. These types of projects, as well as the grant
requests, will be coordinated by the Disaster Operations Task Team in Eugene and
the Emergency Management Committee in Springfield. All federal grant requests
must have prior review by a sub-committee from the City Council.
Summary
When planning for disaster mitigation projects in a pre-disaster environment or facing
the challenges of recovering following a disaster, the Eugene/Springfield metro area
must take into consideration a number of factors when it establishes priorities for
mitigation activities. Some additional considerations may include, for example, habitat
and environmental issues, historic properties, and community concerns. Various City
departments are encouraged to use the mitigation plan as well as considering new
mitigation opportunities presented through lessons learned following a disaster.
4.3 Hazard Specific Mitigation Strategies and Action Items
There are many other mitigation strategies and action items that are specific to each
hazard. There is a caveat with all of the following mitigation strategies and action
items; unless otherwise noted, they may only be implemented when funding has been
identified. The benefits of a project vs the cost of that project will be a consideration
for these communities in prioritizing action items.
4.3,1 Flooding Within FEMA-Mapped Floodplains
a. Complete the inventory of buildings and infrastructure within the
100-year floodplains mapped by FEMA,
b. Collect elevation data for structures within the 100-year floodplain.
c. For structures which have experienced repetitive loss, encourage
property owners to explore mitigation alternatives with FEMA.
d. Encourage FEMA to update the Flood Insurance Study in areas
where the current study does not appear accurate (e.g., Amazon
Creek, Cedar Creek and McKenzie River).
4,3.2 Flooding Outside of FEMA-IVlapped Flood Plains
Public Review Draft: October 12, 2004 4-3
Maintain an inventory of ~ocations in the Eugene/Springfield Metro
Area subjected to frequent storm water flooding,
The four locations in the Eugene/Springfield area with repetitive
flooding and significant damages or losses (road closures, property
damage), determine appropriate mitigation measures, and
implement when federal funding is available.
4.3.3 Winter Storms
a. Continue tree-trimming efforts especially for transmission lines
feeding the Eugene/Springfield Metro Area and trunk distribution
lines within the Eugene/Springfield Metro Area,
b. Educate private property owners about the dangers of vegetation
near distribution lines and service drops,
c. Encourage new development to include underground power
distribution lines,
d. Consider upgrading lines and poles to improve wind/ice/tree loading
capacity and/or undergrounding for critical lines.
e. Consider adding interconnect switches to allow alternative power
feed paths and disconnect switches to reduce areas affected by
future line failures,
f. Encourage critical facilities to have backup power and emergency
operations plans to deal with power outages.
4.3,4 Landslides
a. Encourage the State to complete the inventory of structures and
infrastructure in the Eugene/Springfield Metro Area subject to active
landslides or high landslide potential,
b. Continue to maintain appropriate regulation of steep slope
development.
4,3.5 Wildland/Urban Interface Fires
a. Identify specific parts of the Eugene/Springfield Metro Area at high
risk for wildland/urban interface fires because of fuel loading,
topography, and prevailing construction practices,
b. identify evacuation routes and procedures for high risk areas and
educate the public
c. Educate property owners on fire-safe construction practices for
existing and new construction in high risk areas.
d. On an annual basis, inform and encourage citizens in high risk areas
to create defensible space on their property and apply risk specific
fire prevention practices.
4.3.6 Earthquakes
Continue to inventory commercial and public buildings in the
Eugene/Springfield metro area that may be particularly vulnerable to
Public Review Draft: October 12, 2004 4-4
earthquake damage, including (but not limited to) un-reinforced
masonry buildings and wood frame buildings.
b. Educate and encourage residents and businesses in potentially
vulnerable buildings to undertake retrofits,
c. Consider seismic vulnerability assessments and develop mitigation
strategies of seismic retrofit of critical public buildings and critical
utility infrastructure identified as being particularly vulnerable.
4.3.7 Volcanic Hazards
a. Ensure that emergency planning appropriately addresses responses
and public notifications for ash fall events,
b. Encourage water treatment plant to evaluate its capability to deal
with high turbidity from ash falls and upgrade p~ants and emergency
operations plans as necessary.
c. Seek alternative sources of water supply not vulnerable to ash falls.
4.3,8 Dam Safety
a. Prepare high resolution, digitalized maps of dam failure inundation
areas and ensure that emergency planning appropriately addresses
responses and public notification for dam failures,
b. Encourage the Corps of Engineers to complete seismic vulnerability
assessments for the dams upstream of the Eugene/Springfield
Metro Area and to make seismic improvements, as necessary.
4,3.9 Disruption of Utility and Transportation Systems
a. Educate and encourage residents to maintain several days of
emergency supplies of food, water and medicines for power outages
or road closures,
b. Ensure that emergency response plans appropriately address such
events,
c. Encourage critical facilities to have appropriate backup power
sources.
4.3,10 Hazmat ~ncidents
a. Ensure that first responders have site-specific knowledge of
hazardous chemical inventories in the Eugene/Springfield Metro
Area, along with appropriate response steps and equipment to deal
with incidents,
b. Enhance emergency planning, emergency response, training and
equipment to address hazardous material incidents.
4.3.tl Terrorism
a. Encourage critical facilities to upgrade physical security, detection
and response capability, and cyber security.
Public Review Draft: October 12, 2004 4-5
b. Enhance emergency planning, emergency response, training and
equipment to address potential terrorist incidents.
The following tables contain summaries of long-term and short-term mitigation actions
which address multiple hazards and each of the specific hazards addressed in this
plan.
Pubhc Review Draft: October 12, 2004 4-6
ss~u~Je~¥ o!lqnd x x x x x x x × x
X
X X X X X
X X
X X X X X X X
X × X X X X X
X X X X
X x X X
X X X X x
X X ~< X X × X x
X X
× X × X X x X
~ X X X X x
X X
X x
X X X X X X
X
4.4 The Role of Benefit-Cost Analysis in Implementing Mitigation Measures
The Eugene/Springfield Metro Area recognizes that benefit-cost analysis is required for all FEMA-
funded mitigation projects under both pre-disaster and post-disaster mitigation programs. Any
FEMA-funded mitigation project, in addition to meeting all other eligibility requirements, must, at a
minimum, have a benefit-cost ratio greater than 1.0 (i.e., benefits must exceed costs).
Furthermore, especially for competitive programs such as the Pre-Disaster Mitigation Program,
benefit-cost ratio is a very important factor in the overall ranking. That is, mitigation projects with
high benefit-cost ratios have a higher probability of funding that do mitigation projects which
barely meet the minimum criteria of a benefit-cost ratio greater than I
In completing benefit-cost analyses for potential mitigation projects to be submitted for FEMA
funding, the Eugene/Springfield Metro Area recognizes that detailed documentation of methods,
data and assumptions are essential elements, required by FEMA. Furthermore, all benefit-cost
analyses must be conducted using FEMA software or FEMA-approved software, using
standardized methods and approaches as outlined in FEMA's published guidance for Benefit-
Cost Analysis (e.9., Benefit-Cost Analysis Toolkit CD).
Furthermore, the Eugene/Springfield Metro Area recognizes that benefit-cost analysis of
prospective hazard mitigation projects is a powerful tool for evaluating and prioritizing mitigation
projects, regardless of whether or not FEMA funding is sought. Therefore, City departments,
other public agencies, businesses and private citizens considering undertaking hazard mitigation
projects are encouraged to use benefit-cost analysis as part of their evaluation of possible
projects.
Pubhc Review Draft: October 12, 2004 4-16
5.0 Plan Adoption, Implementation, and Maintenance
5.1 Plan Adoption
The Natural Hazard Mitigation Plan for the Eugene/Springfield Metropolitan Area
was adopted by the Eugene City Council on TBD and the Springfield City Council on
TBD. Both adoptions were with an immediate effective date. Both adoptions were
of the Final Draft Plan submitted to OEM and FEMA for review approval, with the
stipulation that edits required for approval were included in the adoption motion.
The Cities of Eugene and Springfield have the necessary human resources to
ensure that the Plan continues to be an actively used planning document. City staff
have been active in the preparation of the Regional plan, and have gained an
understanding of the process, as well as the importance of having a working
mitigation plan. During the two years of working on this plan, both Cities have
experienced a number of natural hazard events, including two presidential declared
disasters. These events have kept the interest in hazard mitigation planning and
implementation alive at Council and City staff levels.
5.2 Plan Implementation
Both Cities will ensure that the Multi-Hazard Mitigation Plan continues to be an
actively used planning document. The All Hazard Mitigation Plan Technical
Advisory Committee will continue to coordinate the implementation of the Plan. The
Cities will continue to provide staffing for the Advisory Committee through the
Emergency Management Program. Consistent staffing allows for well organized
meetings and will help to ensure that the right people are at the meetings.
Implementing the Action Items identified in the Plan will engage the community. The
participation that led to the Plan has begun to build the network that will be needed
to be successful in this phase of the Plan. Implementation of the mitigation actions
will be a series of community wide activities. Some projects can be done at the
volunteer level, and others will require technical expertise. The stakeholders in the
planning process will become project partners as needed on specific items. There
are many organizations within the City that have common interests and concerns,
including hazard mitigation. Organizations such as the Army Corps of Engineers,
Springfield Utility Board, Eugene Water and Electric Board, and the American Red
Cross will be important partners in the implementation of the Plan. To successfully
complete action items will require project planning with active participation.
The Eugene/Springfield Metropolitan area has well-established history of successful
cooperation among local, state, and federal partners to complete both large and
small projects. This experience will serve the community well with hazard mitigation
projects. In addition, the Cities and other organizations within the Cities, have many
existing programs that will be linked with mitigation projects. Examples include the
Cities' Storm Water Master Plans and the Metro Waterways Project.
Public Review Draft August 6, 2004 5-1
The Multi-Hazard Mitigation Plan will also continue to be connected to other plans,
such as the Eugene/Springfield Metro Plan and the Eugene/Springfield Wastewater
Management Plan. As development plans come into the two Cities' Planning and
Development Offices, reviewers will need to keep in mind potential hazard mitigation
actions that may need to be implemented. The adopted building codes for the Cities
include many standards that mitigate potential hazard damage. The Cities stay
current in adoption of upgraded codes, ensuring that the new construction activities
will meet the highest standard available for hazards such as floods and seismic
events.
5.3 Plan Maintenance
The Eugene/Springfield MultFHazard Mitigation Plan will be monitored and
evaluated on a regular basis as the community implements the action items within
the Plan. The hazards that exist in the community will continue to exist, but the
conditions within the community will continue to change. As these changes occur,
the Plan will be reevaluated. This may be a change in the population or in the
development patterns that were in place when the Plan was developed.
Another change that may have an effect on the Plan would be changes in the values
or priorities of the citizens of the Cities. Community values have been regularly
monitored through Eugene and Springfield's Strategic Plan update processes. As
the Strategic Plan is implemented, the Mitigation Plan will be reviewed as well.
Local, state and federal agencies will conduct or refine studies that may lead to new
or better information on specific hazards. New technical information will be
incorporated into other documents, such as the Comprehensive Plan and the
Mitigation Plan. For example, this could include updated flood plains, identification
of landslide areas or areas subject to seismic vulnerability.
On an annual basis the All Hazard Mitigation Technical Advisory Committee will
meet to review the Plan. This will be the opportunity to include new information into
the Plan and to remove outdated items and completed actions. This will also be the
time to recognize the success of the community in implementation of action items.
All revisions of the Plan will be taken to the City Council for acknowledgement as a
part of the Plan maintenance and implementation program.
Public Review Draft August 6, 2004 5-2
FLOOD HAZARDS
The Eugene/Springfield Metro Area is subject to flooding from several flood sources,
including:
1) over bank flooding from the Middle Fork of the Willamette River, the
Willamette River, and the McKenzie River,
2) over bank flooding from numerous smaller creeks and sloughs
3) local storm water drainage flooding.
Major flooding events generally result from large winter storms with intense rainfall,
with flooding sometimes exacerbated by snow-melt runoff. These large winter storms
often result in simultaneous flooding on all rivers and streams in an affected area.
However, because of differences in drainage areas, slopes, and other watershed
characteristics, the severity of flooding in any given rainfall event often varies
significantly from stream to stream.
6.1 Historical Floods in the Eugene/Springfield Metro Area
Flooding has occurred in the Eugene/Springfield Metro Area throughout the recorded
history of the area, ever since the first European settlers arrived in the area in the mid-
1800$~
The FEMA Flood Insurance Study for Lane County (June 2, 1999) has a brief history
of major historical floods in the Eugene/Springfield Metro Area. Major floods occurred
in 1861, 1890, t945, 1956, and 1964. The 1964 flood was the largest flood event
recorded in Lane County.
In considering these past major floods in Eugene/Springfield and in Lane County it is
important to recognize that construction of major dams upstream from the 1940s to
the 1960s has substantially reduced the potential for major floods on the major rivers.
These dams have reduced the expected 100-year stream discharges (volume of water
flowing in the rivers). Accordingly, expected flood elevations and overall flood
potential for major flood events along the major rivers have been substantially
reduced. The flood hazard areas shown on the current Flood Insurance Study (FIS)
and Flood Insurance Rate Maps (FIRM) for Eugene/Springfield assume that the dams
are operating properly. Dam failure hazards are not addressed by the FIS or the
FIRM.
Despite the reduction in flood potential from construction of the dams, the Eugene/
Springfield Metro Area continues to have flood risk from major rivers as well as from
the numerous creeks and sloughs running through the Eugene/Springfield Metro Area.
Flood risk on these smaller streams has not been reduced by the dams on the larger
rivers.
6.2 The 1996 Flood
The most recent major flood event in occurred in February 1996. Unusually heavy
rains over the four-day period from February 5th to February 8th resulted in significant
Public Review Draft: August 6, 2004 6-1
flooding on numerous rivers and streams throughout western Oregon. The 1996 flood
may have been about a 25-year event. Therefore, this flood was not a really major
flood event, much larger flood events are possible, and the 1996 experience should
not be used empirically to gauge the level of flood risk for the Eugene/Springfield
Metro Area.
During this flood event, rising waters in the McKenzie River forced the evacuation of
about 1,200 to 1,500 people in Iow lying areas of Springfield. In the
Spdngfield/Thurston area along the McKenzie River about 35-40 homes were
damaged, along with about 20 private roads and bridges and about 20 vehicles~
Widespread flooding was also experienced in the Mohawk Valley from Marcola to
Springfield, with flooded homes on Sunderman Road and on Goat Road. The
Springfield Golf Course suffered substantial damage with about 6 inches of silt and
debris deposited on the greens and fairways.
There were widespread road closures in Lane County and even Interstate 5 had water
flowing across it just north of Eugene near the Boston Mill Road overpass.
6.3 Flood Hazards and Flood Risk: Within i~lapped Floodplains
6.3.1 Overview
Flood prone areas of the Eugene/Springfield Metro Area include the FEMA mapped
floodplains for the major rivers, including the Mohawk, McKenzie and Willamette
(including the Middle Fork and the Coast Fork). FEMA mapped floodplains also
include areas along Amazon Creek, the Mill Race and several smaller creeks (mostly
in the western portion of Eugene).
Maps 1E andlS show the FEMA mapped flood plains for Eugene and Springfield,
respectively. The floodplains for each of the rivers and creeks mentioned above, and
the smaller creeks, all contain areas of development at risk from flooding as shown on
Maps 1E and 1S. The 500-year floodplains contain larger areas at some level of
flooding from larger flood events. A few critical facilities have footprints within or very
near the 100-year floodplains, including Camp Creek Elementary School, McKenzie
Camp Creek Fire Station 16~2, Eugene Fire Station 9, and Sanf~a Clara Fire Station
62.
Full details of these mapped floodplains are included on the several panels of the
FEMA Flood Insurance Rate maps (June 2, 1999) that cover the Eugene/Springfield
Metro Area, along with the accompanying Flood Insurance Study. For the
Eugene/Springfield Metro Area, the FEMA floodplain maps include the following types
of mapped flood plain hazard zones:
1. Zone AE, within the 100-year floodplain and with detailed flood hazard
data, including flood elevation data,
2. Zone A, within 100-year flood plain, but without detailed flood hazard data
or flood elevation data,
Public Review Draft: August 6, 2004 6-2
3. Zone AH, flood depths of 1 to 3 feet, usually in areas of ponding, with flood
elevation data,
4. Zone A0, flood depths of 1 to 3 feet, usually sheet flow on sloping terrain,
with average depths determined. For areas of alluvial fan floodin9, flow
velocities also determined.
5. Zone X (shaded), areas within 500-year floodplain, areas of 100-year flood
with depth less than one foot, or with drainage areas less than one square
mile, or areas protected by levees from 100-year flood.
6. Zone X, areas determined to be outside the 500-year floodplain.
For reference, the Eugene and Springfield flood plain maps also show the Urban
Growth Boundary and the Eugene/Springfield Metro Area Plan boundary, which
encompasses a somewhat larger region than the Urban Growth Boundary.
6,3.2 Flood Hazard Data
For mapped floodplain areas, the flood hazard data included in the Flood Insurance
Study (FIS) allow quantitative calculation of the frequency and severity of flooding for
any property within the floodplain. Such calculations are very important for mitigation
planning, because they allow the level of flood risk for any structure to be evaluated
quantitatively. The example below illustrates these concepts.
For example, for Willamette River at State Highway 126 in Springfield, the FEMA FIS
includes the following data:
Figure 6,1
Flood Hazard Data
Willamette River at the State Highway 126 in Springfield
Flood Frequency Discharge Elevation
(yea rs) (cfs) (feet)
10 40,000 435.3
50 59,000 437,8
lO0 71,000 439.4
500 111,000 443.4
The stream discharge data shown above are from the table on page 28 of the FEMA
Flood Insurance Study (FIS) for Lane County. Stream discharge means the volume of
water flowing down the river and is typically measured in cubic feet of water per
second (cfs). The flood elevation data are from the Flood Profile Graph 193P at the
end of the FIS. Flood elevation data vary with location along the reach of the river and
thus separate flood elevation data points must be read from the graph at each location
along the river.
Quantitative flood hazard data, such as shown above, are very important for mitigation
planning purposes because they allow quantitative determination of the frequency and
severity (i.e., depth) of flooding for any building or other facility (e.g., road or water
treatment plant) for which elevation data exist. Such quantitative flood hazard data
Public Review Draft: August 6, 2004 6-3
also facilitate detailed economic analysis (benefit-cost analysis) of mitigation projects
to reduce the level of flood risk for a particular building or other facility. Further details
and examples of how such data are used are given in the Appendix (Mitigation Project
Examples).
Public Review Draft: August 6, 2004 6-4
Legend Flood Hazard
~ ~.~ ~ ~.~o~o~.~ Areas in Eugene
~, Hospitals and Urgea~ Care Metre ~an Boun~r/
F~OOD ~A~D
~ Fire S~uoqS
Floodway (whe~ mapped)
~ Ja,ts Polme Depts, C,ty He~s ~(,,
l~O~Ye~r F'ood Zone
0 Pub',~c WaTer TreatmemJSterege Sour~
~ Mumccpa' Wastewster Fac¢~/ bi
~ Pubho Wof~s Sho~s by ~n~ couac~ cf
6.3.3 Interpreting Flood Hazard Data for Mapped Floodplains
The level of flood hazard (frequency and severity of flooding) is not determined simply
by whether the footprint of a given structure is or is not within the 100-year floodplain,
A common error is to assume that structures within the 100-year floodplain are at risk
of flooding while structures outside of the 100-year floodplain are not. Some important
guidance for interpreting flood hazard is given below,
A. Being in the 100-year floodplain does not mean that floods happen
once every 100 years. Rather, a 100-year flood simply means that
the probability of a flood to the 100-year level or greater has a 1%
chance of happening each year.
B. Much flooding happens outside of the mapped 100-year floodplain.
First, the 100-year flood is by no means the worst possible flood.
For flooding along the Willamette River, the 500-year flood is 4 feet
higher than the 100-year flood. Thus, floods greater than the 100-
year event will flood many areas outside of the mapped 100-year
floodplain. Second, many flood prone areas flood because of local
storm water drainage conditions. Such flood prone areas have
nothing to do with the 100-year floodplain boundaries.
C. The key determinant of flood hazard for structure or other facility is
the relationship of the elevation of the structure or facility to the flood
elevations for various flood events. Thus, homes with first floor
elevations below or near the 10-year flood elevation have drastically
higher levels of flood hazard than other structures with first floor
elevations near the 50-year or 100-year flood elevation.
The importance of first floor elevations in determining flood hazard levels is
illustrated in the data shown below in Figure 6.2. These data show the
statistical return period for flooding reaching the first floor for structures with
various first floor elevations near the Willamette River at State Highway 126 in
Springfield.
Homes with first floor elevations at 434 or 435 feet have return periods for
flooding of less then 10 years. As floor elevations increase, the return period
for flooding increases markedly, with homes a 440 feet expected to flood only
once about every 117 years and homes at 443 feet expected to flood only
about once every 376 years, on average. Thus, even in the same
neighborhood or the same block, the level of flood hazard for homes varies
markedly depending on the specific elevations of each home.
Public Review Draft: August 6, 2004 6-7
Figure 6.2
Flood Return Period vs. First Floor Elevation
Flood Frequency vs. First Floor Elevation
400
300
250
100
434 435 436 437 438 439 440 441 442 443
First Floor Elevation (feet)
6,3.4 Caveats for the Eugene/Springfield Metro Area Flood insurance
Study
The Flood insurance Study (FIS) for the Eugene/Springfield Metro Area is relatively
recent (June 2, 1999), although much of the data is from older sources. Flood
insurance Studies, FiRM maps, and flood hazard data are a snapshot in time and
cannot take into account development or other watershed changes that may occur
subsequent to the study date for a FIS.
Flood hazard data change with time as channels and watersheds evolve with
increasing development and other changes. Increasing development often increases
runoff and increases flood discharges and elevations. Over time, the accuracy of an
FIS typically diminishes and any FIS should be redone periodically to ensure that data
are accurate and up to date for flood zoning and mitigation planning purposes. Simply
because an FIS is old, does not necessarily mean that a FIS is outdated or inaccurate.
However, the older a study is, and the more development that has occurred within the
watershed, the more likely it is that channel or watershed conditions have changed
over time. Therefore, as time passes, care should be taken in interpreting and using
data from the FIS, especially in reaches of rivers or streams where substantial
channel changes are documented or flood control measures have been added. Over
Public Review Draft: August 6, 2004
time, the slow filling of the floodplain and even minor watercourse alterations due to
development may push future floodwaters to unanticipated and unaware areas within
the community.
In at least one location, along Amazon Creek, the FEMA Flood Insurance Study
appears to be already out of date. Evidently, recent significant improvements/
changes in the Amazon Creek channel are not reflected in the FEMA FIS or flood
plain maps for Amazon Creek. The FEMA FIS and maps should be updated to reflect
accurately current flood hazards along Amazon Creek.
There are also significant portions of the floodplains in the Eugene/Springfield Metro
Area that are mapped only as approximate Zone A areas. Zone A areas are based
upon approximate and historical data for which detailed flood hazard studies have not
been performed. Some of these areas, such as the River Road/Santa Clara area are
rapidly developing, although they did not have enough development at the time of the
FIS to warrant a detailed study.
6.4 Flood Hazards and Flood Risk: Outside of Mapped Floodplains
Section 6.3 above applies ONLY to the limited portions of the Eugene/Springfield
Metro Area that are within the FEMA-mapped floodplains of the major rivers and
portions of some of the smaller streams and sloughs. For mitigation planning
purposes, it is very important to recognize that flood risk for a community is not limited
only to areas of mapped floodplains. Other portions of the Eugene/Springfield Metro
Area outside of the mapped floodplains are also at relatively high risk from over bank
flooding from streams too small to be mapped by FEIVlA or from local storm water
drainage.
Repetitive, damaging floods from storm water drainage affect many areas of the
United States, including the Eugene/Springfield Metro Area. As in most cities, local
storm water drainage systems are designed to handle only small to moderate size
rainfall events. Storm water systems are sometimes designed to handle only 2-year
or 5-year flood events, and are rarely designed to handle rainfall events greater than
10-year or 15-year events.
For local rainfall events that exceed the collection and conveyance capacities of the
storm water drainage system, some level of flooding inevitably occurs. In many
cases, local storm water drainage systems are designed to allow minor street flooding
to carry off storm waters that exceed the capacity of the storm water drainage system.
In larger rainfall events, flooding may extend beyond streets to include yards. In major
rainfall events, local storm water drainage flooding can also flood buildings. In
extreme cases, local storm water drainage flooding can sometimes result in several
feet of water in buildings, with correspondingly high damage levels.
in the Eugene/Springfield Metro Area, the storm water drainage system includes a
combination of natural and built systems that have evolved over time. The built
system includes flood control structures on the major rivers, along with smaller scale
local drainage systems.
Public Review Draft: August 6, 2004 6-9
For Eugene, the local drainage basins managed include both those within the City
limits as well as the unincorporated areas west of Interstate 5, both within and outside
the UGB. The total drainage basin management area is about 49,000 acres. There
are about 540 miles of storm water drainage pipes, mostly within city limits, that
convey storm water to receiving waters such as Amazon Creek and the Willamette
River. There are also about 30 miles of open drainage channels maintained by the
City and additional private storm water drainage infrastructure that is not maintained
by the City.
The general characteristics of the Springfield storm water drainage system are
outlined in the City of Springfield Stormwater Management Plan. The drainage area
managed by the City of Springfield includes about 14,000 acres, with about 213rds of
the total area within City limits and 1/3rd outside of City limits within the UGB.
Springfield's storm water drainage includes two major drainages, which flow to the
McKenzie and Willamette Rivers, and 15 separate drainage subbasins.
Springfield's built system includes 170 miles of piped drainage system and 13 miles of
open channel watencvays, as well as 4,000 catch basins and two municipally-owned
storm water detention ponds. As in Eugene, Springfield's storm water system also
includes private storm water infrastructure such as detention ponds that have been
included in new development since the 1980s to reduce the volume and pollutant
content of storm water entering the public storm water system and/or local rivers and
streams.
Historically, the focus of local storm water maintenance practices has been limited to
drainage and flood control. More recently, the focus has widened to include
management of riparian vegetation by allowing it to remain in streams and channels
for the beneficial effects of slowing runoff for filtration and sedimentation.
Performance of the local storm water drainage systems has generally been very good.
The system handled the February 1996 flood event with relatively few problems, even
though much of the system was designed for 5-year or 10-year events and the
February 1996 event was approximately a 25-year event. Historical experience and
hydrologic/hydraulic modeling suggests that the most problematic areas for storm
water drainage in Eugene are the Amazon Creek, Willow Creek and Laurel Hill basins
in the South Hills. Drainage problems in these areas are exacerbated by relatively
thin, impermeable soils.
Many areas of Springfield are served by somewhat inadequate storm water drainage
systems, as shown by the limited capacities of some systems to accommodate new
development and to control flooding. The City's assessment of storm water system
capacity needs and corresponding recommendations for future capital improvements
is in process with the new Stormwater Facility Master Plan, which is scheduled for
completion in 2004.
A partial, preliminary list of sites in the Eugene/Springfield Metro Area, outside of the
mapped floodplains, that have been subjected to repetitive flooding is given below in
Table 6,3
Public Review Draft: August 6, 2004 6-10
Table 6.3
Repetitive F~lood Sites in the Eugene/Springfield Metro Area
(Outside of Mapped Floodplains)
Location
Eugene
Washington St. (15th - 16[h)
East Bank Bike Path (Owosso to Beltline)
Amaxon Channel, Chambers and Garfield
Acorn Park B~ke Path
Tugman Park, Hdyard St
Braburn inlet at 46th and Willamette
34th and Olive
Woodland and Cresta De Ruta
25th and Agate
18th and Hilyard
24th and Lawrence
25th and Jefferson
25th and Alder
Springfield
Harbor Dr~ve Area
Hayden Br~d§e/Yolanda Area
international Way (Sony) Area
Cedar Creek (North Thurston) Area
West D Area
Glenwood Area
6~5 inventory Exposed to Flood Hazards in the Eugene/Springfield Metro Area
As noted above, each of the rivers and streams for which there are mapped flood
plains includes developed areas where streets and buildings are at risk for flood
damages. There are also a few critical facilities, including one school and several fire
stations with footprints within or very near the mapped 100-year flood plains and most
of the water and wastewater treatment plans are located in or near mapped
floodplains.
Data maintained by the Lane Council of Governments show 110,807 addresses within
the Eugene-Springfield Metro Plan area. Of these, 4,460 fall within the mapped 1
year flood plains and 230 are within the mapped floodways. Thus, about 4% and
0.2% of the structures in the Eugene-Springfield Metro Area have footprints within the
mapped 100wear flood plains or floodways, respectively. There are about 1170 miles
of streets and roads in the Metro Plan area, of which about 61 miles lie within the 100-
year flood plains and 5 miles of which lie within the mapped floodways.
To quantify the level of flood hazard by these properties and others within the mapped
floodplains, it is necessary to determine the elevations of these structures. Only by
determining the first floor elevation of each of these potentially flood-prone structures,
can the level of flood hazard (frequency and severity of flooding) be calculated
accurately. Acquiring such elevation data is recommended as a high priority.
Public Review Draft: August 6, 2004 6-11
Similarly, acquiring elevation data for additional structures within the 500-year flood
plain as well as for structures in other flood-prone areas outside of mapped floodplains
wou~d greatly increase the accuracy of hazard, inventory, and vulnerability
assessments for floods in the Eugene/Springfield Metro Area area.
The best structure elevations (first floor elevations) are those determined accurately
by surveying. Flood insurance certificates generally include survey elevation data.
Absent survey data, however, useful estimates of elevations for structures can often
be made by reference to elevations of nearby structures or public infrastructure with
surveyed elevation data.
in addition to elevation data, quantifying the level of risk faced by these structures
requires basic data about each structure, including building data (square footage,
number of stories, with or without basement), and information on the type and
importance of function (residential, commercial, public).
As noted above, some areas of the Eugene/Springfield Metro Area, outside of the
mapped floodplains, are also subject to relatively high levels of flood risk. To quantify
the level of flood risk posed by these areas, historical data should be compiled to
include: frequency and severity of flooding. Severity of flooding can include estimates
of past damages, if available, and/or simple narratives reporting whether the flooding
in a given area is limited to street flooding only, or affects yards or buildings as well.
The flood prone inventory of buildings, infrastructure and people in the
Eugene/Springfield Metro Area is summarized below in Table 6.4.
Table 6.4
F~ood Prone Inventory in the Eugene/Springfield Metro Area
Public Review Draft: August 6, 2004 6-12
inventory Probable ~rnpacts
4,460 of the 110,807 addresses ~n the Metro plan area are w~thln
Buildings: Within the mapped 100-year floodplain, Including 230 within mapped
Mapped Floodplains floodways. These flood prone properties are along the Wdlamette
and McKenz~e Rivers and along smaller FEMA-mapped creeks
Buildings: Buildings located In areas subjected to storm water drainage
Outside Mapped Floodplains flooding and/or overbank flooding from streams too small to be
mapped See 19 problem areas identified in Table 6 3
61 miles of the 1170 miles of streets and roads in the Metro plan
area are within the 100-year floodplain and 5 miles are within
Streets and Roads floodways. Additional streets and roads located ~n areas
subjected to storm water drainage flooding and/or overbank
flooding from streams too small to be mapped See 19 problem
areas idenbf~ed ~n Table 6 3
A few cnt,cal facilities have footprints w~thfn or very near the 100-
year floodplain, including Camp Creek Elementary School.
Critical Facilities McKenz~e Camp Creek Fire Stabon 16-2, Eugene F~re Stabon 9,
and Santa Clara Fire Station 62 Other cntlcal fac~hties may be at
flood risk in extreme flood events
Electric power Relatively minor impacts expected ~n most flood events
Alt water and wastewater treatment plants are located at relatively
Other Utilities Iow elevations in or near mapped floodplains or other water
sources and thus many facd~ties may be at flood risk Generally
m~nor ~mpacts for other ut~hbes
Casualties Small potential for casualbes (deaths and injunes) since most
floods would have substanbal warn~nq time
6.6 Flood Insurance Data for the Eugene/Springfield Metro Area.
The National Flood Insurance Program (NFIP) maintains a database of all flood
insurance policies in the United States. NFIP data for the Eugene/Springfield Metro
Area are summarized below in Table 6.5.
Table 6,5
NFIP Data for Eugene/Springfield Metro Area2
Nepetitive
Jurisdiction Policies Claims Loss
Springfield 145 25 4
Eugene 775 16 0
Lane County~ 3535 320 24
~ Lane County (entire)
2 February 2003 data.
As shown above, there are over 3500 flood insurance policies in place in Lane County
as a whole, with about 920 of these in the Eugene/Springfield Metro Area. Of these
properties with current (as of 2003) flood insurance policies, 41 properties have had
flood loss claims. Of these properties with flood loss claims, 4 are on FEMA's national
repetitive loss list.
FEMA's repetitive loss list includes all insured properties that have experienced two or
more insured ~osses of at least $1,000 for which the flood events were at least 10
days apart but not more than 10 years apart. The FEMA repetitive loss list provides
one indication of properties that may be at high risk for future flooding. However,
because these claims data do not consider the severity or frequency of the flood
Public Review Draft: August 6, 2004 6-13
events causing the flood loss claims, the repetitive loss list is not mathematically
rigorous. For example, some properties on the list may have simply been unlucky and
have experienced two flood events with Iow probabilities (e.g., 100-year or greater
events) within a short time period. Thus, the properties on the repetitive loss list may
be at relatively high flood risk or they may not. Correspondingly, there are almost
certainly other properties within the Eugene/Springfield Metro Area at equal or higher
levels of flood risk that are not on the FEMA repetitive loss list. These properties may
not have flood insurance or simply may have been lucky over the relatively short
reporting period for the NFIP repetitive loss list (data since 1978).
Despite these limitations of FEMA's repetitive loss list, properties within the
Eugene/Springfield Metro Area on the repetitive loss list may be good targets of
opportunity for flood mitigation. Most of FEMA's mitigation programs list repetitive
loss properties as high priorities for mitigation and thus obtaining FEMA funding for
properties on the repetitive loss list may be more likely than for properties not on the
list.
6,7 Estimating Flood Losses and Flood Risk
For most residential structures and many similar commercial and public structures, the
likely amount of building damage from floods of any given depth can be estimated
approximately using FEMA depth-damage tables. These depth damage tables are
derived from Federal Insurance Administration flood insurance claims data for several
million properties and thus represent typical damage levels for typical structures.
Although actual damages will vary somewhat from structure to structure, depending
also on flood conditions such as duration, velocity, and degree of contamination, these
typical values represent a good starting point to estimate flood damages for typical
structures and thus to help quantify the level of flood risk. Current FEMA depth-
damage data for typical structures are given in the Appendix - Example Mitigation
Projects.
When estimating flood losses or evaluating flood risk (for a structure or a whole
community) it is very important to recognize that the economic impact of floods
includes not only damages to buildings and contents but other economic impacts as
well, including:
1. damages to yards, vehicles, and outbuildings (not in depth damage
data above),
2. displacement costs for temporary quarters while repairs are made,
3. loss of business income,
4. loss of public services.
In some cases, these economic impacts of floods can be a significant fraction of
building and contents damages, or even larger, especially for critical facilities or critical
infrastructure. FEMA's publication What is a Benefit? Draft Guidance for Benefit-Cost
Analysis provides an excellent primer, along with typical values and simple economic
methods, to place monetary values on the loss of function of buildings, critical
facilities, roads and bridges, and utility systems.
Public Review Draft: August 6, 2004 6-14
6.8 Common Flood Mitigation Projects
Potential mitigation projects to reduce the potential for future flood losses cover a wide
range of possibilities.
For either major rivers or the creeks, it would be theoretically possible to reduce future
flood losses by building levees or flood walls. In practice, however, such projects are
often very expensive and have a host of environmental and other regulatory hurdles.
For the smaller creeks, channel improvements to improve water conveyance capacity
and removal of flow-restriction obstructions may be desirable. Another possibility for
some of the smaller creeks would be to construct detention ponds upstream (perhaps
outside of the Eugene/Springfield Metro Area planning area) to temporarily store water
during high rainfall periods. Detention ponds are basically leaky dams, designed to be
dry during normal conditions. Detention ponds typically have restricted outlets with
controlled flow rates. Thus, during periods of high inflow into the pond, water is stored
temporarily and then gradually released. The effect of detention ponds is to lower
peak discharge values and thus to lower peak flood elevations.
For portions of the Eugene/Springfield Metro Area subject to flooding from storm water
drainage, various storm water drainage system improvements may be desirable.
Typical improvements include upgrades to the size of drainage ditches or storm water
drainage pipes and upgrades to pumping capacity (for pumped portions of drainage
systems). Another possibility for some areas may be construction of local detention
ponds.
For critical facilities at Iow elevations with high flood risk, such as the water and
wastewater treatment plants, construction of berms or floodwalls to protect the
facilities may be desirable.
For residential, commercial or public facilities at high flood risk, elevation of structures
or, for structures at very high flood risk, acquisition and demolition are potential
mitigation options. Elevation and acquisition (especially), are expensive mitigation
options that are generally not cost-effective unless the levels of flood hazard and flood
risk are rather high. That is, these mitigation options are most attractive for structures
deep in the flood plain (i.e., with first floors below the 10-, or 20-, or 30-year flood
elevations). For structures outside of mapped floodplains, elevation or acquisition
would likely be cost-effective only for structures with a strong history of major,
repetitive flood losses.
For structures near the fringe of the 100-year flood plain, near the 100-year flood
level, or with some history of repetitive flood losses, various small scale flood loss
reduction measures such as elevation of furnaces and utilities may be desirable.
The following table contains flood mitigation action items from the master Action Items
table in Chapter 4.
Public Review Draft: August 6, 2004 6-15
ssouo~¥ o!~qnd x x x x x x x
0
oeo
~ >
-
- ~ o
....
E
0
7,0 WINTER STORMS
7.1 Overview
Winter storms affecting the Eugene/Springfield Metro area are characterized by a
combination of heavy rains and high winds. Heavy rains can result in flooding, as well
as debris slides and landslides. High winds commonly result in tree falls which
primarily affect the electric power system, but which may also affect buildings and
vehicles. This chapter deals primarily with the rain and wind effects of winter storms.
Larger scale flooding is addressed in Chapter 6. Debris flows and landslides are
addressed in Chapter 8.
Winter storms can also involve ice and snow, most commonly at higher elevations
than the immediate Eugene/Springfield Metro Area. The most likely effects of snow
and ice events on the Eugene/Springfield Metro Area are road closures limiting
access/egress to/from the Eugene/Springfield Metro Area, especially roads to higher
elevations such the highways into the Cascades or over the Coast Range. Winter
storms with heavy wet snow and ice storms also may result in power outages from
downed transmission lines and/or poles.
Average annual snowfall in the Eugene/Springfield Metro Area (Eugene Airport
weather station) is 6.0". Since the weather station was established in 1939, maximum
monthly snowfall has been 47.1" (January 1969), with maximum seasonal snowfall
also of 47.1" (1969). Maximum monthly snowfalls for other months for February,
March, November, and December are 8.8", 10.8", 6.0" and 10.2", respectively.
Major snow storm events do occur occasionally. Major snow storms affecting the
Willamette Valley occurred in 1884, 1892, 1909, 1916, 1919, 1937, 1950, 1969, 1989
and 2004. January 1950 snowfalls were especially high, with 54" in Albany and 36" in
Eugene. In January 1969, Eugene had 47" of snow. Thus for Eugene, most winters
result in little snowfall, with major storms of 10" or more snow occurring typically about
every 10 or 20 years. There are few practical mitigation actions for such infrequent
major snow storms, other than commonsense measures applicable to many hazards,
such as encouraging residents to maintain emergency supplies of food and water for a
few days and emergency generators for critical facilities.
For completeness, we also briefly address other severe weather events, including hail,
lightning strikes and tornadoes. Hail events are possible in the Eugene/Springfield
Metro Area, generally during summer thunderstorms, with the most recent significant
event being August 4, 1999. However, hail damage is generally minor and few
practical mitigation alternatives are applicable to hail.
Lightning strikes also occur in the Eugene/Springfield Metro Area. Lightning strike
damage to buildings or infrastructure is generally relatively minor and few practical
mitigation alternatives are applicable to lightning, other than installing lightning
arrestors on critical facilities subject to lightning damage. However, nationwide NOAA
data show that lightning causes about 90 deaths per year, with at least 230 injuries
(NOAA Technical Memorandum NWS SR-193, 1997). Lightning injuries appear to be
systematically underreported and thus the actual injury total is most likely significantly
higher. For Oregon, however, casualties from lightning are very Iow, with totals of
Public Review Draft: August 6, 2004 7-1
For Lane County as a whole, we note that 2-year and 25-year 24-hour precipitation
totals are 4" or more and 5" to 8+", respectively in the Coast Range, with values
almost as high in the Cascades. Such totals are high enough to generate significant
potential localized flooding problems. However, whether or not localized flooding
does occur depends on specific local drainage conditions. For example, 5" of rain in
one area may cause no damage at all, while 5" of rain in a nearby area may cause
road washouts and flooding of buildings.
The rainfall data shown in Table 7.1 give general overview of the potential for winter
storm flooding in the Eugene/Springfield Metro Area and elsewhere in Lane County,
but whether or not flooding occurs at specific sites depends heavily on specific local
drainage conditions.
For the Eugene/Springfield Metro Area, identification of specific sites subject to
localized flooding during winter storms is based on historical occurrences of repetitive
flooding events. Such sites in the area, where localized storm water drainage flooding
has been repetitive and problematic, were tabulated in Chapter 6 Floods (see Table
6.2).
7.2.2 Wind Hazard Data
Wind speeds associated with winter storms vary depending on meteorological
conditions, but also vary spatially depending on local topography. For Lane County,
the wind hazard levels are highest directly at the coast and then fairly uniform across
most of the rest of the county. In the hilly areas, however, the level of wind hazard is
strongly determined by local specific conditions of topography and vegetation cover.
A regional overview of wind hazards is shown by the data in Figures 7.2 and 7.3 which
show contours of wind speed (in kilometers per hour) for western Oregon (Wantz and
Sinclair, Distribution of Extreme Wind Speeds in the Bonneville Power Administration
Service Area, Journal of Applied Meteorology, Volume 20, 1400~1411, 1981). These
data are for the standard meteorological data height of 10 meters (about 39 feet)
above ground level. Figures 7.2 and 7.3 show wind speed contours for recurrence
intervals of 2-years and 50-years, respectively. These data are for sustained wind
speeds. Peak gusts are commonly 30% or so higher than the sustained wind speeds.
These wind-speed data are fairly old, but still representative of overall wind storm
conditions in Oregon.
For the Eugene/Springfield Metro area, the 2-year and 50-year sustained wind speeds
are about 60 km/hour and 100 km/hr, respectively. These values correspond to 2-
and 50-year wind speeds of about 37 miles/hr and 62 miles/hr, respectively. These 2-
year wind speeds are too Iow to cause widespread substantial wind damage.
However, there may be significant local wind damage at sites where local wind
speeds are higher or where there are especially exposed locations, such at the
boundary between clear cut and forested areas.
50-year recurrence interval wind speeds are high enough to cause widespread wind
damage. Damage may be severe at particularly exposed sites. Thus, for the Eugene/
Springfield Metro Area, winter storms with significant direct wind damage are not likely
Public Review Draft: August 6, 2004 7-5
every year or every few years, but perhaps once every decade or so, on average, with
major wind storm events happening at intervals averaging a few decades.
For reference, we note that maximum winds (fastest mile wind speeds) observed in
Eugene range from 29 to 37 mph during June, July and August and from 40 to 63 mph
for the other months, with fall/winter months having the highest recorded wind speeds.
The maximum recorded wind speed in Eugene is 63 mph during the October 12, 1962
windstorm event.
Figure 7,2
Wind Speed Contours for 2-Year Recurrence Interval
(kin/hour)
Public Review Draft: August 6, 2004 7-6
Figure 7.3
Wind Speed Contours for 50-Year Recurrence Interval
(kmlhr)
PuNic Review Draft: August 6, 2004 7-7
7.2.3 Historical Winter Storm Data for the Eugene/Springfield Metro Area
Winter storms can affect the area directly, with damage within the Eugene/Springfield
Metro Areaa, or indirectly, with damage outside the area but affecting transportation
to/from the area and/or utility services (especially electric power). Historically, the
area has often been subject to both direct and indirect impacts of winter storms.
The winter storms that affect the Eugene/Springfield Metro Area are not local events
affecting only the immediate area. Rather, the winter storms are typically large
cyclonic Iow pressure systems moving from the Pacific Ocean and that thus usually
affect large areas of Oregon and/or the whole Pacific Northwest.
Historical winter storm data com¢ied by the Portland Office of the National Weather
Service (www.wrh.noaa.gov/Port~and/windstorm.html) list the following major winter
storm events with substantial wind damage in Oregon: 1. February 7, 2002
2. December 12, 1995
3. November 13-15, 1981
4. March 25-26, 1971
5. October 2, 1967
6. March 27, 1963
7. October 12, 1962
8. November 3, 1958
9. December21-23, 1955
10. December 4, 1951
11.November 10-11, 1951
12. April 21422, 1931
13. January 20, 1921
14. January 9, 1880.
The website referenced above has informative narrative summaries of each winter
storm event, including wind speed data and damage reports. Similar reports of
historical wind storm data have been compiled by Wolf Read (The Storm King) at
Oregon State University (http://oregonstate.edu/-readw/). The OSU website has a
vast archive of historical winter storm data for Oregon.
The effects of the major historical winter storm events listed above varied significantly
with geographic location. Similar variations in effects occur as well with the numerous
smaller winter storm events. However, in terms of sustained wind speeds in the
Willamette Valley and damage levels, the 1880 and 1962 storms stand out as the
most severe such events.
The most recent major winter storm event to significantly affect the Eugene/Springfield
Metro Area was the February 7, 2002 storm. National Weather Service data show
peak sustained winds and peak gusts at the Eugene Airport of 49 mph and 70 mph,
respectively. This windstorm was a Federally-declared disaster (FEMA-1405-DR-OR)
for five counties, including Lane County. In the five county FEMA-dedared disaster
area, damages and costs to public facilities eligible for FEMA reimbursement (75%)
totaled more than $6 million. Damages to private property are not included in this $6
million figure.
Public Review Draft: August 6, 2004 7-8
The 2002 windstorm event had significant effects on the Eugene/Springfield Metro
Area Area, primarily from tree fails. Widespread tree fal~s resulted in significant
damages to utility lines and poles as well as damages to vehicles and buildings. The
most widespread impact on the Eugene/Springfield Metro Area was numerous areas
with localized ~oss of electric power from downed electric lines and poles.
7.3 Winter Storm Risk Assessment
Winter storm flooding and wind damage may affect both infrastructure and buildings.
Localized flooding from winter storms very commonly affects the transportation
system, especially roads. Severe winter storms will result in numerous road closures
due either to washouts or due to depth of water on road surfaces. Such localized
flooding also affects buildings located in the flooded areas. Additional road closures
are likely in some events from landslides/mudslides as well as from snow/ice storms.
Wind impacts from winter storms arise primarily from tree fails, which may affect
vehicles and buildings, to some extent, but whose primary effect is often on utility
lines, especially eiectdc power lines. Wind damages may result in widespread
downing of trees or tree limbs with resulting widespread downage of utility lines. Such
tree-fall induced power outages affect primarily the local electric distribution system.
Transmission system cables are generally less prone to tree fall damage because of
design and better tree-trimming maintenance. In severe wind storms, direct wind
forces and wind driven debris may cause building damages, especially for more
vulnerable types of construction such as mobile homes.
As discussed above in Section 7.1, both winter storm flood hazards and winter storm
wind hazards have highly localized impacts. The location and severity of such
impacts depend very strongly on specific local conditions~ Therefore, it is difficult to
make regional risk assessment or loss estimates from mapping the hazards and
overlaying the inventory: such a risk assessment simply requires too much detailed
data which are not available.
An alternative approach is to document the severity and locations of winter storm flood
and wind damage from historical events. A good example of this approach is the
excellent summary of damages and losses experienced in the February 1996 floods:
The Cascades West Region of Oregon and the February Flood of 1996: A
Regional Flood Recovery P~an for Benton, Lane, Lincoln, and Linn Counties,
Oregon Cascades West Council of Governments, November 1996.
For more quantitative risk assessment of localized flooding and wind damages arising
from winter storms, the best approach is to systematically gather data on sites of
repetitive damages due to localized flooding or wind damages. By documenting (and
mapping using GIS) the sites of repetitive damage events, along with documentation
of the type and cost of damages and losses, the most seriously affected sites can be
clearly identified. Clearly, such repetitive loss sites with significant damages are likely
candidates for mitigation actions.
The potential impacts of winter storms on the Eugene/Springfield Metro Area are
summarized below in Table 7.4.
Public Review Draft: August 6, 2004 7-9
Table 7.4
Potential Impacts of Winter Storms on the Eugene/Springfield I~etro Area
Inventory Probable Impacts
Entire city may be affected by mad closures or loss of electric
Portion of Eugene/Springfield Metro
Area affected power; otherwise direct damages to buildings and infrastructure
are I~kely to be localized and relatively minor
Isolated minor damage from tree falls, some buildings affected by
Buildings flood damage in major storms, especially in the storm water
drainage problem areas identified in Section 6.3
M~nor road closures due to tree falls and flooding: I~m~ted impact
Streets within Metro Area because of short detour routes within Eugene/Spnngfield Metro
Area
Potential closures of major highways due to snow, debns flows or
Roads to/from Metro Area landslides, localized flooding and tree falls, especially routes ~nto
the Cascades and Coast Range
Loss of electric power may be localized due to tree fails on local
Electric power distribution hnes or affect enbre city ~f tree falls affect transmission
lines feeding Eugene/Springfield Metro Area
Other Utilities Generally minor or no impacts on other utilities from w~nter storms
Casualties Small potential for casualties (deaths and injuries) from tree falls
or contact with downed power lines
7.4 i~litigation of Winter Storm Impacts
Potential mitigation projects for winter storms address any of the aspects of such
storms, including floods, winds, and landslides (see Chapter 8). See also Chapter 13
for additional discussion of the disruptions to utility and transportation systems.
For winter storm flooding, the mitigation measures discussed in Chapter 6 (Floods) for
local storm water drainage flooding are exactly the mitigation measures for the flood
aspects of winter storms. Common mitigation projects include: upgrading storm
water drainage systems, construction of detention basins, and structure-specific
mitigation measures (acquisition, elevation, flood proofing)for flood-prone buildings.
For roads subject to frequent winter storm flooding, possible mi[igation actions include
elevation of the road surface and improved local drainage. For utilities subject to
frequent winter storm flooding, possible mitigation actions include improved local
drainage, elevation or relocation of the vulnerable utility elements to non-flood prone
areas nearby.
For wind effects of winter storms, the most common and most effective mitigation
action is to increase tree trimming efforts, because a high percentage of wind damage
to utilities, buildings, vehicles, and people arises from tree falls. However, economic,
political and esthetic realities place limits on tree trimming as a mitigation action.
Future wind storm damage in the Eugene/Springfield Metro Area could be almost
eliminated by cutting down all large trees in the area. Obviously, such an extreme
mitigation measure is neither practical nor desirable for many reasons.
Effective tree trimming mitigation programs focus on limited areas where tree falls
have a high potential to result in major damages and economic losses. High pdority
areas include examples such as the following:
Public Review Draft: August 6, 2004 7-10
1) Transmission lines providing electric power to the area,
2) Major trunk lines providing the backbone of the electric power distribution
system within the area
3) Distribution Nines for electric power to critical facilities in the area,
4) Specific circumstances where falling of large trees poses an obvious threat
to buildings, people or major transportation arteries.
The report on the February 1996 floods, The Cascades West Region of Oregon and
the February Flood of '1996: A Regional Flood Recovery P/an for Benton, Lane,
Lincoln, and Linn Counties, November 1996, contains many dozens of examples of
sites which experienced winter storm flooding (mostly) and other winter storm impacts.
This report also contains many dozens of excellent examples of possible mitigation
projects, in the sections for each county dealing with "county-wide strategies" and
"community strategies," including measures for the Eugene/Springfield Metro Area.
Detailed analysis, benefit-cost analysis, and priodtization of winter storm mitigation
projects for localized flooding or wind effects follows a methodology essentially
identical to that described in Section 3.2 of the Phase One Regional All Hazard
Mitigation Master Plan for Benton, Lane, Lincoln, and Linn Counties (1998). The
analysis in Section 3.2 of the Phase One Plan 1998 for flooding outside of mapped
floodplains uses a frequency-damage relationship to annualize risk and then to
estimate the benefits of alternative mitigation projects. This same approach is
applicable to evaluation of mitigation projects for wind effects of winter storms as well
as for flood effects. This approach is also illustrated by examples in the Appendix to
this Eugene/Springfield Metro Area Multi-Hazard Mitigation Plan.
The following table contains winter storm mitigation action items from the master
Action Item table in Chapter 4.
Public Review Draft: August 6, 2004 7-11
× Public Awareness
Life Safety
Protect Property
Minimize Losses
Partnerships &
Implementation
emergency
Services
Protect
Environment
8.0 LANDSLIDES
8,i Landslide Overview and Definitions
The term "landslide" refers to a variety of slope instabilities that result in the downward
and outward movement of s~ope-forming materials, including rocks, soils and artifidal
fill. Four types of landslides are distinguished based on the types of materials
involved and on the mode of movement. These four types of ~andslides are illustrated
in Figures &1 to 8.4 from the Regional All Hazard Mitigation Master P~an for Benton,
Lane, Lincoln, and Linn Counties (Phase One, Technical Appendix, 1998) which
includes a more technical discussion of these four types of landslides.
Rockfa~ls are abrupt movements of masses of geologic materials
(rocks and soils) that become detached from steep slopes or cliffs.
Movement occurs by free-fa~L bouncing and roiling. Fa~s are strongly
influenced by gravity, weathering, undercutting or erosion.
Rotational Slides are those in which the rupture surface is curved
concavely upwards and the slide movement is rotationa~ about an axis
parallel to the slope. Rotational slides usually have a steep scarp at the
upslope end and a bulging "toe" of the slid material at the bottom of the
slide. Roads constructed by cut and fill along the side of a slope are
prone to slumping on the fill side of the road. Rotational slides may
creep slowly or move large distances suddenly.
Translational Slides are those in which the moving material slides
along a more or less fiat surface. Translational slides occur on surfaces
of weaknesses, such as faults and bedding ptanes or at the contact
between firm rock and overlying loose soils. Translational slides may
creep slowly or move large distances rather suddenly.
Debris Flows (mudflows) are movements in which loose soils, rocks
and organic matter combine with entrained water to form slurries that
flow rapidly downsiope.
All of these types of landslides may cause road blockages by dumping debris on road
surfaces or road damages if the road surface itself slides downhill. Utility lines and
pipes are prone to breakage in slide areas. Buildings impacted by slides may suffer
minor damage from small settlements or be completely destroyed by large ground
displacements or by burial in slide debris. Also, as evidenced by 1997 winter storms
in Oregon, landslides may also result in casualties.
There are main factors that determine susceptibility (potential) for landslides: 1 ) slope,
2) soil/rock characteristics,
3) vegetative cover, and
4) water content.
Steeper slopes are more prone to all types of landslides. Loose, weak rock or soil is
more prone to landslides than is more competent rock or dense, firm soils. Slopes
Public Review Draft: August 6, 2004 8-1
with little or no vegetative cover are somewhat more prone to landslides, especially
shallow, surficial slides than are areas with heavier vegetative cover. Water
saturated soils or rock with a high water table are much more prone to landslides
because the water pore pressure decreases the shear strength of the soil and thus
increases the probability of sliding.
Figures 8.1 to 58,4
Major Types of Landslides
SOFT ~.RODIItitLE ROCK
Fig. 8-1. Rockfall Fig. 8-2. Rotational Landslide
Fig. 8-3. Translational Landslide
Soi~ or Col iuvium,~
Scar (oreo of initial feilure)
/
Track (m(~y or may not be eroded)-.,,,. //
Zone of depositio~ (fan),
Fig, 8-4. Debris Flow
Public Review Draft: August 6, 2004 8-2
The water content of soils/rock is a major factor in determining the likelihood of sliding
for any given slide-prone location. Thus, most landslides happen during rainy months,
when soils are saturated with water. However, landslides may happen at any time of
the year. In addition to landslides triggered by a combination of slope stability and
water content, landslides may also be triggered by earthquakes. Areas prone to
seismically triggered landslides are exactly the same as those prone to ordinary (i.e.,
non-seismic) landslides. As with ordinary landslides, seismically triggered landslides
are more likely for earthquakes that occur when soils are saturated with water.
Debris flows and landslides are a very common occurrence in Oregon. DOGAMI
conducted a statewide survey of landslides arising from the winter storms in February
1996, November 1996, December 1996 and January 1997 and found 9,582
documented landslide locations. The actual number of landslides was estimated to be
many times the documented number.
8.2 Landslide Hazard Assessment for the Eugene/Springfield l~etro Area
Areas with high landslide potential within the Eugene/Springfield Metro Area's urban
growth boundary are shown on Maps 3E, 3S, 4E, and 4S.
Maps 3E and 3S show localities in the Eugene/Springfield Metro Area with high
potential for surficial debris flows. Concentrations of high potential areas include the
hilly regions northeast of the Eugene/Springfield Metro Area and hilly regions south of
the Eugene/Springfield Metro Area. Fortunately, most of these high hazard areas are
largely undeveloped and most of these areas are outside of the Eugene/Springfield
Metro Area Planning Boundary and the Urban Growth Boundaries. However, there
are small pockets of high debris flow hazard within the developed areas, primarily in
the southern hilly portions of both Eugene and Springfield.
Maps 4E and 4S show DOGAMI's classification of landslide hazard areas for the
overall Eugene/Springfield Metro Area (Relative Slope Instability maps). The high
landslide potential areas on Maps 4E and 4S represent areas with high potential for
earthquake induced landslides which are also representative of high potential for
rockfalls, rotational slides, and translational slides from non-earthquake events (such
as heavy rainfalls). The geographic distribution of these landslide hazard areas within
the Eugene/Springfield Metro Area is generally similar to that shown on Maps 3E and
3S, although with some differences in details.
Maps 3E, 3S, 4E and 4S should be interpreted cautiously. These maps provide a
regional overview of areas with generally high potential for debris flows or slope
instabilities. However, such regional maps have limited spatial resolution and thus
may not represent the specific landslide risk for any particular parcel in the
Eugene/Springfield Metro Area. Thus, these maps are useful for generally hazard
awareness and mitigation planning purposes, but should not be used for regulatory
purposes.
Specific areas that have had historical problems with debris flows and/or landslides
within the Eugene/Springfield Metro Area are summarized below in Table 8.5 (which
follows the maps). More detailed landslide hazard assessment requires a site-specific
Public Review Draft: August 6, 2004 8-3
analysis of the slope, soil/rock, vegetation and groundwater characteristics ~ Such
assessments are often conducted prior to major development projects in areas with
moderate to high landslide potential, to evaluate the specific hazard at the
development site,
Public Review Draft: August 6, 2004 8-4
Legend Debris-Flow Hazard
¢ 9,,~m~ ~.te~ .... ~ U~a. Gro~Boundar,e. Areas in Eugene
' % R~vem and ~ams O 1 2 ~1~
~ ~h~is
F~ ~s
~ ~, Pol~ ~., C~y Hails
~AMt
~ Publm Wa~r Tre~me~¢~r~ge
0 ~bl~ Works Shops
Legen~ Relative Slope Instability
911 Corem
1 - No Hazard
Police Dept. a~d C,ry Hd~ 3 - Moderate t~ard
Public Wa~r Treatrnent/S~rage , ,, , ' 4 - H~gn Hazard
Was~ewater
Face;ti
~ubhc WoWs Shops sou-ce aela~ve Ea~quake Hamrd Map Oi
Table 8.5
Historica~ Debris F~ow and Landslide Problem Areas ir~ the Eugene/Springfield ~Jetro Area
Location
EuQene
Capital - Essex Lane
Dillard Road
Brooks~de Drive
Cresta De Ruta
Goodpasture Island Road
Springfield
Thurston Hills area
Willamette Heights area
Kelly Butte area
8.3 Landslide Risk Assessment for the Eugene/SpringfieM Metro Area
In this section, we review a methodology for estimating landslide losses due to winter
storm induced landslides. Winter storms with intense rainfalls are the most common
trigger for landslides in Oregon, including within Lane County and within the Eugene/
Springfield Metro Area Area. Major storms with intense rainfall can result in numerous
landslides in slide-prone areas.
Of course, at any given slide-prone location, landslides can occur with or without
winter storms, but such occurrences are isolated and not likely to result in the type of
fairly widespread landslide effects that are possible during winter storms. Widespread
landslides can also be triggered by earthquakes, especially if the earthquake occurs
during the rainy season when soils are saturated. See Chapter 10 (Earthquakes) for
further commentary on earthquake-triggered landslides.
As with any risk assessment, we must overlay the hazard assessment (frequency and
severity of landslides) with the inventory exposed to the hazard (value and
vulnerability). The Level One risk assessment method given in the Regional All
Hazard Mitigation Master Plan for Benton, Lane, Lincoln, and Linn Counties (Phase
One, 1998) considers:
1) extent of landslide susceptible areas,
2) inventory of buildings and infrastructure in landslide susceptible areas,
3) severity of winter storm event (inches of rainfall in 24 hours),
4) percentage of landslide susceptible areas that will move and the range of
movements (displacements)likely, and
5)vulnerability (amount of damage for various ranges of movement).
For the Eugene/Springfield Metro Area, the threat posed by landslides is significant in
the pockets of high hazard potential which overlap with developed areas (cf. Maps 8E,
8S, 8ES. Significant landslides in these areas could damage or destroy one or more
homes, damage utilities and roads in the area, and pose some level of life safety risk
for residents.
Public Review Draft: August 6, 2004 8-9
In addition to direct landslide damages within the Eugene/Springfield Metro Area, the
area is subject to the economic impacts of road closures due to landslides, which
disrupt access/egress to/from the Eugene/Springfield Metro Area. Landslide induced
road closures affecting the Eugene/Springfield Metro Area are possible in or near the
Eugene/Springfield Metro Area in the high hazard areas shown on the maps, as well
as further away on highways into the Cascades or through the Coast Range. The
February 1996 winter storms provided numerous examples of landslide damages,
especially to the road system, with landslides and mudslides closing many roads in
Lane County and other nearby counties.
The potential impacts of landslides and debris flows on the Eugene/Springfield Metro
Area are summarized below in Table 8.6.
Table 8,6
Potential Impacts of Landslides and Debris Flows on the Eugene/Springfield Metro Area
Inventory Probable Impacts
Portion of Eugene/Springfield Metro Landslides are hkely to directly affect only limited portions of
Area affected Eugene/Spnngfleld Metro Area as shown above on Maps 3E, 3S,
4E and 4S.
Medium and high landslide potenbal areas are residential, Small
Buildings landslides are likely to affect no buildings or only 1 or 2 buddings,
Larger landslides could affect several buildings
Minor road closures possible from landslides; limited impact
Streets within Metro Area because of short detour routes within Eugene/Spnngfield Metro
Area
Potential closures of major h~ghways due to lands~des, especially
Roads to/from Metro Area
roads into the Cascades and Coast Range,
Potential for localized loss of etectdc power due to landslides
Electric power affecting power hnes in or near Eugene/Springfield Metro Area
Potential minor outages of water, wastewater and natural gas
Other Utilities from pipe breaks from landslides, Probable ~mpacts would
generally be very localized.
Landslides that impact buildings or roads could result Jn a small
Casualties number of casualbes (deaths and Jniunes)
8.4 Mitigation of Landslide Risk
Mitigation of landslide risks is often quite expensive. In some cases, slope stability
can be improved by addition of drainage to reduce pore water pressure, by
construction of appropriate retaining walls or by other types of geotechnical
remediation. In some cases, buildings can be hardened to reduce damages. An
alternative mitigation strategy for existing buildings or infrastructure with high potential
for landslide losses is to relocate the facilities outside of known slide areas.
Mitigation of landslide risk can also be accomplished by effective land use planning to
minimize development in slide-prone areas. Generally, such land use planning
requires rather detailed geotechnical mapping of slide potential so that high hazard
areas can be demarcated without unnecessarily including other areas of Iow slide
potential.
Public Review Draft: August 6, 2004 8~10
The effects of slide damage on road systems can also be partially addressed by
identifying areas of high slide potential or of repetitive past slide damages so that
alternative routes for emergency response can be pre-determined.
The following table contains landslide mitigation action items from the master Action
Item table in Chapter 4.
Public Review Draft: August 6, 2004 8-11
ssaue~A¥ oHqnd x x
9.0 WILDLAND/URBAN iNTERFACE FIRES
Fire has posed a threat to mankind since the dawn of civilization. Fires may cause
significant damage to property and may also result in deaths and injuries. For the
purposes of mitigation planning, we consider three types of fires: structure fires,
wildland fires, and wildland/urban interface fires. Structure fires are fires in urban,
suburban or rural areas where buildings (and contents) are the primary fire fuel.
Structure fires may also affect other types of structures, including bulk fuel storage,
hazmat facilities, as well as vehicles, aircraft, and railcars. Structure fires of these
types require more specialized fire suppression techniques and may be particularly
hazardous to both firefighters and nearby residents. Wildland fires are fires where
vegetation (grass, brush, trees) is the primary fire fuel. Wildiand/urban interface fires
are fires where the fire fuel includes both structures and vegetation.
This chapter considers all types of fires. However, the emphasis is on wildland/urban
interface fires because such fires may affect large developed areas and large numbers
of people. Thus, wildland/urban interface fires are of special concern for mitigation
planning. Most structure fires are limited to one structure. Structure fires involving
bulk fuel, hazardous materials, pipelines, and transportation fires have many
similarities in response strategies and impacts to the more general discussion of
Hazmat Incidents, as discussed in Chapter 14. Wildland fires, by definition, affect
wildlands with limited impacts on developed areas.
In 2002, according to National Fire Protection Association (NFPA) data there were over
30,000 fire departments in the United States. About 88% of these are all volunteer or
mostly volunteer departments with only about 12% being career or mostly career fire
fighting staff departments. However, the career fire departments tend to serve large
communities. Thus, about 60% of the total population in the United States is served by
career departments, while about 40% is served by volunteer departments.
in Oregon, historical fire statistical data are generally good because each local fire
agency is required to file reports of every fire incident with the State Fire Marshal's
Office. National fire statistics are available through the National Fire Incident
Reporting System (NFIRS)that is maintained by the U.S. Fire Administration (USFA).
National fire data are published by the USFA and by the National Fire Protection
Association (NFPA), a private association. THE NFIRS database contains incident
reports from 49 states and over 11,000 fire agencies and includes about one-third of all
reported fires that occur annually in the United States.
The Eugene/Springfield Metro Area is bordered by a mix of agricultural land,
grasslands, brush and forests. Forest cover patterns for lands surrounding the
Eugene/Springfield Metro Area are shown in Maps 5E and 5S. As shown on these
maps, much of the southern hilly areas of both Eugene and Springfield have significant
forested areas which interface directly with built areas or are close to built areas.
Other areas, including northeast Springfield, also have large areas with high vegetative
fuel loads interfacing with or very close to developed or developing built areas. Given
the large acreage of forest lands in immediate proximity to both Eugene and
Springfield, portions of the Eugene/Springfield Metro Area may have significant risk
from wildland/urban interface fires.
Public Review Draft: August 6, 2004
9~1
Legend Forest Cover
~ 911 Corem Ce~ers ~ ~ Urbar~ Growth ~ou~dane~
',; ~' Hosp~[ais a~d Urgent Cam ¢~ '~ Metre Plan Bounda~
~ SchooJs R~vers and Streams o
~ Generalized Forest ~ver
0 ~bhc Water Tm~(men~'Storage
Public WO¢~
9.1 Fire Primer
For this section of the multi-hazard mitigation plan, the focus is on wildland/urban
interface fires. However, to provide a context for the discussion of wildland/urban
interface fires, we first briefly review the characteristics of all three types of fires.
Structure Fires
Structure fires are fires in urban, suburban or rural areas where structures (and
contents) are the primary fire fuel. Ever since the first volunteer fire department was
established in the United States in 1648, the primary focus of most fire departments
has been to reduce the risk of structure fires. Historically, structure fires have posed
the greatest threat to both property and life safety. In dealing with structure fires, fire
departments have three primary objectives: first, minimize casualties; second, prevent
a single structure fire from spreading to other structures; and third, minimize damage
to the structure and contents.
In recent decades, the rate of structure fires (number of fires per year per 1,000
structures) and the total number of structure fires have declined sharply even though
the number of structures has increased with increasing population. This decrease in
structure fires is attributed to a number of factors, most importantly better building
codes that have reduced both the numbers of ignitions and the likelihood that a small
fire will quickly spread. Building code improvements include better wiring, smoke
detectors, better design of furnaces, reduced use of portable heating devices, the
widespread use of fire resistant materials such as sheet rock and non-flammable roofs,
and more widespread use of automatic fire suppression systems (i.e., sprinklers).
In addition to the building code improvements, fire suppression capabilities have also
improved over the decades. Improved water systems provide greater and more
reliable water flows for fire suppression efforts. Better training, better communication
equipment, better fire fighting equipment and apparatus have also all contributed to
improved fire suppression capabilities. Widespread use of smoke detectors has also
reduced the number of casualties by providing occupants more warning time for
evacuation. In recent decades, a decline in the percentage of smokers in the United
States has also had a beneficial impact on the rate of accidental ignitions from
careless handling of smoking materials.
The decrease in the number of structure fires has been accompanied by a
corresponding decrease in the number of deaths from structure fires as shown below
in Table 9-1.
Public Review Draft: August 6, 2004
9-4
Table
Recent History of Fire Deaths in the United States
Year Fire Deaths~
U.S. Oregon
1980 5,809 50
1990 4,162 33
2000 4,045 42
2002 3,380 45
I Fire deaths are as estimated by the Nabonal F,re Protection Assoc~abon
(www nfpa org), with 2000 and 2002 Oregon data from Oregon Office of State Fire
Marshal.
Despite the dramatic reductions over the decades, structure fires still cause a great
deal of damage and many casualties. NFPA estimates for 2002, the most recent year
for which statistics are available, are that structure fires caused about 3,380 deaths
and $10 billion in property damage.
In addition to dealing with structure fires, urban, suburban and rural fire departments
also deal with other common types of fires including vehicle fires, trash fires, and small
debris or vegetation fires. For 2002, NFPA estimates for total fire department
responses to fires are as summarized below in Table 9-2.
Table
2002 NFPA Fire Statistics
Type of F~re Fire Agency
Responses
Structure Fires 519,000
Vehicle Fires 329,500
Fires Outside Structures 71,000
Rubbish Fires 204,000
Wildland Fires 399,000
All Other Fires 165,000
TOTAL 1,687,500
The complete NFPA fire statistics estimates are given in their report "Fire Loss in the
United States During 2002," that is downloadable from their website (www.nfpa.org).
Additional data are available at the USFA website (www.usfa.fema.gov). Oregon fire
data are discussed later in this chapter (see Section 9.3).
9.1.2 Wildland Fires
Wildland fires are fires where vegetation (grass, brush, or trees) is the primary fire fuel.
Wildland fires in Oregon typically occur in national or state forests and parks or in
Pubhc Review Draft: August 6, 2004
9-5
forest tracts of private land that may be owned by forest industries or by other private
owners. By definition, wildland fires generally involve few or no structures. Fires that
involve a mixture of vegetation and structures are considered wildland/urban interface
fires and are discussed below in Section 9.1.3.
Fire suppression strategy for wildland fires is significantly different than for structure
fires. For wildland fires, the most common suppression strategy is to contain the fire at
its boundaries, to stop the spread of the fire and then to let the fire burn itself out. Fire
containment typically relies heavily on natural or human-made fire breaks. Water and
chemical fire suppressants are used primarily to help make or defend a fire break,
rather than to put out an entire fire, as would be the case with a structure fire.
Fires that are purely wildland fires, without threatening structures, nevertheless cause
environmental and ecological damage. Wildland fires kill wildlife and damage habitat.
Areas that have burned are also subject to erosion and landslides due to loss of
ground cover. Such fires also may result in large fire suppression costs, with a
potential for casualties among firefighting personnel. Historically, fire suppression
strategy for wildland fires has generally been to try to minimize the acreage burned in
each wildland fire, by applying the maximum available fire suppression resources and
trying to contain each fire as quickly as possible.
In recent years, however, fire suppression strategy for wildland fires has evolved
substantially in two important aspects. First, to a greater extent than previously,
wildland fires are being recognized as part of the natural ecology and natural life cycles
of wildlands. Fires create open spaces with different habitats for both plants and
animals than existed previously. Second, the emphasis on maximum suppression of
wildland fires has resulted in many fires being smaller than would naturally occur.
Because of the reduction in frequent, smaller fires, many wildland areas have
developed extraordinarily high fuel loads. Thus, the potential for very large,
catastrophic wildland fires may actually be increased by the effective suppression of
smaller fires. In recent years, evolving strategies for dealing with wildland fires have
focused more attention on fuel management. Strategies include more controlled burns
and greater tolerance for allowing smaller fires to burn, with the objective of reducing
fuel loads of smaller vegetation and thus reducing the potential for target fires.
Wildfires may be started by natural causes, such as lightning strikes, or by human
activity. US Forest Service data indicate that about 13% of wildfires are started by
lightning, about 25% of wildfires are arson, while the rest are due to a variety of human
causes including debris burns, discarded smoking materials, sparks from vehicles,
sparks from power lines and so on.
Wildfire hazard depends on three main factors: vegetative fuel load, weather, and
topography.
There are several parameters that define the fire potential of vegetation. Vegetative
fuel loads are typically expressed as tons per acre. The greater the amount of fuel
loading the greater the amount of energy that will be released in a fire. Vegetative
fuels are also classified by burn index, which is a measure of the amount of energy per
pound of fuel. Fuels may also be classified by potential duration of burning. For
example, wildfires fueled by grass may spread very quickly, but grass contains
Public Review Draft: August 6, 2004
9-6
relatively little fuel energy and tends to burn out quickly. Wildfires fueled by larger
vegetation may spread more slowly, but larger vegetation contains more fuel energy
and tends to burn for a longer duration.
Moisture content of vegetative fuels is also a major determinant of wildland fire
potential. The lower the moisture content the greater the fire potential. Moisture
content at any given time depends on antecedent (before the given time) weather
conditions. The moisture content of larger fuels (e.g., trees) depends on previous
weather conditions over periods of several weeks or even months. The moisture
content of smaller fuels (brush) depends on previous weather conditions over several
days or a week or two. The moisture content of very small fuels (e.g., grasses )
depends ~argely on previous weather conditions over a few hours or a day or two.
The fire hazard posed by vegetative fuel loads also depends on fuel continuity, both
horizontally and vertically. Horizontal continuity, the distribution of fuels over the
landscape, strongly affects the spread and containment of wildfires in a given
geographic area. Vertical continuity of fuels, the linkage between fuels at ground level
and tree crowns, also affects the fire potential. Forests with strong ladder fuels
(understory growth between ground fuels and tree crowns) are more likely to have
major fires involving tree crowns. Forests with limited ground fuels and little or no
ladder fuels are much more likely to experience minor ground fires without a fire
involving tree crowns.
Weather also has a profound impact on wildland fire potential. Weather conditions of
high temperatures, Iow humidity, and high winds may greatly accelerate the spread of
a wildland fire and make containment difficult or impossible. Changes in weather
conditions can greatly accelerate a fire's spreading rate. Many casualties have
occurred when firefighting personnel were trapped by sudden bursts of fire spread in
response to changes in wind conditions. For many larger fires, containment is possible
only with a little help from mother nature via lower temperatures, reduced winds or
significant rainfall.
Local topography is also a major factor in the spread of wildfires. Fires burn much
more quickly up slope than they do down slope. Doubling a slope approximately
doubles the rate of fire spread. Canyons, gulches and other local topographic effect
can act as chimneys, intensifying fires in certain areas. Fires tend to slow at ridge tops
and thus ridge tops are often chosen as locations for fire breaks.
Suppression of wildland fires depends on the three main factors - vegetative fuel load,
weather, and topography - that, in combination, govern fire potential. High fuel loads,
hot, dry, windy weather and steep slopes increase fire potential and make fire
suppression much more difficult. Conversely, Iow fuel loads, cool, moist weather with
Iow winds, and gentle slopes make fire suppression easier.
In addition, however, fire suppression also depends on two other important factors:
availability of fire suppression resources and access. Fire suppression resources
include firefighting personnel, equipment and apparatus, as well as water and chemical
fire suppressants. The greater the availability of fire suppression resources, the more
likely it is that a given fire will be contained quickly. Fire suppression also depends on
access. Fires in remote areas without ground access via roads are more difficult to
Public Review Draft: August 6, 2004
9-7
fight and thus harder to contain than are fires with better access for fire suppression
crews and apparatus.
in the 1930s, wildfires consumed an average of 40 to 50 million acres per year in the
contiguous United States, according to US Forest Service estimates (US Forest
Service, Managing the impact of Wildfires on Communities and the Environment,
September 8, 2000). By the 1970s, the average acreage burned had been reduced to
about 5 million acres per year. Over this time period, fire suppression efforts were
dramatically increased and firefighting tactics and equipment became more
sophisticated and effective. For the 11 Western states, the average acreage burned
per year since 1970 remained relatively constant at about 3.5 million acres per year.
However, because of this pattern of more effective suppression of wildland fires, the
patterns and characteristics of wiidland fires are changing. Vegetation species that
would have normally been minimized by frequent fires became more dominants Over
time, many species have become susceptible to disease and insects, leading to an
increase in dead and dying trees. The resulting accumulation of debris has created
the types of fuels than promote intense, rapidly spreading fires, in many areas
introduction of nonmative species has also added to the fuel load. Decades old
patterns of ~ogging and fire suppression have also changed the characteristics of
forests. Older forests were typically ~ess dense, with smaller numbers of larger, more
fire-resistant trees. Newer forests are denser with larger numbers of smaller less fire-
resistant trees, in combination these effects over the last several decades have
resulted in many recent wildland fires that are hotter, faster, and larger than those
experienced in the past.
9,1.3 Wildland/Urban interface Fires
Wild,and/urban interface fires are fires where the fuel load consists of both vegetation
and structures. In Oregon, as elsewhere in the United States, recent patterns of
development have led to increasing numbers of homes being built in areas subject to
wildland fires. Development in these areas may pose high levels of life safety risk for
occupants as well as high levels of fire risk for homes and other structures.
Urban or suburban areas may have a significant amount of landscaping and other
vegetation. However, in such areas the fue~ load of flammable vegetation is not
continuous, but rather is broken by paved areas, open space and areas of mowed,
often irrigated, grassy areas with Iow fuel loads. In these areas, the vast
preponderance of all significant fires are single structure fires. The combination of
separations between buildings, various types of fire breaks, and generally Iow total
vegetative fuel loads make the risk of fire spreading much lower than in wildland areas.
Furthermore, most developed areas in urban and suburban areas have water systems
with good capacities to provide water for fire suppression and organized fire
departments who typically respond quickly to fires, with sufficient personnel and
apparatus to control fires effectively. Thus, in such areas the risk of a single structure
fire spreading to involve multiple structures is generally quite Iow.
Areas subject to wildland/urban interface fires have very different fire hazard
characteristics. The defining characteristic of the wildland/urban interface area is that
structures are built in areas with essentially continuous (and often high) vegetative fuel
Public Review Draft: August 6, 2004
9-8
loads. In other words, structures are built in areas subject to wildland fires. When
wildland fires occur in such areas, they tend to spread quickly and structures in these
areas may, unfortunately, become little more than additional fuel sources for wildland
fires.
The fire risk to structures and occupants in wildland/urban interface areas is high not
only because of the high vegetative fuel loads but also because fire suppression
resources are typically much lower than in urban or suburban areas. Homes in
wildland/urban interface areas are most commonly on wells rather than on municipal
water supplies. Thus, the availability of water for fire suppression is often severely
limited. Less availability of water resources makes it more likely that a small wildland
fire or a single structure fire in an urban/wildland interface area will spread before it can
be extinguished.
Furthermore, because many developments in interface areas have relatively low
populations and are some distance from population centers, the availability of
firefighting personnel and apparatus is generally lower than in more populated areas
and response times are typically much longer. The longer typical response times arise
in part because of 9rearer travel distances and, thus, greater travel times, but also
because most fire departments in lower population density areas are entirely or largely
composed of volunteer staff. Response times from volunteer staff fire departments are
typically longer than response times for career staff departments, where fire stations
are commonly staffed continuously. In some cases, narrow winding roads also impede
access by fire fighting apparatus. As with water supplies, the lower availability of fire
fighting personnel and apparatus and the longer response times increase the
probability that a small wildland fire or a single structure fire in an urban/wildland
interface area will spread before it can be extinguished.
Developments in urban/wildland interface areas often face high fire risk because of the
combination of high fire hazard (high vegetative fuel loads) and limited fire suppression
capabilities. Unfortunately, occupants in many wildland/urban interface areas also face
high life safety risk. High life safety risk arises because of the high fire risk, especially
from large fires that may spread quickly and block evacuation. Life safety risk in
interface areas is often exacerbated by limited numbers of roads (in the worst case
only one access road) that are often narrow and winding and subject to blockage by a
wildland fire.
Life safety risk in interface areas is also often exacerbated by homeowners' reluctance
to evacuate homes quickly. Instead, homeowners often try to protect their homes with
whatever fire suppression resources are available. Such efforts generally have very
little effectiveness. For example, the water flow from a garden hose is far too small to
control even a single structure fire (once the structure is significantly engulfed by
flames) and is profoundly too small to have any impact on a wildland fire.
Unfortunately, home owners who delay evacuation in well meant but misguided
attempts to save their homes often place their lives in grave jeopardy by delaying
evacuation until it may be impossible.
Major fires in the urban/wildland interface have the potential for enormous destruction
and very high casualties. For example, the October 20, 1991 East Bay Fire in Oakland
California burned 1,600 acres with 25 fatalities, 150 injuries, and over 3300 single-
Public Review Draft: August 6, 2004
9~9
family homes and 450 apartment units destroyed. Total damages were over $1.5
billion. This fire was fueled by very high vegetative fuel loads and occurred on an
unusually hot, dry, windy day. The fire spread extremely quickly, with over 800 homes
engulfed by fire within the first hour, and completely overwhelmed initial fire
suppression efforts.
In October 1991, rural counties near Spokane Washington experienced 92 separate
fires that burned about 35,000 acres and 114 homes. Between October 25 and
November 3, 1993, 21 major wildland fires broke out in California. These fires burned
over 189,000 acres and destroyed over 1,100 structures with 3 fatalities and hundreds
of injuries. The worst wildland/urban interface fire in United States history as far as
casualties are concerned occurred in 1871 in Peshti9o, Wisconsin. This fire burned
over 1.2 million acres and killed over 1,200 people. In 2003, a series of wildland/urban
interface fires in southern California burned over 750,000 acres and destroyed over
3,000 homes. These few examples dramatically illustrate the potential for disasters in
the urban/wildland interface area.
9.2 Measures of the Level of Fire Hazard
There are several quantitative and semi-quantitative measures of the level of fire
hazard. Most of these measures have been developed by the United States Forest
Service in cooperation with other fire agencies. National maps of these fire hazard
measures (Wildland Fire Assessment System) are available at the Forest Service
website (www.fs.fed.us/land/wfas). These maps are updated very frequently, in some
cases daily. All of the Forest Service Fire Danger maps and related technical maps
are viewable at the website by going to the INDEX category, then to Fire, Wildland Fire
Assessment System.
The spatial resolution of the web-published maps is relatively Iow. For example, the
Oregon data are based on about 90 reporting stations scattered across the state.
Thus, these maps are intended to show regional differences in the level of fire hazard,
rather than detailed local differences. However, as a regional guide to fire hazard
levels, these maps are enormously useful and readily accessible.
The most useful major fire danger measures are briefly reviewed below. For
reference, we note that the Forest Service website also has an extensive glossary of
fire-related terms, which may be helpful for those unfamiliar with fire terminology and
nomenclature.
Observed Fire Danger Class Maps
Fire danger class is a five level fire danger classification scheme that is based largely
on moisture content in fuels and weather conditions (temperature, humidity, wind).
Daily nationwide maps are viewable and printable from the Forest Service website
(www.fs.fed.us/land/wfas). This fire danger classification is widely used for purposes
such as restricting campfires and outdoor burning and is widely reported in the media.
The formal definitions of the five levels of danger are given below.
Public Review Draft: August 6, 2004
9-10
LOW (dark green). Fuels do not ignite readily from small firebrands, although
a more intense heat source, such as lightning, may start many fires in duff or
punky wood. Fires in open cured grassland may burn freely a few hours after
rain, but woods fires spread slowly by creeping or smoldering, and burn in
irregular fingers. There is little danger of spotting.
MEDIUM (light green or blue). Fires can start from most accidental causes,
but with the exception of lightning fires in some areas, the number of starts is
generally Iow. Fires in open-cured grassland will burn briskly and spread
rapidly on windy days. Timber fires spread slowly to moderately fast. The
average fire is of moderate intensity, although heavy concentrations of fuel,
especially draped fuel, may burn hot. Short-distance spotting may occur, but is
not persistent. Fires are not likely to become serious, and control is relatively
easy.
HIGH (yellow), All fine dead fuels ignite readily and fires start easily from most
causes. Unattended brush and campfires are likely to escape. Fires spread
rapidly and short-distance spotting is common. High-intensity burning may
develop on slopes, or in concentrations of fine fuels. Fire may become serious
and their control difficult, unless they are attacked successfully while small.
VERY HIGH (orange). Fires start easily from all causes and, immediately after
ignition, spread rapidly and increase quickly in intensity. Spot fires are a
constant danger. Fires burning in light fuels may quickly develop high intensity
characteristics such as long-distance spotting and fire whirlwinds when they
burn into heavier fuels.
EXTREME (red). Fires under extreme conditions start quickly, spread furiously,
and burn intensely. All fires are potentially serious. Development into high-
intensity burning wilt usually be faster and occur from smaller fires than in the
very high danger class. Direct attack is rarely possible, and may be dangerous,
except immediately after ignition. Fires that develop headway in heavy slash or
in conifer stands may be unmanageable while the extreme burning condition
lasts. Under these conditions, the only effective and safe control action is on the
flanks until the weather changes or the fuel supply lessens.
Fire Potential Index Map
This experimental product portrays a more quantitative measure of fire danger than the
Fire Danger Classification map discussed above. This map is primarily of interest for
fire service professionals and fire researchers.
Other Maps
The Forest Service website also provides several other types of technical maps which
are intended for fire service professionals and fire researchers. These maps and all of
the more common maps summarized above can also be found at the FDR (Fire
Danger Rating) web page which can be accessed via the search button on the Forest
Service Home Page referenced above.
Public Review Draft: August 6, 2004
9-11
9,3 Historical Data for Wild,and Fires in Oregon
The Oregon Department of Forestry website (www.odf. state.or, us) has a table of the
most important historical fires in Oregon over the past 150 years. Of the 12 major
fires, the five largest fires ali occurred between 1848 and 1868. The two largest fires,
the 1868 Coos Bay fire and the 1849 Siletz fire consumed 988,000 and 800,000 acres
of wildland, respective~y. The next four largest fires occurred between 1933 and 1945,
with each fire consuming between 240,000 and 180,000 acres. The most recent fire
listed, the 1987 Silver Fire burned 97,000 acres. None of these major fires occurred in
Lane County. More recent major fires include the 2002 Biscuit Fire that burned nearly
500,000 total acres (with about 471,000 acres in Oregon and nearly 29,000 acres in
California) and the 2003 B&B Complex fire that burned 90,769 acres.
The Oregon Department of Forestry website (www.odf. state.or, us) has severa~
categories of wildland fire data listed, including: numbers of forest fires and numbers of
acres burned in Oregon forest ~ands for 1986 to 2003. However, these ODF data are
only for ODF-responsibility ~ands and do not include forest lands where primary fire
suppression responsibility is federal or local. These data, which wil~ presumably be
updated from time to time, provide one measure of wildland fire data for Oregon. For
ODF responsibility lands in Oregon as a whole, the 10-year average number of
wildland fires is 1,062. Since 1986, the largest number of acres burned in one year
was 99,060 in 2002, while the lowest number of acres burned in one year was 1,410 in
1997. For the entire state of Oregon, both the number of fires and the acres burned
are higher than these ODF data alone.
The United States Forest Service (Department of Agriculture), in cooperation with
several agencies from the Department of the Interior, has recently published a report
identifying wildland/urban interface communities within the vicinity of Federal lands that
are a high risk from wildfire (Federal Register, Volume 66, Number 3, pages 751-777,
January 4, 2001). For Oregon, these identified high-risk communities and areas did
not include the Eugene/Springfield Metro Area or any communities in Lane County.
The Oregon Department of Forestry website 0A~,vw.odf. state.or.us) has an excellent
map showing forest coverage and forest type throughout Oregon. Oregon Department
of Forestry data on forest ownership areas are shown below in Table 9-3 for Oregon.
Public Review Draft: August 6, 2004
9-12
Table 9.3
Forest Land Ownership in Oregon
Ownership Acres Percent of Total
Federal 15,968,000 57.51%
State 885,000 3.19%
Other Public Lands 123,000 0.44%
Tribal 414,000 1,49%
Forest Industry 5,870,000 21 14%
Other Private 4,506,000 16.23%
Total 27,766,000 100.00%
For Oregon as a whole, about 61% of the forest lands are public, 1.5% are tribal, with
the remainder being privately owned. Of the privately owned forest land, about 57% is
owned by the forest industry. Statewide, the Oregon Department of Forestw has
responsibility for about 15.8 million acres of forest land, or about 57% of the total
forests in Oregon. The overall forest ownership pattern for Lane County appears to be
roughly similar to the statewide pattern shown above.
9.4 UrbanNViidland ~nterface Fire Hazards for the Eugene/Springfield Metro Area
Much of the areas east and south of the Eugene/Springfield Metro Area are heavily
forested. As shown on Maps 5E and 5S above, developed areas impinge into forested
areas in significant portions of the Eugene/Springfield Metro Area, especially in the
south hil~s of both Eugene and Springfield and northeast of Springfield.
Overview and Background information
As discussed above in Section 9,1, wi~dland/urban interface fires are wiMiand fires in
areas where structures provide additional fuel ~oad. Thus, the fire hazard (i.e., the
probability and severity of fires) for wildland/urban interface fires may be similar to the
fire hazard for wildland fires. Wildland/urban interface areas have a higher incidence
of fire ignitions from human causes, but fires are also more likely to be extinguished
quickly because of quicker discovery, better access, and quicker response. Fire risk,
the threat to people and the bulk environment, depends on the level of fire hazard and~
on the extent of development in fire-prone areas.
The main primary factors governing the level of hazard for wiMland fires or
wildland/urban interface fires are: fuel load, weather, topography and the presence of
ignition sources. For the Eugene/Springfield Metro Area, the fue~ load in the nearby
forested areas is generally high and relatively continuous across large geographic
areas. Because of historical ~oggin9 activities, much of the forest is composed of
relatively young trees, with a high density of trees per acre. Such forests may pose a
higher fire hazard than do old growth forests with fewer, larger trees.
Public Review Draft: August 6, 2004
9-13
Topography contributes to fire hazard because fires spread much more quickly up
steep slopes. Weather is very important in governing the level of fire hazard. Rainfall
amounts and patterns contribute to the level of fuel load and also to moisture levels in
vegetation. During fires, temperature, humidity and wind speed are major factors
9oveming the rate of spread of wildland fires and thus major factors governing the
ease or difficulty with which a given fire is likely to be contained.
Typical annual rainfall amounts for the Eugene/Springfield Metro Area are moderately
high to high, with annual rainfal~ of about 46 inches. However, rainfall is not evenly
distributed through the year. Summer months are typically quite dry, with the highest
temperatures, lowest humidity, and highest fire danger. Fire hazards near the Eugene/
Springfield Metro Area would be highest during prolonged periods of drought,
especially after periods of normal to above normal rainfall, which would result in a
combination of high fuel loads and unusually dry conditions.
Historical Fire Data
The Oregon Department of Forestry (Jim Wolf) provided records for all wildland fires in
ODF responsibility lands in Lane County from 1970 to 2003. These records provide an
useful resource to evaluate both the historical frequency and severity of wildland fires
in Lane County For this 34-year pedod, the ODF records show a total of 2,566
wildland fires, or an average of about 75 per year. These ODF data are summarized
below in Table
in interpreting these data, it is important to keep in mind that these data are for ODF
responsibility areas only, and do not include fires in areas covered only by local fire
departments or areas where federal agencies have fire suppression responsibility.
Table 9.4
ODF Data for Wildland Fires (1970-2003)
Lane County
Genera~ Cause Fires Fires by Acres Burned Number
Arson 91 >1,000 1
Debris Burning 591 100 to 1,000 18
Equipment Use 357 10 to 100 76
Equipment Use (logging) 110 5 to 10 103
Juvemles 174 Tota~ 5 acres or more 198
L~ghtnlng 278
Misc 237
Railroad 136
Recreabomst 304
Smoking 287
Under Investigat~on 1
Total Fires 2,566
Fires Per Year 75
Acres Burned 11,267
Acres Burned Per Year 331
The ODF data show 2,566 fires over the 34-year time period, or an average of 75 fires
Public Review Draft: August 6, 2004
9-14
per year. The total acres burned are 11,267 or about 331 acres per year. Only 198 of
these 2,556 fires were reported as 5 acres or more, with only 19 fires of 100 acres or
more. The Largest fire reported consumed 1080 acres.
The most common fire causes include debris burning equipment use (general and
logging), recreationists, smoking, and lightning.
For reference, we also show summary ODF data for the most recent five year period
from 1999 to 2003 in Table 9.5 below.
Table 9.5
ODF Data for Wildland Fires (1999-2003)
Lane County
Total Fires 544
Fires Per Year 109
Acres Burned 3,272
Acres Burned Per Year 654
In this most recent five-year period, there has been an average of 109 fires per year.
The average acres burned per year has been 654. The number of fires and acres
burned per year are higher than the 34 year average which may be a result of drier
than normal conditions over the past several years, with a correspondingly higher fire
risk for Lane County.
For the full data period (1970 - 2003), only 198 of the 2,556 fires were reported as 5
acres or more, with only 19 fires of 100 acres or more. The largest fire reported
consumed 1,080 acres.
The Oregon State Fire Marshal's office compiles fire data for all local fire departments
in Oregon. The most recent annual report (2002) lists 3,422 fires in natural vegetation
(trees, brush, and grass). The report does not breakdown data by counties. However,
a rough estimate can be made based on population, because the vast majority of these
fires are human caused. On this basis, Lane County has about 9.4% Oregon's
population and thus may have roughly 9.4% of the reported vegetation fires responded
to by local fire departments or roughly 320 such fires in 2002.
Local fire departments also maintain data on vegetation fires. Data for the Eugene
Fire Department are shown below in Table 9.6.
Public Review Draft: August 6, 2004
9-15
Table 9~6
Eugene Fire Data
Brush, Grass, Wild,ands~ Outside of Structures2
Year Fires Damage Fires Damage
1997 119 $9,213 41 $10,868
1998 118 $6,363 64 $92,096
1999 138 $1,620 50 $41,375
2000 130 $1,764 47 $51,885
2001 109 $2,651 46 $18,575
2002 134 $3,277 72 $50,225
2003 141 $8,700 40 $43,730
Average 127 $4,798 51 $44,108
Excludes crops and timber.
Excludes vehicles, includes outside storage, crops and timber. The vast
majority of these fires are outside storage, rather than crops or timber.
Ideally, historical fire data should suffice to estimate the annual probably for fires in the
wildland/urban interface areas of Lane County. However, current data do not appear
adequate to make credible calculations because the data for local, state, and federal
responsibility areas are not commensurate and are not sortable by type of location
(wildland, interface, developed areas). Nevertheless, the data reviewed above provide
a general picture of the level of wildland/urban interface fire risk for Lane County
overall. For the Eugene/Springfieid Metro Area in particular, the Lane County data
provide a reasonable measure of long-term overall hazard level for wildland/urban
interface fires.
However, there are several reasons why the fire risk may be higher than suggested
above, especially in developing wildland/urban interface areas.
1) Large fires may occur' infrequently, but statistically they will occur. One large
fire could significantly change the statistics. In other words, 30 years of
historical data may be too short to capture large, infrequent wildland fire events.
A seismic analogy is the Cascadia Subduction Zone earthquake discussed in
Chapter 10. This event has not occurred in the past 30 years and probably has
not occurred since 1700. Nevertheless, large earthquakes have occurred in the
past and are likely in the future. Thus, a 30-year record does not completely
reflect the hazard from large earthquakes or large wildland fires.
2) The level of fire hazard depends profoundly on weather patterns. A several
year drought period would substantially increase the probability of large wildland
fires in Lane County. For smaller vegetation areas, with grass, brush and small
trees, a much shorter drought period of a few months or less would
substantially increase the fire hazard.
3) The level of fire hazard in wildland/urban interface areas, with the greatest
risk for life safety and property, is likely significantly higher than for wildland
areas as a whole. The probability of fires starting in interface areas is much
higher than in wildland areas because of the much higher population density in
Public Review Draft: August 6, 2004
9-16
interface areas. Most wildland or interface fires have human sources of ignition
- arson, sparks from vehicles or electric lines, discarded smoking materials, or
trash or debris fires that 9et out control, and so on. Thus, the probability of a
given acre burning is higher in interface areas than for the wildland areas of
Lane County as a whole.
Developments in wildland/urban interface areas face a range of levels of fire risk,
depending on a number of factors. Developments that have all of most of the following
attributes are at the highest level of risk:
1 ) High vegetative fuel loads, with a high degree on continuity of fuel load
few significant firebreaks). Risk may be particularly high if the fuel load is
grass, brush and smaller trees, subject to being at very low moisture levels in
short duration drought periods.
2) Higher slopes, which cause fires to spread more rapidly than in flatter terrain.
3) Limited fire suppression capacity, including limited water supply capacity for
fire suppression purposes, limited fire fighting personnel and apparatus, and
typically long response times for fire alarms.
4) Limited access for fire fighting apparatus and limited evacuation routes for
residents at risk.
5) Construction of structures to less than fully fire-safe practices, and
6) Lack of maintenance of firebreaks and defensible zones around structures.
Overall, for central Lane County, including the Eugene/Springfield Metro Area, the
threat of wildland fire and/or wildland/urban interface fires appears moderate, in large
part because of the typically high levels of rainfall. However, depending on specific
conditions in developments in wildland/urban interface areas, the threat may be
moderate to high, especially during periods of drought. The specific level of risk for
each development depends on the particular risk factors as summarized above. A
comprehensive evaluation of the level of risk for developments in wildland/urban
interface areas requires a specific evaluation of the risk attributes listed above for each
development area.
A review of topography, forest cover and development patterns for the Eugene/
Springfield Area suggest that the following portions of the Eugene/Springfield Metro
Area likely have higher levels of risk for wildland/urban interface fires than the
Eugene/Springfield Metro Area as a whole:
1. the south hills areas of Eugene,
2. the south hills areas of Springfield, especially areas south of Main between
South 2nd Street and the quarry off South 28th Street and east of 58th Street, and
3. the northeastern portion of Springfield, including areas outside the
Eugene/Springfield Metro Area Plan boundary.
Public Review Draft: August 6, 2004
9-17
The potential impacts of wildlandturban interface fires on the Eugene/Springfield Metro
Area are summarized below in Table 9.7.
Table 9.7
Potential Impacts of Wildland/Urban Interface Fires on the Eugene/Springfield Metro Area
Inventory Probable Impacts
Portion of Eugene/Springfield Metro Highest risk areas are residential areas bordenng heawly
Area affected vegetated wddland areas as shown above on Maps 5E and 5S
and discussed ~n Section 9.4
Small wildland/urban interface fires could affect a few residential
Buildings buildings. Larger fires could effect entire neighborhoods and
extreme events (cf Oakland Hills 1991 fire) could affect hundreds
of buildings
M~nor road closures possible from fires; bm/ted impact because of
Streets within Metro Area
short detour routes within EugenelSpnngfield Metro Area
Potential closures of major highways due to fires, especially roads
Roads to/from Metro Area
into the Cascades and Coast Ranqe,
Potential for localized loss of electric power due to fires affecting
Electric power
power lines m or near Eugene/Spnngfleld Metro Area
Generally minor or no ~mpacts on other utiht~es from fires, except
Other Utilities for possible loss of telephone service due to fires affecting phone
poles/lines
Casualties Potential for deaths and injuries in major wddland/urban interface
fires, especially if evacuations are not completed expeditiously
Public Review Draft: August 6, 2004
9-18
9.5 Mitigation Strategies
This section outlines suggested strategies for reducing the leve~ of risk to both property
and life safety in wildland/urban interface development areas that may be at high risk
from wildland/urban interface fires. The suggested mitigation strategy has four
elements:
1) reduce the probability of fire ignitions,
2) reduce the probability that small fires will spread,
3) minimize the life safety risk, and
4) minimize property damage.
Reduce the probability of fire ignitions
Efforts to reduce the probability of fire ignitions should focus on human causes of
ignition through a combination of fire prevention education, enforcement, and other
actions. Fire prevention education actions could include efforts to heighten public
awareness of fire dangers, especially during high danger time periods and better
education about fire safe practices, such as careful disposal of smoking materials, and
adhering to restrictions on burning of rubbish and debris. Fire prevention enforcement
action could include strict enforcement of burning restrictions and vigorous
investigation and prosecution of arson cases. An important physical action to reduce
the probability of ignitions is to maintain or upgrade tree-trimming operations around
power lines to minimize fires starting by sparking from lines to vegetative fuels.
Reduce the probability that small fires will spread.
Possible mitigation actions to reduce the probability that small fires will spread include
enhancement of water supply and fire suppression capabilities for high risk areas,
expansion of existing firebreaks, creation of new firebreaks and expanding defensible
spaces around structures in wildland/urban interface areas.
IVljinimize Life Safety Risk
The mitigation actions above may help to minimize life safety risk by helping to reduce
the number of ignitions, by reducing the probability that smal~ fires will spread, and by
encouraging more fire-safe practices of building construction and fire-safe
landscaping. These practices are meritorious for reducing the fire hazards to
structures. However, they may also give homeowners a false sense of ~ife safety
security. A false sense of security may encourage people to stay in homes at risk
during wildfires, rather than evacuating immediately at the first fire warning.
The most important action to minimize life safety risk during wildland/urban interface
fires is immediate evacuation, when indicated as necessary by the responsible fire
agencies. Thus, reducing life safety risk requires public education and emergency
planning to encourage and expedite warnings and evacuations. Evacuation notices
need to be carefully communicated and evacuation recommended only when
necessary. Otherwise, mass evacuations of residents fleeing the area of a minor or
controllable fire could potentially delay firefighters from gaining access to the fire and
controlling it.
Public Review Draft: August 6, 2004
9-19
Life safety risk during wildland/urban interface fires is exacerbated by limited
evacuation routes. Improving evacuation roads (widening, straightening) and, most
importantly, providing as many alternate evacuation routes as possible can significantly
reduce evacuation times and lower the probability that residents seeking to evacuate
may be trapped by fire-blocked routes.
Minimize Prope~y Damage
The education and action items discussed above may help to reduce future property
damages by reducing the number of fire ignitions and by reducing the probability that a
small fire will spread. In addition, specific fire safe building practices should be
implemented (if not yet implemented) and enforced vigorously (if not yet vigorously
enforced). Fire safe building practices have two main elements: first, design of
structures, and second, creation of defensible spaces around structures.
There is an excellent "Firewise" communities program with a highly informative
website (www.firewise.org). Firewise is the product of a consortium of public and
private agencies, including the US Forest Service, the Department of the Interior, the
US Fire Administration, the National Association of State Foresters, and the Nationa~
Fire Protection Association. The Firewise website has very informative publications
and videos for ~ocal officials and homeowners to help understand, evaluate, and
improve the fire safety of structures at risk from wildland/urban interface fires. The
Firewise construction and Firewise landscaping checklists are particularly
recommended as concise summaries of the primary fire-safe designs and practices for
homeowners at risk from wildland/urban interface fires.
The Firewise Construction Checklist, makes the following main recommendations
(among others):
1 ) site homes on as level terrain as possible, at least 30 feet back from cliffs or
ridge lines,
2) build homes with fire-resistant roofing materials, such as Class-A asphalt
shingles, slate or clay tiles, concrete or cement products, or metal
3) build homes with fire-resistant exterior wall cladding, such as masonry or
stucco,
4) consider the size and materials for windows; smaller panes hold up better
than larger ones, double pane and tempered glass windows are more fire
resistant than single pane windows; p~astic skylights can melt and a~low access
for burning embers,
5) prevent sparks and embers from entering vents by covering vents with wire
mesh no larger than 1/8", box eaves, and minimize places to trap embers on
decks and other attached structures, and
6) keep roofs, eaves, and gutters free of flammable debris.
The Firewise Landscaping Checklist includes the following main recommendations
(among others), based on a four-zone planning concept around the house:
Public Review Draft: August 6, 2004
9-20
1) Zone I should be a well irrigated area of closely mowed grass or non-
flammable landscaping materials such as decorative stone, at least 30' in all
directions around the home,
2) Zone 2 should be a further irrigated buffer zone with only a limited number of
Iow-growing, fire-resistant plants,
3) Zone 3, further from the house, can include Iow growing plants and well-
spaced, well-pruned trees, keeping the total vegetative fuel load as Iow as
possible, and
4) Zone 4 is the natural area around the above three landscaped zones. This
area should be thinned selectively, with removal of highly flammable vegetation
and removal of ladder fuels that can spread a grass fire upwards into tree tops.
The following table contains wildland urban interface fire mitigation action items from
the master Action Item table in Chapter 4.
Public Review Draft: August 6, 2004
9-21
x × x Public Awareness
x x Life Safety
× Protect Property
Minimize Losses
Partnerships &
Implementation
x x Emergency
Services
Protect
Environment
10.0 EARTHQUAKES
Historically, awareness of seismic risk in Oregon has generally been Iow, among both
the public at large and public officials. This iow level of awareness reflected the Iow
level of seismic activity in Oregon, at least in recent historical time. However, over the
past several years, awareness of seismic risk in Oregon has significantly increased.
Factors in this increased awareness include the 1993 Scotts Mills earthquake in
Clackamas County, widespread publicity about possible large magnitude earthquakes
on the Cascadia Subduction Zone, and recent changes in Seismic Zonation in the
Oregon Building Code which increased seismic design levels for new construction in
western Oregon.
Before reviewing the levels of seismic hazard and seismic risk in Lane County and the
Eugene/Springfield Metro Area, we first present a brief earthquake "prime¢' that
reviews some basic earthquake concepts and terms.
10,1 Earthquake Primer
In the popular press, earthquakes are most often described by their Richter Magnitude
(M). Richter Magnitude is a measure of the total energy released by an earthquake. In
addition to Richter magnitude, there are several other measures of earthquake
magnitude used by seismologists, but such technical details are beyond the scope of
this discussion. The Scotts Mills (Oregon) earthquake was M = 5.6, while the
Northridge (California) earthquake was about M = 6.7. Great earthquakes, for
example, on the San Andreas Fault or on the Cascadia Subduction Zone, may have
magnitudes of 8 or greater.
It is important to recognize that the Richter scale is not linear, but rather logarithmic. A
M8 earthquake is not twice as powerful as a M4, but rather thousands of times more
powerful. A M7 earthquake releases about 30 times more energy than a M6, while a
M8 releases about 30 times more energy than a M7 and so on. Thus, great M8
earthquakes may release thousands of times as much energy as do moderate
earthquakes in the M5 or M6 range.
The public often assumes that the larger the magnitude of an earthquake the "worse"
the earthquake. Thus, the "big one" is the M8 earthquake and smaller earthquakes
(M6 or M7) are not the "big one". However, this is true only in very general terms.
Larger magnitude earthquakes affect larger geographic areas, with much more
widespread damage than smaller magnitude earthquakes. However, for a given site,
the magnitude of an earthquake is NOT a good measure of the severity of the
earthquake at that site. Rather, the intensity of ground shaking at the site depends on
the magnitude of the earthquake and on the distance from the site to the earthquake.
An earthquake is located by its epicenter - the location on the earth's surface directly
above the point of origin of the earthquake. Earthquake ground shaking diminishes
(attenuates) with distance from the epicenter. Thus, any given earthquake will produce
the strongest ground motions near the earthquake with the intensity of ground motions
diminishing with increasing distance from the epicenter.
Public Review Draft: August 4, 2004
10~1
Thus, for a given site, a smaller earthquake (such as a M6.5) which is very close to the
site could cause greater damage than a much larger earthquake (such as a M8) which
is quite far away from the particular site.
However, earthquakes at or below M5 are not likely to cause significant damage, even
locally very near the epicenter. Earthquakes between about M5 and M6 are ~ikely to
cause some damage very near the epicenter, with the extent of damage typically being
relatively minor (e.g., the 1993 Scotts Mills earthquake). Earthquakes of about M6.5 or
greater can cause major damage (e.g., the Northddge earthquake), with damage
usually concentrated fairly near the epicenter. Larger earthquakes of M7+ cause
damage over increasingly wider geographic areas with the potential for very high levels
of damage near the epicenter. Great earthquakes with MS+ can cause major damage
over wide geographic areas. For example, a M8+ on the Cascadia Subduction Zone
could affect the entire Pacific Northwest from British Columbia, through Washington
and Oregon, and as far south as Northern California.
The intensity of ground shaking varies not only as a function of M and distance but also
depends on soil types. Soft soils may amplify ground motions and increase the level of
damage. Thus, for any given earthquake there will be contours of varying intensity of
ground shaking. The intensity will generally decrease with distance from the
earthquake, but often in an irregular pattern, reflecting soil conditions (amplification)
and possible directionality in the dispersion of earthquake energy.
There are many measures of the severity or intensity of earthquake ground motions. A
very old, but commonly used, scale is the Modified Mercalli Intensity sca~e (MMI),
which is a descriptive, qualitative scale that relates severity of ground motions to types
of damage experienced. MMls range from I to XlI.
More useful, modern intensity scales use terms that can be physically measured with
seismometers, such as the acceleration, velocity, or displacement (movement) of the
ground. The most common physical measure, and the one used in the Mitigation Plan
and in the Technical Appendix, is Peak Ground Acceleration or PGA. PGA is a
measure of the intensity of shaking, relative to the acceleration of gravity (g). For
example, 1.0 g PGA in an earthquake (an extremely strong ground motion) means that
objects accelerate sideways at the same rate as if they had been dropped from the
ceiling. 10% g PGA means that the ground acceleration is 10% that of gravity and so
on.
Damage levels experienced in an earthquake vary with the intensity of ground shaking
and with the seismic capacity of structures. Ground motions of only 1 or 2% g are
widely felt by people; hanging plants and lamps swing strongly, but damage levels, if
any, are usually very Iow. Ground motions below about 10% g usually cause only
slight damage. Ground motions between about 10% g and 30% g may cause minor to
moderate damage in well-designed buildings, with higher levels of damage in poorly
designed buildings. At this level of ground shaking, only unusually poor buildings
would be subject to potential collapse. Ground motions above about 30% g may cause
significant damage in well-designed buildings and very high levels of damage
(including collapse) in poorly designed buildings. Ground motions above about 50% g
may cause high levels of damage in most buildings, even those designed to resist
seismic forces.
Public Review Draft: August 4, 2004
10-2
10.2 Seismic Hazards for Lane County and the Eugene/SpringfieM [~etro Area
Earthquakes in Western Oregon, and throughout the world, occur predominantly
because of plate tectonics - the relative movement of plates of oceanic and continental
rocks that make up the rocky surface of the earth. Earthquakes can also occur
because of volcanic activity and due to other geologic processes. The earthquake
hazard for the three counties addressed in the regional multi-hazard mitigation plan for
Benton, Lane and Linn Counties is reviewed in detail in Chapter 3 of the Regional Al~
Hazard Mitigation P~an, Phase Two Technical Appendix, Benton, Lane and Linn
Counties Oregon, Seismic Loss Potential (2001). The main findings of that chapter are
briefly summarized here.
The Cascadia Subduction Zone is a geologically complex area off the Pacific
Northwest coast from Northern California to British Columbia. In simple terms, several
pieces of oceanic crust (the Juan de Fuca Plate, Gorda Plate and other smaller pieces)
are being subducted (pushed under) the crust of North America. This subduction
process is responsible for most of the earthquakes in the Pacific Northwest as well as
for creating the volcanoes in the Cascades. Figure 10-1 (from the Regional All Hazard
Mitigation Plan, Phase Two Technical Appendix) shows the geologic (plate~tectonic)
setting for Oregon.
There are three source regions for earthquakes that can affect the Eugene/Springfield
Metro Area:
1) ~lnterface" earthquakes on the boundary between the subducting oceanic
plates and the North American plate,
2) "intraslab" or "intraplate' earthquakes within the subducting oceanic plates,
and
3) "crustal" earthquakes within the North American Plate.
The geographic and geometric relationships of these earthquake source zones are
shown in Figure 10-2 (from the Phase Two Technical Appendix). A full discussion of
current understanding of these subduction zone and crustal earthquakes is given in
Chapter 3 of the Phase Two Technical Appendix.
The "interface" earthquakes on the Cascadia Subduction Zone may have magnitudes
of 8 or greater, with probable recurrence intervals of 500 to 800 years. The last major
earthquake in this source region probably occurred in the year 1700, based on current
interpretations of Japanese tsunami records. Such earthquakes are the great
Cascadia Subduction Zone eadhquake events that have received attention in the
popular press. These earthquakes occur about 20 to 60 kilometers (12 to 40 miles)
offshore from the Pacific Ocean coastline. Ground shaking from such earthquakes
would be very strong near the coast and moderately strong ground shaking would be
felt throughout Lane County, with the level of shaking decreasing towards eastern
Lane County.
Public Review Draft: August 4, 2004
10-3
~ J~ DE FUCA ~ '2 . ~
, PLATE ~ - 0
'
PAC~F~ P~T~ ::: CAL~F ORN~A
0 200 ,. -
Figure 10-1. Cascadia Subduction Zone
Public Review Draft: August 4, 2004
1
Ben,on Linn, Eastern Lane
Western Lane
Coast
L~na Co~staf Eugene Cas=~des
LONGITUDE
DISTANCE
10 30. 50 ?0 90 11 o. 130 150 1~0 190 21 o. 230 250 270, 290.
50. Locked Zon~
-- / ~-~ Crusta~ ~ 50.
130. _ 'xx N, _ 130
LONGITUDE
Figure 10-2. Cross Section of Seismicity Centered
on Latitude 45.5 with Inferred Location of
Subduction Portion of ,Juan de Fuca Plate
Public Review Draft: August 4, 2004
10-5
The 'intraslab" earthquakes, which are also called "intraplate" earthquakes, occur
within the subducting oceanic plate. These earthquakes may have magnitudes up to
about 7.5, with probable recurrence intervals of about 500 to 1000 years (recurrence
intervals are poorly determined by current geologic data). These earthquakes occur
quite deep in the earth, about 30 or 40 kilometers (18 to 25 miles) below the surface
with epicenters that would likely range from near the Pacific Ocean coast to about 50
kilometers (30 miles) inland. Thus, epicenters from these types of earthquakes could
be located in Lincoln County or western Lane County or possibly in western Benton
County. Ground shaking from such earthquakes would be very strong near the
epicenter and moderately strong ground shaking would be felt throughout all of Lane
County, with the level of shaking decreasing towards eastern Lane County.
"Crustal" earthquakes within the North American plate are possible on faults mapped
as active or potentially active as well as on unmapped (unknown) faults. Historically
observed crustal earthquakes in Northern Oregon from 1841 to 1986 are shown in
Figure 3-3 from the Regional Mitigation Plan Phase Two Technical Appendix. During
this time period, several dozen, mostly small, earthquakes have occurred in Lane
County.
Section 3.3 of the Phase Two Technical Appendix discusses the current geologic
knowledge about crustal faults in the three county area. Several faults have been
mapped in the area, especially in Benton and Lane Counties. In the Willamette Valley,
the geological processes of erosion and deposition have obliterated most of the
possible evidence for past surface fault ruptures. In the three county area, the mapped
faults are generally considered to be inactive, with no evidence for activity within the
past 11,000 years.
Based on the historical seismicity in Western Oregon and on analogies to other
geologically similar areas, small to moderate earthquakes up to M5 or M5.5 are
possible almost anyplace in Western Oregon, including almost anyplace in Lane
County. Such earthquakes would be mostly much smaller than the Scotts Mills
earthquake up to about the magnitude of that 1993 earthquake. The possibility of
larger crustal earthquakes in the M6+ range cannot be ruled out. However, in the
absence of known, mapped faults, the probability of such events is likely to be very
Iow.
Because the probability of large crustal earthquakes (M6 or greater) affecting Lane
County is so low and because any damage in smaller crustal earthquakes is likely to
be minor and very localized, crustal earthquakes are not considered significant for
hazard mitigation planning purposes. Therefore, our analysis focuses on the larger,
much more damaging earthquakes arising from the Cascadia Subduction Zone.
Public Review Draft: August 4, 2004
10-6
Legend Relative Amplification
, 9,,Comm. Ce~,e,, .~..::¢'J~a,¢~*Bo,nda,,e, Hazard Zones in Eugene
~ ~', Hosp~als a~ U~em Cam ~ ~-~ Metro Plan ~u~a~
~ ~oois Rivers and Streams 9 ~ 2 M~i~
~ Pubhc W~er T~ment/Storage Zone 2 - Moderate H~
~ Mun~opal Wastewater Fac~l~tg Zone 1 - [ ow H~am AN ~
Amplffl~t,op
~ Monroe ~-- ~
~'~Y q-~ Lane
~ 8.o+ t
~0 5 0 10 20 30 40 ~ Mdes /
60+ I0 5 0 10 20 ~ 40 ~ ~ ~domefers
Figure 10-3. Central Oregon Seismicity, 1841-1986
Public Review Draft: August 4, 2004
10-7
The characteristics of the subduction zone earthquakes affecting Lane County are
summarized in Table 10.4 below. The maximum magnitudes are estimated from the
~ength and width of the mapped fault plane or from similar earthquakes elsewhere in
the Pacific Northwest (for the intraslab earthquakes). Recurrence intervals are based
on current best estimates.
Table 10.4
Seismic Sources Affecting Lane County
Fau~t Maximum Probable Recurrence
Magnitude Interval (years)
Cascadla Subducbon Zone 8,5 500 to 800
(interface earthquake)
Cascadla Subduction Zone 7.5 500 to 1000
(intraslab earthquake)
Chapter 4 of the Regional Mitigation Plan Phase Two Technical Appendix analyses
these two scenario earthquakes affecting the three counties: a Cascadia Subduction
Zone interface earthquake (M8.5) and a Cascadia Subduction Zone intrasiab
earthquake (M7.5)~ For each of these earthquakes, appropriate attenuation
relationships are used to calculate the levels of ground shaking (peak ground
acceleration, PGA) with distance from the earthquake.
10.3 Other Aspects of Seismic Hazards in Lane County
Most of the damage in earthquakes occurs directly because of ground shaking which
affects buildings and infrastructure. However, there are several other aspects of
earthquakes that can result in very high levels of damage in localized sites:
liquefaction, landslides, dam failures and tsunamis.
10,3.1 Soil Effects
Liquefaction is a process where loose, wet sediments lose strength during an
earthquake and behave similarly to a liquid. Once a soil ~iquefies, it will tend to settle
and/or spread laterally. With even very slight slopes, liquefied soils tend to move
sideways downhill (lateral spreading). Settling or lateral spreading can cause major
damage to buildings and to buried infrastructure such as pipes and cables.
Figure 3-6 in the Regional Mitigation Plan Phase Two Technical Appendix shows the
areas in the three counties where liquefaction potential is high. These areas of high
liquefaction potential largely follow the main river and stream drainage channels in the
three county area; these are the areas with loose, wet sediments. Liquefaction does
not occur in all such areas or in all earthquakes. However, in ~arger earthquakes with
strong ground shaking and long duration shaking, liquefaction is likely in many of these
high liquefaction potential areas. Settlements of a few inches or more and lateral
spreads of a few inches to several feet are possible. Even a few inches of settlement
10-8
or lateral spreading is likely to cause significant to major damage to affected buildings
or infrastructure.
For the Eugene/Springfield Metro Area, a DOGAMI study of areas with soil types prone
to amplification of seismic ground motions found scattered pockets of moderate hazard
soils scattered throughout the Eugene/Springfield Metro Area. In total, these areas
cover perhaps 10% of the total area ((DOGAMI, Relative Earthquake Hazard Map of
the Eugene-Springfield Metropolitan Area, Lane County, Oregon IMS-14, 2000).
These DOGAMI maps of Relative Amplification Hazard Zones are shown below as
Maps 6E and 6S, for Eugene and Springfield, respectively.
There are significant portions of both Eugene and Springfield identified on Maps 6E
and 6S as moderate amplification hazard. One area of high hazard was identified in
the southwestern part of Eugene, in the vicinity of West 11th Avenue and Green Hill
Road. Some of these moderate and high hazard areas for amplification may also be
subject to liquefaction, settlement, and lateral spreading. However, specific areas
potentially subject to these hazards have not yet been mapped.
t0,3.2 Landslides
Earthquakes can also induce landslides, especially if an earthquake occurs during the
rainy season and soils are saturated with water. The areas prone to earthquake-
induced landslides are largely the same as those areas prone to landslides in general.
As with all landslides, areas of steep slopes with loose rock or soils are most prone to
earthquake-induced landslides.
Maps 4E and 4S (Chapter 8~ shows areas of the Eugene/Springfield Metro Area
subject to earthquake-induced (and other) landslides, To date, relatively limited
development has occurred in these high landslide potential areas although a few
homes and streets/roads are located in these areas. See Chapter 8 for further
discussion of landslide hazards,
Dam Failures
Earthquakes can also cause dam failures in several ways. The most common mode of
earthquake-induced dam failure is slumping or settlement of earthfill dams where the
fill has not been properly compacted. If the slumping occurs when the dam is full, then
overtopping of the dam, with rapid erosion leading to dam failure is possible. Dam
failure is also possible if strong ground motions heavily damage concrete dams. In a
few cases, earthquakeqnduced landslides into reservoirs have caused dam failures.
Earthquake-induced dam failures are addressed in more detail in Chapter 12 which
covers dam failures that could affect the Eugene/Springfield Metro Area.
10.3,4 Tsunamis and Seiches
Tsunamis, which are often incorrectly referred to as "tidal waves," result from
10-9
earthquakes which cause a sudden rise or fall of part of the ocean floor. Such
movements may produce tsunami waves, which have nothing to do with the ordinary
ocean tides. In the open ocean, far from land, in deep water, tsunami waves may be
only a few inches high and thus be virtually undetectable, except by specia~ monitoring
instruments. These waves travel across the ocean at speeds of several hundred mikes
per hour. When such waves reach shallow water near the coastline, they slow down
and can gain great heights.
Tsunamis affecting the Oregon coast can be produced from very distant earthquakes
off the coast of Alaska or elsewhere in the Pacific Ocean. For such tsunamis, the
warning time for the Oregon coast would be at least several hours. However, interface
earthquakes on the Cascadia Subduction Zone can also produce tsunamis. For such
earthquakes the warning times would be very short, only a few minutes. Because of
this extremely short warning time, emergency planning and public education are
essential before such an event occurs.
However, the Eugene/Springfield Metro Area, not being located on the coast, cannot
be affected by such tsunamis on the Oregon Coast.
Another earthquake related phenomenon is "seiches" which are waves from sloshing
of inland bodies of waters such as lakes, reservoirs, or rivers. In some cases, seiches
have caused damages to shorefront structures and to dams. However, for the
Eugene/Springfield Metro Area vicinity the potential for seiches of sufficient magnitude
to cause significant damage to upstream appears Iow.
10.4 Risk Assessment for Scenario Earthquakes
As part of the Regional All Hazard Mitigation Plan (Phase Two), a seismic risk
assessment for Benton, Lane and Linn Counties was conducted by estimating the
extent of damage and casualties likely in each of the two scenario earthquakes on the
Cascadia Subduction Zone discussed above: a M8.5 interface earthquake and a M7.5
intraplate earthquake. For Level One Loss modeling, earthquake ground motions were
calculated at the center of each census tract and these values were used for the entire
census tract. Further technical details of the loss estimation calculations are given in
Chapter 4 of the Regional Mitigation Plan Phase Two Technical Appendix.
The census data used for these loss estimates were from the 1990 census, as 2000
census results were not available at the time of this data compilation. Building
inventory and thus damages and casualties are generally proportional to population.
Thus, these 1990-based calculations can be adjusted to current population levels.
Lane County's population rose about 14% between 1990 and 2000 and thus, the 2000
equivalents for the damage and casualty estimates would also be about 14% higher
than the t990 values from the Regional Plan.
For each of these scenario earthquakes, building damage estimates for Lane County
are approximately $1.6 to $1.7 billion. Injuries were estimated to be about 2,600 to
2,700 for daytime earthquakes and about 700 for nighttime earthquakes. Deaths were
estimated to be about 45 for daytime earthquakes and about 4 for nighttime
earthquakes. Casualties are much lower for nighttime earthquakes, because most of
10-10
the population is in mostly wood-frame residential buildings, which typically have lower
casualty rates than many other types of structures. Summary results are shown below
in Tables 10-5 and 10-6.
10.4.1 M8.5 Cascadia Subduction Zone interface Earthquake
The estimated impacts of this earthquake on the building stock in Lane County and the
Eugene/Springfield Metro Area are summarized below in Table 10.5. Further details of
the loss estimates are given in the Regional Mitigation Plan (Chapter 4 of the Phase
Two Technical Appendix). Estimates for the Eugene/Springfield Metro Area are
approximate, based simply on pro-rata population vis-a-vis Lane County.
Table 1
M8.5 Cascadia Subduction Zone lntetrface Earthquake
Loss Estimate Lane County Eugene/Springfield
Metro Area
Building Damage $1,732,000,000 $1,039,200,000
Percent Damage~ 11 30% 11 30%
Daybme deaths4 48 30
Daybme ~njur~es 2,736 1,642
Nighttime deaths4 4 About 2
Nightbme ~njur~es 773 464
Heawly damaged 5,329 3,197
residential buildings2
Esbmated number 10,658
of people needing 6,395
emergency shelter3
~ Percent damage is relabve to building replacement value.
2 Heavily damaged buildings are those in the extensive or complete damage states.
3 Of the total displaced people, perhaps 1/3 will need public emergency shelter, with the
rest finding shelter with relabves, friends, or in commercial lodgings.
4 Fractional deaths are stabsbcal results. For example, 0 1 death means about 10%
chance of one death.
The direct loss estimates shown above are for the building
stock only. Including the direct damages to contents,
infrastructure and direct economic impacts from loss of
function, the total direct economic impacts of these scenario
earthquakes may be about double the estimates shown
above
In addition to building damages, utility systems are also likely to experience significant
damage. The Phase Two Regional Mitigation Plan had generalized comments about
the expected ~evels of damages. However, for an area as small as the Eugene/
10-11
Springfield Metro Area, estimating the specific levels of utility damages and outages
would require site-specific analyses.
10.4.2 M7.5 Cascadia Subduction Zone Intraplate Earthquake
The estimated impacts of this earthquake on the building stock in Lane County and the
Eugene/Springfield Metro Area are summarized below in Table 10.6. Further details of
the loss estimates are given in the Regional Mitigation Plan (Chapter 4 of the Phase
Two Technica~ Appendix. Estimates for the Eugene/Springfield Metro Area are
approximate, based simply on pro-rata population vis-a-vis Lane County,
Table 10.6
M7.5 Cascadia Subduction Zone Intrap~ate Earthquake
Loss Estimate Lane County Eugene/Springfield
iVletro Area
Bu,lding Damage $1,633,000,000 $980,000,000
Percenl Damage~ 11.65% 11.65%
Daytime deaths4 45 27
Daytime injuries 2,561 1,537
N~ghtbme deaths4 4 About 2
Nightbme injunes 712 427
Heavily damaged
residential buildings2 7,818 4.691
Esbmated number
of people needing 15,636 9,382
emergency shelter3
~ Percent damage is relabve to bulld~ng replacement value.
2 Heavily damaged build,rigs are those in the extensive or complete damage states.
3 Of the total displaced people, perhaps 1/3 will need public emergency shelter, with the
rest finding shelter w~th relatives, friends, or ~n commercial lodgings.
4 Fracbonal deaths are stabstical results. For example, 0.1 death means about 10%
chance of one death
The direct ~oss estimates shown above are for the buiMing
stock only. including the direct damages to contents,
infrastructure and direct economic impacts from loss of
function, the total direct economic impacts of these scenario
earthquakes may be about double the estimates shown
above
In addition to building damages, utility systems (electric power, water, wastewater,
natural gas) and transportation systems (bridges, pipelines) are also likely to
experience significant damage. The Phase Two Regional Mitigation Plan had
generalized comments about the expected levels of damages, However, for an area
10-12
as small as the Eugene/Springfield Metro Area, estimating the specific levels of
damages and outages would require site-specific analyses.
The potential impacts of major earthquakes on the Eugene/Springfield Metro Area are
summarized below in Table 10.7.
Table '10.7
Potential Impacts of Earthquakes on the Eugene/Springfield Metro Area
Inventory Probable Impacts
Portion of Eugene/Springfield Metro
Area affected Entire City and surrounding region
Many buddings w~ll have no damage or I~ght to moderate damage,
Buildings w~th heavy damage concentrated ~n vulnerable buddings (wood
frame buildings with cripple walls, unreinforced masonry, etc.).
Total building damage estimated to be about $1,000,000,000.
Streets within Metro Area Minor damage possible in areas of soft soils. Some bridges
have moderate to extensive damage.
Minor damage possible in areas of soft soils. Some bridges will
Roads to/from Metro Area
have moderate to extensive damage
Electric power Short outage of electric power is hkely, with duration ranging from
a few hours to 1 day.
Generally moderate damage to water, wastewater and natural gas
Other Utilities systems, ~nclud~ng p~pe breaks. Probable damage to water and
wastewater treatment plants.
Up to 30 deaths and about 1,600 injuries. Casualties wdl be
Casualties h~gher for daytime earthquake than mghtt~me earthquake,
because mostly wood frame residential buildings have lower I~fe
safety risk,
The above summary of potential impacts is for major earthquakes on the Cascadia
Subduction Zone, as shown above in Tables 10.5 and 10.6. Smaller earthquakes
would have generally substantially smaller impacts than shown above.
In addition, there is a Iow probability that a major earthquake could result in substantial
damage or failure of the major dams upstream of the Eugene/Springfield Metro Area.
If dam failure were to occur, however, the impact on the Eugene/Springfield Metro
Area could be very large with very high damage levels in inundation areas and
potentially high casualties (depending on the extent of dam damage, the amount of
warning time of dam failure, and the effectiveness of evacuations).
~10,5 Earthquake Risk Assessment: Technical Guidance
For planning purposes, it is sometimes useful to consider three levels of earthquake
risk assessment.
A Level One Risk Assessment means that nationally available data are
used. For example, FEMA's HAZUS loss estimation software uses
national data and HAZUS risk assessments for a community are Level
One. The risk assessments presented in the previous section were
Level One Assessments made using methods and data very similar to
10-13
HAZUS.
A Level Two Risk Assessment is a more refined evaluation using local
data such as soil maps, assessor's records, local building code history
and so on to more accurately reflect local conditions than when using
only national data. Level Two Assessments are generally more accurate
than Level One Assessments, but still rely on generalized, typical data,
rather than building specific data.
A Level Three Risk Assessment is building- or facility-specific, using
detailed data for each facility. A Level Three Risk Assessment cannot
be done for an entire community, but rather is typically done for a single
building or a few buildings or other facilities that may be particularly
vulnerable or for which mitigation of seismic hazards is a high priority.
10.5.1 Level Two Risk Assessment
The Level One earthquake loss estimates presented above are based on census-tract
level data. For a given community, such as the Eugene/Springfield Metro Area, a more
accurate loss estimate could be obtained by incorporating Level Two local data into the
loss calculations. Such data could include:
1) better inventory data,
2) spatial distribution of inventory within census tracts,
3) overlay of soils information with inventory to identify areas subject to
amplification, liquefaction, settling and displacements, and
4) refinement of building fragility curves to reflect local inventory.
Such Level Two loss estimates would be more accurate than the Level One
assessments presented above. However, the Level One estimates probably provide
accurate enough estimates of the approximate magnitude of losses for emergency
planning purposes. Furthermore, conducting a Level Two loss estimate would require
very intensive data collection and processing efforts, without providing enough detail
for specific mitigation projects. Therefore, Level Two risk assessments may not be as
useful for the Eugene/Springfield Metro Area as the Level Three Assessments
suggested below.
10.5,2 Level Three Risk Assessment
The potential damages and losses from earthquakes affecting Lane County and the
Eugene/Springfield Metro Area are very high. However, the probability of such
earthquakes is relatively Iow and many types of buildings, such as wood frame homes,
are generally expected to perform reasonably well in earthquakes. Therefore,
widespread mitigation of seismic hazards is probably not called for in the case of most
ordinary or typical buildings. That is, seismic mitigation actions are probably necessary
only for a small percentage of the total building stock in the Eugene/Springfield Metro
Area.
Furthermore, buildings constructed since the early 1990s generally meet current
seismic design requirements and will generally perform fairly well in future
10-14
earthquakes. Similarly, new buildings will be built in accordance with current Seismic
Zone 3 requirements and thus the seismic capacity of the building stock in the
Eugene/Springfield Metro Area will gradually improve over time as the existing stock is
gradually replaced and/or upgraded.
However, for some types of buildings which are more vulnerable or more important
than typical buildings, seismic retrofit may be highly desirable. Prime candidates for
possible seismic retrofits include:
any buildings that are substantially more vulnerable than typica~
buildings (e.g., unreinforced masonry buildings),
· buildings on soft soil sites, and
- essential service facilities such as major medical facilities, police and fire
stations, schools, and emergency shelters.
Specific buildings may be substantially more vulnerable than typical buildings because
of their structural system. Examples of vulnerable building types include: unreinforced
masonry, precast concrete frame, concrete or steel frame with unreinforced masonry
infill walls, concrete moment resisting frame, and precast concrete tiltup walls.
Buildings may also be substantially more vulnerable than typical buildings because of
their design characteristics. Examples include buildings with soft first stories (taller
than other stories and/or with large expanses of windows without shear walls) and
buildings with major configurational irregularities, as well as wood frame buildings with
cripple wall foundations or with sill plates not bolted to the foundation. Thus, we
suggest that Level Three risk assessments focus primarily on such buildings,
especially for essential service facilities.
A Level Three assessment provides a building-specific evaluation, more accurate than
generic assessments based on typical buildings. Ideally, a Level Three assessment
would include a site specific seismic hazard analysis, taking into account soil
conditions, and a building-specific evaluation of the seismic vulnerability of each
building under evaluation.
In addition to buildings, there are other critical facilities which may be vulnerable to
seismic damage, including utility and transportation system infrastructure. Minimizing
earthquake damage to such facilities is particularly important to a community because
loss of function of critical utility or transportation system infrastructure may have a very
large economic impact on the community. Facilities that should have a high priority for
Level Three Risk Assessments include: electric power substations (especially high
voltage substations), water and waste-water treatment plants, water reservoirs, bulk
fuel storage tanks and hazmat storage tanks, dams and bridges. For utilities in
general, non-structural mitigation measures are often very cost-effective and should
have a high priority.
For buildings, utilities and other important facilities, the seven-step Mitigation Planning
methodology outlined in Chapter I is appropriate. For prioritizing between mitigation
projects, the principles of benefit-cost analysis apply to mitigation projects for all
hazards, including seismic hazard mitigation. FEMA has software available to conduct
such analyses of prospective earthquake hazard mitigation projects. See also the
example seismic mitigation project in the Appendix.
10-15
10.6 Other Earthquake Loss Estimates and Comments for the Eugene/Springfield
Metro Area
10.6.1 Probable Maximum Loss Study of City BuiLdings in Eugene
A probable maximum loss study for 20 City-owned buildings in Eugene was completed
in 2001 for two ~eve~s of ground shaking, representing probabilistic leve~s of shaking
with a 10% and 2% probability of occurring over a 50-year time period. Ground
shaking levels range from 0.137 g to 0.16 g and from 0.296 g to 0.353 g respectiveJy,
for these two leve~s of probabilistic shaking. The variation for a given probability of
shaking represents variation due to local soi~ conditions.
Estimated building damages (as percentage of replacement value) range from 2.5% to
32% and from 8.3% to 60.2%, for the two levels of probabilistic shaking. Buildings with
high seismic vulnerability (that is, expected high levels of damage) include City
the Overpark at 10th and Oak, the Hult Center, the Hu~t Center Parking structure, the
Public Works Administration Building, and the Public Works Maintenance Building #1,
a~ of which are estimated to have 40% or greater damage at the higher level of ground
shaking.
10.6,2 DOGAMI Study of 200 Buildings
DOGAMI (1999) completed a preliminary loss estimate study of 200 representative
buildings using FEMA's HAZUS loss estimation methodology. For ground shaking of
0.3 g (similar to the higher level in the 2001 probable maximum loss study discussed
above). For 200 buildings only, total building structural and non-structural damages
were estimated at about $39,000,000, with total direct economic losses of about
$110,000,000, including contents, business inventory, and income losses.
10,6,3 Windshield Survey and General Comments
A "windshield" survey means a quick, preliminary seismic risk evaluation of a building
or other facility, based on readily observable external attributes. A windshield survey
may literally be done from a vehicle, but more commonly includes a quick walk around
inspection. Conclusions drawn from such preliminary evaluations must be interpreted
carefully as giving only a general indication of the probable level of seismic risk posed
by the building or facility.
Overall, a majority of the building inventory in the Eugene/Springfield Metro Area is
residential with most residential structures being wood frame buildings. In general,
wood frame buildings perform wel~ in earthquakes, with a few notable exceptions.
Wood frame buildings with the following characteristics are generally substantially
vulnerable to major seismic damage:
1) sill plates not bolted to foundation,
2) cripple wall perimeter systems, and
3) buildings on steep slopes, partially supported on "sti~tso"
Cripple wa~l perimeter systems are short wooden wal~s which raise the first floor
elevation above grade by typically about 2 to 4 feet. Unbolted sil~ p~ates and cripple
10-16
wall construction are common in pre-WW2 construction. Visua~ inspection and the
general vintage of building stock in the Eugene/Springfield Metro Area suggest that
there are likely significant numbers of buildings in the Eugene/Springfield Metro Area
with cripple wall foundations or with unbolted sill plates.
Unreinforced masonry buildings are also subject to major damage in earthquakes.
The Eugene/Springfield Metro Area has several dozen masonry buildings (most
commercial or industrial) which may be unreinforced or reinforced masonry. These
buildings may be highly vulnerable to damage and thus should have a high priority for
detailed evaluation, especially those buildings with high occupancies or important
functions.
A detailed inventory of wood frame buildings with the above noted seismic deficiencies
and inventory of unreinforced masonry buildings would be useful to further quantify the
level of risk posed by such structures in the Eugene/Springfield Metro Area.
10.7 Earthquake Hazard Mitigation Projects: General Examples
There are a wide variety of possible hazard mitigation projects for earthquakes. The
most common projects include: structural retrofit of buildings, non-structural bracing
and anchoring of equipment and contents, and strengthening of bridges and other
infrastructure components.
The seismic hazard (frequency and severity of earthquakes) is moderate in the
Eugene/Springfield Metro Area. However, the risk (potential for damages and
casualties) may be fairly high because some buildings and infrastructure may be highly
vulnerable to earthquake damages. The risk assessment methodology outlined above
for earthquakes provides the basis for identifying the high risk facilities that then
become the primary targets for mitigation.
Structural retrofit of buildings should not focus on typical buildings, but rather on
buildings that are most vulnerable to seismic damage. Priorities should include
buildings on soft soil sites subject to amplification of ground motion and/or liquefaction
and especially on critical service facilities such as hospitals, fire and police stations,
emergency shelters, and schools.
Non-structural bracing of equipment and contents is often the most cost-effective type
of seismic mitigation project. Inexpensive bracing and anchoring may protect very
expensive equipment and/or equipment whose function is critical such as medical
diagnostic equipment in hospitals, computers, communication equipment for police and
fire services and so on. For utilities, bracing of control equipment, pumps, generators,
battery racks and other critical components can be powerfully effective in reducing the
impact of earthquakes on system performance. Such measures should almost always
be undertaken before considering large-scale structural mitigation projects.
The strategy for strengthening bridges and other infrastructure follows the same
principles as discussed above for buildings. The targets for mitigation should not be
typical infrastructure but rather specific infrastructure elements that have been
identified as being unusually vulnerable and/or are critical links in the lifeline system.
For example, vulnerable overpasses on major highways would have a much higher
10-17
pdodty than overpasses on lightly traveled rural routes.
See the Appendix (Mitigation Project Examples) for a detailed evaluation of a possible
seismic retrofit of the Eugene City Hall, as an example of how to evaluate a
prospective seismic mitigation project.
The following table contains earthquake mitigation action items from the master Action
Item table in Chapter 4.
10-18
11,0 VOLCAN}C HAZARDS
11,1 Overview
The Cascades, which run from British Columbia through Washington and Oregon into
northern California, contain more than a dozen major volcanoes and hundreds of
smaller volcanic features. In the past 200 years, seven of the Cascade volcanoes in
the United States have erupted, including: Mt. Baker, Glacier Peak, Mt. Ranier, Mount
St. Helens, Mt. Hood, Mt. Shasta, and Mt. Lassen.
Over the past 4000 years (a geologically very short time period) in Oregon there have
been three eruptions of Mt. Hood, four eruptions in the Three Sisters area, and two
eruptions in the Newberry Volcano area and minor eruptions near Mt. Jefferson, at
Blue Lake Crater, in the Sand Mountain Field (Santiam Pass), near Mt. Washington,
and near Belknap Crater. During this time period, the most active volcano in the
Cascades has been Mount St. Helens with about 14 eruptions.
In addition, many other volcanoes in Oregon are deemed active or potentially active.
The Smithsonian Institution's Global Volcanism Project lists 20 active volcanoes in
Oregon. These volcanoes are listed below in Table 11
Table 11.1
Active VoLcanoes in Oregon
Volcano Type Last Eruption
Mt, Hood Stratovolcano 1866
95O
Mt. Jefferson Stratovolcano main volcano inacbve for
>10,000 years
Blue Lake Crater Crater 1490 BC
Sand Mountain Field Cinder cones 1040 BC?
620
Mt Washington Shield volcano
main volcano inactive
Belknap Field Shield volcanoes 460?
North S~ster Field Complex volcano 350
South Sister Complex volcano 50 BC?
Mt. Bachelor Stratovolcano 5800 BC
Davis Lake Volcamc field 2790 BC?
620
Newberry Volcano Shield volcano crater formabon 300,000 to
500,000 years ago
Devis Garden Volcanic field unknown
Squaw Rid,ge Lava Field Volcanic field unknown
Four Craters Lava Field Volcanic field unknown
Cinnamon Butte Cinder cones unknown
2290 BC
Crater Lake Caldera Crater formation about
7,700 years ago
Diamond Craters Volcanic field unknown
Saddle Butte Volcanic field unknown
Jordan Craters Volcamc field 1250 BC
Jackies Butte Volcanic field unknown
Public Review Draft: October 11, 2004
t1-1
On a longer geological time scale, volcanic activity in the Cascades has been very
widespread. A DOGAMI report on prehistoric and historic volcanic eruptions in Oregon
(see website below) notes that in the Cascades as a whole, over 3000 large and small
volcanoes have erupted over the past five million years. Within histodca~ times,
between 1843 and 1860 there were a series of 21 eruptions in the Cascades and there
is some scientific speculation that the Northwest may be entering another period of
volcanic activity.
A great dea~ of general background information on Oregon volcanoes and on
volcanoes in general is available on several websites, including the following.
Table 11.2
Volcano Websites
institution Website
Smithsonian institution
www.volcano.si.edu
(Global Volcanism Project)
United States Geological Survey
www usgs gov
(USGS) - general site
USGS Cascades Volcano
Observatory (Vancouver, WA) http://vulcan'wr'usqs'g°v
DOGAMI www.oreqonc~eoloqy com
The numerous volcanoes of the Cascades differ markedly in their geological
characteristics. The largest volcanoes are generally what geologists call composite or
stratovolcanoes. These volcanoes may be active for tens of thousands of years to
hundreds of thousands of years. In some cases, these large volcanoes may have
explosive eruptions such as Mt. St. Heiens in 1980 or Crater Lake about 7,700 years
ago. The much more numerous sites of volcanic activity are generally what geologists
call mafic volcanoes. This type of volcano is typically active for much shorter time
periods, up to a few hundred years, and generally forms small craters or cones. Mafic
volcanoes are not subject to large explosive events.
11.2 Volcanic Hazard Types
in Oregon, awareness of the potential for volcanic eruptions was greatly increased by
the May 18, 1980 eruption of nearby Mount. St. Heiens in Washington which killed 57
people. In this eruption, lateral blast effects covered 230 square miles and reached 17
miles northwest of the crater, pyroclastic flows covered six square mi~es and reached 5
miles north of the crater, and landslides covered 23 square mi~es. Ash accumulations
were about t0 inches at 10 miles downwind, I inch at 60 mi~es downwind, and ½ inch
at 300 miles downwind. Lahars (mudflows) affected the North and South Forks of the
Toutle River, the Green River, and ultimately the Cok~mbia River as far as 70 miles
from the volcano.
Volcanic eruptions often involve several distinct types of hazards to people and
property, as well evidenced by the Mount St. Helens eruption. Major volcanic hazards
include: ~ava flows, blast effects, pyroclastic flows, ash flows, lahars, and landslides or
debris flows. Some of these hazards (e.g., lava flows) only affect areas very near the
Public Review Draft: October 11, 2004
11-2
volcano. Other hazards may affect areas 10 or 20 miles away from the volcano, whi~e
ash falls may affect areas many miles downwind of the eruption site.
Lava flows are eruptions of molten rock. Lava flows for the major
Cascades volcanoes tend to be thick and viscous, forming cones and
thus typically affecting areas only very near the eruption vent. However,
flows from the smaller mafic volcanoes may be less viscous flows that
spread out over wider areas. Lava flows obviously destroy everything in
their path.
Blast effects may occur with violent eruptions, such as Mount St.
Helens in 1980. Most volcanic blasts are largely upwards. However, the
Mount St. Heiens blast was lateral, with impacts 17 miles from the
volcano. Similar or larger blast zones are possible in future eruptions of
any of the major Cascades volcanoes.
Pyroclastic flows are high-speed avalanches of hot ash, rock
fragments and gases. Pyroclastic flows can be as hot as 1500 °F and
move downslope at 100 to 150 miles per hour. Pyroclastic flows are
extremely deadly for anyone caught in their path.
Ash falls result when explosive eruptions blast rock fragments into the
air. Such blasts may include tephra (solid and molten rock fragments).
The largest rock fragments (sometimes called "bombs") generally fa~l
within two miles of the eruption vent. Smaller ash fragments (less than
about 0.1") typically rise into the area forming a huge eruption column.
In very large eruptions, ash falls may total many feet in depth near the
vent and extent for hundreds or even thousands of miles downwind.
Lahars or mudflows are common during eruptions of volcanoes with
heavy loading of ice and snow. These flows of mud, rock and water can
rush down channels at 20 to 40 miles an hour and can extend for more
than 50 miles. For some volcanoes, lahars are a major hazard because
highly populated areas are built on lahar flows from previous eruptions.
Landslides or debris flows are the rapid downslope movement of
rocky material, snow and/or ice. Volcano landslides can range from
small movements of loose debris to massive collapses of the entire
summit or sides of a volcano. Landslides on volcanic slopes may be
triggered be eruptions or by earthquakes or simply by heavy rainfall.
11.3 Volcanic Hazards for the Eugene/Springfield IVletro Area
Severa~ of the 20 active volcanoes in Oregon (See Table 11.1 ) are located along the
crest of the Cascades near the eastern boundary of Lane County. These volcanoes
include the Three Sisters, Mt. Bachelor and the Davis Lake volcanic field. Other
relatively nearby active volcanoes include several near the eastern boundary of Linn
County, including: Mt. Jefferson, Blue Lake Crater, Mt. Washington, the Be~knap
Crater field, and the Sand Mountain field. Other relatively nearby volcanoes include
Public Review Draft: October 11, 2004
11-3
the Newberry Volcano in Deschutes County and Crater Lake in Klamath County.
Among the Linn County volcanoes, Mt. Jefferson has not been active for perhaps
15,000 years and Mt. Washington has not been active for several hundred thousand
years. Mt. Jefferson is potentially active, while Mt. Washington is probably extinct.
Most of the other Linn County volcanoes are smaller mafic volcanoes or volcanic fields
(clusters of cones, vents, craters) that typically have smaller, much more localized
eruptions compared to the larger volcanoes. Newberry Volcano had minor eruptions
about 1,500 years ago, but the major crater formation probably occurred about
300,000 to 500,000 years ago. Crater Lake has not been active for about 4,000 years,
with major crater formation about 7,700 years ago.
The Eugene/Springfield Metro Area is approximately 50 miles from the nearest
volcanoes (Three Sisters). This distance is large enough that the Eugene/Springfield
Metro Area is unlikely to have major impacts from eruptions of any of these volcanoes.
However, for completeness, we review the volcanic hazards posed by the Three
Sisters, which are the nearest, most recently active major volcanoes near the
Eugene/Springfield Metro Area. Awareness of potential volcanic activity at the Three
Sisters has been raised because of the recent discovery of an uplift (bulge) on the
west side of South Sister. In May 2001, the USGS announced that it had detected a
slight swelling or uplift of the west side of South Sister. This bulge, which occurred
between 1996 and 2000, covers an area about 9 to 12 miles in diameter, with a
maximum bulge in the center of about 4 inches. The cause of this uplift (bulge) is most
likely intrusion of a small amount of magma (molten rock) deep under the surface,
probably at a depth of about 4 miles.
This observation confirms that South Sister is still an active volcano, but needs to be
interpreted cautiously. For comparison, a bulge was also observed on the north side of
Mount St. Helens in the months prior to the May 18, 1980 eruption. However, the
Mount St. Helens bulge was 450 feet high and growing at a rate of 5 feet per day prior
to the eruption. Thus, the South Sister bulge of 4 inches is certainly no;~ an indication
of an imminent eruption.
The UGSG analysis of Volcano Hazards in the ThreE; Sisters Region, Oregon was
published in 1999 (Open-File Report 99-437).
The Three Sisters area includes two large composite volcanoes (Middle and South
Sister). Large composite volcanoes in the Cascades (e.g., Mt. Hood, Mt. Jefferson,
Newberry Volcano, Crater Lake) are often active for hundreds of thousands of years
and are subject to sometimes explosive eruptions (e~g., Mount St. Helens in 1980).
Hazards from eruptions of composite volcanoes include all of the hazards listed above
in Section 11.2.
Between the major composite volcanoes, the crest of the Cascades is built up of
hundreds of "mafic" volcanoes. Mafic volcanoes typically erupt for a few weeks to a
few centuries, although some can be nearly as large as the composite volcanoes.
Prominent mafic volcanoes in the Three Sisters area include North Sister, Mount
Bachelor, Belknap Cater, Black Butte, and Mount Washington. Mafic volcanoes often
form broad fields of volcanic vents such as in the Sand Mountain Field near the
Public Review Draft: October 11, 2004
11~4
Santiam Pass, north of the Three Sisters.
Mafic volcanoes typically erupt less explosively than do composite volcanoes, so that
impacts of eruptions are less widespread. Most mafic eruptions in the Three Sisters
areas have produced tephra deposits and lava flows that typically traveled 3 to 9 miles
from the vents and rarely 9 to 12 miles from the vents. Tephra deposits rarely exceed
4 inches in thickness at distances 6 miles from the vent.
Belknap Crater, about 1,500 years old, is one of the youngest mafic volcanoes in the
Cascades. The Sand Mountain field, a cluster of cones and lava flows west of Santiam
Pass, was formed during three eruptive periods between about 2,000 and 4,000 years
ago.
The USGS study of Volcano Hazards in the Three Sisters Region includes three
hazard zones: proximal hazards, distal hazards, and a regional lava flow hazard zone.
The proximal hazard zone is limited to the immediate area around the
Three Sisters and is an oval area about 8 miles (east-west) by 10 miles
(north-south). The proximal hazard area is the area subject to the most
intense volcanic hazards including lava flows, tephra flows, pyroclastic
flows, landslides and debris flows and lahars. Fortunately, this area is
predominantly wilderness with very Iow population.
The distal hazard zones are river valleys extending away from the
proximal hazard zone that are subject to landslides, debris flows and
lahars. The distal hazard zone has three levels for areas subjected to
lahars (and other flows) of varying sizes. Areas subjected to lahars
include Squaw Creek into Sisters, Tumalo Creek into Bend, the valley
between Sparks Lake and Crane Prairie Reservoir, and the McKenzie
River (and tributaries) west of the Three Sisters.
The regional lava flow hazard zone includes a band about 30 to 40
miles wide covering the entire crest of the Cascades. Locations
throughout this zone, which includes Sisters, Bend, and the Santiam
Pass, are subject to lava flows from mafic volcanism which could occur
anywhere in this entire zone.
Of these Three Sisters volcanic hazards zones, only the distal hazard zone potentially
affects the Eugene/Springfield Metro Area. The proximal hazard zone, the lava flow
hazard zone, and the direct effects of the distal hazard zone do not extend to the
Eugene/Springfield Metro Area. However, substantial landslides, debris flows, lahars,
or ash falls affecting the McKenzie River or it tributaries would affect the water system
in the Eugene/Springfield Metro Area. Water drawn from the McKenzie River would
likely have high turbidity and potentially cause operational problems at water treatment
plants and degradation of water quality. Current proximal hazard zone maps indicate
that minimal impact would occur in the upper Willamette tributaries, presenting Iow risk
to SUB's treatment plant on the middle fork of the Willamette.
Furthermore, substantial landslides, debris flows, lahars and snowmelt runoff from an
eruption of one of the Three Sisters volcanoes could have significant impacts on the
Pubhc Review Draft: October 11,2004
11-5
McKenzie River, with flooding potential extending downstream including the
Eugene/Springfield Metro Area. The worst case scenario would probably be failure of
a debris dam that had impounded a substantial quantity of water. Major flooding could
occur along the McKenzie River, with the most flood prone area being very similar to
the FEMA-mapped floodplains of the McKenzie River.
Importantly, because of distance and topography, possible lahars and other distal zone
effects would not affect the Blue River or Cougar Reservoirs in northeastern Lane
County or any of the upstream reservoirs on the Willamette.
Thus, the extent of volcanic hazards for the Eugene/Springfield Metro Area appears
most likely to be limited to the possibility of minor ash falls from eruptions at the Three
Sisters, at other locations in the Cascades or elsewhere (e.g., Mount St. Helens) and
possible impacts on the water system. In all but the most extreme events, ash falls in
the Eugene/Springfield Metro Area are likely to be very minor with an inch or less of
ash likely. In addition, volcanic events in the Three Sisters area, the McKenzie Pass
area or in the Santiam Pass area could temporarily close some highways thus affecting
transportation to/from the Eugene/Springfield Metro Area to a minor extent. There is
also a possibility that a major eruption in the Cascades could affect public water
supplies via heavy ash falls or lahars into streams/rivers upstream from public water
supply intakes.
There is also a possibility that some major volcanic eruptions could result in major
flooding downstream along the McKenzie River all the way to the Eugene/Springfield
Metro Area.
The potential impacts of volcanic eruptions on the Eugene/Springfield Metro Area are
summarized below in Table 11.3.
Table 11.3
Potential Impacts of Volcanic Eruptions on the Eugene/Springfield Metro Area
Inventory Probable Impacts
Portion of Eugene/SpdngfieM Metro
Enbre C~ty and surrounding region
Area affected
Buildings Negligible impact, other than minor cleanup required
Streets within Metro Area Negligible impact, other than minor cleanup required
Roads to/from Metro Area Neglig,ble impact, other than minor cleanup required
Electric power Power outages likely from short circuits caused by ash falls
Negligible impact, other than minor cleanup required for most
Other Utilities ublities. Potential to impact water treatment plants which may
require additional maintenance to deal with high turbidity water
Casualties Some potential for health impacts, especially for frail people with
resplratow problems.
Volcamc erupbons, especially of Three Sisters, have the potential
McKenzie River Floodgain to cause major flooding along the McKenzie River. A worst case
scenario would be fadure of debris dams ~mpound~n9 substanbal
quanbties of water.
Public Review Draft: October 11, 2004
11-6
11,4 Mitigation of Volcanic Hazards
Mitigation of volcanic hazards is predominantly in the areas of monitoring volcanic
activity, warnings and evacuation, and emergency response. That is, there are few, if
any, practical physical measures to mitigate the direct impacts of volcanic activity.
The USGS actively monitors volcanic activity in the Cascades via networks of seismic
sensors (which can detect earthquakes related to magma movements) as wel~ as very
accurate ground surface measurements, such as that which has detected the very
small bulge on South Sister. The USGS also has a volcanic warning system with
several levels of a~ert as a potential eruption becomes more likely and more imminent.
For the Cascades, the USGS volcano warning system (www. usgs.gov) has three
levels. Level One (Volcanic Unrest) means anomalous conditions that could be
indicative of an eventual volcanic eruption. Level Two (Volcanic Advisory) means that
processes are underway that have a significant likelihood of culminating in hazardous
volcanic activity, but when the evidence does not indicate that a life- or property-
threatening event is imminent. Level Three (Volcano Alert) means that monitoring or
evaluation indicate that precursory events have escalated to the point where a volcanic
event with attendant volcanologic or hydrologic hazards threatening to life and property
appears imminent or is underway.
For the Eugene/Springfield Metro Area, which is located well outside of any of the
direct hazard zones for any Cascades volcanic events, mitigation for volcanic activity is
likely a Iow priority. In the event of a minor ash flow, public warnings directing peoCe
(especially those with respiratory problems) to remain indoors, and minor cleanup are
most likely the only necessary responses for the Eugene/Springfield Metro Area.
~n addition, water treatment plants should be evaluated to ensure that they can handle
possible high turbidity events from volcanic ash falls into water supplies.
Emergency response plans for the Eugene/Springfield Metro Area should be updated
to acknowledge that major flooding along the McKenzie River is possible in some
volcanic eruption events.
The following table includes the volcanic hazards mitigation action items from the
master Action items table in Chapter 4.
Public Review Draft: October 11,2004
11-7
DAM SAFETY
12,1 Overview of Dams
Dams are structures built to impound water. Dams are built for many purposes
including water storage for potable water supply, ~ivestock water supply, irrigation, or
fire suppression. Other dams are built for flood control recreation, navigation,
hydroelectric power or to contain mine tailings. Many dams provide recreationa~
activities, but recreation is rarely the primary motivation for dam construction. Dams
are also commonly multifunctional, serving two or more of these purposes.
The National inventory of Dams, NID, which is maintained by the United States Army
Corps of Engineers, is a database of approximately 76,000 dams in the United States~
The NID does not include all dams in the United States. Rather, the NID includes
dams that are deemed to have a high or significant hazard potential and dams deemed
to pose a Iow hazard if they meet inclusion criteria based on dam height and storage
volume. Low hazard potential dams are included if they meet either of the following
selection criteria: 1 ) exceeds 25 feet in height and 15 acre-feet of storage, or 2)
exceeds 6 feet in height and 50-acre feet of storage. There are many thousands of
dams too small to meet the NID selection criteria. However, these small dams are
generally too small to have significant consequences if they fail and thus are generally
not considered for purposes of risk assessment or mitigation planning.
This N~D potentia~ hazard classification is solely a measure of the probable impacts Lf a
dam fails. Thus, a dam classified as High Potential Hazard does no___t mean that the
dam is unsafe or ~ikely to fail. The level of risk (probability of failure) of a given dam is
not even considered in this classification scheme. Rather, the High Potential Hazard
classification simply means that there are people at risk downstream from the dam in
the inundation area, if the dam were to fail The N~D potentia~ hazard classification
system for dams is as summarized below in Table 12.1.
Table 12,1
N~D Hazard Potential Classification for Dams~
Hazard Potential Loss of Human Life Economic, Environmental, or
Classification Lifeline Losses
Low None expected Low and generally bruited to dam owner
Sigmflcant None expected Yes
High Probable, one or more expected Yes, but not necessary for th~s class~ficabon.
Dams assigned the Iow hazard potential classification are those where failure or mis-
operation results in no probable loss of human life and Iow economic and/or
environmental losses. Losses are principally limited to the dam owner's property.
Dams assigned to the significant hazard potential classification are those where failure
or mis-operation results in no probable Doss of human life but can cause economic
loss, environmental damage, or disruption of lifeline facilities. Significant hazard
Public Review Draft: August 6, 2004
12-1
potential dams are often located in predominantly rural or agricultural areas.
Dams assigned to the high hazard potential classification are those where failure or
mis-operation will probably cause loss of human life. Failure of dams in the high
classification will generally also result in economic, environmental or lifeline losses, but
the classification is based solely on probable loss of life.
Of the dams in the NID, nearly 60% are privately owned. In addition to the dams in the
NtD, there are many thousands of dams too small to meet the selection criteria for the
NID. Most of these small dams are also privately owned.
The NID is available online through several links at FEMA and the United States Army
Corps of Engineers. However, since September 11,2001, access is somewhat
restricted. Basic NID information and links to the database are available at
http://crunch.tec.army, mil/nid/webpages/nid.cfm
12.2 Dam Primer
In the simplest terms, dams are impervious structures that block the flow of water in a
river or stream and thereby impound water behind the dam. Dams have been built for
thousands of years from a wide range of materials, including earth, stone, masonry,
wood, and concrete. Large modern dams are almost always embankment dams (built
primarily from soil, rock, or mixtures) or concrete darns.
Large modern dams almost always have control mechanisms such as gated spillways
or outlet pipes for releasing water in a controlled fashion. Typically, dams are operated
to smooth natural variations in water flow. During high water flow periods, water is
stored behind a dam, while in low water flow periods, water is released to increase
flows. Controlled releases typically result in lower peak (flood) flows and higher
minimum flows than in uncontrolled streams. The specific patterns of water storage
and release vary from dam to dam, depending on the primary purpose(s) of the dam
and on a wide variety of economic, regulatory and environmental considerations.
12,2.1 Dam Nomenclature and Types of Dams
Modern dams, whether embankment dams or concrete dams, are typically constructed
on a foundation, which may be concrete, natural rock or soils, or compacted soils.
Dams are usually constructed along a constricted part of a river valley to minimize
cost. Dams are also connected to the surrounding natural valley walls, which become
the abutments of the dam structure itself.
Embankment dams are commonly termed earthfill or rockfili dams, depending on the
primary material used in their construction. Historically, a wide range of earth and rock
materials have been used to construct embankment dams, with various construction
techniques including hydraulic fill and compaction. Embankment dams are broad flat
structures, typically at least twice as wide at the base as their height. In cross section,
embankment dams are typically trapezoidal, with a wide flat base, sloping slides and a
narrower flat top.
Depending on the permeability of the materials used in an embankment dam,
Public Review Draft: August 6, 2004
12-2
impervious layers may be added to the upstream side of the structure or in the center
core of the structure. Embankment dams are subject to erosion by running water.
Thus, modern embankment dams always have erosion-resistant materials used in the
water release and control mechanisms of the dam. Typically, concrete spillways with
concrete or steel gates are used to control releases. Many dams also have outlet pipe
systems with concrete or steel pipes as part of the water release control system.
Modern concrete dams fall into two major classes: gravity dams and arch dams.
Concrete gravity dams are designed on principles similar to embankment dams.
Concrete gravity dams are broad structures, generally triangular in shape with a fiat
base, a narrow top, a flat upstream side and a broad sloping downstream side. Much
of these dams' capacity to impound water arises from the weight of the dam. Typically,
gravity dams are keyed into bedrock foundations and abutments to increase the
stability of the dam.
Concrete arch dams rely primarily on the strength of concrete to impound water,
Concrete arch dams are much thinner in cross section than concrete gravity dams and
are always convex on the upstream side and concave on the downstream side
because concrete is much stronger in compression than in tension, With this arch
design, the pressure of impounded water compresses the concrete and makes the
dam stronger. Like concrete gravity dams, concrete arch dams are also keyed into
bedrock foundations and abutments to provide stability. A less common variation of a
concrete arch dam is a concrete buttress dam. Buttress dams are arched or straight
dams with additional strength provided by buttresses perpendicular to the long axis of
the dam.
An excellent introduction to dam nomenclature and descriptions of types of dams is
given in the FEMA publication: Dam Safety: An Owner's Guidance Manual? For
further details, the reader is referred to this publication and the references therein.
12.2.2 Dam Failure Modes
Dam failures can occur at any time in a dam's life; however, failures are most common
when water storage for the dam is at or near design capacity. At high water levels, the
water force on the dam is higher and several of the most common failure modes are
more likely to occur. Correspondingly, for any dam, the probability of failure is much
lower when water levels are substantially below the design capacity for the reservoir.
For embankment dams, the most common failure mode is erosion of the dam during
prolonged periods of rainfall and flooding. When dams are full and water inflow rates
exceed the capacity of the controlled release mechanisms (spillways and outlet pipes),
overtopping may occur. When overtopping occurs, scour and erosion of either the
dam itself and/or the abutments may lead to partial or complete failure of the dam.
Especially for embankment dams, internal erosion, piping or seepage through the dam,
foundation, or abutments can also lead to failure. For smaller dams, erosion and
weakening of dam structures by growth of vegetation and burrowing animals is a
common cause of failure.
For embankment dams, earthquake ground motions may cause dams to settle or
spread laterally. Such settlement does not generally lead, by itself, to immediate
Public Review Draft: August 6, 2004
12~3
failure. However, if the dam is full, relatively minor amounts of settling may cause
overtopping to occur, with resulting scour and erosion that may progress to failure.
For any dam, improper design or construction or inadequate preparation of foundations
and abutments can also cause failures. Improper operation of a dam, such as failure
to open gates or valves during high flow periods can also trigger dam failure. For any
dam, unusual hydrodynamic (water) forces can also initiate failure. Landslides into the
reservoir, which may occur on their own or be triggered by earthquakes, may lead to
surge waves which overtop dams or hydrodynamic forces which cause dams to fai~
under the unexpected toad. Earthquakes can also cause seiches (waves) in reservoirs
that may overtop or overload dam structures. In rare cases, high winds may also
cause waves that overtop or overload dam structures.
Concrete dams are also subject to failure due to seepage of water through foundations
or abutments. Dams of any construction type are also subject to deliberate damage
via sabotage or terrorism. For waterways with a series of dams, downstream dams are
also subject to failure induced by the failure of an upstream dam. If an upstream dam
fails, then downstream dams also fail due to overtopping or due to hydrodynamic
forces.
An excellent review of the common mechanisms for dam failures is given in the FEMA
publication: Dam Safety: An Owner's Guidance Manuat.3 For further details, the
reader is referred to this publication and the references therein.
A National Research Council study4 of dam failures in the United States and Western
Europe from 1900 to 1969 compiled historical data on the observed probability of
failure as a function of type of dam. Dam failures are quite common in the United
States. For example, FEMA data from Tropical Storm Alberto (1994) show 230 dam
failures in the State of Georgia from this single event.5 Fortunately, most dam failures
are of small dams where the failure poses little or no risk to life safety and only minor,
localized property damage. Most failures are of dams that are too small to be included
in the NID database or dams in the NID Low Hazard Potential Category.
However, in the United States between 1960 and t997 there were 23 dam failures that
caused at least one death, with total fatalities from these 23 failures estimated at 318
people.5 Since 1874, there have been six dam failures in the United States which
killed over 100 people.2 The worst dam failure, in terms of casualties, was the 1889
Johnstown Pennsylvania dam failure which killed over 2,200 people. Three of the high
fatality dam failures occurred in the 1970s: Black Hills, South Dakota, Big Thompson
River, Colorado, and Buffalo Creek, West Virginia. These three failures alone resulted
in an estimated 514 deaths.2 (Note: the published death statistics in this paragraph
from these two FEMA sources are inconsistent, but these differences are not
significant for the present purposes).
12.3 Oregon Dam Data
The National Inventory of Dams (NID)lists 812 dams in Oregon. Of these NID dams,
34 are in Lane County. The statistical breakdown of these dams by NID Potential
Hazard Categories is shown below in Table 12.2.
Pubhc Review Draft: August 6, 2004
12-4
Table 12.2
Numbers of Dams by NID Potential Hazard Categories
NID Hazard Oregon Lane County
High 128 9
Significant 151 7
Low 521 16
Undetermined 12 2
Total 812 34
For Oregon, there are 128 dams in the High Potential Hazard Category. In Lane
County, there are 9 dams in the High Potential Hazard Category. These 9 dams, all of
which are federally owned and operated are listed individually in Table 12.3 below.
Table 12.3
NID High Potential Hazard Dams
Lane County
NID NIB
County Dam Name River City Height Storage
{feet) {acre feet)
Lane Cottage Grove Coast Fork W~llamette River COTTAGE GROVE 103 50,000
Lane Dexter Middle Fork Wdlamette River EUGENE 117 29,900
Lane Fall Creek Fall Creek SPRINGFIELD 205 125,000
Lane Dorena Row River COTTAGE GROVE 154 131,000
Lane Lookout Point Middle Fork Willamette River EUGENE 276 477,700
Lane Blue River Dam Blue River SPRINGFIELD 312 89,000
Lane Hills Creek M~ddle Fork Willamette River OAKRIDGE 341 356,000
Lane Cougar South Fork McKenzle River SPRINGFIELD 519 219,000
Lane Fern Ridge Long Tom River EUGENE 49 121,000
Of these NID High Potentia~ Hazard dams all except Fern Ridge are upstream from the
Eugene/Springfield Metro Area.
12.4 Dam Failure Hazard Assessment: Eugene/Springfield l~etro Area
A 1987 report6 on Dam/Levee Failure by the Oregon Emergency Management Division
lists 51 historical dam failures in Oregon from 1896 through the 1980s. As of the time
of this report, no dam failure fatalities had been recorded in Oregon. However, the
potential for dam failure fatalities certainly exists in Oregon, in Lane County and in the
Eugene/Springfield Metro Area, albeit with a Iow probability of occurrence.
To evaluate the level of risk posed by the dams affecting the Eugene/Springfield Metro
Area, we consider the nine dams in the NID high potential hazard classification where
the potential impacts of failure, including life safety, are greatest. Much smaller dams
in the significant and Iow potential hazard categories do not pose a life safety threat
Public Review Draft: August 6, 2004
12-5
and the risk of property damage is minimal or Iow. Additional data on these NID high
potential hazard dams are given below in Table 12.4.
Table 12.4
Additional Data on NID High Hazard Potential Dams
Storage Date Dam
County Dam Name River (acre EAP Owner
feet) Built Type
Lane Cottage Grove Coast Fork Willamette 50 000 1942 RE Y Corps
Lane Dexter Middle Fork Willamette 29 900 1955 RE Y Corps
Lane Fall Creek Fall Creek 125.000 1965 ER Y Corps
Lane Dorena Row River 131.000 t949 RE Y Corps
Lane Lookout Point Middle Fork W~llamette 477.700 1953 RE Y Corps
Lane Blue River Dam Blue River 89 000 1968 RE Y Corps
Lane. Hills Creek Middle Fork Willamette 356000 1962 RE Y Corps
Lane Cougar South Fork McKenzie 219,000 1964 ER Y Corps
Lane Fern Ridge Long Tom 121,000 1941 RE Y Corps
In the table above, the Owner Type Classification is: Federal (F), Local (L), Private (P)
and Utility (U). The NID dam type classification includes the following types of dams:
RE rockfill/earthfill embankment dams, primarily rockfill (fill >3" size)
ER rockfill/earthfill embankment dams, primarily earthfill (fill <3" size)
PG concrete gravity dams
REPG combination dams incorporating rockfill/earthfill and concrete gravity.
These dams were completed between 1941 and 1968. All dams are rockfill/earthfill
embankment dams, except Cougar which is an earthfill/rockfill embankment dam. All
dams are operated by the US Army Corps of Engineers and all have emergency
operations plans in place. All Corps dams are maintained on a regular schedule and
undergo regular inspections, with major re-inspections every five years. Furthermore,
the Corps is highly experienced in the construction, operation, and maintenance of
dams.
As noted previously, the NID classification as High Potential Hazard means only that
there is probable loss of life i_f one of these dams fails. The NID classification contains
no information whatsoever about the safety or lack of safety of a given dam and no
information about the probability of failure.
For embankment dams, as discussed above, the most common failure modes are
overtopping, foundation failures, and seepage through the dam. For concrete dams,
the most common failure modes are overtopping and foundation failures. Under
normal or flood conditions, failure of the Corps operated dams appears highly unlikely.
Failure is perhaps possible, however, in extreme flood events well above the design
basis, especially if the reservoirs were close to full at the onset of flooding. The
spillway capacities could be exceeded with a potential for overtopping failures.
There are, however, two other circumstances that may pose significant threats to any
of these dams: landslides and earthquakes.
Public Review Draft: August 6, 2004
12-6
A major landslide into a reservoir, whether triggered by seismic activity or not,
could result in a large surge wave that could result in dam failure from a
combination of overtopping and hydrodynamic forces.
A major earthquake, either a Cascadia Subduction Zone earthquake, or a
smaller, interplate or intraplate earthquake in Western Oregon, could cause
sufficient damage to these dams to pose a risk of failure.
12,5 Risk Assessment (Preliminary)
Each of these major dams which pose a potential life safety hazard for the
Eugene/Springfield Metro Area is operated by the United States Army Corps of
Engineers. The Portland District of the Corps, Geotechnical Engineer Branch,
Concrete and Dam Safety Section has safety responsibilities for these dams. As of
early 2001, the Dam Safety Coordinator was Jim Hinds, whose phone number is (503)
808-4846. A variety of dam safety related information is also available on the Portland
District's web site at www. nwp.usace.army, mil. Under the Corps normal dam operating
practices, dams are inspected annually, with a more complete evaluation every five
years on a rotating schedule.
12.5.1 Flood Damage to Dams
All of the Corps dams were designed and built with specific flood capacities. Current
dam designs are based on Standard Project Floods. Standard Project Floods, as
defined in the Corps Engineer Manual 1110-2-1411 (March 1, 1965) are floods
resulting from the Standard Project Storm. In turn, the Standard Project Storm is
defined, somewhat imprecisely, as the most severe flood-producing rainfall-snowmelt,
depth-area-duration event that is considered "reasonably characteristic" of the
drainage basin. Discussions with Corps staff in the Portland District Office indicated
that the Standard Project Flood is approximately a 500-year flood event.
The Corp dams' discharge design levels include the combination of spillway discharge
capacity and reservoir outlet pipe discharge capacity. For example, for the Hills Creek
Dam, the Standard Project Flood is 64,500 cubic feet per second. The maximum
controlled discharge capacity of the dam is 151,760 cubic feet per second, or nearly
two and one-half times the Standard Project Flood discharge. These data are included
on the Hills Creek Project, Emergency Response Flowchartz. At discharges beyond
the maximum controlled discharge capacity of the dam, the dam would be overtopped,
discharges would be uncontrolled, and there would be a high probability of damage to
the dam, with some potential for dam failure. The large margin of safety in the
discharge capacity of the dam suggests that the Hills Creek Dam likely has the
capacity to withstand floods at least as large as a 1,000 year flood event without
expected damage. The other Corps dams have similar margins of flood design safety.
12.5.2 Earthquake Damage to Dams
All of these dams were designed and built in the 1940s to 1960s. Seismic design
considerations were thus significantly lower than current seismic design
considerations. A summary tabulation of the seismic design basis and inspection
Public Review Draft: August 6, 2004
12-7
history of these dams is given below in Table 12.5 (Corps of Engineers, Portland
District Office, March, 2001).
Table 12.5
Seismic Design, Evaluation and Inspection Data
Corps of Engineers Dams
Date of Last Seismic Design Basis Date of Last
Dam Seismic Periodic
Evaluation Original Current inspection
Cottage Grove 1981 None 0 21 g 1997
Dexter 1981 0 10 g 0.21 g 1996
Fall Creek 1981 0.10 g 0 21 g 1999
Dorena 1981 none 0 21 g 1997
Lookout Point 1981 0.10 g 0 21 g 1999
Blue River 1994 0.t 0 g 0.24 g 1996
Hills Creek 2000 0.10 g 0.22 g 1999
Cougar 1994 0 10 g 0.24 g 1997
Fern Ridge 2001 none 0~35 g 2000
As shown in Table 12.6, the Corps has conducted at least preliminary seismic
evaluations of all of these dams. However, some of lhese evaluations were conducted
in the 1980s and thus do not reflect current understanding of the seismic hazard in
Oregon or current state-of-the-art seismic evaluation engineering principles. The
Corps has an ongoing regular inspection program and an ongoing seismic evaluation
program. Presumably, updated seismic evaluations of these dams will be completed
over the next few years.
Seismic considerations were completely absent in the design of two of these dams:
Dorena and Fern Ridge. The others were explicitly designed or probably designed to
ground shaking levels of 0.10 g, which is the maximum seismic design level for any of
the Corps dams in western Oregon. In contrast, the current Corps seismic design
levels for dams at these sites (i.e., if new dams were to be built today) would be 0.21 g
to 0.24g for the dams in eastern Lane County and 0.35 g for Fern Ridge. Thus,
current seismic design requirements are for levels of ground shaking about two times
higher than the probable design levels for most of these dams and about three times
higher for Fern Ridge.
Seismic evaluations of dam safety are a highly technical, highly specialized art.
Separate evaluations must be done for each dam. The evaluation requires a detailed
analysis of the design and construction of the dam, an analysis of the current condition
of materials and components, geotechnical analysis of the foundation and site, and a
site-specific seismic hazard analysis. For emergency planning purposes, a seismic
evaluation should include the probabilities of failure for a scenario earthquake such as
a large magnitude event on the Cascadia Subduction Zone.
12.5,3 Loss Estimates (Preliminary)
Detailed loss estimates for possible failures of these dams are beyond the scope of
this mitigation plan. However, we note that in 1987 the Oregon Emergency
Management Division6 estimated that a completely catastrophic failure of the Hills
Public Review Draft: August 6, 2004
12-8
Creek Dam, an extremely unlikely event, could require the evacuation of over 250,000
people with damages in excess of $10 billion. Adjusting these 1987 estimates for
inflation and for population growth suggests that damages could easily exceed $20
billion. Detailed casualty estimates have not been made for catastrophic dam failures
affecting Lane County. However, given the large inundation areas, high water depths,
and the logistical difficulties in evacuating 250,000 people to safe ground, it is not
difficult to imagine that a truly catastrophic dam failure could potentially result in 1,000
or more deaths.
The probability of catastrophic failure of these dams is impossible to estimate with any
accuracy, from present data. Most likely, the probability is less than 0.1% per year
(less than once in 1,000 years, on average) and perhaps substantially less. However,
the consequences of failure are so high that careful evaluation is certainly warranted.
The potential impacts of dam failures on the Eugene/Springfield Metro Area are
summarized below in Table 12.6
Table 12.6
Potential Impacts of Dam Failures on the Eugene/Springfield Metro Area
Inventory Probable Impacts
Portion of Eugene/Springfield Metro Direct ~mpacts limited to mapped inundation areas for dam
Area affected failures, or to smaller areas for more t~kely partial failures
Buildings Heavy damage in inundation areas
Streets within Metro Area Damage and closures in inundabon areas
Roads to/from Metro Area Damage and closures in inundation areas
E~ectdc power Damage and loss of service in inundation areas
Damage and loss of service ~n ~nundation areas. Potenbal for
Other Utilities major damage to water and wastewater treatment plants in
extreme events
Potential for high casualbes (deaths and injuries) in extremely
Casualties unlikely major dam failures, depending on warmng time avadable
and effectiveness of evacuabons
12,6 IVlitigation Strategies
Possible dam failures affecting the Eugene/Springfield Metro Area are Iow probability
events, but the potential casualties and economic consequences are extremely high.
The combination of Iow probability but large consequences makes analysis of such
situations difficult from both a technical and a public policy perspective. The evaluation
is difficult technically because it requires detailed engineering analysis of each dam
and careful probabilistic risk analysis. As always, communication with the public must
be non-alarmist, but factual, realistic and informative.
Recommendations
1. Because of the age of these dams, the seismic design basis of all of the dams
potentially affecting the Eugene/Springfield Metro Area is significantly below current
seismic design requirements. Preliminary seismic evaluations have been done but
without sufficient detai~ to evaluate the probabilities of dam failures. Because of the
Public Review Draft: August 6, 2004
12-9
extreme consequences of potential failure of one or more of these dams, we
recommend that detai~ed seismic evaluations be conducted for al~ of these dams. A~l
of these dams are owned and operated by the U.S. Army Corps of Engineers.
Therefore, pragmatically, the role of the Eugene/Springfield community wou~d be
pdmad~y to strongly encourage the Corps of Engineers to complete these urgently
required seismic evaluations as soon as possible.
2. A key step in mitigation planning for dam safety is emergency planning. Emergency
planners in the Eugene/Springfield Metro Area should obtain copies of the inundation
maps for each of the major dams to familiarize themselves with the areas of potentia~
flooding. For emergency planning, the estimated flood depths and the time periods
from dam failure are particularly important. Flood depths and flood times both vary
markedly with distance downstream from the dam locations. For emergency p~anning,
key elements include community emergency notification procedures and evacuation
planning (routes and traffic control). Because of the 'very large numbers of potentia~
evacuees, training seminars and scenario exercises are strongly recommended.
3. All of these dams have Emergency Action Plans. These plans should be reviewed
to ensure that they are complete and up to date. Emergency planning officials in each
county should be fully informed of the detailed consequences of the potential failure of
each dam. Public notification and evacuation plans should be updated and tested.
For some types of dam failures, for example, those due to extreme floods, there may
be some warning time. Decision making procedures, protocols~ and procedures for
issuing watches, warnings, and evacuation notices should be reviewed and updated
and coordinated among all responsible federal, state, and local agencies.
The table on the following page contains dam safety mitigation action items from the
master Action Items table in Chapter 4.
References
1. FEMA, Federal Guidelines for Dam Safety: Hazard Potential Classification Systems
for Dams, FEMA 333, October 1998.
2. FEMA, Multihazard Identification and Risk Assessment, A Cornerstone of the
National Mitigation Strategy, Chapter 20, Dam Failures, 1997.
3. FEMA, Dam Safety: An Owner's Guidance Manual, FEMA 145, August 1987.
4. National Research Council, Safety of Existing Dams, Evaluation and Improvement,
National Academy Press, 1983.
5. FEMA website (www.fema.gov), National Dam Safety Program webpage.
6. Oregon Emergency Management Division, Dam/Levee Failure, Statewide Hazard
Analysis, March, 1987.
7. Hills Creek Lake Project, Emergency Response Flowcha~, Distributed January
2000, United States Army Corps of Engineers, Portland District, 5 pages.
Public Review Draft: August 6, 2004
12-10
13.0 DISRUPTION OF UTILITY AND TRANSPORTATION SYSTEMS
The previous chapters dealt with each of the major natura~ hazards affecting the
Eugene/Springfield Metro Area including floods, winter storms, landslides, wildland/
urban interface fires, earthquakes and volcanic hazards. These chapters evaluated
each of the hazards and the risk arising from the hazards as they affect the buildings,
infrastructure and people of the Eugene/Springfield Metro Area.
Each of these hazards may result in not only damage to buildings but also damage to
and disruption of utility and transportation systems. Mitigation projects may be
formulated to reduce or avoid such damage and disruptions and a few examples were
discussed in the previous chapters. In this sense, evaluating the potential damage and
disruption of utility and transportation systems from each hazard is part of the risk
assessment for each locality affected by a hazard.
However, disruption of utility and transportation systems may have consequences for
the affected communities which are far broader than the direct damage and
corresponding direct loss of service. In this sense, disruption of utility and
transportation systems may be viewed almost as a hazard. As for other hazards, the
probability, duration, and extent of such outages can be assessed and the impacts (risk)
associated with such outages can be quantified. Among the major utilities, loss of
electric power generally has the most widespread effect on other utilities and on the
community as a whole. Therefore, this chapter dea~s with electric power outages in
more detail than for the other utility and transportation systems.
13,1 Transportation Systems
Streets, roads, and highways are subject to closure during flood events because of
high water levels on road surfaces. This type of closure may occur either during a
major flood event on the larger rivers and streams in the Eugene/Springfield Metro
Area and surrounding areas or during winter storms as a result of localized flooding on
smaller drainage systems. ~n major floods or major winter storms, such road closures
may be widespread, if flow velocities are Iow, then such closures are usually due
primarily to water depth and there is generally little damage to the road system;
reopening the road simply requires waiting for the water level to drop and then cleaning
up mud and debris on the road surface.
However, if flow velocities are higher then erosion of the road surface or undermining
of the road may occur. This type of damage is most common in hilly areas with
relatively steep slopes and occurs most often on smaller roads rather than on major
highways. Reopening such roads requires repair of the damaged road surface.
The flood of February 1996 provided ample evidence of the effects of flooding on roads.
For example, in Lane County, there were dozens of flood-caused road closures. These
closures included major routes such as US 101 North and South of Florence, Highway
36 in three ~ocations, Highway 126 at Noti, the Marcola Road in the Mohawk Valley, and
the McKenzie Highway at Milepost 24. Even ~nterstate 5 had water flowing across it just
north of Eugene near the Boston Mil~ Road overpass. In addition numerous smaller
roads also had closures.
Public Review Draft: August 6, 2004 13-1
Some sites of road closures are difficult to mitigate without large scale flood control
projects. However, mitigation is possible at many locations with high potential for road
closures. Common measures include raising the road surface to reduce the
probability of water overtopping the road or improving local drainage (e.g., culvert
upsizings).
Risk assessments for road closures must include a measure of the importance of the
road for transportation as well as an evaluation of the direct physical damages to the
road. In many cases, the disruption of transportation has a larger economic impact that
the direct physical damages.
To evaluate and prioritize hazard mitigation projects for roads, we suggest three
measures of the relative importance of a road:
1 ) number of vehicle trips per day,
2) detour time around a road closure, and
3) road use as primary access/egress, including emergency vehicles and utility
repair vehicles for major transmission lines.
The number of vehicle trips per day is an obvious measure of the importance of a road.
All other factors being equal a road with 500 trips per day is more important than a road
with 50 trips per day and thus should have a higher priority for mitigation projects.
However, a better measure of the importance of a road is obtained if the detour time is
also considered. ~f traffic loads were equal, a mitigation project on a road where a
closure required a one hour detour would have a higher priority than a road where a
closure only required a five minute detour. More accurately, it is the combination of
traffic load and detour time that provides a measure of the impact of road closure. The
product of number of trips per day and the detour time gives a measure of the number of
vehicle-hours of delay that result from a closure. Consider the following example:
Table 13.1
Calculation of Vehicle-Hours of Delay from Road Closures
Road Trips Detour Time Vehicle-Hours
per Day (hours) of Delay per
day of Closure
A 500 0 10 50
B 100 I 00 100
In this example, Road A has fives times the traffic of Road B, but because the detour
time is much longer for a closure on B than on A, the number of vehicle-hours of delay
is greater on Road B and on Road A. On this basis, mitigation of the hazard causing
the closure would have a higher priority on Road B than on Road A.
The number of vehicle hours of delay is a proxy for the economic impact of the
closure. The current FEMA value (for benefit-cost analysis purposes) for the
economic impact of lost time due to road closures is $32.23 per vehicle hour of delay
(What is a Benefit?, FEMA 2001). This value is based on national average wage and
benefits level and national average vehicle occupancy data, along with the
Public Review Draft: August 6, 2004 13-2
assumption that an hour of leisure time is worth the same to a person as an hour of
work (a common economic assumption). Then, for example, 100 vehicle hours of
delay per day has an estimated economic impact of $3,223 and so on. For the vast
majority of roads, with "typical" traffic loads, using a economic value of $32.23 per
vehicle per hour of delay provides a reasonable measure of the economic impact of
road closures. Everything else being more or less equal, roads which serve as
primary access/egress routes and/or serve many emergency vehicles may be given a
higher priority for mitigation.
For completeness, we note that roads are networked systems and a more accurate
analysis of the relative priority of mitigation projects to reduce road closures should
consider the network characteristics of a ~ocai road system. However, network
analysis is complex, requires specialized expertise and is expensive. Network
analysis may be justified for very expensive projects, such as a multi-million dollar
relocation of a bridge to reduce the potential for flood washouts. However, the simple
three parameter prioritization methodology suggested above is probably sufficient for
evaluation of most small to medium sized mitigation projects.
Rail systems are subject to the same sorts of closures as are road systems.
Evaluation and pdodtization of mitigation projects for rail systems would follow a
methodology closely analogous to that discussed above for road systems, with
economic impact parameters appropriate for a rail system.
Other transportation systems (air, ports, ferry) are also subject to disruption due to the
impacts of hazards. The analysis of such systems is roughly similar to that discussed
above, but mitigation projects for such systems are encountered far less frequently
than are mitigation projects for roads.
Air traffic to/from the Eugene Airport is subject to delay or disruption due to bad
weather conditions, including rain, snow, wind, and ice. However, there are few if any
mitigation actions practical to reduce such delays or disruption. Possible disruptions
of air service due to loss of electric power could be minimized by ensuring that all
critical airport functions have adequate emergency power supplies.
13,2 Utility Systems - Overview
Evaluation of hazard mitigation projects for utility systems have some commonalities
between systems that we briefly review before addressing each major utility system in
turn.
Utility systems such as potable water, wastewater, natural gas, telecommunications,
and electric power are all networked systems. That is, they consist of nodes and
links. Nodes are centers where something happens - such as a pumping plant, a
treatment plant, a substation, a switching office and the like. Links are the
connections (pipes or lines) between nodes.
Risk assessments for utility systems are similar to risk assessments for buildings, in
that the inventory of utility components is overlaid on the hazard map and the
vulnerability of utility components is evaluated for the hazards impacting the utility. A
Public Review Draft: August 6, 2004 13-3
major difference arises, however, because of the networked nature of utilities. As a
simple example, consider an electric utility which suffers damage to 10% of its
transmission lines. The extent of service outage might be essentially zero if there are
redundant lines with sufficient capacity to handle the demand for eiectdc power. Or,
the extent of service outage might be 100% if the damaged lines provide the sole
power feed for a community. Thus, the operating characteristics and network
characteristics (especially the amount of redundancy) must be considered.
in conducting risk assessments or evaluating hazard mitigation projects
for utility systems, the networked nature of such systems must be
considered. The extent or lack of redundancy for particular elements in a
system profoundly affects the extent to which a given level of damage
results in system outages.
The general procedure for conducting a risk assessment or evaluating a hazard
mitigation project for a networked utility system is outlined below in six steps.
1) Overlay utility system components with hazard maps,
2) Estimate the vulnerability of each component to effects from each hazard,
3) From the estimated amount of damage to the system and the system's
network operating characteristics, estimate the extent and duration of service
outage,
4) From the damage estimates and the resources available, estimate the
restoration time,
5) From the service outage (number of customers and duration) estimate the
economic impacts of such loss of service, and
6) If a mitigation project is being evaluated estimate the reduction in direct
damages and the reduction in service interruption attributable to mitigation
project.
An important caveat for conducting risk assessments or evaluation of hazard
mitigation projects for networked utility systems is that specialized expertise is often
required. The analyst must thoroughly understand the operating characteristics of
utility system components and their vulnerability to each hazard as well as thoroughly
understand the network operating characteristics of the system as a whole. In the
absence of sufficient experience and expertise risk assessments or evaluation of
hazard mitigation projects may produce inaccurate and misleading results.
CAVEAT: conducting risk assessments or evaluation of hazard mitigation
projects of networked utility systems often requires specialized expertise
to produce meaningful results.
For reference, a detailed discussion of how to evaluate seismic hazard mitigation
projects for water systems is given in the American Society of Civil Engineers
monograph "Guide#nos for the Seismic Upgrade of Existing Water Transmission
Public Review Draft: August 6, 2004 13-4
Facilities," (J. M, Eidinger, editor, 1999; chapter by K. A. Goettel "Seismic Upgrades of
Water Transmission Systems: When Is It Worth It?"). Very similar principles appty to
evaluating hazard mitigation projects for other utility systems for any type of hazard.
The following sections briefly review utility systems with emphasis on identifying the
system components which are most vulnerable to damage and loss of service from
hazards covered in this Mitigation Plan: flooding, winter storms, landslides and
earthquakes. Such components are thus logical targets for high priority mitigation
projects whenever important components are subject to the hazards.
13.3 Potable Water Systems
Water treatment plants, including those in the Eugene/Springfield Metro Area, are
often located in flood prone areas and are subject to inundation when raw water
enters the filters, sedimentation or floccu~ation basins, resulting in loss of capability to
treat incoming raw water properly. Water system control buildings and pump stations
may also be subject to flood damages. Public or private water systems with wells as
the water source are subject to outages when flood waters contaminate well heads;
this is a common problem for smaller water systems.
Water transmission or distribution pipes are rarely damaged by flood waters, unless
there are soil settlements or major erosion, because the ~ines are sufficiently
pressurized (for water quality) to prevent intrusion of flood waters. Water transmission
or distribution pipes are, however, subject to breakage when they cross landslide
areas or in earthquakes~ Water treatment plants are also subject to earthquake
damages to the building and to process and control equipment.
Water systems, including the Eugene/Springfield Metro Area's water systems, are
also highly vulnerable to electric power outages. Many water systems include
pumped storage systems where water is pumped to storage tanks which are typically
located 60 to 200 feet above the elevation of water system customers. Such tanks
generally contain no more than 1 or 2 days of storage beyond typical dai~y usage (for
reasons of water quality). Thus, electric power outages of more than 1 or 2 days may
result in loss of potable water due to the inability of pumping plants to pump water.
The most logical mitigation projects to minimize such outages are to provide back-up
generators at key pumping plants or to provide quick connects so that portable
generators (if available) can be quickly installed. Water treatment plants are also
subject to outages due to loss of e~ectric power.
Common mitigation projects for water systems include flood protection for treatment
plants, providing back-up power, moving pipes from active landslide areas, and
seismic upgrades for treatment plants.
13.4 Wastewater Systems
Wastewater systems are often highly vulnerable to flood impacts. Rising water may
cause collection pipes to backup and overflow. Intrusion of storm water into collection
systems may result in flows that exceed treatment plant capacities, resulting in
Public Review Draft: August 6, 2004 13-5
release of untreated or only partially treated flows. Treatment plants are often located
in flood plains, at Iow elevations, to facilitate gravity flow. However, such locations
also facilitate flood damages. Wastewater treatment plans may be inundated,
resulting in full or partial plant shutdown or plant bypass with corresponding release of
untreated or only partially treated flows.
Lift stations and treatment plants are also subject to loss of function due to electric
power outages, with resulting overflows or releases. Collection pipes are also subject
to breakage due to landslides. However, such occurrences are not particularly
common, since most wastewater collection systems are in more urbanized areas with
only selected areas subject to slides. Wastewater pipes are, however, subject to
breakage in earthquakes. Wastewater treatment plants are also subject to
earthquake damages to the building and to process and control equipment.
Common mitigation projects for wastewater systems include flood protection for
wastewater treatment plants, providing back-up power for nodes such as lift stations,
moving collection pipes from active landslide areas, and seismic upgrades for
treatment plants.
13,5 Natural Gas Systems
Natural gas transmission and distribution pipes are not usually affected by flooding,
because the pipes are pressurized. However, compressor stations may be subject to
inundation damage or loss of electrical power to run electrical and mechanical
equipment.
Transmission and distribution pipes are also subject to rupture in slide areas. Buried
utility pipes are very subject to failure in small ground movements. Movements as
small as an inch or two are often sufficient to break the relatively brittle pipe materials.
Possible mitigation projects for natural gas systems include providing back-up power
for important nodes (e.g, compressor stations) and moving pipes from active
landslide areas.
13.6 Telecommunications Systems
Telephone (land lines and cellular) systems, broadcast radio and TV systems, and
cable TV systems may al~ be vulnerable to damages and services outages from
hazards. However, in general, such systems have proved to be somewhat less
vulnerable to service outages than other utility systems. System nodes (broadcast
studios, switching offices and such) are subject to flooding if located in flood-prone
areas. However, because of the importance of such facilities, few are located in
highly flood-prone sites.
Similarly, few such facilities are likely to be located in landslide prone areas. Cellular
towers in hilly areas, however, may be more subject to landslide hazards.
Buried communications (copper and fiber optic) and cable television cables are
usually flexible enough to accommodate several feet of ground movement before
Public Review Draft: August 6, 2004 13-6
failure. Thus, while major landslides may rupture such cables, minor settlements or
small slides are not nearly as likely to affect such cables as they are to break buried
gas or water pipes.
Above ground communications and cable television cables are subject to wind-
induced failures from tree falls and pole failures. However, such failures are about ten
times less common than failures of electric power lines. The better performance of
communications cables arises in part because the electrical cables are always highest
on the poles, thus a falling branch is usually first resisted by the power cables. Also,
because the voltage levels in communications cables are much lower than those in
power cables, the communication cables are not subject to "burn down" or shorting if
wind-swayed cables touch each other or get too close.
Some telecommunications facilities are subject to failure as a result of loss of electric
power. However, key facilities almost always have backup battery power and/or
generators. Therefore, telecommunications facilities are generally much less
vulnerable to outages from loss of electric power than are water or wastewater
systems.
Possible mitigation projects for telecommunications systems include flood proofing of
important nodes, adding back-up power, relocating facilities out of active slide areas
and seismic retrofits.
13.7 Electric Power Systems
The electric power system is central to the functioning of a modern society. The
consequences of loss of electric power are very large: residential, commercial and
public customers are all heavily dependent on electric power for normal functioning.
Furthermore, as discussed above, other utility systems, especially water systems, are
heavily dependent on electric power for normal operations. Loss of electric power,
therefore, may have large impacts on affected communities, especially if outages are
prolonged.
The Regional All Hazard Mitigation Plan for Benton, Lane, Lincoln and Linn Counties
included reviews of the operating characteristics of electric power systems and the
major failure modes (Phase One, Technical Appendix). We briefly summarize this
information here. Electric systems have three main parts: generation, transmission,
and distribution.
Generation is the production of electric power. Generating plans can be hydroelectric,
fossil fuel (oil, gas, or coal), nuclear, or various renewable fuels (wind, solar, biomass,
etc.). Most of the electric power consumed within Lane County is thus produced
elsewhere and transmitted via high-voltage transmission lines. The Bonneville Power
Administration (BPA) is the primary source of power for Lane County. BPA's power
comes from hydroelectric facilities (57%) operated by the Corps of Engineers or the
Bureau of Reclamation, from a nuclear plant (3%), from interchanges and wheeling
(37%) of power transmitted by BPA but not owned by BPA and from other sources
(3%). Through the Pacific Interties (high voltage AC or DC transmission lines) power
Public Review Draft: August 6, 2004 13-7
is moved back and forth between California, the Pacific Northwest and western
Canada.
The transmission system is a network of high voltage lines (500 kV and 230 kY) and
substations which transmit power between generation plants and the local distribution
system. The distribution system is a network of lower voltage lines and substations
which carries power from transmission system substations to neighborhoods and
eventually to individual customers.
Power outages in Lane County are most likely to result from disruption of the
transmission lines carrying power from outside Lane County or within Lane County, or
damage to the local distribution lines within the Eugene/Springfield Metro Area. The
generating plant system has sufficient redundancy so that failures of one or more
plants do not usually lead to significant power outages. However, because of the
limited generation capacity within Lane County, major disruptions in the transmission
system would result in substantial curtailment of available power. A major ice storm in
the Columbia River area could conceivably fail all of the 500 kV transmission lines
feeding Lane County from the north. However, the transmission system has enough
redundancy that the power needs of Lane County would likely be met by a
combination of local generating capacity and transmission of power from California.
However, a severe ice storm with 2 to 4" of ice over much of Lane County could result
in failure of all north-south 500 kV and 230 kV transmission lines within Lane County.
Such a failure, which is unlikely, but certainly not impossible, would probably entail
widespread power outages for 2 to 5 days.
The most frequent power outages, however, are due to failure of the local
subtransmission or distribution system lines. Winter storms are the most frequent
cause of significant electric power outages, with wind being the primary culprit.
Electric distribution lines, the Iow voltage lines that deliver power to neighborhoods,
are the most vulnerable electric system component in winter storms. Failures most
commonly result from tree falls or from "burn downs" when wind-swayed cables touch
or get too close to each other and short circuit. Distribution system failures may also
be due to utility pole failures. Distribution lines may also fail due to ice loading in
excess of design specifications or from landslides or debris flows or flooding which
knock out utility poles.
Failures of distribution system lines are thus the most common failure mode for
electric power systems. Power system outages are more common and of longer
duration in rural areas compared to urban or suburban areas. Rural areas are more
prone to electric outages because they have a higher percentage of above-ground
lines and are more likely to have hilly areas with high concentrations of trees and
higher wind speeds than in flatter terrain. In rural areas, with lower population density,
there is also a higher ratio of length of distribution lines per customer. With a longer
length of exposed line, the probability of an outage is higher for a rural customer than
for an urban customer.
Once a portion of a power distribution circuit fails, all customers in that part of the
circuit lose power. The duration of the power outage depends on the number of
outages and the number of repair crews available for repairs. A typical power utility
Public Review Draft: August 6, 2004 13-8
repair crew (2 or 3 people with necessary equipment) can restore power to a
distribution circuit with common types of damage in 1 or 2 hours after ardvin9 at the
damage site.
Electric transmission lines (110 kV and higher) are less vulnerable to winter storm
damage because of more robust design specifications. Also, such lines are usually
higher above the ground and much less prone to tree branches falling on lines.
Furthermore, because of the higher voltage (compared to distribution lines), power
utilities must diligently pursue tree trimming programs to avoid flashovers from lines
being too close to trees. Nevertheless, transmission lines do sometimes fai~ due to
large tree falls, rapid growth of trees near lines, unusually high winds or heavy ice
loads.
The Eugene/Springfield Metro Area is subject to outages of electric power primarily
due to line failures. One possible failure mode would be the transmission lines that
feed the Eugene/Springfield Metro Area from the north and south. More common
failure modes would be failures of the trunk distribution lines within the Eugene/
Springfield Metro Area and failures of distribution circuits or service drops from
distribution lines to individual buildings. All of these ~ailures are most likely due to tree
falls during wind storm events.
Mitigation projects to reduce the frequency and duration of electric power systems
include: augmenting tree trimming programs and hardening lines and poles in
locations where ice loading or wind effects result in repeated outages. In some cases,
adding connections to improve redundancy of power feed paths and adding
disconnect switches to minimize areas affected by any given failure are also
worthwhile. In addition to such "hard" mitigation possibilities, there are also "soft" or
planning mitigation projects. For example, enhancing mutual aid agreements with
nearby utilities can reduce the duration of major outages by increasing the number of
crews and equipment for making repairs. Other planning/logistics measures such as
ensuring that adequate supplies of parts and equipment are available may also
reduce the duration of future outages.
For the Eugene/Springfield Metro Area, augmenting tree trimming programs,
especially for the transmission lines and the trunk distribution lines is probably the
most effective mitigation measure, in selected locations upgrading lines and poles to
better withstand loads from trees, wind and ice may also be appropriate. If there are
key links in the systems that are highly prone to repetitive failures, undergroundin9 of
limited portions of such links may also be appropriate.
13,8 Potentia~ Impacts on the Eugene/Springfield Metro Area
The potential impacts of closures, disruptions, and outages of transportation systems
and utilities are summarized below in Table 13.2.
Public Review Draft: August 6, 2004 13-9
Table 13,2
Probable impacts of Disruption of Utility and Transportation Systems
Invento~y Probable impacts
Impacts may be localized for damage to ~ocaI ublity d~stnbutlon
Portion of Eugene/Springfield Metro systems or street closures, or may effect the enbre Metro Area for
Area affected damage to transmission lines or closures of major highways
to/from Eugene/Spnngfield Metro Area
Negligible impacts to buildings, but loss of utilities may
Buildings substantially affect func[ion of buildin,~s
Streets within Metro Area Some incidents may include temporary street closures
Roads to/from Metro Area Some incidents may include temporary road closures
Some incidents may include temporary loss of electric power in
localized parts of Eugene/Springfield Metro Area or for the enbre
Electric power City, Duration of disrupbons can range from an hour to up to a
probably maximum outage of I or 2 days,
Some incidents may include temporary loss of utilities in localized
Other Utilities parts of Eugene/Springfield Metro Area or for the entire City.
Duration of disruptions can range from an hour to up to a probably
maximum outaqe of I or 2 days,
Low potenbal for direct casualties, but some incidents such as
loss of electric power dunng cold weather may require
CasuaLties evacuations and displacement of people (especially fragile or
special needs populations) to temporary shelters.
The following table contains action items for mitigation of disruptions of utility and
transportation systems, from the master Action Items table in Chapter 4.
Public Review Draft: August 6, 2004 13-10
14.0 Hazardoas atedals
14,1 ~ntroduction
The 2002 Regional All Hazard Mitigation Plan for Benton, Lane and Linn Counties
(Phase Three) covers hazardous materials at length. For the Eugene/Springfield
Metro Mitigation Plan, a brief synopsis of the Phase Three materia~ is presented,
along with the Eugene/Springfield Metro Area specific data.
For mitigation planning, hazardous materials may be defined simply as any materials
that may have negative impacts on human health. That is, exposure to hazardous
materials may result in injury, sickness, or death. The impacts of hazardous materials
may be short-term with negative effects immediately or in a few seconds, minutes or
hours or they may be long-term with negative effects in days, weeks, or in some cases
years after exposure. Hazardous materials also include materials that may cause
negative impacts on the environment or on animal or plant species.
Hazardous materials vary widely in their toxicity to humans. Some hazardous
materials are highly toxic so that even brief exposures to small amounts may be
dangerous or even fatal. Other hazardous materials are much less toxic and negative
effects may occur only after exposure to large amounts over longer time periods. The
technical term "toxic," which is widely used to describe hazardous materials, is simply
a synonym for the more common terms "poison" or "poisonous."
Hazardous chemicals are widely used in heavy industry, manufacturing, agriculture,
mining, the oil and gas industry, forestry, and transportation as we~l as in medical
facilities and commercial, public, and residential buildings. There are literally
hundreds of thousands of chemicals that may be hazardous to human health, at least
to some extent. A typical single family home may contain dozens of potentially
hazardous materials including fuels, paints, solvents, cleaning chemicals, pesticides,
herbicides, medicines and others.
However, for mitigation planning purposes, small quantities of slightly or moderately
hazardous materials being used by end users are rarely the focus of interest. Rather,
interest is focused primarily on larger quantities of hazardous materials in industrial
use and on hazardous materials being transported, where the potential for accidental
spills is high. Situations involving extremely hazardous materials or large quantities of
hazardous materials in locations where accidents or malevolent actions (terrorism or
sabotage) may result in significant public health risk are of special concern for
planning purposes.
For mitigation planning purposes, the toxicity of particular hazardous materials is an
important measure of the potentia~ impact of hazardous materials on affected
communities, but not the only important measure. Other characteristics of hazardous
materials, especially the quantity of material and the ease of dispersal of the material
may be as important as or more important than toxicity in governing the level of
potential threat to a community. For example, a small quantity of a very toxic solid
hazardous matedal in a research laboratory may pose a much smaller level of risk for
Public Review Draft: October 12, 2004 14-1
a community than a large quantity of a less toxic gaseous material in an industrial site
upwind from a populated area.
The severity of any hazardous material release incident for an affected community
depends on several factors, including:
a) the toxicity of the hazardous material,
b) the quantity of the hazardous material released,
c) the dispersal characteristics of the hazardous material,
d) the local conditions such as wind direction and topography, soil and ground
water characteristics and proximity to vulnerable resources such as public
drinking water resources,
e) the population of nearby areas likely to be affected by hazardous materials
incidents, and
f) the efficacy of response and recovery actions.
14.2 Effects of Hazardous Materials on Humans
There are three principal modes of human exposure to hazardous materials:
a) Inhalation of gaseous or particulate materials via the respiratory (breathing)
process,
b) Ingestion of hazardous materials via contaminated food or water, and
c) Direct contact with skin or eyes.
Exposure to hazardous materials can result in a wide range of negative health effects
on humans. Hazardous materials are generally classified by their health effects. The
most common classes of hazardous materials are summarized below.
Flammable materials are substances where fire is the primary threat,
although explosions and chemical effects listed below may also occur.
Common examples include gasoline, diesel fuel, and propane.
Explosives are materials where explosion is the primary threat, although fires
and chemical effects listed below may also occur. Common examples include
dynamite and other explosives used in construction or demolition.
Irritants are substances that cause inflammation or chemical burns of the
eyes, nose, throat, lungs, skin or other tissues of the body in which they come
in contact. Examples of irritants are strong acids such as sulfuric or nitric acid.
Asphyxiants are substances which interfere with breathing. Simple
asphyxiants cause injury or death by displacing the oxygen necessary for life.
Nitrogen is a good example. Nitrogen is a normally harmless gas that
constitutes about 78% of the atmosphere. However, nitrogen releases in a
confined space may result in asphyxiation by displacing oxygen. Chemical
asphyxiants are substances that prevent the body from using oxygen or
otherwise interfere with the breathing process. Common examples are carbon
monoxide and cyanides.
Public Review Draft: October 12, 2004 14-2
Anesthetics and Narcotics are substances which act on the body by
depressing the central nervous system. Signs and symptoms include
drowsiness, weakness, fatigue, and incoordination, unconsciousness, paralysis
of the respiratory system and death. Examples include numerous hydrocarbon
and organic compounds.
Hazardous materials may also have a wide variety of more specialized impacts on
human health. Other types of toxic effects are bdefly summarized in TabLe 14.1.
Table 14.1
Other Types of Hazardous Nlaterials
Type of Hazardous Effects on Humans
Hepatotoxin Liver damage
Nephrotoxin Kidney damage
Neurotoxin Neurological (nerve) damage
Carcinogen May result ~n cancer
Mutagen May produce changes in the genebc material of ceils
Teratogen May have adverse affects on sperm, ova, or fetal tissue
Rad~oacbve matenals May result directly ~n radiation s~ckness at h~gh exposure levels or
act as carcinogen, mutagen, or teratogen
infectious substances Biological materials such as bacteria or viruses that may cause
illness or death
Much of the information above was summarized from Chapter Six of the Handbook of
Chemical Hazard Analysis Procedures~. The first few chapters of this handbook
contain a concise summary of many of the technical aspects of hazardous materials.
These chapters may be useful to readers seeking a more technical introduction to the
nomenclature and science of hazardous materials.
14.3 Classification System and Emergency Response Protocols
A standardized system is used to classify and identify hazardous materials. The 2000
Emergency Response Guidebook (A Guidebook for First Responders During the
Initial Phase of a Dangerous Goods/Hazardous Material Incident)2 outlines the
classification system. The 2000 Emergency Response Guidebook is an extremely
useful reference book that provides standardized first response protocols and detailed
reference sheets for the most common classes of hazardous materials.
Hazardous mateda~ releases are predominantly accidental results of traffic accidents,
equipment failures or human errors, in rare cases, hazardous material releases may
result from deliberate actions of sabotage or terrorism.
First responders for hazardous matedal incidents are generally public safety
personnel (po]ice, fire or EMS). The standard protocols for first responders are bdefly
summarized below, following guidance in the 2000 Emergency Response
Guidebook,
The primary guidance for first responders is to:
a) resist rushing in,
Public Review Draft: October 12, 2004 14-3
b) approach the incident site from upwind, uphill or upstream, and
c) stay clear of all spills, vapors, fumes and smoke.
Upon approaching the incident site, a three-step procedure is recommended:
a) identify the material,
b) find the material's three digit guide number, and
c) read the numbered guide carefully and respond accordingly.
identification of hazardous materials is by finding any one of the following:
a) the four-digit iD number on a placard or orange panel,
b) the four-digit ID number on a shipping document or package, or
c) the name of the matedal on a placard, shipping document or package.
Once identified by iD number or name, the material's three-digit guide number is
~ooked up in either the ID number index or the name index. Then, the procedures and
precautions outlined in the guide for the identified class of material are carefully
followed. For each class of material, the guides have cdtical information on potentia~
hazards, suggested evacuation distances for small and large spills, and
recommended emergency response actions, including first aid. For further technical
details see the 2000 Emergency Response Guidebook.
In Oregon, the Office of State Fire Marshal has defined standard response protocols
for hazardous materials incidents in a series of Standard Operating Guidelines3. This
series of about a dozen standard operating guidelines covers every main aspect of
emergency response and recovery, including decisions to respond, levels of
response, general response guidelines, mitigation methods, decontamination
procedures, personal protective equipment, and others.
In Oregon, there is a three-level response plan for hazardous material incidents
involving first responders and specialized emergency response teams.
First responders are local staff, generally public safety staff (police and fire) that are
trained in basic procedures for the initial (first) response to hazardous materials
incidents. The responsibilities of first responders include securing the incident scene
and making a preliminary assessment of the potential severity of the hazardous
material incident and the level of threat, if any, to persons in and outside of the
immediate incident area.
Emergency response teams are specialized teams, composed primarily of public
safety staff, with higher-level training and more specialized equipment for dealing with
hazardous materials incidents than first responders. In Oregon, there are fourteen
emergency response teams, each with a defined geographic area of primary
responsibility. Statewide, these emergency response teams respond to about 350
hazardous material incidents per year, or about one per day, on average (Standard
Operating Guidelines, Team Background3). For the Eugene/Springfield Metro Area,
the Hazardous Materials Response Team primary responsibility is the HM02 Eugene
Team with responsibility for Lane County.
Public Review Draft: October 12, 2004 14-4
The three-level response plan for hazardous materials incidents is characterized as
Level I Response, Levd Il Response and Level Ill response. The distinction between
Levels I, H, and tli depends on:
a) class of hazardous material
b) size of container
c) fire/explosion potential
d) ~eak severity and container integrity, and
e) threat to life safety.
Level I Responses are those incidents readily controlled or stabilized
by first responders. The HazMat Emergency Response Team
personnel may provide technical assistance via telephone or omsite
assistance, but full response by an Emergency Response Team is not
required,
Level Il Responses are those incidents that require response from a
HazMat Emergency Response Team for control or stabilization of the
spill. The Emergency Response Team response level may be 2-4
personnel for identification of the matedal and guidance on appropriate
response actions or the response level may be a small team response
of 6-8 personnel.
Level III Responses are those incidents that require specia~ resources,
including one or more full Emergency Response Teams and possibly
other outside agencies for support.
Further technical details of the Level I, II, and III responses are given in the Standard
Operating Guidelines, Levels of Response to Hazardous Materials Incidents, %003.3
A very useful glossary of technical terms used for hazardous materials incidents is
given in the Glossary of Terms (Standard Operating Guidelines, Glossary of Terms,
SOG-T002.3)
14.4 Statutory and Regulatory Context
The manufacture, storage, use, transportation, and disposal of hazardous materials
are subject to a myriad of federal, state, and local regulations. In the context of
mitigation planning and emergency response, we focus on reporting requirements for
chemicals subject to mandatory risk management planning and extremely hazardous
substances subject to additional reporting and planning requirements.
Section 112(r) of the Clean Air Act Amendments was designed to prevent accidental
releases of hazardous substances. The rule establishes a list of chemicals and
threshold quantities that identify facilities subject to subsequent accident prevention
regulations. The listed substances have the greatest potential to pose the greatest
hazard to public health and the environment in the event of an accidental release.
The full list of Section 112(0 chemicals, including planning threshold quantities (TPQ)
is given in Appendix 1, Table A1.1 of the Phase Three Plan.
Public Review Draft: October 12, 2004 14-5
Hazardous materials may be released to the environment either routinely during
manufacturing and other ongoing processes or accidentally. Certain types of
businesses are required to report such releases annually for a specified ~ist of
chemicals. The paragraph below, quoted from the Office of State Fire Marshal,
Hazardous Substance Information System (HSIS)4, summarizes the intent and
content of the regulatory requirements for substances covered under the Toxic
Release Inventory regulations.
"The Toxics Release Inventory (TRI) Program was established by
section 113 of the Emergency Planning and Community Right to Know
Act (EPCRA) of 1986. Under this program certain businesses are
required to submit reports each year on the amounts of toxic chemicals
their facilities release into the environment, either routinely or as a result
of accidents."
There are additional reporting and planning requirements for materials deemed to be
extremely hazardous. The paragraphs below, quoted from the Office of State Fire
Marshal, Hazardous Substance Information System (HSIS)4, summarize the intent
and content of the regulatory requirements for extremely hazardous materials.
"SARA Title Ill, section 302 requires owners and operators to notify the
State Emergency Response Commission (SERC) regarding the
presence of Extremely Hazardous Substances (EHS) at their facilities.
Section 303 requires facilities that possess a threshold p~anning
quantity (TPQ) of an EHS to develop a contingency plan in case of an
accidental release, and assist emergency planners and emergency
response organizations in developing a plan to protect the community
from possible injury from a release of dangerous chemicals."
The full list of substances designated as Extremely Hazardous Substances (EHS) is
given in Appendix 1 as Table A1.3 of the Phase Three Plan.
In addition to the Oregon and Federal requirements, the City of Eugene also has a
Toxics Righbto-Know program that was adopted by local voters in November 1996.
The intent of this regulation is to make information about use and release of
hazardous materials more available to the general public. The Eugene program
requires affected businesses to provide materials balance accounting, meaning that
inputs and outputs of hazardous substances must be reported and must balance.
Annual reports are available at the Eugene Public Library and online at
www.d.eugene.or, us/toxics. These additional reporting requirements apply to
stationary facilities which employ the equivalent of ten or more full-time employees,
are engaged in manufacturing, and have inputs of hazardous materials totaling 2,640
pounds or more of hazardous substances in a calendar year.
The Federal Safe Drinking Water Act of 1986 required all states to have a Drinking
Water Protection Program to guard against contaminants to groundwater; these
requirements were extended in 1996) to include surface water sources. EPA certified
Oregon's Wellhead Protection Program in 1995. Under this program, communities
are required to delineate the drinking water protection areas around public drinking
water supply wells and develop contamination source inventories, identifying potential
Public Review Draft: October 12, 2004 14-6
sources of groundwater contamination within the delineated areas and the risks
associated with those potential sources, The primary risk for contamination to the
public ddnkin9 water is from hazardous materials spilled onto the 9round or allowed to
enter the storm drains or surface water.
Springfield has delineated the drinking water protection areas around the public water
supply wells operated by the Springfield Utility Board and Rainbow Water Distdct in
addition to the surface water protection area for the water treatment plant on the
middle fork of the Willamette River operated by the Springfield Utility Board. The
delineations have been certified by the Department of Human Services Ddnkin9 Water
Program, Certification Number 002. As part of the risk evaluation done in developing
the Drinking Water Protection Plan, aquifer sensitivity analysis were preformed that
identified hazardous materials as a high risk with dense nomaqueous phase liquids
(DNAPL's) posing the highest risk for aquifer contamination. DNAPL's are a separate
subset of hazardous materials (most are chlorinated solvents) that are heavier than
water, sink in the aquifer, and are very hard to clean up.
Springfield has adopted Article 17, which identifies an overlay zone and protective
measures addressing hazardous material use and storage for new businesses inside
the zones of contribution in the Drinking Water Protection Areas. All new or
expanding businesses inside the overlay zone are required to 9o through the plan
review and approval process to assure compliance with the ordinance and protection
of the drinking water resource. Inspection and follow up are provided by Springfield
Utility Board in cooperation with the City of Springfield.
14.5 Fixed Site Hazardous N~aterials Locations in Lane County and the
EugenelSpringfie~d N~etro Area
The Oregon Office of State Fire Marshal maintains a comprehensive listing of
hazardous substances locations in Oregon4, Key data for Lane County and the
Eugene/Springfield Metro Area are shown below in Table 14.2,
Table 14.2
Summary of Hazardous Substance information System (HSIS) Data
Sites with:
Tota~ Reportable 112(r)~ 313 (TRI)2 EHS3
County Reports Quantities Chemicals Chemicals Chemicals
Lane 4474 1773 1048 450 157
Eugene 2489 939 559 281 77
Springfield 735 292 180 97 38
Metro Area 3224 1231 739 378 115
~ Chemicals reportable under Section 112(r)
2 Chemicals reportable under Section 313,Toxics Release Inventory
3 Extremely hazardous substances
For Lane County, the HSIS database has hazardous materials reports for 4474
companies and other entities such as cities and universities that have hazardous
Public Rewew Draft: October 12, 2004 14-7
materials. Of these report locations, 1773, or about 40%, have reportable quantities
of hazardous materials.
For the Eugene/Springfield Metro Area, the HSIS database has hazardous materials
reports for 3224 companies and other entities, including the Cities of Eugene and
Springfield and the U of O that have hazardous materials. 1231 of these sites in the
Eugene/Springfield Metro Area have reportable quantities.
As shown in Table 14.2, the Eugene/Springfield Metro Area also has 739 sites with
Section 112(0 chemicals, 378 sites with Section 313 Toxics Release Inventory
chemicals, and 115 sites with Extremely Hazardous Substances. Over time, some
sites with certain chemicals may no longer have such chemicals and existing or new
sites may add chemicals. Overall, however, the data in Table 14.2 are representative
of the overall hazmat inventory picture for Lane County and the Eugene/Springfield
Metro Area. See annual updates of the HSIS database for current inventory data.
For mitigation planning purposes, Extremely Hazardous Substances are of special
concern. At present, the EPA maintains a list of 366 chemicals that are considered
extremely hazardous or acutely toxic. This list was developed under the Superfund
Amendments and the Reauthodzation Act. The designation of a substance as
Extremely Hazardous is a regulatory designation that triggers mandatory reporting
requirements. This designation is not a technical classification. That is, there are
many other substances, besides these 366, which are in fact extremely hazardous to
human health. Thus, for planning purposes, the consideration of extremely hazardous
substances should not be limited only to those substances on EPA's list of EHS.
14.6 Hazardous Materials Transport: Truck Shipments, Rail Shipments and
Pipelines
t4.6.1 Overview and Truck Shipments
Chapters 4 and 5 of the 2002 Regional All Hazard Mitigation Plan for Benton, Lane
and Linn Counties (Phase Three) covers hazardous material transport by truck, rail
and pipelines in detail. This section of the Eugene/Springfield Metro Area Mitigation
Plan provides a brief summary.
Hazardous materials may be transported once or many times during their "life cycle"
of raw materials, manufacturing, incorporation in other products, wholesale and retail
trade, use, waste disposal, and recycling. The transport of hazardous materials may
be local within a single city or across a state, across the country or internationally.
For the Eugene/Springfield Metro Area, a general perspective on hazardous materials
incidents is provided by annual statistics of hazardous materials incidents5, prepared
by the Office of State Fire Marshal. These incident reports include all reported
hazardous material incidents, at fixed sites and during transportation, except generally
excluding:
a) motor fuels which are spilled in quantities less than 42 gallons,
b) sewage overflows,
Public Review Draft: October 12, 2004 14-8
c) structure fires or other emergencies where hazardous substances are
involved as exposures, if the quantities exposed are less than 42 gallons.
For 2002, there were a total of 260 incidents or less than one per day statewide, with
only 29 reported incidents in all of Lane County. In Lane County, 23 of the reported
incidents were in Eugene and 3 were in Springfield. Statewide. 72 incidents, or about
27% of the total incidents occurred on public roads or highways. Only 21 incidents
were identified as being due to motor vehicle accident. The majority of reported
incidents on roads must therefore be a result of equipment failures (e.g, leaking
tanks) or law enforcement actions (e.9., drug lab chemicals).
Incidents were also reported in private structures (67), private land (62), public
structures (25), waterways (18), public lands (11 ), private roads (2), forests (3) and
other (11). These state wide data are probably approximately representative of the
long term distribution of incidents expected for Lane County and for the
Eugene/Springfield Metro Area.
Most of the reported year 2002 incidents involve a relatively small number of
hazardous materials, as shown below in Table 14.3. Table 14.3 contains the most
common materials involved in incidents as well as particularly hazardous materials.
Overall, the 2002 incidents involved a total of 98 different materials. These statewide
data present a very useful overview of hazardous material incidents in Oregon. For
Lane County and the Eugene/Springfield Metro Area, the general pattern of
hazardous materials is likely to be similar to the statewide pattern below. Most
hazardous materials incidents in the Eugene/Springfield Metro Area are likely to be
the most commonly involved materials as shown below (i.e., drug lab chemicals, fuels,
and motor vehicle fluids). Fuels include gasoline and diesel fuel, propane, and natural
gas,
Table 14.3
Hazardous Materials Incidents in 20025
Reported Categories of Hazardous Materials
Chemical Number of
Incidents
D~esel, gasohne, fuel oil 44
Drug lab chemicals 26
Natural 9as 19
Antifreeze, motor oil, hydraulic 12
fluld, transmission fluid
Propane 10
No chemical involved 15
Subtotal 126
Unknown chemical 36
Munabc acid 7
Red phosphorus 6
iodine 4
Ammoma 4
Chlonne 3
Acetone 3
Methanol 3
Methane 2
Public Review Draft: October 12, 2004 14-9
Red Devil Lye 2
Sodium hydroxide 1
Sulfuric ac~d 1
Subtotal 72
Substantial hazmat releases from truck shipments, especially of extremely hazardous
substances, may pose a significant life safety risk to workers and nearby residents.
Highway transport of hazardous materials also poses a risk of contamination to
surface water that provides drinking water to the City of Eugene and to both surface
and groundwater that provide ddnking water for the City of Springfield.
14.6,2 Rail Shipments
There are 21 railroads currently operating in Oregon, according to 2002 data from the
Oregon Department of Transportation website (www.odot.state.or.us/rail).
Addresses and contact information for all of these railroads are given on the above
referenced website, as are website addresses for several of the larger railroads.
The main railroads serving the Eugene/Springfield Metro Area are the Burlington
Northern Santa Fe and the Union Pacific. Representative data on hazardous
materials shipments by these rail lines are given in the Regional All Hazard Mitigation
Master Plan for Benton, Lane, and Linn Counties (Phase Three, 2002), Tables 5.3 to
5.{5.
Substantial hazmat releases from rail shipments, especially of extremely hazardous
substances, may pose a significant life safety risk to workers and nearby residents.
Railroads often parallel or cross streams and rivers in Lane County. Rail transport of
hazardous materials thus poses a risk of contamination to surface water supplies for
both Eugene and Springfield.
However, the overall safety record for rail shipments is good. In 2002, the State Fire
Marshal's Annual Report of Hazardous Material Incidents does not include any rail
events.
14,6.3 Pipelines
There are three types of major fuel pipeline systems in Lane County:
1) the Williams natural gas transmission line which runs from British
Columbia, through Oregon and Washington to California,
2) natural gas distribution systems run by utilities in most cities, and
3) the Kinder Morgan petroleum products pipeline which runs from Portland to
Eugene/Springfield.
For more detailed information about these pipelines see Chapter 6 of the Phase Three
Regional Plan. A brief synopsis is presented below.
The Williams natural gas pipeline runs through Eugene, with two compressor stations
in the area. The United States Department of Transportation Office of Pipeline Safety
regulates interstate pipelines. USDOT imposes a broad range of standards and
inspection requirements for pipeline design, material specifications, construction
Public Review Draft: October 12, 2004 14-10
standards, maintenance and testing requirements. For the United States as a whole, a
network of about 300,000 miles of natural gas transmission ~ines serve about 1.5
million miles of distribution system lines which serve about160 million customers.
Overall the safety record of natural gas transmission pipelines is good with relatively
few significant accidents.
The Eugene/Springfield Metro Area also has a natural gas distribution system within
Eugene and Springfield operated by Northwest Natural Gas. The natural gas pipeline
systems of local gas utilities, including the systems in the Eugene/Springfield Metro
Area, almost always follow road and street patterns because of established utility
rights of way and because of the need to connect with each building served. Thus, for
areas served by natural gas, the local street network is essentially identical to the
natural gas distribution pipe network.
Overall, the safety record of natural gas distribution pipelines is good with relatively
few significant accidents. Natural gas is not toxic (i.e., not poisonous). However,
natural gas can be an asphyxiant if it displaces oxygen in an enclosed space. Natural
gas burns readily when ignited, but only when gas concentrations are between 4%
and 15% in air. In its pure state, natural gas is both colorless and odorless. The
strong odor normally associated with natural gas is an odorant deliberately introduced
at Iow concentrations to serve as a warning of the presence of natural gas. The
strong odorant is generally added to natural gas at the local distribution level, by local
gas utilities.
Fires and/or explosions from natural gas leaks in pipelines are rare. In part, the rarity
of fires and/or explosions is due to the fact that natural gas is about 1/3rd less dense
than ordinary air. Thus, leaking natural gas does not accumulate near the ground or
"pond" in Iow-lying areas (as heavier gases such as liquefied natural gas or gasoline
fumes may do). Instead, leaking natural gas rises rapidly and is dissipated by dilution
in the atmosphere. The fires and/or explosions that do occur from natural gas leaks
are generally in buildings where the confined space allows leaking gas to accumulate
until ignited. In 2000, annual statistics of hazardous materials incidents5, prepared by
the Office of State Fire Marshal, show only 45 natural gas incidents statewide in
Oregon.
Pipeline breaks due to natural causes may occur due to landslides or earthquakes.
Earthquake induced pipe breaks for natural gas transmission lines are most likely to
occur in areas of soft soils subject to liquefaction and/or lateral spreading which cause
significant pipe displacements. The most likely locations for such breaks during an
earthquake are on slopes of soft ground near where pipelines cross rivers or streams.
The most common human-related cause of pipeline breaks is pipeline rupture due to
pipes breaking when heavy construction equipment is used to excavate for
construction projects. Most such breaks occur in local distribution lines. For major
transmission lines, breaks are possible, but much less common, because of the
robustness of the transmission pipelines and because the major transmission lines are
generally well marked with frequent warning signs. Major pipeline breaks could disrupt
gas service over wide areas with resulting significant economic impacts. Pipeline
breaks can also be caused by deliberate actions of sabotage or terrorism. Although
Public Review Draft: October 12, 2004 14-11
pipelines are not symbolic targets with political, historical, and cultural significance,
they are potentia~ targets for terrorist actions.
Natural gas utilities and local emergency responders are generally well prepared to
deal with natural gas breaks, because such incidents occur frequently enough to have
well-standardized response procedures. Evacuations for natural gas distribution
system pipeline ruptures are generally limited to the immediate area of the break.
The Kinder Morgan petroleum pipeline transports refined petroleum products,
including gasoline, diesel fuel and both commercial and military jet fuel. This pipeline
runs from Portland to the Eugene terminal, with an intermediate truck-load/n9 terminal
near Albany. From the terminals, petroleum products are transported by truck to
customers.
Major petroleum transmission lines, such as the Kinder Morgan line in Oregon, are
heavily engineered and generally constructed of welded steel pipe that is strong and
reasonably flexible. Major failures are rare, but may occur due to natural or human-
related causes. Pipeline breaks due to natural causes may occur due to landslides or
earthquakes. Earthquake induced pipe breaks for petroleum transmission lines are
most likely to occur in areas of soft soils subject to liquefaction and/or lateral
spreading which cause significant pipe displacements. The most likely locations for
such breaks during an earthquake are on slopes of soft 9round near where pipelines
cross rivers or streams.
14.7 Potentia~ Impacts of Hazardous Material Incidents
The potential impacts of hazardous materials incidents on the Eugene/Springfield
Metro Area are summarized below in Table 14.4
Table 14.4
Potentia~ impacts of Hazardous Mateda~ incidents on the Eugene/Springfield Metro Area
Inventory Probable Impacts
Most hazmat incident impacts would be Iocahzed near source of
Portion of Eugene/Springfield Metro
Area affected spdl, but major spills could have extensive evacuation zones and
affect a significant port~on of the Eugene/Springfield Metro Area
Negligible impact, except for very near incidents which revolve
BuiMings explosions
Streets within Metro Area Temporary street closures likely
Roads to/from Metro Area Temporary road closures likely
E~ectdc power Neghg~ble impact, except for very near incidents which involve
explosions
Negligible impacts, except for incidents which spdled hazmat into
Other Utilities rivers upstream from water intakes for Eugene/Springfield water
systems
Potential for casualties (deaths and injuries), depending on
Casualties location and identify of hazmat material(s) involved, bme of day
and effecbveness of evacuations
Public Review Draft: October 12, 2004 14-12
14,8 Summary and Mitigation Strategies
14.8,1 P~anning and Response
Hazardous materials vary dramatically in their degree of toxicity to humans. The
impact of a hazardous material release incident on an affected community depends on
several factors including:
g) the toxicity of the hazardous material,
h) the quantity of the hazardous material released,
i) the dispersal characteristics of the hazardous material,
j) the local conditions such as wind direction and topography, soil and ground
water characteristics, and proximity to critical public resources such as
drinking water supplies,
k) the population of nearby areas likely to be affected by hazardous materials
incidents, and
I) the efficacy of response and recovery actions.
Effective mitigation planning and effective emergency response planning can help
reduce the number or frequency of hazardous materials incidents and also reduce the
severity of incidents that do occur. In combination, these benefits can significantly
reduce the negative impacts of hazardous materials incidents on affected
communities. The general principles of mitigation planning and emergency response
planning (and training) are well standardized and practiced by Lane County and the
Eugene/Springfield Metro Area.
Perhaps the single most critical factor in enhancing both mitigation planning and
emergency response planning is specific inventory awareness for major hazardous
materials sites within each jurisdiction. Specific inventory awareness means detailed
knowledge of the types of hazardous materials, quantities of hazardous materials and
locations of every location in a jurisdiction with significant quantities of hazardous
materials. In this context, what constitutes a significant quantity varies depending on
the toxicity of the material, the dispersal characteristics and the nature and population
of nearby areas likely to be affected by hazardous materials incidents.
The Office of State Fire Marshall's Hazardous Substance Information System (HSIS)
database contains a vast amount of information on the inventories of hazardous
materials at fixed locations in the Eugene/Springfield Metro Area. This detailed
inventory information along with data hazardous materials being transported within or
through the Eugene/Springfield Metro Area, provides the basic data for specific
inventory awareness. In combination, with the chemical data and emergency
response information provided in the 2000 Emergency Response Guide and in other
sources, these are the basic data necessary for effective planning and effective
emergency response.
The complexity and overload of information is compounded by numerous labeling,
placarding, and classification systems for hazardous materials, with countless cross
references to guide numbers, material safety reports and so on. Because of this vast
amount of complex information, effective mitigation planning and emergency response
planning must occur before an incident occurs, not after. During an incident, the most
Public Review Draft: October 12, 2004 14-13
effective response is precluded and impossible to achieve if emergency personnel are
thumbing through databases trying to figure out which hazardous materials are at a
given location and what the appropriate response precautions and protocols are for
the specific materials involved in a hazardous materials incident.
Specific inventory awareness means that for every site with hazardous materials of
sufficient toxicity, dispersal characteristics and quantities to pose a significant life
safety risk to on-site employees and nearby residents must be identified in advance.
Ideally, the Eugene/Springfield Metro Area should have detailed specific inventory
awareness of every significant fixed site in its jurisdiction. Similarly, each jurisdiction
should have specific inventory awareness of the most toxic, most common, large
voiume shipments of hazardous materials within and through the jurisdiction. For
each hazardous matedal deemed to pose a significant life safety threat, the necessary
chemical data, response protocols, initial isolation distances, protection distances for
small and large spi~ls, and all other data necessary for safe and effective response
should be compiled and readily available before incidents occur.
Public Review Draft: October 12, 2004 14-14
14.8.2 ~itigation Nieasures
Specific inventory awareness is one cornerstone of reducing the potential for negative
impacts from hazardous materials incidents by helping to optimize emergency
planning and response planning. The other cornerstone is pro*active mitigation
actions to reduce the number and severity of hazardous materials incidents.
The most common mitigation measures for reducing the potential of damaging
hazardous materials incidents are briefly summarized below.
14.8.2.1 Physical Safety Measures
Tanks and other storage containers and transfer systems (valves, pipes etc.) for
hazardous materials are frequently subject to damage in earthquakes, with a
correspondingly high potential for accidental releases. Proper seismic design, bracing
and anchoring of storage systems for hazardous materials can greatly reduce the
potential of accidental releases during earthquakes. Bracing and anchoring measures
for storage containers and transfer systems (e.g., piping) are often relatively
inexpensive, with a large improvement in seismic performance. For small quantities of
materials stored in bottles or jugs on shelving, bracing shelving and restraining
containers so that they do not fall in earthquakes are particularly important.
Over time, the storage containers and other material handling elements for hazardous
materials may be changed many times. In some cases, later modifications may not
be designed to the same seismic standards as the original installation or later
modifications may compromise the seismic stability of the original installation.
Therefore, periodic review and inspections of seismic design, bracing and anchoring
are highly recommended for all hazardous material facilities.
For facilities located in mapped flood plains or other areas subject to floodwaters there
are two important physical safety measures. First, any containers subject to floating
should be properly restrained. In many floods, improperly restrained tanks break flee
and float downstream, with high potential for negative consequences, including fires
from tanks containing flammable materials as well as accidental releases of
hazardous materials. Second, special precautions should be taken with water-
reactive materials. Such materials should never be stored in Iow-elevation areas
subject to flooding or in locations subject to water from storm water drainage or
plumbing failures in a facility.
14.8.2.2 Standard Operating Procedures
Standard operating procedures for storing, transporting, and handling hazardous
materials should be strictly enforced at all facilities. Appropriate training for all staff,
with review courses and appropriate protective gear are essential for safety. Rigorous
inspection and enforcement of hazardous materials regulations (federal, state, and
local) are an important part of the overall process of ensuring safety.
Public Review Draft: October 12, 2004 14-15
14.8.2.3 Mitigation and Emergency Response Planning
Effective pre-event mitigation planning and emergency response planning can help
reduce the severity of hazardous material incidents. From the mitigation planning
perspective, specific inventory awareness of the types and quantities of hazardous
materials present at each faciJity is particular important. Local fire departments and
other responders should be thoroughly familiar with the specific inventory at each
facility containing hazardous materials and with the appropriate response protocols for
each hazardous mater'iai. First responders and emergency response teams must
both have the full range of protective gear and equipment necessary for their
respective roles in responding to hazardous materials incidents.
Emergency response planning should include thorough training in all aspects of
hazardous materials response, including appropriate response protocols (procedures,
protective gear and equipment). Frequent refresher training and frequent exercises
(both tabletop and full field exercises) are essential for safe and effective emergency
response. Training exercises should include both first responders and emergency
response teams, to help ensure appropriate coordination of efforts during actual
hazardous materials incidents.
14.8.2.4 Drinking Water Protection Planning
Public drinking water sources for both the cities of Eugene and Springfield originate in
Springfield. Surface water from the McKenzie River is treated at Eugene Water &
Electric Board's (EWEB) Hayden Bridge Treatment Plant in Springfield for use in
Eugene. Water for the city of Springfield is provided by the Springfield Utility Board
(SUB) from 3t public supply wells (90%) supplemented with water drawn from the
Middle Fork Willamette River (10%). Surface and a portion of the well water are
treated at SUB's slow sand filtration plant in the Willamette wellfield. However, SUB's
filtration plant does not treat for hazardous materials and at EWEB's plant, treatment
for hazardous materials is minimal.
Public drinking water is a vital resource that is vulnerable to the release of hazardous
materials. Many facilities that store hazardous materials are located close to these
resources and transportation lines, both highway and rail, pass within yards of supply
wells and surface water sources. To address this issue, regulatory steps have been
taken by the community to help reduce the risk of drinking water contamination from
hazardous materials.
In 1999, the City of Springfield adopted a Drinking Water Protection Plan (DWPP).
This was followed in 2000, by Article 17 of the Land Use Development Code that
effectively limits quantities, storage, and types of hazardous materials that can be
used, stored, or produced by new businesses within a defined area surrounding
Springfield's public supply wells. When surface water was added as a drinking water
resource in 2002, the city adopted an addendum to the DWPP that directed public
policy to support outside agencies and organizations in their efforts to protect water
within the supply areas outside their political boundaries.
Public Review Draft: October 12, 2004 14-16
Other protective programs include the McKenzie Watershed Emergency Response
System (MWERS) spearheaded by EWEB and the Unified Release Notification
System (URNS) coordinated by SUB for the Middle Fork Willamette Watershed.
The MWERS will coordinate efforts by initial responders up and down the McKenzie
River watershed to mitigate damage from hazardous materials to vital and/or sensitive
resources. MWERS contains GIS information on: watershed characteristics; threats;
critical resources; spill response strategies to protect critical resources; response
equipment; emergency contact and notification information; and incident
communications. First responders and others are able to use this GIS application in
the field to efficiently and effectively stabilize accidental or intentional chemical
releases as soon as possible and to minimize the initial confusion often associated
with spills. URNS is an interim step in development of a Middle Fork Willamette
Watershed Emergency Response Plan to be modeled after MWERS. The URNS
uses a central point of contact (911) to provide timely notification of an upstream
release of hazardous materials to requesting agencies with vita~ or sensitive resources
adjacent to the Middle Fork Willamette River. This system allows individual agencies
to close off intakes and/or provide other protective measures for their own resources.
The table on the following page has hazmat mitigation action items from the master
Action Items table in Chapter 4.
References
1. Handbook of Chemical Analysis Procedures, Federal Emergency Management
Agency, U.S. Department of Transportation, and U.S. Environmental Protection
Agency, U.S. Government Printing Oflqce, 1988.
2, 2000 Emergency Response Guidebook (A Guidebook for First Responders
During the Initial Phase of a Dangerous Goods/Hazardous Material Incident),
developed jointly by the U.S. Department of Transportation, Transport Canada,
and the Secretariat of Transport and Communications of Mexico, 2000.
3. Hazardous Materials Emergency Response Teams Standard Operating
Guidelines, May 7, 2001 Office of State Fire Marshal (Oregon). This series of
about a dozen standard operating guidelines covers every main aspect of
emergency response and recovery, including decisions to respond, levels of
response, general response guidelines, mitigation methods, decontamination
procedures, personal protective equipment, and others.
4. Hazardous Substance Information System (HSIS), Office of State Fire Marshall,
Version 1.3P, March 2002. Microsoft Access Database on CD-ROM.
5. 2002 Annual Report of Hazardous Materials Incidents in Oregon as Reported
by Oregon Fire Service, Office of State Fire Marshal (Oregon), 2002.
6. 1998 Milepost Inventory Update Form, Burlington Northern & Santa Fe Railroad,
April 30, 1999.
Public Review Draft: October 12, 2004 14-17
15.0 TERRORISM
15.1 Overview
For mitigation planning, terrorism is broadly inclusive of a wide range of deliberate
malevolent acts intended to damage buildings, infrastructure or to result in deaths and
injuries. The possibility of international terrorist organizations targeting the Eugene/
Springfield Metro Area, is not zero, but is certainly small. However, the Eugene/
Springfield Metro Area is certainly subject to deliberate malevolent acts from many
sources including vandals, mentally disturbed individuals, domestic terrorist groups, as
well as by disgruntled residents, and past or present employees.
The range of possible malevolent actions includes vandalism, arson, explosions and
armed attacks, as well as use of chemical, biological, radiological or nuclear materials.
Chemical attacks include deliberate release of on-site chemicals as well as deliberate
dispersal of transported hazardous materials. Biological attacks include deliberate
dispersal of biologically active materials (e.g., anthrax) capable of causing sickness or
death. Radiological attacks include deliberate dispersal of radioactive materials, via dirty
bombs (conventional explosives laced with radioactive materials) or other methods.
Nuclear attacks include explosion of nuclear devices and the radioactive fallout from such
explosions.
The range of possible malevolent actions also includes cyber-terrorism, or deliberate
disruption/damage of computer systems and data. Especially for utility systems, cyber-
terrorism can also result in loss of service due to disruption/damage to automated SCADA
(Supervisory Control and Data Acquisition) systems widely used by utilities.
15.2 Threat Spectrum
For purposes of mitigation p~anning, we consider three sources of terrorist (malevolent)
actions: outsiders, insiders, and hackers. In each case, we consider three levels of
attack, with the levels reflecting the numbers of individuals involved, the level of technical
knowledge or expertise, and the level of equipment or tools available. This threat
spectrum is summarized below in Table 15.1.
In Table 15.1, outsiders means anyone who is not an employee of the facility under
potential terrorist attack. Outsiders could be vandals, disturbed individuals, or members
of domestic or international organized groups. For the Eugene/Springfield Metro Area,
the most likely terrorist or malevolent acts are minor vandalism or actions by disturbed
individuals or employees. Deliberate terrorist actions are most likely from domestic
groups and are unlikely to be from international organizations.
In Table 15.1, insiders means anyone who is an employee of the target under potential
attack. Acts of vandalism, theft and other relatively minor actions are common. Larger
scale malevolent acts are less common but still occur with some frequency. Such acts
include larger scale damage, arson, explosives, and such actions as contamination of
water supplies.
Public Review Draft: October 14, 2004 15-1
In Table 15.1, computer hackers means individuals or groups using remote access to
explore, vandalize, or destroy websites, computer databases and such. For utility
systems, hackers can also interfere with or usurp contro~ of SCADA systems and may
thus affect system operations directly.
Table 15.1
Threat Spectrum for Terrorist Actions
Adversary Number of Equipment
Adversaries Level of Knowledge Weapons Objectives
Tools
Extensive knowledge of hand tools, handguns or automabc Extensive damage to cnbcal
Outs,der h~gh level 1 to small group security systems, power tools, weapons, ~ncend~ary dewces, faclllbes, w~despread
facfl~bes and modes of
vehicles expios,ves, contaminants damage or casualties
attack
Limited knowledge of hand tools,
OutsCder medium leve[ 1 to 3 secunty systems, handguns, ~ncendlary devices,
facilities and modes of power tools, exploslves, contaminants Damage or casualues
vehicle
attack
M~mmal knowledge of
Outsider low level 1 or 2 secunty systems, hand tools None Vandahsm, damage or
facdltles and modes of casualties
attack
Extensive knowledge of On s~te tools,
Insider h~gh leve~ I secunty systems, chemicals, handguns or automatic
facd~bes, operabons, equipment, weapons, incendiary devices, Damage or casualbes
pohc~es and procedures vehicles explosives, contaminants
Moderate knowledge of On s~te tools,
security systems, chemicals, handguns, ~ncendlary devices, Damage or casualbes
Insider med~ujm level 1 facdltles, operations, equ~pmem, explosives, contaminants
pohcles and procedures vehicles
L~mlted knowledge of On s~te tools,
secunty systems, chemicals, Vandalism, damage or
Insider Iow level 1 facq~bes, operabons, equipment, handgun or none casualties
pohc~es and procedures vehicles
Fud knowledge of IT Soph~sbcated Destruction of data and
Hacker high level 1 to small group ~ntrastructure, security
systems, SCADA hacker tools N/A systems, bus,ness
and methods operabons
systems
Moderate knowledge of Moderately Demal of servc~e or
Hacker, medium level 1 or 2 IT ~ntrastructure, security sophlsbcated N/A d~srupt~on of some bus,ness
systems, SCADA hacker tools
systems and methods serwces
Dm~ted knowledge of IT
Hacker Iow tevel I ~ntrastructure, security N/A N/A Minor cyberwandahsm to
systems, SCADA non-critical bus,ness areas
system s
The probable impacts of terrorist events on the Eugene/Springfield Metro Area are
summarized below in Table 15.2. For the Eugene/Springfield Metro Area, the most
probable malevolent events are small scale events (vandalism or minor damage) by
insiders or local outsiders or computer hackers. Large scale terrorist actions by domestic
or international groups are possible, but with a low probability.
Evaluation of the potential for terrorist actions has many similarities to other hazards such
as dam failures or major earthquakes where the annual probability of such events is low,
but the consequences may be extremely high. Thus, such unlikely, but certainly possible,
events must be included in prudent mitigation planning. The consequences of major
terrorist actions are extremely high and therefore, pragmatic measures to reduce the
probability of such occurrences and/or to reduce the consequences if they do occur are
certainly warranted.
Public Review Draft: October 14, 2004 15-2
Table 15,2
Probable Impacts of Terrorist Incidents on the Eugene/Springfield Metro Area
Inventory Probable Impacts
Portion of Eugene/Springfield Metro Localized impacts for minor incidents, large porbons or the enbre
Area affected C~ty for extremely unlikely malor incidents
Localized impacts to a single building or a few nearby buddings,
Buildings except for extremely unlikely major ~nc~dents
Streets within Metro Area Some incidents may include temporary street closures
Roads to/from Metro Area Some incidents may include temporary road closures
Some incidents may include temporary loss of electric power in
Electric power localized parts of Eugene/Springfield Metro Area or for the enbre
C~ty
Some incidents may ~nclude temporary loss of ubht~es ~n localized
Other Utilities parts of Eugene/Springfield Metro Area or for the enbre C~ty.
Major damage to water or wastewater treatment plant could result
,n full or par[iai loss of service for extended time periods
Casualties Major events may result in s~gmflcant casualties (deaths and
mjunes)
15,3 Mitigation Actions
Evaluation of the threat of terrorist or other malevolent actions generally includes severa~
steps:
1) determine critical facilities,
2) identify the specific adverse consequences to be avoided,
3) review the likelihood of malevolent actions,
4) evaluate existing countermeasures, and
5) implement a prioritized risk reduction plan.
For the Eugene/Springfield Metro Area, critical facilities include key elements of the water
system, electric power substations, other facilities with hazardous materials (cf. Chapter
14) and important public facilities such as police and fire stations. There are also other
sites of some political significance including the Federal Building, City Hall, and the
University of Oregon.
The most likely adverse consequences are vandalism and minor destructive actions by
outsiders, insiders, or hackers. The evaluation of existing countermeasures should
include:
1) physical security measures, such as fencing, locks and key control, structural
integrity of critical assets, and detection capabilities such as intrusion detection
systems, alarms, operational alarms for utility systems, and general
security/access issues,
2) Cyber security measures, such as protection measures for
business/operational computer systems and SCADA systems, including fire
walls, access, security policies and protocols, including vendor access and
system diagnostics, and
Public Review Draft: October 14, 2004 15-3
3) Security procedures and polices, such as personnel security, physical security,
key and badge control, system control and operational data, chemical and
other vendor deliveries, as well as security and emergency response training,
exercises and drills,
For the Eugene/Springfield Metro Area, vigilance and modest upgrades to existing
physical security, cyber security, and security procedures and policies may be all that are
reasonably required. For the highest profile buildings, such as the Federal Building,
barriers to restrict vehicles reaching close proximity to the building, to the extent practical,
might also warrant consideration.
The potential impacts of terrorism or other malevolent deliberate actions in the
Eugene/Springfield Metro Area can also be mitigated by improving emergency response
capabilities, Such types of actions, such as fires or explosions, are self-evident and
emergency responders are well trained for dealing with such situations,
Other types of actions such as release of radiological materials, bioterrorism, or
contamination of water or food supplies may not be immediately recognized. For such
types of actions, close cooperation with public health officials and awareness of the
possibility of deliberate actions are important. Such situations also commonly require
specialized expertise and equipment to detect and identify the radiologicah biological or
chemical materials used in an attack. Emergency response plans should be updated and
expanded, as necessary, to cover such situations, including protocols for public
notifications and information about appropriate public responses such as shelter in place
or evacuation.
The following table contains terrorism mitigation action items from the master Action Items
table in Chapter 4,
Public Review Draft: October 14, 2004 15-4
sseua~e~¥ o!lqnd
Benefit-Cost Analysis:
Eugene City Hall
Structural and Non-Structural
Seismic Retrofit
Prepared by:
Kenneth A. Goettel
Goettel & Associates Inc.
1732 Arena Drive
Davis, CA 95616
(530) 750-0440
Draft 02
March 18, 2004
1.0 INTRODUCTION
1.1 Eugene City Hall
The Eugene City Hall is a two-story structure designed in 1962 and built in 1964.
The lower level includes a parking structure, mechanical equipment rooms and a
fire station, with about 87,608 square feet. The upper level includes office space
and City Council Chambers, with about 74,777 square feet (excluding the open
plaza area). The building footprint is rectangular (323' x 323').
The structural systems for this building are a combination of moment-resisting
non-ductile reinforced concrete frames coupled with some reinforced concrete
shear walls. As discussed below, the building was built well before current
seismic design standards were established for western Oregon. The building
has significant structural and non-structural seismic deficiencies, with a
significant probability of extensive damage and/or possible collapse at levels of
ground shaking likely in major earthquakes.
The building includes police headquarters, a major downtown fire station, the Fire
Marshal's office, City Manager's office, Human Resources and Risk Management
department, and the municipal courts and court offices.
2.0 MITIGATION PROJECT
A preliminary seismic vulnerability assessment has been conducted for the
Eugene City Hall. Full details of the seismic vulnerability engineering evaluation
(including seismic capacity calculations), along with synopses of previous
seismic vulnerability evaluations, are given in Chapters 2, 3 and 5 of the
Technical Appendix. These chapters include engineering analyses and
numerous photographs of structural building elements (where exposed) and non-
structural elements (including critical equipment) with extensive commentary on
the specific seismic deficiencies identified in this building. These chapters also
include discussion of necessary mitigation actions (seismic retrofits) and
engineering costs estimates for these structural and non-structural retrofits.
This seismic vulnerability assessment has clearly identified specific structural and
non-structural deficiencies. The building was designed in 1962 and completed in
1964. Overall, the amount of steel reinforcing in structural concrete members
and the extent of confinement provided by the steel is much lower than current
design requirements. A major structural deficiency is inadequate shear walls to
provide necessary lateral capacity for earthquake ground motions. Major
structural deficiencies also include "short column" deficiencies on the perimeter
of the first level (retaining walls adjacent to the columns do not have expansion
joints at the column); such deficiencies are known to result in load concentrations
with resulting structural failures to the short columns, leading to partial collapse.
As a result of the design/construction prior to adoption of current seismic building
code and of the specific seismic deficiencies identified by the vulnerability
assessment, the facility is subject to significant damage in future earthquakes,
including:
a) building damage,
b) contents/equipment damage,
c) casualties for occupants,
d) loss of police, fire and other services provided from the building and
accompanying economic impacts.
The proposed mitigation project for this facility addresses all of the major
building-specific structural and non-structural deficiencies identified by the
vulnerability assessment.
The estimated mitigation project costs of $1,435,382 include $1,197,872 for
structural upgrades and $237,510 for non-structural upgrades. Together, these
upgrades total only about $9 per square foot. This modest per square foot cost
arises because the retrofits target only specifically identified seismic deficiencies
rather than bringing the entire building to current code, which would entail a
much higher cost, without significantly improving seismic performance beyond
the level achievable with the proposed mitigation project. A modest retrofit cost
is also possible because the open parking level allows easy access to structural
- members without requiring demolition and restoration of architectural finishes or
' electrical and mechanical systems.
~-~ ~ Table 1
Mitigation Project Engineering Cost Estimate
Structure Cost ($2003)
New Shear Walls, footings, tie beams, attachments
- Assume 53 cubic yards of placed concrete average
- Assume 16 new wall systems
- Assume $600 / cubic yard placed concrete
Construction cost = $600/yd x 53 yds * 16 walls $ 508,800
Allowance for Council Chambers $ 80,000
Initial testing program $ 20,000
Repair of finishes, allowance $ 100,000
Total $ 708,800
Contingency ~ 30% $ 212,640
Total Construction $ 921,440
Engineering, PM, Inspection ~30% $ 276,432
Total $ 1,197,872
Non Structural Retrofit Cost Estimate Cost ($2003)
Council Chamber suspended ceiling - allowance $ 15,000
Pedestrian bridge - allowance $ 20,000
,~-~ Roof level heat exchangers $ 1,500
Main level HVAC Equipment - lateral restraints $ 6,000
Suspended Ceilings - life safety retrofit $ 40,000
Suspended Ceilings - continued operations retrofit $ 20,000
Desk top computer monitors and sensitive equipment $ 8,000
Anchor electrical panel in basement $ 2,000
Pipe lateral restraint / flexibility fittings $ 3,000
Overhead pressure tanks - lateral restraint $ 2,000
Restrain horizontal tank on supports $ 3,000
Restrain dry-type transformer $ 750
Enclose hazardous materials in suitable cabinet $ 2,000
Restrain cabinets with backup power, plus nearby cabinets $ 2,000
Add extra restraint to communication equipment racks $ 750
Anchor large horizontal tank $ 2,000
Anchor heat exchangers $ 1,000
Elevator improvements - allowance $ 6,000
Generator mounts, batteries, fuel supply - allowance $ 1,500
Total $ 139,500
Contingency ~ 20% $ 27,300
Total Construction $ 163,800
Engineering, PM, Inspection ~45% $ 73,710
Total $ 237,510
4
3.0 SEISMIC HAZARD DATA FOR EUGENE
Seismic hazard data from the USGS are summarized in Chapter 4 of the
Technical Appendix. The seismic hazard curve, showing the annual probability
of seismic ground motions is reproduced below. In this figure, the annual
probability is on the vertical axis and the level of ground shaking, expressed as
peak ground acceleration (PGA, in percent of "g" the acceleration of gravity) is on
the horizontal axis. These USGS seismic hazard data are 1996 data, using the
same USGS database as the FEMA Seismic Hazard Calculator. However, these
data use the full USGS (unpublished) seismic hazard data and thus are more
accurate (but completely compatible with) the three data points available on the
USGS website as used in the FEMA Seismic Hazard Calculator.
Figure 1
Seismic Hazard Curve for Eugene
01
001
0004
OODO001
00(I)00001 ....................
00 05 10 t5 20 25
Peak ~l'ouad ~ccelerat(:n - O
The seismic hazard curve above represents the cumulative probabilities of
ground motions from all possible earthquake sources. The three main
earthquake sources are:
1) large earthquakes on the Cascadia subduction zone off the Oregon
coast (interpolate earthquake on the boundary between the subducting
plate and the North American plate)
2) large earthquakes within the subducting plate (intraplate earthquake),
and
3) moderate earthquakes within the continental crust near Eugene.
For purposes of benefit-cost analysis, the seismic hazard data used to generate
the figure above were interpolated to determine the annual probabilities of
various levels of ground shaking (in PGA), as used in the FEMA benefit-cost
analysis software. The exceedance probabilities in Figure 1 were converted to
interval probabilities by subtraction of values at bin boundaries. These results
are shown below in Table 2.
Table 2
Seismic Hazard Data for Benefit-Cost Analysis
Eugene, Oregon
Return
PGA Bin Annual Interval
Period
(% g) Probability (years)
4 - 8 0.004179 239
8 - 16 0.002265 442
16 - 32 0.001324 755
32 - 55 0.000273 3,658
55 - 80 0.000047 21,302
80- 100 0.000009 108,950
>100 0.000006 176,612
As an example, the data in Table 2 may be interpreted as follows. For ground
shaking between 16% and 32% of g, the annual probability is 0.001324 and this
level of ground shaking is expected in Eugene about once every 755 years, on
average.
4.0 BENEFIT-COST ANALYSIS: DATA DOCUMENTATION
4.1 Seismic Hazard Data
Seismic hazard data for Eugene, Oregon are derived from USGS data, using the
same approach as in FEMA's Seismic Hazard Calculator, but using the full
USGS seismic hazard curve which is more accurate than the three data points
available on the USGS website. Seismic hazard data were presented in full in
Section 3.0 above. These data are for a rock site, with a thin layer of firm soil, as
appropriate for this facility's location (see Technical Appendix for documentation).
4.2 Data Documentation Summary
Data sources and documentation are given in Table 3 below and following text.
The following sections contain detailed documentation for building and contents
values, building demolition damage percentage, building specific fragility curves,
casualty rate estimates (derived from building fragility curves), displacement
costs and times, and economic impact of loss of public services provided from
the Eugene City Hall.
Table 3
Data Documentation Summary
concrete frame with
site visit and architectural/engineering drawings
Building type (structural system) some reinforced
concrete shear walls See Technical Appendix for details
Building construction date designed in 1962,
built in 1964 City of Eugene and building engineering drawings
Number of stories 2 Site visit. Photos, Figures 2-3 to 2-7 in Technical Appendix
parking level: 87,608
Building square footage office level: 74,777 Engineering drawings and site visit
total: 162,385
1995 building replacement value (Dames & Moore), less value
Build~ng replacement value $27,774,330 of fire apparatus, adjusted to 2004 value
Building seismic damage function Building specific See report and Technical Appendix. Site visit, engineering
fragihty curves analysis and engineering calculations
Default value of 50% adjusted to reflect the seismic and
Building demolition damage percent 40% functional deficiences of this 40-year old buildng, as per the
FEMA guidance in User's Manual for Seismic BC Module
Contents values
Office contents $2,329,200 2003 insured value, which is $31.15/sf
1995 replacement value (Dames & Moore), adjusted to 2004
Fire apparatus $1,291,847 value
Includes police and general (permit parking) vehicles. See
Vehicles in parking area $2,985,600 ~nventory and value calculation in report.
Total contents value $6,606,647 sum of above three contents categories
FEMA Accept typical FEMA assumption that contents damage
Contents seismic damage function typical/default values percentage is same as building damage percentage at each
PGA level
Displacement costs
Estimate for Eugene office space after an earthquake event.
Monthly rental costs per sf $2.00 Eugene has limited availability of office space of this square
footage
Other monthly costs: rental costs $50/space Estimate for Eugene, monthly cost for 194 spaces equals
for secure parking spaces $9700
Estimated rental costs for temporary communications
Other monthly costs $75,000
equipment and office furnishings
One time costs $100,000 Estimated wiring, connecbon/disconnection costs for
temporary communications equipment and moving costs
various, see report City of Eugene staff and visitor data (March, 2004)
Occupancy data and BCA flies
Statistical values for deaths and
FEMA 2004 values What is a Benefit? Guidance, adjusted to 2004 values
injuries
Engineering cost estimate; see report and Technical Appendix
Mitigation Project Cost $1,435,382 for detailed breakdowns of cost elements
Annual maintenance costs None No difference before and after m~tigation
Relocation costs for mitigation None Assumes that retrofit can be done in stages, without vacating
project the building.
See detailed table in report, excludes pass-through amounts
Annual Operating Budget $16,640,561
in Human Resources budget as per FEMA guidance.
What is a Benefit? Guidance for commercial or public
Mitigation Project Useful Life 50 years facilities, reasonable for this facility
Discount Rate 7% OMB A-94 as per What is a Benefit? Guidance
7
4.3 Building Data
The total building area of 162,385 square feet consists of 74,777 square feet on
the upper (office) level and 87,608 square feet on the lower (parking and fire
station level).
Building replacement value of $27,774,330 was estimated from the 1995
engineering estimate made by Dames & Moore as part of an earlier seismic
vulnerability study, adjusted to 2004 values using FEMA's Inflation Adjuster.
Using the Inflation Adjuster, with recent federal data on inflation rates for the past
several years, yields an adjustment factor between 1995 and 2004 of 1.227.
The building demolition damage percentage was estimated to be 40% of building
replacement value. The default FEMA value is 50%. However, the FEMA
guidance in the User's Manual (FEMA, October 25, 1995) for the Full Data
Module for Benefit-Cost Analysis of Seismic Hazard Mitigation Projects notes
that: "For older, somewhat substandard buildings, the demolition threshold may
be quite Iow (e.g., 20% to 30%). Earlier studies of the building (Dames and
Moore, 1995) assumed a 25% demolition percentage.
Therefore, using a 40% threshold is conservative and fully consistent with FEMA
guidance. The building is 40-years old and has significant functional deficiencies
---- as well as substantial seismic deficiencies. Therefore, using a demolition
' percentage less than 50% appears fully justified.
4.4 Building Seismic Damage Functions
The vulnerability of the existing building to seismic damage is expressed
mathematically by fragility curves. Fragility curves incorporate the engineering
analyses of the building and express the vulnerability as the probability that a
building will be in each of several defined damage states at any level of ground
shaking. Fragility curves include "A" values (acceleration as a fraction of g)
which are the level of shaking at which there is 50% chance of the building being
in the defined damage state or higher. Fragility curves also include "beta" values
which are Iognormal dispersion (standard deviation) parameters reflecting the
uncertainty and randomness.
Fragility curves in Chapter 5 of the Technical Appendix (Table 5-3) were input
into the FEMA Fragility Curve Calculator to calculate seismic damage functions
(percent damage for various bins of PGA) in the format used in the FEMA Full
Data Module for Benefit-Cost Analysis of Seismic Hazard Mitigation Projects.
8
Table 4
Building Fragility Curves (from Technical Appendix)
Structure Slight Moderate Extensive Complete
Case A Beta A Beta A Beta A Beta
1. As Is 0.08 0.60 0.12 0.60 0.20 0.60 0.40 0.60
2. Upgraded 0.21 0.50 0.30 0.50 0.90 0.50 1.60 0.50
The resulting seismic damage functions and casualty rates were entered into the
FEMA Full Data Module for Benefit-Cost Analysis of Seismic Hazard Mitigation
Projects. Similarly, for the after-mitigation state of the buildings, fragility curve
based calculations were done and the results input into the Full Data Module.
The seismic damage function values (damage as percentage of building
replacement value) calculated from the fragility curves are shown below.
Table 5
Seismic Damage Functions for Eugene City Hall
Building Damage (% of Replacement Value)
Before Mitigation After Mitigation
FEMA FEMA
PGA
HAZUS User- Used In HAZUS User- Used In
(% of g) Default Entered Calc. Default Entered Calc.
4-8 2.67% 2.56% 2.60% 0.32% 0.02% 0.02%
8-16 15.01% 14.51% 14.89% 3.08% 0.53% 0.53%
16-32 45.18% 43.58% 44.34% 15.45% 4.00% 4.00%
32-55 75.51% 73.74% 73.57% 39.38% 11.17% 11.17%
55-80 90.46% 89.55% 88.79% 61.81% 22.97% 22.97%
80-100 95.73% 95.34% 94.62% 75.29% 36.13% 36.13%
>100 98.37% 98.27% 97.79% 85.89% 52.80% 52.80%
4.5 Casualty Rate Estimates
Casualty rate estimates for the existing building were calculated directly from the
fragility curves (see previous section), using the FEMA Fragility Curve Calculator.
Results for the existing building are shown below. After mitigation, the standard
FEMA assumptions about the effectiveness of life-safety seismic retrofits (FEMA
Full Data Module) were used for benefit-cost analyses.
Table 6
Casualty Rate Estimates for Eugene City Hall (per 1,000 occupants)
(Before Mitigation)
FEMA Method
PGA Minor Major
(%of g) Injuries Injuries Deaths
4-8 3.255 0.706 0.255
8-16 25.203 11.123 5.021
16-32 111.424 83.246 40.542
32-55 247.146 225.557 1tl.950
55-80 335.309 324.959 162.082
80-100 370.409 365.458 182.539
>100 388.803 386.877 193.364
After mitigation, the standard FEMA assumption about the effectiveness of life
safety seismic retrofits in avoiding deaths and injuries was used for the benefit-
cost calculations.
4.6 Occupancy Data
Occupancy data (employees and visitors) were provided by the City of Eugene
(March 2004). Data for weekdays during normal business hours are shown
below in Table 7.
Table 7
Weekday Occupancy Data
Employees Occupancy
Police 90
City Manager 30
Courts 38
Human Resources 28
Fire 9
Fire marshalls 7
Subtotal 202
Visitors
City Manager 30
Courts 250
Human Resources 100
Other 20
Subtotal 400
Average time per visitor 1 hour
Average visitor occupany 50
Total average occupancy 252
Evenings and nights (weekdays and weekends), there are an average of 17
police and fire staff in the City Hall Building. Evenings and weekend days, we
l0
estimate an average of 5 other staff in the building. In addition, City Council
meetings (twice per month for about two hours) and other meetings in the
Council Chambers, combine to provide an additional average weekday evening
occupancy of about 5 people. Entering these data into the occupancy table in
the FEMA Full Data Module for Benefit-Cost Analysis yields and estimated
average occupancy of 75.81 people on a 24/7/365 basis.
4.7 Contents Inventory and Value
Building contents include general office contents, fire apparatus, and vehicles in
the lower level parking area. Estimated contents values are shown below in
Tables 8 and 9.
Table 8
Contents Values
Category Value
Office Contents $2,329,200
Fire apparatus $1,291,847
Vehicles $2,985,600
Total $6,606,647
- Office contents value is based on the City's 2003 insured value for contents. Fire
apparatus value is based on the 1995 replacement value estimate by Dames and
Moore, adjusted to 2004 values, using FEMA's Inflation Adjuster. Vehicle
occupancy and values are as estimated below in Table 9.
Table 9
Vehicle Occupancy and Values
Parking spaces Average Average Average
Value Occupancy Value
Police 98 $32,000 75% $2,352,000
Permit 96 $20,000 33%~ $633,600
Total 194 $26,062 $2,985,600
~ 90 vehicles 40 hours per week, 10 vehicles 24/7
Average replacement value for police vehicles and average occupancy
percentages are as per City estimate. Average replacement value for non-police
vehicles is estimated to be $20,000. Average occupancy percentage for non-
police vehicles is based on permit parking (approximately 40 hours per week with
nearly 100% occupancy), plus City-owned motor pool vehicles with an average
occupancy of about 10 vehicles on a 24/7 basis.
4.8 Contents Seismic Damage Functions
The Technical Appendix contains facility-specific fragility data (cf. Tables 5-4a
and ,5-4b) for several types of contents and equipment at this facility. However,
most of the occupied portion of this building is "ordinary" office space and the
building does not contain a high percentage of specialized equipment. Thus, for
this analysis, we accept the typical or "default" assumption built into the FEMA
Full Data Module for Benefit-Cost Analysis of Seismic Mitigation Projects. That
is, that the contents percentage damage is equal to the building percentage
damage at each level of ground shaking (PGA bins in the Full Data Module).
4.9 Displacement Costs and Times
For ordinary residential, commercial, or public buildings, displacement means
that damage to buildings is severe enough so that occupants are displaced to
temporary quarters while repairs are made. Displacement costs include monthly
rental, other monthly costs, and one time costs such as round-trip moving costs.
For this building, facility-specific displacement costs were estimated as
documented in the Data Documentation Table (Table 3) above. Rental cost of
temporary office space is estimated to be $0.92. This Iow value arises because
the estimated rental cost of temporary office space is $2.00/sf, but somewhat
less than half of the square footage is office space. The FEMA Full Data Module
requires data entry as $/sf/month and thus the entered value of $0.92 takes into
account actual rental rates and the proportion of the building which is office
space.
Other costs of displacement include replacement parking and other costs as
summarized above in Table 3.
Standard FEMA values (Full Data Module) for displacement times, which are
proportional to estimated building damage percentages are used for Iow to
moderate levels of damage. These values are a reasonable estimate of the time
period necessary to complete repairs if the building were damaged in future
earthquakes. However, for damage levels severe enough to require replacement
of the entire building, we estimate that a minimum time to design and build a
structure of this size and importance would be two years.
4.7 Economic Impacts of Loss of Function
FEMA's What is a Benefit? Guidance contains a standard methodology to
calculate the economic impact of loss of function of facilities providing public
services. The base value of service is simply the cost of providing services (i.e.,
the annual operating budget). For the Eugene City Hall, there are several
municipal departments/agencies providing services from the building. The
annual operating budgets for these departments/agencies are given below in
Table 10. Budget data below was provided by the City of Eugene, March 2004.
Table 10
Annual Operating Budgets for Eugene City Hall
Agency Budget
Police $5,469,688
Fire Dept. $1,949,651
Fire Marshal's Offfice $727,433
Courts $3,399,650
City manager's office $2,590,154
Human resources and risk management $18,503,985
Total $32,640,561
Adjustment for pass throughs -$16,000,000
Net Annual Operating Budget $16,640,561
The total annual operating budget for the Eugene City Hall is above $32,000,000.
However, for the Human Resources and Risk Management Department, the
annual operating budget includes pass through payments for benefits applicable
to employees working elsewhere and benefits for retirees. Thus, following FEMA
guidance, these pass through amounts are subtracted from the annual operating
budget to obtain the value of services actually provided from the Eugene City
Hall.
However, as per FEMA guidance ( What is a Benefit? and in the User's Manual
for the Full Data Manual), public services that are critical for immediate response
during disaster events are subject to post disaster continuity premiums to reflect
the greater importance (and value) of such services during disaster events.
For police and fire services, the FEMA standard continuity premium is 10x the
normal daily cost of service. Similarly, for EOCs and other emergency services
directly related to emergency response, the FEMA standard continuity premium
is 10x the normal daily cost of services. As shown in Table 11 below, this FEMA
standard continuity premium is applied to the police and fire services provided
from the Eugene City Hall.
Ordinary public services, not directly related to critical emergency response
functions, do not have any post-disaster continuity premiums (e.g., the municipal
court functions in the Eugene City Hall). The City Manager's Office and the
Human Resources and Risk Management Department provide mostly "ordinary"
public services, and thus no post-disaster continuity premiums as applicable to
most of these services. However, these departments also provide critical staffing
for the EOC and related emergency response functions. We estimate that about
10% of the staff would be providing such emergency services in a major disaster.
Thus, we apply the 10x normal daily cost of service to 1/10th of the annual
operating budget for these departments. Mathematically, this is equivalent to a
lx continuity premium for the entire annual operating budget as shown in Table
11.
Table 1t
Post-Disaster Continuity Premiums and Daily Value of Public Services
Agency Budget Continuity Total Value
Premium of Service
Police $5,469,688 $54,696,880 $60,166,568
Fire $1,949,651 $19,496,510 $21,446,161
Fire Marshal's Offfice $727,433 $7,274,330 $8,001,763
Courts $3,399,650 $0 $3,399,650
City manager's office $2,590,154 $2,590,154 $5,180,308
Human resources and risk management~ $2,503,985 $2,503,985 $5,007,970
Total $16,640,561 $86,561,859 $103,202,420
Daily value of Service $45,591 $237,t56 $282,746
~ budget after subtraction of pass through amounts
4.8 Functional Downtimes
,-'--' FEMA's What is a Benefit? Guidance notes that services with high continuity
premiums or high values tend to have lower functional downtimes than ordinary
facilities. This would certainly apply to police and fire services provided from the
Eugene City Hall, as well as to the EOC and other emergency services provided
by staff from the City Manager's Office and the Human Resources and Risk
Management Department.
FEMA's What is a Benefit? Guidance suggests that functional downtimes for
critical police and fire services may be one-third of those for "ordinary" buildings.
A similar relationship, with functional downtimes about one-third of typical values
also appears appropriate for EOC and other emergency functions.
On the other hand, for "ordinary" services, standard (typical) FEMA functional
downtimes are appropriate. The fractions of value of services provided from the
Eugene City Hall which are "ordinary" or "emergency" are summarized in Table
12 below.
14
Table 12
Fractions of Value of Services Which are Ordinary or Emergency
I I Continuity I TotalValue
Agency Budget Premium of Service
Services with Functional Downtime -- 1/3rd of typical
Police $5,469,688 $54,696,880 $60,166,568
Fire $1,949,651 $19,496,510 $21,446,161
Fire Marshal's Office $727,433 $7,274,330 $8,001,763
City Manager's Office $2,590,154 $2,590,154
Human resources and risk management $2,503,985 $2,503,985
TOTAL $94,708,631
Services with Typical Functional Downtime
Courts $3,399,650 $3,399,650
City manager's office $2,590,154 $2,590,154
Human resources and risk management $2,503,985 $2,503,985
TOTAL $8,493,789
As shown in Table 13 below, about 92% of the total daily value of services
provided from the Eugene City Hall (including post-disaster continuity premiums)
are "emergency", with functional downtimes 1/3rd of typical values. About 8% of
the total daily value of services are "ordinary" (without continuity premiums), with
functional downtimes equal to the FEMA standard or default values, as built into
the Full Data Module for Benefit-Cost Analysis of Seismic Hazard Mitigation
Projects.
For a mix of "emergency" and "ordinary" services, we calculate a composite ratio
of functional downtimes, relative, to the FEMA standard or default values, in
proportion to the percent of services (daily value of service) in the "emergency"
and "ordinary" categories. The weighted average functional downtime is 38.82%
of the FEMA standard or default values.
Table 13
Functional Downtime Calculation
Value of
Service Percentage
Services with Functional Downtime = ll3rd of typical $94,708,631 91.77%
Services with Functional Downtime = 100% of typical $8,493,789 8.23%
All Services $103,202,420 100.00%
Weighted average functional downtime 38.82%
As always, functional downtime may be fractional. One day of loss of service
may be one day with complete loss of service to all customers, or two days with
50% loss of service, or 10 days with 10% loss of service and so on.
]5
/
{!___ 5.0 BENEFIT-COST RESULTS
5.1 Software and Documentation
Benefit-cost calculations were performed using the FEMA Full Data Module for
Benefit-Cost Analysis of Seismic Hazard Mitigation Projects. Data inputs for
benefit-cost analysis were as described and documented above in Section 4.0.
The benefit-cost analysis for this mitigation project considers:
Building damages
Contents damages
Displacement Costs
Casualties, and
Loss of Public Services.
The Appendix includes a full print-out of this benefit-cost analysis and of the
FEMA Fragility Curve Calculator. The FEMA Fragility Curve Calculator was used
to calculate seismic damage functions (percent building damages) from the
building specific fragility curves documented in the Technical Appendix. The
FEMA Fragility Curve Calculator was also used to calculate casualty rates
(deaths and injuries) for this facility.
'~....
' 5.2 Results
The results of these benefit-cost analyses are summarized in Table 14 below.
Table 14
Benefit-Cost Results
Benefits Category Benefits
Building Damages $758,292
Contents Damags $105,491
Displacement Costs $149,051
Loss of Public Services $126,823.
Casualties Avoided $332,037
Total Benefits $1,471,694
~roject Costs $1,435,382
Net Benefits $36,312
'BCR 1.03
In Table 14 above, each benefits category indicates damages or losses which
are avoided by the mitigation project. The total project costs are $1,435,382.
The total project benefits are $1,471,694 and the benefit-cost ratio is 1.03 Thus,
this seismic mitigation project is cost-effective, with the net present value of
benefits slightly higher than the estimated mitigation project costs.
The largest categories of benefits are avoided building damages and avoided
casualties. Avoided contents damages, avoided displacement costs, and
avoided loss of public services are also significant benefits for this project.
The result that the project is just cost-effective, arises because of the relatively
modest seismic hazard level for Eugene and the relatively modest occupancy of
the building on a 24/7/365 basis. These results are preliminary and further
analysis may yield somewhat higher benefits.
l?
FEMA Benefit-Cost Analysis of Hazard Mitigation Projects
EARTHQUAKE
Full Data Module
Version 5.1 a
April 1, 2000
Report of Benefit-Cost Analysis
Building Name Eugene City Hall
Address
Eugene, Oregon
Project Description Structural and non-structural seismic retrofit
Project Number
Application Date
Scenario Run ID 01
Analyst K.A. Goettel 3118/04
FEMA Disclaimer:
The results produced by th~s analys~s are neither conclusive evidence that the proposed project is cost-effective
nor a guarantee that a project is eligible for any government grant for whatever purpose.
Earthquake Mitigation Project Version 5 1 December 31, 1997
iLEVEL ONE DATA Page
BUILDING INFORMATION
Building Name Eugene City Hall
Address
City, State, Zip Eugene, Oregon
Owner City of Eugene
Contact Person
Disaster Number
Project Number
Application Date
Discount Rate 7.00%
Scenario Run ID 01
Analyst K.A. Goettel 3/18/04
BUILDING TYPE
Building Type Selected ICONCRETE MOMENT FRAME
Default User-Entered Override
Building SDF Selected Before Mitigation: Typical YES
Building SDF Selected After Mitigation: Default YES
BUILDING INFORMATION
BUILDING DATA
Number of Stories Above Grade 3
Construction Date 1964
Historic Building Controls no
BUILDING SIZE AND USE
Total Floor Area (sf) 162,385 I
Area Occupied by Owner or Public/Nonprofit Agencies (sf) 162,385
I
BUILDING VALUE
Building Replacement Value ($/sf) $171.04
Total Building Replacement Value ($) $27,774,330
Building Damage that would Result in Demolition Percent 40
Value $11,~09,732
BUILDING CONTENTS
Contents Description Ioffice furnishings, fire appartus, vehicles
Total Value of Contents $6,606,647
Value of Contents ($/sf) $40.69
DISPLACEMENT COSTS DUE TO EARTHQUAKE DAMAGE
Rental Cost of Temporary Building Space ($/sf/month) $0.92
Rental Cost of Temporary Building Space (S/month) $J49,554
Other Costs of Displacement (S/month) $84,700
Total Displacement Costs (S/month) $234,254
Eugene C~ty Hall BCA 01 xls 3/22/2004
Earthquake M~t~gat~on Project Version 5 1 December 31, 1997
LEVEL ONE DATA (Continued) Page 2
IEugene City Hall Eugene, Oregon
Analyst I K.A. Goettel 3/18/04 ~ Scenario Run ID 101
BUILDING OCCUPANCY
Weekdays Weekends
Day Evening Night Day Evening Night
Occupants 252 27 17 22 17 17
Days per Week 5 5 5 2 2 2
Hours per Day 8 8 8 8 8 8
Months per Year 12 12 12 12 12 12
Average Occupancy (24 hours, 7 days per week) 75.81
VALUE OF AVOIDED CASUALTIES
Value of Avoiding a Minor Injury $16,663
Value of Avoiding a Serious Injury $16,632
Statistical Value of Life $2,889,227
VALUE OF PUBLIC/NONPROFIT SERVICES
Description of Services Provided IPolice, Fire and general City services
Annual Budget of Public/Nonprofit Agencies
Is Rent Included in this Budget? ]Rent Not Included
If Rent is NOT Included, a Proxy Rent is Added to the Budget (S/month) I $162,017
User-Entered Rent Estimate, in Place of Proxy Rent (S/month) ~ $0
Cost of Providing Services from this Building (S/day) $50,917
Post-Disaster Continuity Premium (S/day) $237,156
Total Value of Lost Services (S/day) $288,073
RENT & BUSINESS INCOME
Total Monthly Rent from All Tenants (S/month)
Estimated Net Income of Commercial Businesses (S/month) ~ n/a
I
MITIGATION PROJECT DATA
Project Description IStructural and non-structural seismic retrofit I
Project Useful Life (years) 50
Mitigation Project Cost (excluding relocation costs) $1,435,382
Base Year of Costs 0
Annual Maintenance Costs (S/year) $0
Present Value of Annual Maintenance Costs ($) $0
Relocation Costs for Mitigation Project
Relocation Time Due to Project (months) 0
Rental Cost during Occupant Relocation ($/sf/month) $0.00
Rental Cost during Occupant Relocation (S/month) $0
Other Relocation Costs (S/month) $0
Total Relocation Costs $0
Total Mitigation Project Costs $1,435,382
Eugene C~ty Hall BCA 01 xts 3/22/2004
Earthquake Mitigation Project Version 5 1 December 31, 1997
ISEISMIC HAZARD Page 3 I
IEugene City Hall Eugene, Oregon ~
Analyst I K.A. Goettel 3/18/04 I Scenario .un 101 I
SOIL TYPE
Soil Type Selected I S2 I
SEISMIC HAZARD DATA
Spectral Acceleration Contours Peak Ground Acceleration
Period (seconds) 0.3 Adjustment Factor 2.5
Time Period % of g Time Period % of g
50 I Year 32.0 50 I Year 12.8
250 Year 82.0 250 Year 32.8
EXPECTED ANNUAL NUMBER OF EARTHQUAKES
PGA Default User
MMI (% of g) Estimate Estimate
VI 4-8 3.25E-02 4.18E-03
VII 8-16 6.55E-03 2.27E-03
VIII 16-32 1.32E-03 1.32E-03
IX 32-55 2.38E-04 2.73E-04
X 55-80 5.54E-05 4.70E-05
XI 80-100 1.62E-05 9.00E-06
XII >100 2.41E-05 6.00E-06
DATA SOURCES AND DOCUMENTATION
User entered seismic hazard data from same USGS database as FEMA seismic hazard calculator.
Estimates above use full seismic hazard curve. See text for details.
Eugene C~ty Hall BCA 01 xls 3/22J2004
Earthquake M~agat~on Project Version 5 1 December 31, 1997
ILEVEL TWO DATA: BUILDING SEISMIC-DAMAGE FUNCTION Page 4 I
IEugene City Hall Eugene, Oregon ~
Analyst IK.A. Goettel 3/18/04 I Scenario Run ID: 101 I
Building Type: ~-CONCRETE MOMENT FRAME
Number of Stories Above Grade 3
Construction Date 1964
Historic Building Controls no
Total Floor Area (square feet): 162,385
Total Building Replacement Value: 27,774,330
Demolition Threshold Damage Percentage: 40%
BUILDING DAMAGE FUNCTION (SDF) BEFORE MITIGATION
ESTIMATED BUILDING DAMAGE BEFORE MITIGATION
(% of replacement value)
Select SDF (Before Mitigation) SDF User- Estimated
Selected Entered Modified Building
PGA Seismic Typical Estimate SDF Damage
MMI (% of g) Poor Typical Design California Typical (%) ($)
VI 4-8 12.21 1.27 N/A 2.80 1.27 2.56 2.56 $711,023
VII 8-16 23.00 4.21 N/A 5.10 4.21 14.51 14.51 $4,030,055
VIII 16-32 34.23 12.21 N/A 14.43 12.21 43.58 100.00 $27,774,330
IX 32-55 47.63 23.00 N/A 22.00 23.00 73.74 100.00 $27,774,330
X 55-80 60.00 34.23 N/A 33.83 34.23 89.55 100.00 $27,774,330
XI 80-100 73.41 47.63 N/A 48.46 47.63 95.34 100.00 $27,774,330
Xll >100 85.78 60.00 N/A 65.14 60.00 98.27 100.00 $27,774,330
ESTIMATED BUILDING DAMAGE AFTER MITIGATION
(% of replacement value)
Select SDF (After Mitigation) SDF User- Modified Estimated Resulting
Existing Selected Entered SDF Building Mitigation
Building Seismic Typical Estimate (%) Damage Eft. (%)
MMI SDF (%) Default Typical Design California Default
VI 2.56 t.66 1.27 N/A 2.80 1.66 0.02 0.02 $5,555 99.22
VII 14.51 9.43 4.21 N/A 5.10 9.43 0.53 0.53 $147,204 96.35
VIII 43.58 29.96 12.21 N/A 14.43 29.96 4 4.00 $1,110,973 90.82
IX 73.74 53.46 23.00 N/A 22.00 53.46 11.17 11.17 $3,102,393 84.85
X 89.55 68.28 34.23 N/A 33.83 68.28 22.97 22.97 $6,379,764 74.35
Xl 95.34 76.27 47.63 N/A 48.46 76.27 36.13 36.13 $10,034,865 62.10
Xll 98.27 78.62 60.00 N/A 65.14 78.62 52.8 100.00 $27,774,330 46.27
DATA SOURCES AND DOCUMENTATION
Building specific damage functions derived from building specific seismic vulnerabilty assessment.
Fragility curves from engineering analysis input into FEMA Fragility Curve Calculator to get seismic
damage function (bulding damage percentages) entered above.
Eugene C~ty Hall BCA 01 xls 3/2222004
Earthquake M~t~gat~on Project Version 5 1 December 31, 1997
iLEVEL TWO DATA: CONTENTS SEISMIC-DAMAGE FUNCTION Page 5 I
I
~Eugene City Hall Eugene, Oregon ~
Analyst: I K.A. Goettel 3/t8/04 ~Scenario Run ID: ~01 ~
REFERENCE INFORMATION FROM LEVEL ONE DATA
Contents Description: Ioffice furnishings, fire appartus, vehicles
Total Value of Contents: $6,606,647
Value of Contents ($/sf): $40.69
CONTENTS SEISMIC-DAMAGE FUNCTION (SDF)
Building ESTIMATED CONTENTS DAMAGE - BEFORE
PGA SDF (%) Default User-Entered Contents
MMI (% of g) Before SDF (%) SDF (%) Damage
VI 4-8 2.56 2.56 $169,130
VII 8-16 14.51 14.51 $958,624
VIII 16-32 43.58 43.58 $2,879,177
IX 32-55 73.74 73.74 $4,871,741
X 55-80 89.55 89.55 $5,916,252
XI 80-100 95.34 95.34 $6,298,777
Xll >100 98.27 98.27 $6,492,352
Building ESTIMATED CONTENTS DAMAGE -AFTER
PGA SDF (%) Default User-Entered Contents Effective
MMI (% of g) After SDF (%) SDF (%) Damage (%)
VI 4-8 0.02 0.02 $1,321 99.22
VII 8-16 0.53 0.53 $35,015 96.35
VIII 16-32 4.00 4.00 $264,266 90.82
IX 32-55 11.17 11.17 $737,962 84.85
X 55-80 22.97 22.97 $1,517,547 74.35
Xl 80-100 36.13 36.13 $2,386,982 62.10
XII >100 52.80 52.80 $3,488,310 46.27
DATA SOURCES AND DOCUMENTATION
Use FEMA typical/default assumption in Full Data Module - that contents damage percentages are
typically same as building damage percentages.
Eugene C~ty Hall BCA 01 xls 3/22/2004
E~rthquake M~bgabon Project Version 5 1 December 31, 1997
ILEVEL TWO DATA: DISPLACEMENT TIME Page 6 I
~Eugene City Hall Eugene, Oregon I
Analyst: ~K.A. Goettel 3118/04 IScenario Run ID:~01 I
REFERENCE INFORMATION FROM LEVEL ONE DATA
Rental Cost of Temporary Building Space ($/sf/month): $0.92
Rental Cost of Temporary Building Space (S/month): $149,554
Other Costs of Displacement (S/month): $84,700
Total Displacement Costs (S/month): $234,254
One Time Displacement Costs ($) $100,000
Total Monthly Rent from All Tenants (S/month): n/a
DISPLACEMENT TIME DUE TO BUILDING SEISMIC DAMAGE BEFORE MITIGATION
Building
PGA Modified Default User-Entered Displacement Rental Income
MMI (% of g) SDF (%) (days) (days) Costs Losses
VI 4-8 2.56 0 $0 $0
VII 8-16 14.51 66.08 $615,983 $0
VIII 16-32 100.00 365 730 $5,800,181 $0
IX 32-55 100.00 365 730 $5,800,181 $0
X 55-80 100.00 365 730 $5,800,181 $0
Xl 80-100 100.00 365 730 $5,800,181 $0
Xll >100 100.00 365 730 $5,800,181 $0
DISPLACEMENT TIME DUE TO BUILDING SEISMIC DAMAGE AFTER MITIGATION
Building
PGA Modified Default User-Entered Displacement Rental Income
MMI (% of g) SDF (%) (days) SDF (%) Costs Losses
VI 4-8 0.02 0 $0 $0
VII 8-16 0.53 0 $0 $0
VIII 16-32 4.00 0 $0 $0
IX 32-55 11.17 39.36 $407,341 $0
X 55-80 22.97 134 $1,144,461 $0
Xl 80-100 36.13 239 $1,966,536 $0
Xll >100 100.00 365 730 $5,800,181 $0
DATA SOURCES AND DOCUMENTATION
Accept FEMA typical/default values for displacement times, except for complete replacement
of building.
For building of this size and importance, consider two years (730 days) a minimum time to
design/building a replacement building.
Eugene C~ty Hall BCA 01 xls 3/22/2004
Earthquake M~t]gation Project Version 5.1 December 31, 1997
'ILEVEL TWO DATA: FUNCTIONAL DOWNTIME Page
IEugene City Hall Eugene, Oregon
Analyst: I K.A. Goettel 3118/04 IScenario Run ID:101
REFERENCE INFORMATION FROM LEVEL ONE DATA
Cost of Providing Services from this Building (S/day): $50,917
Post-Disaster Continuity Premium (S/day): $237,156
Total Value of Lost Services (S/day): $288,073
Estimated Net Income of Commercial Businesses (S/month): n/a
FUNCTIONAL DOWNTIME ESTIMATES BEFORE MITIGATION
Building Default User- Value of Lost Business
PGA SDF Downtime Entered Lost Income
MMI (% of g) (%) (Days) Estimate Services
VI 4-8 2.56 3 0.993792 $286,285 $0
VII 8-16 14.51 15 5.632782 $1,622,653 $0
VIII 16-32 43.58 30 11.646 $3,354,900 $0
IX 32-55 73.74 30 11.646 $3,354,900 $0
X 55-80 89.55 30 11.646 $3,354,900 $0
Xl 80-100 95.34 30 11.646 $3,354,900 $0
Xll >100 98.27 30 11.646 $3,354,900 $0
FUNCTIONAL DOWNTIME ESTIMATES AFTER MITIGATION
Building Default User- Value of Lost Business
PGA SDF Downtime Entered Lost Income
MMI (% of g) (%) (Days) Estimate Services
VI 4-8 0.02 0 0.007764 $2,237 $0
VII 8-16 0.53 I 0.205746 $59,270 $0
VIII 16-32 4.00 4 1.5528 $447,320 $0
IX 32-55 11.17 11 4.336194 $1,249,141 $0
X 55-80 22.97 23 8.916954 $2,568,735 $0
Xl 80-100 36.13 30 11.646 $3,354,900 $0
Xll >100 52.80 30 11.646 $3,354,900 $0
DATA SOURCES AND DOCUMENTATION
Use shorter functional downtimes than FEMA typical/default values, reflecting proportion of
total value of services with high continuity premium and thus lower expected functional
downtimes, as per FEMA guidance in What is a Benefit?
See report text for details.
Eugene City Hall BCA 01 xls 3/22/2004
ILEVEL TWO DATA: CASUALTY RATES Page 8
Eugene City Hall Eugene, Oregon
Analyst: IK.A. Goettel 3118/04 ~ Scenario Run ID: 101 I
REFERENCE INFORMATION FROM LEVEL ONE DATA
Building Type Selected: CONCRETE MOMENT FRAME
Default Bldg SDF Before Mitigation: Typical IUser-Entered SDF? ~ YES
Default Bldg SDF After Mitigation: Default 'lUser-Entered SDF?~ YES
CASUALTY RATES BEFORE MITIGATION (per 1,000 Occupants)
Building Minor Injury Rates Major Injury Rates Death Rates
Damage (per 1,000 occupants) (per 1,000 occupants) (per 1,000 occupants)
PGA Function User- User- User-
MMI (% of g) (%) Default Entered Default Entered Default Entered
VI 4-8 2.56 1.65E-01 3.26E+00 2.20E-02 7.06E-01 5.50E-03 2.55E-01
VII 8-16 14.51 2.10E+00 2.52E+01 2.80E-01 1.11E+01 7.00E-02 5.02E+00
VIII 16-32 43.58 2.89E+01 1.11E+02 3.86E+00 8.32E+01 9.64E-01 4.05E+01
IX 32-55 73.74 2.54E+02 2.47E+02 3o38E+01 2.26E+02 8.46E+00 1.12E+02
X 55-80 89.55 3.50E+02 3.35E+02 2.20E+02 3.25E+02 1.05E+02 1.62E+02
Xl 80-100 95.34 3.75E+02 3.70E+02 3.10E+02 3.65E+02 1.53E+02 1.83E+02
Xll >100 98.27 3.90E+02 3.89E+02 3.64E+02 3.87E+02 1.81E+02 1.93E+02
CASUALTY RATES AFTER MITIGATION (per 1,000 Occupants)
Building Minor Injury Rates Major Injury Rates Death Rates
Damage (per 1,000 occupants) (per 1,000 occupants) (per 1,000 occupants)
PGA Function User- User- User-
MMI (% of g) (%) Default Entered Default Entered Default Entered
VI 4-8 0.02 3.26E-01 7.06E-03 2.55E-04
VII 8-16 0.53 2.52E+00 1.11E-01 5.02E-03
VIII 16-32 4.00 1.11E+01 8.32E-01 4.05E-02
IX 32-55 11.17 2.47E+01 2.26E+00 1.12E-01
X 55-80 22.97 3.35E+01 3.25E+00 1.62E-01
Xl 80-100 36.13 3.70E+01 3.65E+00 1.83E-01
Xll >100 52.80 3.89E+01 3.87E+00 1.93E-01
ISUMMARY OF DAMAGES BEFORE MITIGATION Page 9 I
IEugene City Hall Eugene, Oregon I
Analyst: IK.^. Goettel 3/18104 I Scenario Run ,D: 101 I
Building Type: CONCRETE MOMENT FRAME
Selected Default Building SDF Before Mitigation: Typical
User-Entered Building SDF Before Mitigation: YES
Project Description: Structural and non-structural seismic retrofit
SCENARIO DAMAGES BEFORE MITIGATION ($ per event)
Building Contents Displacement Business Rental Public/
(% of g) Damages Damages Costs Losses Losses Nonprofit Total
4-8 $711,023 $169,130 $0 $0 $0 $286,285 $1,166,438
8-16 $4,030,055 $958,624 $615,983 $0 $0 $1,622,653 $7,227,317
16-32 $27,774,330 $2,879,177 $5,800,181 $0 $0 $3,354,900 $39,808,587
32-55 $27,774,330 $4,871,741 $5,800,181 $0 $0 $3,354,900 $41,801,152
55-80 $27,774,330 $5,916,252 $5,800,18t $0 $0 $3,354,900 $42,845,663
80-100 $27,774,330 $6,298,777 $5,800,18t $0 $0 $3,354,900 $43,228,188
>100 $27,774,330 $6,492,352 $5,800,181 $0 $0 $3,354,900 $43,421,763
EXPECTED ANNUAL DAMAGES BEFORE MITIGATION ($ per year)
Building Contents Displacement Business Rental Public/
(% of g) Damages Damages Costs Losses Losses Nonprofit Total
4-8 $2,971 $707 $0 $0 $0 $1,196 $4,875
8-16 $9,128 $2,171 $1,395 $0 $0 $3,675 $16,370
16-32 $36,773 $3,812 $7,679 $0 $0 $4,442 $52,707
32-55 $7,582 $1,330 $1,583 $0 $0 $916 $11,412
55-80 $1,305 $278 $273 $0 $0 $158 $2,014
80-100 $250 $57 $52 $0 $0 $30 $389
>100 $167 $39 $35 $0 $0 $20 $261
Total $58,177 $8,394 $11,018 $0 $0 $10,437 $88,026
SUMMARY OF DAMAGES AFTER MITIGATION Page 10 I
Eugene City Hall Eugene, Oregon I
Analyst: IK.A. Goettel 3/18/04 I Scenario Run ID: 101 I
Building Type: CONCRETE MOMENT FRAME
Selected Default Building SDF After Mitigation: Default
User-Entered Building SDF After Mitigation: YES
Project Description: Structural and non-structural seismic retrofit
SCENARIO DAMAGES AFTER MITIGATION ($ per event)
Building Contents Displacement Business Rental Public/
(% of g) Damages Damages Costs Losses Losses Nonprofit Total
4.8 $5,555 $1,321 $0 $0 $0 $2,237 $9,113
8-16 $147,204 $35,015 $0 $0 $0 $59,270 $24t ,489
16-32 $1,110,973 $264,266 $0 $0 $0 $447,320 $1,822,559
32.55 $3,102,393 $737,962 $407,341 $0 $0 $1,249,141 $5,496,837
55-80 $6,379,764 $1,517,547 $1,144,461 $0 $0 $2,568,735 $11,610,506
80-100 $10,034,865 $2,386,982 $1,966,536 $0 $0 $3,354,900 $17,743,283
>100 $27,774,330 $3,488,310 $5,800,181 $0 $0 $3,354,900 $40,417,720
EXPECTED ANNUAL DAMAGES AFTER MITIGATION ($ per year)
Building Contents Displacement Business Rental Public/
(% of g) Damages Damages Costs Losses Losses Nonprofit Total
4-8 $23 $6 $0 $0 $0 $9 $38
8-16 $333 $79 $0 $0 $0 $134 $547
16-32 $1,471 $350 $0 $0 $0 $592 $2,413
32-55 $847 $201 $111 $0 $0 $341 $1,501
55-80 $300 $71 $54 $0 $0 $121 $546
80-100 $90 $21 $18 $0 $0 $30 $160
>100 $167 $21 $35 $0 $0 $20 $243
Total $3,231 $750 $217 $0 $0 $1,248 $5,447
ISUMMARY OF BENEFITS FROM MITIGATION Page 11
IEugene City Hall Eugene, Oregon
Analyst: IK.A. Goettel 3/18/04 I Scenario Run ID: 101
Building Type: CONCRETE MOMENT FRAME
Default Building SDF Before Mitigation: Typical ~User-Entered SOF? ~YES
Default Building SDF After Mitigation: Default ~User-Entered SDF? ~YES
Project Description Structural and non-structural seismic retrofit
EXPECTED ANNUAL BENEFITS FROM MITIGATION ($ per year)
Building Contents Displacement Business Rental Public/
(% of g) Damages Damages Costs Losses Losses Nonprofit Total
4-8 $2,948 $701 $0 $0 $0 $1,187 $4,836
8-16 $8,795 $2,092 $t ,395 $0 $0 $3,541 $15,823
16-32 $35,302 $3,462 $7,679 $0 $0 $3,850 $50,294
32-55 $6,735 $1,129 $t ,472 $0 $0 $575 $9,911
55-80 $1,006 $207 $219 $0 $0 $37 $1,46a
80-100 $160 $35 $35 $0 $0 $0 $229
>100 $0 $18 $0 $0 $0 $0 $18
Total $54,946 $7,644 $10,800 $0 $0 $9,190 $82,579
iCASUALTIES Page 12
iEugene City Hall Eugene, Oregon
Analyst: ~K,A. Goettel 3118/04 ~ Scenario Run ID: ~01 ~
Building Type Selected: CONCRETE MOMENT FRAME
Default Bldg SDF Before Mitigation: Typical I User-Entered SDF? ~ YES
Default Bldg SDF After Mitigation: Default ~ User-Entered SDF?~ YES
CASUALTIES BEFORE MITIGATION (number)
Building SCENARIO EXPECTED ANNUAL
PGA SDF Injuries ~number) Deaths Injuries 'number) Deaths
MMI (% of g) (%) Minor Major (number) Minor Major (number)
VI 4-8 2.56 2.47E-01 5.35E-02 1.93E-02 1.03E-03 2.24E-04 8.08E-05
VII 8-16 14.51 1.91E+00 8.43E-01 3.81E-01 4.33E-03 1.91E-03 8.62E-04
VIII 16-32 43.58 8.45E+00 6.31E+00 3.07E+00 1.12E-02 8.36E-03 4.07E-03
IX 32-55 73.74 1.87E+01 1.71E+01 8.49E+00 5.11E-03 4.67E-03 2.32E-03
X 55-80 89.55 2.54E+01 2.46E+01 1.23E+01 1.19E-03 1.16E-03 5.78E-04
XI 80-100 95.34 2.81E+01 2.77E+01 1.38E+01 2.53E-04 2.49E-04 1.25E-04
Xll >100 98.27 2.95E+01 2.93E+01 1.47E+01 1.77E-04 1.76E-04 8.80E-05
Totals: 2.33E-02 1.67E-02 8.12E-03
CASUALTIES AFTER MITIGATION (number)
Building SCENARIO EXPECTED ANNUAL
SDF Injuries Jnumber) Deaths Injuries .'number) Deaths
MMI (% of g) (%) Minor Major (number) Minor Major (number)
VI 4-8 0.02 2.47E.02 5.35E-04 1.93E-05 1.03E-04 2.24E-06 8.08E-08
VII 8-16 0.53 t.91E-01 8.43E-03 3.81E-04 4.33E-04 1.91E-05 8.62E-07
VIII 16-32 4.00 8.45E-01 6.31E-02 3.07E-03 1.12E-03 8.36E-05 4.07E-06
IX 32-55 11.17 1.87E+00 1.71E-01 8.49E-03 5.11E-04 4.67E-05 2.32E-06
X 55-80 22.97 2.54E+00 2.46E-01 1.23E-02 1.19E-04 1.16E-05 5.78E-07
Xl 80-100 36.13 2.81E+00 2.77E-01 1.38E-02 2.53E-05 2.49E-06 1.25E-07
Xll >100 52.80 2.95E+00 2.93E-01 1.47E-02 1.77E-05 1.76E-06 8.80E-08
Totals: 2.33E-03 1.67E-04 8.12E-06
CASUALTIES AVOIDED FROM MITIGATION (number)
Building SCENARIO EXPECTED ANNUAL
PGA SDF Injuries Jnumber) Deaths Injuries .'number) Deaths
MMI (% of g) (%) Minor Major (number) Minor Major (number)
VI 4-8 0.02 2.22E.01 5.30E-02 1.93E,02 9.28E-04 2.21E-04 8.07E-05
VII 8-16 0.53 1.72E+00 8.35E-01 3.80E.01 3.89E-03 1.89E-03 8.61E-04
VIII 16-32 4.00 7.60E+00 6.25E+00 3.07E+00 1.01E-02 8.27E-03 4,07E-03
IX 32-55 11.17 1.69E+01 1.69E+01 8.48E+00 4.60E-03 4.62E-03 2.31E-03
X 55-80 22.97 2.29E+01 2.44E+01 1.23E+01 1.08E-03 1.15E-03 5.77E-04
Xl 80-100 36.13 2.53E+01 2.74E+01 1.38E+01 2.27E-04 2.47E-04 1.24E-04
Xll >100 52.80 2.65E+01 2.90E+01 1.46E+01 1.59E-04 1.74E-04 8.79E-05
Totals: 2.10E-02 1.66E-02 8.11E-03
E=rthquake Mifagation Project Version 5 1 December 3% t997
IBENEFIT-COST RESULTS Page 13 I
IEugene City Hall Eugene, Oregon ~
Analyst: I~-~ ~oe.el =,~8,04 I Scenario Run ID: I 0~ I
Building Type Selected: CONCRETE MOMENT FRAME
Default Bldg SDF Before Mitigation: Typical ~User-Entered SDF? ~ YES
Default Bldg SDF After Mitigation: Default ' ~User-Entered SDF? ~ YES
Project Description: Structural and non-structural seismic retrofit
REFERENCE INFORMATION FROM LEVEL ONE DATA
Discount Rate (%) 17.001
Project Useful Life (years) 50
Present Value Coefficient 13.80
SUMMARY OF EXPECTED ANNUAL DAMAGES AND BENEFITS
WITHOUT CASUALTIES AVOIDED
Expected Annual Expected Annual Expected Annual Present Value of
Damages Damages Benefits Annual Benefits
Before Mitigation After Mitigation
Building Damages $58,177 $3,231 $54,946 $758,292
Contents Damages $8,394 $750 $7,644 $105,491
Displacement Costs $11,018 $217 $10,800 $149,051
Business Income Lost $0 $0 $0 $0
Rental Income Lost $0 $0 $0 $0
Services Lost $10,437 $1,248 $9,190 $126,823
Total Losses & Benefits $88,026 $5,447 $82,579 $1,139,657
SUMMARY OF BENEFITS AND COSTS WITHOUT CASUALTIES AVOIDED
PROJECT BENEFITS I $1,139,657
PROJECT COSTS ~ $1,435,382
BENEFITS MINUS COSTS I ($295,725)~
BENEFIT-COST RATIO WITHOUT CASUALTIES AVOIDED i 0.79
SUMMARY OF BENEFITS AND COSTS WITH CASUALTIES AVOIDED
Expected Annual Expected Annual Value of Present Value of
Casualties Casualties Expected Annual Annual Avoided
Before Mitigation After Mitigation Avoided Casualties Casualties
Minor Injuries 2.33E-02 2.33E-03 $349 $4,819
Major Injuries 1.67E-02 1.67E-04 $276 $3,804
Deaths 8.12E-03 8.12E-06 $23,435 $323,414
Total Casualties Avoided $24,059 $332,037
PROJECT BENEFITS WITHOUT CASUALTIES AVOIDED I $1'139'657 I
PROJECT BENEFITS WITH CASUALTIES AVOIDED $1,471,694
PROJECT COSTS ~ $1,435,382
BENEFITS MINUS COSTS I $36,312
BENEFIT-COST RATIO WITH CASUALTIES AVOIDED I 1 °03
FEMA Disclaimer: The results produced by this analysis are neither conclusive evidence that the proposed project is
cost-effective, nor a guarantee that a project is eligible for any government grant for whatever purpose.
Eugene C~ty Hall BCA 01 xls 3/22/2004
City of Eugene City Hall
Seismic Vulnerability Assessment
Prepared for:
The City of Eugene
Prepared under subcontract to:
Goettel and Associates, Inc.
Prepared by:
G&E Engineering Systems Inc.
6315 Swainland Rd
Oakland, CA 94611
(510) 595-9453 (510) 595-9454 (fax)
eidinger@earthlink, net
Principal Investigator:
John Eidinger
G&E Report 32.19.04, Revision B
September 9, 2003
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
Table of Contents
TABLE OF CONTENTS ..................................................................................................................................... I
1.0 INTRODUCTION ......................................................................................................................................... 1
1.1 L~flTATIONS ................................................................................................................................................ 1
1.2 ACKNOWL~G~NT .................................................................................................................................. 1
1.3 ABBREVIATIONS AND DEFINITIONS ............................................................................................................. 2
2.0 EUGENE CITY HALL .................................................................................................................................. 3
2.1 FACILITY OVERVIEW .................................................................................................................................... 3
2.2 STRUCTURAL SYSTEMS ................................................................................................................................ 5
2.3 NON STRUCTURAL SYSTEMS ..................................................................................................................... 13
3.0 PRIOR SEISMIC EVALUATIONS ......................................................................................................... 23
4.0 SEISMIC HAZARDS ................................................................................................................................... 24
5.0 FRAGILITY AND COST INFORMATION ............................................................................................ 27
5.1 COSTS ......................................................................................................................................................... 27
5.2 FRAGmrrms ................................................................................................................................................ 29
6.0 REFERENCES ............................................................................................................................................. 34
G&E Engineering Systems Inc. Page i
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
1.0 Introduction
This report includes a seismic vulnerability assessment of the City Hall complex for
Eugene, Oregon.
Section 2 of this report outlines the observed structural vulnerabilities for the City Hall
complex.
Section 3 of this report summarizes the fmdings from a prior seismic vulnerability
assessment for the City of Eugene City Hall complex.
Section 4 of this report presents the seismic hazard for the City Hall complex.
Section 5 presents the mitigation costs for reservoir, as well as fragilities of the City Hall
complex in its as-is and potentially upgraded conditions.
The complete benefit cost analyses for the City Hall complex is not included in this
report. The benefit cost analyses consider the structural and performance issues described
in this report, as well as the impacts from repair costs, possible impact on loss of service,
possible losses due to in casualties, and societal economic impacts should the City Hall
complex be damaged in earthquakes.
1.1 Limitations
The findings in this report are meant for benefit cost analyses by GAl under the intent of
the FEMA hazard mitigation grant program. The professional services have been
performed using the degree of care and skill ordinarily exercised under similar
circumstances by reputable engineers practicing in the field of structural or civil
engineering in this or similar localities at this time. No other warranty, expressed or
implied, is made as to the professional advice included in this report. Use of this
information by other parties or for different purposes may not be appropriate.
1.2 Acknowledgement
G&E would like to thank a number of people for their support in the preparation of this
report. These include: Chuck Solin, Mike Penwell, Meredith (City Architect), Chuck
Smith, (City of Eugene), and Ken Goettel of GAI Inc.
G&E Engineering Systems Inc. Page 1
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
1.3 Abbreviations and Definitions
A Median horizontal peak ground acceleration to reach a particular damage
state
g acceleration (lg = 32 feet/second/second)
GAI Goettel and Associates, Inc.
IBC International Building Code (successor to UBC)
km kilometer
M Magnitude (moment magnitude)
PGA Peak Ground Acceleration (units in g)
UBC Uniform Building Code
V Base shear coefficient, as used in the UBC and similar codes
W Weight of building coefficient, as used in the UBC and similar codes
G&E Engineering Systems Inc. Page 2
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
2.0 Eugene City Hall
2.1 Facility Overview
The City of Eugene, Oregon City Hall complex is located at 777 Pearl Street, Eugene.
The City Hall complex was designed in 1962 and built in 1964. Its structural systems are
a combination of moment-resisting non-ductile reinforced concrete frames coupled with
some reinforced concrete shear walls.
According to Dames and Moore (1995), the facility has an insured value of $14,713,740
($1995). The City Hall complex can be subdivided into eight parts, as listed in Table 2-1.
Portion of City Hall Primary Occupancy Replacement Value
Complex ($1995)
Northeast Wing Fire Marshal, Fire Station $2,413,800
Northwest Wing Risk Services, Human $1,205,250
Resources, Job Applications,
Parking Tickets, Jury room,
Municipal Court, Traffic Tickets
Southeast Wing Police $1,437,900
Southwest Wing Human rights, $1,712,100
Intergovernmental Relations,
Mayor, City Council, City
Manager, City Recorder
Council Chambers Council Chambers $633,750
Basement - Section H Mechanical Equipment $2,205,150
Basement Parking Level Parking $201,300
- Section G
Basement Parking Level Parking $3,851,640
Fire Station No. 1 Emergency Vehicles (ladder $1,052,850
truck, pumper track, paramedic
unit)
Total $14,713,740
Table 2-1. City Hall Complex - Replacement Values ($1995)
The City Hall complex is a low-rise two-story concrete structure. Approximate plan
dimensions of the complex is 323' x 323'. There are two main levels for the complex:
o Parking Level. This is at- or slightly below grade, and covers the entire complex.
Most of the level is used for parking of city vehicles (police cars, etc.) and office
worker cars. Figure 2-1 shows the existing layout, along with locations for
proposed seismic mitigation.
G&E Engineering Systems Inc. Page 3
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
o Main Level. This is where the four Office Wings and the City Council chambers
are located. The Main Level is located atop the parking level. Figure 2-2 shows
the existing layout, along with locations for proposed seismic mitigation.
o Basement Level. There is a partial basement located in the northwest comer of the
building, under the parking level. The basement houses mechanical equipment
and some police files.
.L~.~[.N~ PROPOSED NEW
_P.A_R._KE~'~ LEVEL PLAN ~,=,,==CONCR[TE SHEAR
~e 1" = 50' OR. STOL B~CED
Figure 2-1. Parking Level Plan, Showing
Existing Layout and Proposed New Walls
G&E Engineering Systems Inc. Page 4
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
~J~,..l~.: PROPOSED NEW
C~a{~ 1" .-50' OR STEEL B~CED
Figure 2-2. Main Level, Showing
Existing Layout and Proposed New Walls
2.2 Structural Systems
Figure 2-3 shows the general entrance area to the City Hall complex, looking eastwards.
The walkway in the foreground crosses Pearl Street to the Lane County buildings.
G&E Engineering Systems Inc. Page 5
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
Figure 2-3 City Hall Entrance Area
Figure 2-4 shows the northwest wing of the building. The doors to the Fire Station can be
seen in the background.
Figure 2-4. Northwest Wing
Figure 2-5 shows the garage doors at the ground level of the Fire Station. There are two
roll-up style garage doors. The structural system in this vicinity includes reinforced
concrete frames and some reinforced concrete shear walls; it is not likely that racking of
the building would seriously hamper operation of the garage doors; when interviewed,
Engineering Systems Inc. Page 6
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
firemen indicated that they could cut open the garage doors if necessary to allow egress
of the vehicles. The floor level of the dormitory portion of the fire station is about 4 feet
higher than the floor level in the remainder of the City Hall complex.
Figure 2-5. Garage Doors to Fire Station No. 1
Figure 2-6 shows the southwest wing of the complex.
Figure 2-6. Southwest Wing of Complex
G&E Engineering Systems Inc. Page 7
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
Figure 2-7 shows the Council Chambers structure.
Figure 2-7. Council Chambers
The interior of the Council Chambers includes a recently installed suspended ceiling
(Figure 2-8). Installation details were not available, but due to its recent installation (post
year 2000), it is assumed that it was designed and installed for seismic loads consistent
with Z=0.3g - this should be validated under f'mal design. The vertical timber colunms
seen in Figure 2-8 are assumed to be non-structural, with load bearing support for the
roof system being provided by steel (concrete?) columns within the wood veneer of some
(or all) of the main columns. The lateral resistance for the structure is provided primarily
by the lightly-reinforced masonry block walls in the exterior and the (assumed)
reinforced concrete walls at the second circular level, coupled with reinforced concrete
roof diaphragms.
Figure 2-8. Suspended Ceiling Over Council Chambers
G&E Engineering Systems Inc. Page 8
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
There are covered walkways that connect between the four office wings on the main
level. These walkways can be characterized as reinforced concrete frames with a waffle
slab roof (Figure 2-9).
Figure 2-9. Walkway Structures
Figure 2-10 shows the steel pedestrian structure connecting the City Hall complex with
Lane County buildings on the west side of Pearl Street.
Figure 2-10. Pedestrian Bridge Structure over Pearl Street
G&E Engineering Systems Inc. Page 9
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
Figures 2-11 and 2-12 show the typical layout of the parking level. The floor system of
the main level makes up the roof level of the parking level - it is a concrete slab using
waffle-style rib construction for support. This waffle slab in turn is supported by
reinforced concrete columns at 35 foot spacing. This rather wide spacing is permitted at
the waffle slab is reinforced using high tensile steel tendons.
Figure 2-11. Parking Level
"',,, ,, ;~ ~.,'~r ,'~',,~'?~ ~:,, ' ..~.,,,~'¥'~:"'"'~' .~'~' ~
Figure 2-12. Parking Level
Along the exterior of the building, there are reinforced concrete retaining walls located
between the columns; these retaining walls do not have expansion joints at the columns,
and thus create a serious structural weakness in that the columns adjacent to the walls
have "short column" deficiencies. Based upon drawing reviews (1995b), the columns
have modest vertical steel plus very light hoop steel (#3 ties at 16" spacing for main floor
G&E Engineering Systems Inc. Page 10
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
to roof, #5 spiral reinforcing at 2" pitch at basement level). Once the elastic capacity of
these columns is reached in lateral drift, the exterior concrete will rapidly spall and the
vertical steel will buckle soon thereafter. Serious structural damage and partial collapse
will occur at the first floor level at seismic loads that impose ductility demands much
over 1.5 to 2.
Figure 2-13 shows the typical block wall construction used for all four of the office
wings. Drawing review (1995b) suggests that these walls are lightly reinforced (#4 bars at
48"), but actual reinforcement might differ. As outlined in Section 5, a test program to
confmn the reinforcement, interior grouting and wall connections to floor / roof is
recommended as part of a final design retrofit effort.
Figure 2-13. Block Walls at Main Level
The roof over the four office wings is composed of a reinforced concrete waffle slab with
gravel topping (Figure 2-14). There are also HVAC heat exchangers pieces of equipment
atop the roof; access panels were not opened to con£u-m how these were restrained to the
roof- likely they are adequate.
There is also a microwave communication tower atop the roof. Assuming the tower was
designed to accommodate ice and severe wind loading, the tower should be adequate for
seismic loading up to Z=0o3g or even larger.
G&E Engineering Systems Inc. Page 11
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
There are several skylights at the roof level to the walkway and office spaces below.
These skylights use heat treated glass panels and should present no significant hazard in
earthquakes.
Figure 2-14. Roof Level Equipment
G&E Engineering Systems Inc. Page 12
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
2.3 Non Structural Systems
Each of the four office wings at the main level includes a HVAC mechanical room. Each
room includes similar quantities and types of equipment. Figure 2-15 shows the vibration
isolation spring mounts used for the HVAC fans in the southeast wing. This style of
vibration isolation mount is highly susceptible to toppling under moderate levels of
lateral ground motion. These units should be replaced with suitable seismically-designed
isolation mounts; or at a minimum suitable heavy angle snubbers can be added (bolted to
floor, free from the equipment) to prevent excessive lateral movements (1/8" to 1/4" or
so) of the equipment.
Figure 2-15. Vibration Isolation Mounts
The HVAC fan equipment in the other HVAC rooms were mounted using rubber pad-
type isolation mounts (Figure 2-16). These types of mounts are less vulnerable to seismic
loads than those in Figure 2-15; however, the addition of low-cost snubber restraint
angles is prudent, unless it can be shown that the light bolts can withstand the lateral
loads from Z=0.3g, including bending and shear, while remaining nearly elastic.
G&E Engineering Systems Inc. Page 13
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
Figure 2-16. Alternate Style Vibration Isolation Mounts
Figure 2-17 shows the typical suspended ceiling system used in the office buildings. It is
assumed that the t-bar ceiling system is lightly strong form the concrete roof system
above, with little to no suitable seismic lateral supports.
This type of ceiling system will tend to "disassemble" itself under moderate to strong
ground shaking. At shaking levels of PGA = 0.25g and higher, many of the ceiling tiles
will fall, creating a mess (but not a significant life safety hazard), and the t-bars may
become warped. It will usually take a day to clean this up.
Possible seismic mitigation would include the addition of diagonal wires, to connect the
t-bars to the roof above (this would be a code-style retrofit, intended to provide minimum
protection to occupants). Note: code-only diagonal wires have not shown to be effective
in limiting damage to the roof: their primary function is to limit the chance of
components falling. In areas of the City Hall complex where continued operations are
essential (not even allowing a few hours to clean up racked t-bar ceiling components),
then a more expensive style of retrofit is suggested, including structural load-rated t-bars;
connections or t-bars to walls; and lateral bracing using compression struts and diagonal
angles, etc. This more elaborate type of suspended ceiling retrofit might cost about $20
per square foot. For cost estimating purposes, it is assumed that about 1,000 square feet
of office space will be so-designated; and the remainder being upgraded just for life-
safety purposes.
G&E Engineering Systems Inc. Page 14
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
Figure 2-17. Suspended Ceiling System
There are several closets with communication equipment. Most equipment was found to
be suitably anchored (Figure 2-18).
G&E Engineering Systems Inc. Page 15
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
Figure 2-18. Communication Equipment Rack
There are many unrestrained desktop computer monitors and similar equipment
throughout the offices (Figure 2-19). Some computer monitors can be expected to slip off
the desk tops and fall under ground shaking of about Z=0.25g or larger.
G&E Engineering Systems Inc. Page 16
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
Figure 2-19. Desktop Monitors
Figure 2-20 shows one of ~e elec~c~ consol p~els for ~e Ci~ H~I complex.
~spection of ~e p~el suggests ~at it is un~chored ~d u~es~ned to the concrete
w~l be~nd it. Under moderately strong sh~ng (Z over 0.15g), ~s panel will rock; at
sh~ng levels approac~ng Z~.25g, t~s p~el ~ght topple.
Figure 2-20. Electrical Panel
There are two vertical pumps in the lower level basement, Figure 2-21. Pumps of this
kind are very rugged under seismic loading, and are not expected to fail (except for loss
of electric power). The function of these pumps could not be validated with facility staff
G&E Engineering Systems Inc. Page 17
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
- they may be part of a City-wide steam plant system; a sewage lift station; etc.
Connected pipes use screwed fittings, which are quite susceptible to leakage if
excessively stressed under seismic loads. If important to immediate post-earthquake
operations, suitable lateral restraints should be added to the attached pipes (carefully not
to increase seismic loads on weaker parts of the system.
Figure 2-21. Vertical Pumps
Figure 2-22 shows two overhead horizontal pressure tanks rated to 125 psi at 350°F.
Their nameplates indicate they were installed in 1962. These are likely part of the stem
heat system. These should be suitable restrained for lateral loads in order to prevent
excessive loading on attached pipes.
G&E Engineering Systems Inc. Page 18
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
Figure 2-22. Overhead Pressure Tanks
Figure 2-23 shows a horizontal tank resting on two saddles that in turn are resting on four
unanchored and unrestrained legs. This tank can slide under moderate levels of ground
shaking (z over 0.15g), and possibly topple. The tank support system should be retrofitted
to suitably accommodate seismic loads.
Figure 2-23. Horizontal Tank
Figure 2-24 shows a small dry-type transformer resting on a wooden pad. This should be
suitable restrained.
G&E Engineering Systems Inc. Page 19
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
Figure 2-24. Transformer
Figure 2-25 shows various paint buckets that are stacked. These present a falling hazard
at Z---O. 15g or higher. While the value of the paints is relatively small, the spillage might
result in slower emergency response times to perform other maintenance activities. These
paint buckets could be stored in a suitable metal enclosure cabinet; and the cabinet should
be suitably secured to the concrete floor.
Figure 2-25. Paints
Figure 2-26 shows two cabinets with backup power batteries. Inspection under the
cabinets showed no positive anchorage to the floor below. Two more small electrical
G&E Engineering Systems Inc. Page 20
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
cabinets opposite those in Figure 2-26 are also unanchored. All four of these cabinets
should be restrained.
Figure 2-26. Electrical Cabinets
Two communication equipment racks are located in the basement (Figure 2-27). These
appear to need extra restraint.
Figure 2-27. Communication Equipment Racks
G&E Engineering Systems Inc. Page 21
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
Figure 2-28 shows a large horizontal tank in the basement. It is saddle-supported, with
the saddles resting on steel channels that in turn rest on the floor. This tank should be
suitably restrained.
Figure 2-28. Horizontal Tank
The basement also houses two floor-mounted air compressors (adequate for seismic
loads), and two heat exchangers (anchorage should be upgraded for seismic loads).
There is a standby emergency generator located inside the building. Access to this room
could not be made available during the site visit. City staff should confirm if the lead-acid
batteries for this engine generator are unanchored / unrestrained. Under strong ground
motion, unrestrained batteries will rock and possibly topple (partially), likely leading to
battery malfunction. The loss of offsite power is likely to the site in a major earthquake
for a period of 6 to 24 hours. If unrestrained, it is recommended that the batteries be
suitably restrained. In addition, if the engine set is on vibration isolators similar to those
in Figure 2-15, then these should be replaced or the skid pad of the engine generator set
should be snubbed. Finally, the exhaust muffler should be configured to prevent
excessive displacement and possible breakage under Z=0.3g, if the exhaust is not easily
vented to the outside of the building.
G&E Engineering Systems Inc. Page 22
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
3.0 Prior Seismic Evaluations
The City of Eugene has had three seismic vulnerability studies performed on the City
Hall building over the past eight years. The first analysis was by Dames and Moore (ref.
Dames and Moore 1995); the second by Berry Architects (ref. Berry Architects 1995);
and the latest by URS (ref. URS 2001). The following paragraphs highlight the key
findings from those reports.
o The 1995 Dames and Moore report (ref. 1995a) predicted earthquake-induced
losses for the City Hall complex using ground motions measured by the Modified
Mercalli Intensity scale (MMI) and loss models from ATC-13. The buildings
were characterized as reinforced concrete structures. Three deterministic scenario
earthquakes were considered for seismic loss estimates: Cascadia Subduction
Zone (CSZ) Interplate M 8.5 (PGA = 0.27g), CSZ Intraplate M 7.5 (PGA =
0.16g) and a local random crustal M 6.0 event (PGA = 0.20g). The projected
losses for the City Hall Complex were 100%, 13% and 22%, for these three
earthquakes, respectively. Note that Dames and Moore assumed that a loss
requiring repairs costing 25% or more of the building replacement value would in
fact be totally replaced, thus leading to the 100% loss estimate for the CSZ M 8.5
events.
o The 1995 Berry Architects report (ref. 1995b) evaluated the City Hall complex
using he FEMA 178 checklist methods coupled with a linear static-force analysis
of the structure by Kanda and Tso Associates. The K&T analysis used the
following general method: Site PGA = 0.05g; V = 0.045W; consideration of
torsion and relative stiffness of all walls and piers. The K&T analysis made the
very conservative assumption that essentially all the existing masonry walls in the
building were unreinforced and ungrouted. Given these assumptions, the K&T
analysis showed that some wall elements were as much as 20 times overloaded as
compared to nominal code allowables.
o For the current effort, we make the observation that the findings in the
K&T analysis are not realistic. Even for a building designed in 1962, there
would have been some provision for lateral loads, whether earthquake
(about V=0.05W) or wind (at least V = 0.02W or so). K&T's assumptions
about the masonry walls is based on lack of drawings, not a confirmed
knowledge. If in fact the walls are unreinforced / unconnected and
ungrouted, then this building should "probably" have failed the original
plan check reviews / structural engineer's approval.
c> The K&T analysis has a second major assumption, in that the as-is
analysis is for a level of ground shaking of just PGA = 0.05g. Even in
1995, when K&T performed their analysis, it was widely recognized that
Eugene could be exposed to PGA = 0.2 to 0.3g given a Cascadia
Subduction Zone event.
G&E Engineering Systems Inc. Page 23
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
o Given these issues, for the current effort we apply the K&T findings as
follows: the building will likely remain nearly elastic under lateral loading
of about V = 0.05W to 0.06W (this assumed the masonry walls are
reinforced and mostly grouted).
o The 2001 URS report presents a probable maximum loss estimate for the City
Hall complex. Loss models were based on ATC-13 coupled with on-site
inspections and adjustments. Losses were calculated for two earthquake events,
corresponding to a 10% chance of exceedence in 50 years (PGA = 0.137g) and a
2% chance of exceedence in 50 years (PGA = 0.296g). URS suggests
characterizing the site as soil profile type SD, in accordance with the nomenclature
used is the 1997 UBC and 2000 IBC codes. The projected median losses for the
City Hall Complex were 28.3%, and 53.9%, for these two earthquakes,
respectively.
4.0 Seismic Hazards
The understanding of the seismic hazard for Oregon City has changed substantially over
the past 20 years. Prior to 1980 (or so), The central regions of Oregon were considered to
be largely aseismic. Studies suggested that the area of Eugene could experience ground
motions, as measured by Peak Ground acceleration, of about 0.05g once every 500 years
or so. At this very low level of shaking, damage is uncommon or limited even to poorly
constructed buildings, and in all practicality, local building codes excluded seismic forces
as a design requirement; or if required, set at such a low level that wind-level design
forces would exceed those from seismic.
As of 2003, it is now understood that Eugene faces three distinct types of seismic
hazards.
First, a great subduction magnitude (M) 8 to 9 earthquake under the Pacific
Ocean, near the Oregon coastline about 110 km west of Eugene, can cause strong
shaking of perhaps PGA = 0.20 to 0.35g for 60 to 90 seconds in Eugene.
Second, a very large M 7 to 7.5 earthquake within the subducting plate (so-called
Intra-plate) could occur directly beneath Eugene, but at substantial depth or
possibly 60 to 75 kin. While smaller in magnitude, this event will still cause
ground shaking in the range of PGA = 0.20 to 0.35g in Eugene.
Third, a moderate M 5.5 to 6.5 earthquake can occur in the top 10 to 20 km of the
earth's crust, rather near Eugene. While smaller in magnitude, this event can cause
ground shaking in the range of PGA = 0.10 to 0.60g (or higher) in Eugene,
depending upon exactly where the earthquake occurs.
G&E Engineering Systems Inc. Page 24
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
Given these issues, it is possible to establish a probabilistic level of ground shaking
that might be expected to occur in or near Eugene, for various return periods. For the
common return periods for a shallow soil over rock site in Eugene, the following
ground motions are established:
Once every 475 years: 0.14 g or more
o Once every 975 years: 0.20 g or more
o Once every 2,475 years: 0.30 g or more
Figure 4-1 shows a complete seismic hazard curve for Eugene. For new designs to the
1997 Edition of the UBC, the design PGA is 0.3g. It should be noted that while the
design PGA of 0.3g reflects a return period longer than 475 years, a dominant source of
the hazard is the potential for a moderately distant M 8.5 to 9 earthquake; this large
magnitude earthquake would cause a longer duration of ground shaking (more than 60
seconds) than more common crustal events in California, and probably more damage to
many types of ductile structures. Table 4-1 provides the digitized values in Figure 4-1.
l
':
o O(~OOi
o ooo0~ol _
O0 05 10 t 5 2B 25
Peak Ground Accea~ra~c:n - O
Figure 4-1. Seismic Hazard Curve for Eugene
Frequency of Occurrence per Year PGA (g)
5.39E-02 0.005
4.58E-02 0.007
3.71E-02 0.0098
2.81E-02 0.0137
1.98E-02 0.0192
1.32E-02 0.0269
8.62E-03 0.0376
5.84E-03 0.0527
4.20E-03 0.0738
G&E Engineering Systems Inc. Page 25
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
3.05E-03 0.103
1.96E-03 0.145
1.03E-03 0.203
4.53E-04 0.284
1.76E-04 0.397
5.93E-05 0.556
1.65E-05 0.778
3.67E-06 1.09
6.59E-07 1.52
9.09E-08 2.13
Table 4-1. Tabulated data for Figure 4-1
Given the occurrence of an earthquake, there are four hazards that might occur: ground
shaking, liquefaction (and related types of ground failure), landslide and surface faulting.
These hazards are further described below (largely adopted from (Dames and Moore
1995) - no site subsurface investigations were performed as part of the current effort:
o Ground shaking hazard. This is covered in Figure 4-1 and Table 4-1. For design
purposes, a broad-banded response spectra suitable for firm soils sites tied to the
PGA levels of Table 4-1 is appropriate.
o Liquefaction. The subsurface conditions in the Eugene area are controlled by the
ancient courses of the Willamette and McKenzie Rivers. Historical courses of the
rivers scoured relatively deep channels in the underlying bedrock, where were
filled gradually and episodically by alluvial deposits. Most of Eugene is underlain
by older alluvial deposits which have been locally eroded and replaced by
younger alluvium along the present courses of the Willamette and McKenzie
Rivers. The older alluvium in the valley floor is generally capped by a surficial
layer of wind-deposited silt. In the downtown area where City Hall is located, the
subsurface conditions generally consist of 5 to 15 feet of silty soils underlain by
gravel and cobble deposits of the older alluvium. The foundation system for City
Hall is assumed to extend through the silty layer and is established on the gravelly
soils. The older alluvium generally consists of dense silty and sandy gravel with
cobbles. Soft soil conditions are not indicated at City Hall. Given these
conditions, the site has a very low susceptibility to liquefaction-induced
settlements or lateral spread.
o Landslide. The site geology is not considered prone to landslide.
o Surface Faulting. Surface faulting is not considered likely for this site for
subduction zone earthquakes. There are no known active or potentially active
faults that traverse the site.
G&E Engineering Systems Inc. Page 26
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
5.0 Fragility and Cost Information
Section 5 presents fragility and cost information to be used for benefit cost analysis
purposes. The information in Section 5 may not be complete enough for final design
purposes.
5.1 Costs
As highlighted in Section 4 of this report, the existing capacity of the building is probably
not much more than what was envisioned in the original design of circa 1962. Most
likely, the nominal elastic lateral limit of the building is in the range of PGA = 0.05 to
0.07g or so. If in fact the existing masonry walls at the main floor level are unreinforced
and ungrouted, the existing capacity could be lower than these amounts.
As part of any seismic retrofit measures, it is recommended that a in-sim test program be
included at the project outset, in order to verify the style of construction of the in-situ
masonry walls on the main floor level, both in the wings as well as the city council
chambers areas. This test data will necessarily be partially destructive, but only in so far
as to uncover the interior style of construction (rebar, grout) and connection systems. The
test data would be used for two main purposes: assess the tree as-built capacity of these
walls; and to assess how these walls can be re-used in the final upgrades, and / or
connected thereto. Any testing effort would include a task to rebuild the damaged walls
immediately after the testing process, so that there is no degradation of the structural
capacity or significant adverse architectural degradation for the interim period until the
final retrofits are installed.
The ultimate seismic retrofit for this building is based upon a design upgrade equal to
about V = 0.14W (suitable for this type of building in zone 3), using I= 1. About one-
third of the total seismic capacity will come from the existing elements, and two-thirds
will come from the new structural elements added to the building. Based upon V =
0.10W, and allowing for good ductile detailing of the new structural elements, then the
following new elements would be added to the building:
o New shear walls in the North-South and East-West directions (14 to 16 walls
total). Each wall would run full height of the building (parking level to roof).
Most walls would be about 35 feet long, 1 foot wide, and include suitable
boundary elements (existing columns with additional reinforcement). Floor
diaphragms might be thickened locally as needed to make for a good transfer of
floor loads to the walls. The walls would have suitable new foundations, along
with tie beams as needed to adjacent elements.
o An allowance is provided to provide improved structural load capacity for the
council chambers.
G&E Engineering Systems Inc. Page 27
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
o As the upgraded structure may rely upon both ductile components (new
construction) and some marginal non-ductile components (existing construction),
a drift compatibility analysis is suggested. This analysis would show how the new
walls would perform at PGA = 0.30g (but no less than PGA = 0.225g) while
keeping existing non-ductile columns at ductility demand levels that would not be
too high for their style of construction. Local overloads at PGA = 0.30 g are
acceptable as long as life-safety of the complete structural system is maintained.
Table 5-1 list the costs associated with the structural upgrade of the City Hall complex,
plus provides for construction contingency, engineering, project management and
inspection. The total dollars in Table 5-1 are considered a more accurate figure than the
individual line items; as detailed engineering is completed, the costs for individual items
might increase / decrease, but the overall costs should be kept within this budget.
Stmcture Cost ($2003)
New Shear~alls, footings, tie beams, attachments
- Assume 53 cubic yards of placed concrete average
- Assume 16 new wall systems
- Assume $600 / cubic yard placed concrete
Construction cost = $600/yd x 53 yds * 16 walls $ 508,800
Allowance for Council Chambers $ 80,000
Initial testing program $ 20,000
Repair of finishes, allowance $ 100,000
Total $ 708,800
Contingency @ 30% $ 212,640
Total Construction $ 921,440
Engineering, PM, Inspection @30% $ 276,432
Total $ 1,197,872
Table 5-1. Costs for Structural Mitigation
Table 5-2 lists the costs for the mitigation of the non-structural items outlined in Section
2 of this report. The order of items listed in Table 5-2 corresponds to the order in which
the non-structural weaknesses are outlined in Section 2. The last two line items, for
elevations and the emergency generator, were not observed during the site visit, so the
cost allowances are based on the observations provided in the 1995 Berry report (ref.
1995b). Costs are also provided for construction contingency, engineering, project
management and inspection. It is assumed that only a limited amount of the non-
structural mitigations will be performed by facility maintenance staff using simplified
design sketches; the bulk will be performed by an outside contractor with contract
documents. Engineering inspection is required for all non-structural upgrades. The
contingency allowance provides for some non-structural items that might not have been
listed individually in Table 5-2. The total dollars in Table 5-2 are considered a more
accurate figure than the individual line items; as detailed engineering is completed, the
costs for individual items might increase / decrease, but the overall costs should be kept
within this budget.
G&E Engineering Systems Inc. Page 28
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
Non Structural Cost ($2003)
Council Chamber suspended ceiling - allowance $ 15,000
Pedestrian bridge - allowance $ 20,000
Roof level heat exchangers $ 1,500
Main level HVAC Equipment - lateral restraints $ 6,000
Suspended Ceilings - life safety retrofit $ 40,000
Suspended Ceilings - continued operations retrofit $ 20,000
Desk top computer monitors and sensitive equipment $ 8,000
Anchor electrical panel in basement $ 2,000
Pipe lateral restraint / flexibility fittings $ 3,000
Overhead pressure tanks - lateral restraint $ 2,000
Restrain horizontal tank on supports $ 3,000
Restrain dry-type transformer $ 750
Enclose hazardous materials in suitable cabinet $ 2,000
Restrain cabinets with backup power, plus nearby cabinets $ 2,000
Add extra restraint to communication equipment racks $ 750
Anchor large horizontal tank $ 2,000
Anchor heat exchangers $ 1,000
Elevator improvements - allowance $ 6,000
Generator mounts, batteries, fuel supply - allowance $ 1,500
Total $ 139,500
Contingency @ 20% $ 27,300
Total Construction $ 163,800
Engineering, PM, Inspection @45% $ 73,710
Total $ 237,510
Table 5-2. Costs for Non-Structural Mitigation
5.2 Fragilities
Table 5-3 provides fragilities for the various structures and equipment components
discussed in this report.
The prediction of damage for the structure is done using fragility curves. Fragility curves
are presented for each of four damage states:
· Collapse
· Extensive
· Moderate
· Slight
These damage states are descriptive. From the descriptions of the damage states provided
in this section, the user can understand the nature and extent of the physical damage to
the building from the damage prediction output. From these descriptions, life-safety,
societal and monetary losses which result from the damage can be estimated. Building
G&E Engineering Systems Inc. Page 29
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
damage can best be described in terms of the nature and extent of damage exhibited by its
components (floors, columns, walls, ceilings, piping, HVAC equipment, etc.). For
example, such component damage descriptions as "shear walls are cracked", "ceiling tiles
fell", "wall panels fell out", etc., used together with such terms as "some" and "most"
would be sufficient to describe the nature and extent of overall building damage.
Damage to nonstructural components of buildings (i.e., architectural components, such as
partition walls and ceilings, and building mechanical/electrical systems) primarily affect
monetary and societal losses while damage to structural components (i.e., the gravity and
lateral load resisting systems) of buildings affect the expected casualty estimates, as well
as other losses. For this project, we have provided fragility curves for damage to the
structural components, and separately for the nonstructural components.
Another characteristic of building damage is that it varies from "none" to "complete" as a
continuous function of building deformations (building response). Wall cracks may vary
from invisible or hairline cracks to cracks of several inches width. Furthermore, damage
of different nature or form may occur at different building deformations. As it is
impractical to linguistically describe building damage as a continuous function, it is
necessary to develop general descriptions for ranges of damage.
This methodology describes extent and severity of damage to structural components of a
building separately by one of four ranges of damage or damage states: slight, moderate,
extensive, and complete. General descriptions of these damage states are provided
reference to observable damage incurred. Damage predictions resulting from this
physical damage estimation method are then expressed in terms of the probability of a
building being in any of these four damage states.
G&E Engineering Systems Inc. Page 30
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
Reinforced Masonry Walls
Slight Structural Damage: Diagonal hairline cracks on masonry wall surfaces; larger
cracks around door and window openings in walls with large proportion of openings;
minor separation of walls from the floor and roof diaphragms.
Moderate Structural Damage: Most wall surfaces exhibit diagonal cracks; some of the
shear walls have exceeded their yield capacities indicated by larger diagonal cracks; some
walls may have visibly pulled away from the roof.
Extensive Structural Damage: Most shear walls have exceeded their yield capacities
and some of the walls have exceeded their ultimate capacities indicated by large, through~
the wall diagonal cracks and visibly buckled wall reinforcement.
Complete Structural Damage: Structure has collapsed or is in imminent danger of
collapse due to failure of the wall panels.
Concrete Columns and Floor System
Slight Structural Damage: Flexural or shear type hairline cracks in some portions of
waffle slabs and columns near joints or within joints.
Moderate Structural Damage: Most waffle slabs near columns and most columns
exhibit hairline cracks; a few locations may exhibit larger shear cracks and spalling.
Extensive Structural Damage: Some of the columns and waffle slabs have reached their
capacity indicated by spalled concrete and buckled main reinforcement; short columns
may have suffered shear failures or bond failures at reinforcement splices which may
result in partial collapse.
Complete Structural Damage: Structure is collapsed or in imminent danger of collapse
due to brittle failure of nonductile elements or loss of frame stability.
Concrete Shear Walls
Slight Structural Damage: Diagonal hairline cracks on most concrete shear wall
surfaces; minor concrete spalling at few locations.
Moderate Structural Damage: Most shear wall surfaces exhibit diagonal cracks; some
shear walls have exceeded yield capacity indicated by larger diagonal cracks and concrete
spalling at wall ends.
Extensive Structural Damage: Most concrete shear walls have exceeded their yield
capacities; some walls have exceeded their ultimate capacities indicated by large,
through-the wall diagonal cracks, extensive spalling around the cracks and visibly
buckled wall reinforcement.
Complete Structural Damage: Structure has collapsed or is in imminent danger of
collapse due to failure of most of the shear walls and failure of some critical columns.
G&E Engineering Systems Inc. Page 31
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
The basis for development of the fragility data for these selected structures is past
earthquake experience data, calculations provided in (1995b), and judgment.
For each item for which fragility data was developed, two building states were
considered:
Existing structure in its pre-earthquake condition
Existing structure in its retrofitted condition
The fragility curves represent the damage attributable to the structural load beating part
of the building.
Structure Slight Moderate Major Collapse
Case A Beta A Beta A Beta A Beta
1. As Is 0.08 0.60 0.12 0.60 0.20 0.60 0.40 0.60
2. Upgraded 0.21 0.50 0.30 0.50 0.90 0.50 1.60 0.50
Table 5-3. Fragilities
For equipment, the damage states are as follows:
Suspended Ceiling. Extensive damage. Many panels fall. Adverse interactions
with equipment above the ceiling tiles may occur.
HVAC. Equipment displaces and is damaged.
Desktop equipment, monitors. Item slides and falls off desktop / countertop and is
likely damaged / non-functional. Upgrade precludes sliding and essentially
eliminates the risk of damage.
Electrical Panels (including motor control center). Unanchored / unrestrained
panels rock and potentially topple. Possibly some components within the panel
are damage. Upgrade prevents toppling.
Pipes runs. Each run suffers some type of damage (sometimes leaks or breaks in
pipe, sometimes excessive damage to support). Upgrade is to preclude breaks in
pipe / conduit due to excessive seismic anchor movements
Overhead Tanks. Excessive lateral movement distresses supports and puts
excessive loads on attached pipes. Upgrade is to ensure that the tank does not fall
and the loads on attached pipes do not cause them to break.
Floor mounted tanks (and heat exchangers). Anchorage slips / breaks and allows
tanks to move laterally / rock. Could lead to damage of attached pipes. Upgrade is
to anchor / restrain the tanks to preclude their excessive movement.
G&E Engineering Systems Inc. Page 32
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
Hazardous materials. Materials (paints, etc.) topple and spill. Upgrade is to put
them into a suitable cabinet and to anchor the cabinet.
Equipment Racks. Racks topple leading to general equipment failure.
Elevator. Excessive movement of counterweight damages car. Excessive
movement of electrical and drive equipment. (Note: the elevator system was not
inspected, so the type of damage described is highly generalized and adopted
from 1995b).
Emergency Generator - Generator fails to start due to excessive lateral movement
putting loads on attached hoses; pounding or toppling of unrestrained battery;
toppling of fuel supply; or otherwise. Repair times about 2 to 8 hours after
maintenance crew is mobilized. (Note: the emergency generator was not
inspected, so the type of damage described is highly generalized and adopted
from 1995b).
Equipment Suspended Suspended HVAC On Roof HVAC at Main
Ceiling - Code Ceiling - Level
Up~rade Functional
Case A Beta A A A Beta A Beta
1. As Is 0.50 0.50 0.50 0.50 0.60 0.50 0.30 0.60
2. Upgraded 0.80 0.50 1.30 0.40 1.00 0.50 0.60 0.40
Table 5-4a. Fragilities- Equipment
Equipment Desk Top Electrical Panel Overhead Overhead
Equipment Screwed Pipes Tanks -
Attachments
Case A Beta A Beta A Beta A Beta
1. As Is 0.30 0.50 0.50 0.60 0.60 0.70 0.60 0.70
2. Upgraded 1.30 0.50 1.50 0.50 3.00 0.60 3.00 0.60
Table 5-4b. Fragilities- Equipment
Equipment Floor Mounted Hazardous Equipment Racks Floor Mounted
Horizontal Materials Heat
Tanks Exchangers
Case A Beta A Beta A Beta A Beta
1. As Is 0.50 0.60 0.20 0.50 0.50 0.50 0.60 0.60
2. Upgraded 1.50 0.50 1.50 0.40 1.50 0.40 1.50 0.50
Table 5-4c. Fragilities- Equipment
G&E Engineering Systems Inc. Page 33
Eugene City Hall R32.19.04 Rev. B. September 9, 2003
Equipment Elevators Backup
Generator
Case A Beta A Beta
1. As Is 0.50 0.70 0.30 0.60
2. Upgraded 1.00 0.60 0.60 0.40
Table 5-4d. Fragilities- Equipment
6.0 References
URS, Report of Probable Maximum Loss, Earthquake Risk Analysis, City-Owned
Buildings, Eugene, Oregon, Prepared for the City of Eugene, Oregon, November, 2001.
Dames and Moore, Report, Maximum Probable Loss, Earthquake Risk Analysis, City-
Owned Buildings, Eugene, Oregon, Prepared for the City of Eugene, Oregon, June 22,
1995a.
Berry Architects, Seismic Evaluation of Facilities Owned by the City of Eugene, Oregon,
Phase Five, City Hall / Fire Station No. 1, FEMA-178 Analysis, February 15, 1995b.
G&E Engineering Systems Inc. Page 34