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HomeMy WebLinkAboutAdmin Order 58-12-14ADMINISTRATIVE ORDER NO. 58 -12 -14 of the Executive Director of the Public Works Department APPROVING THE RIVER ROAD -SANTA CLARA STORMWATER BASIN MASTER PLAN. The Executive Director of the Public Works Department finds that: A. Under the provisions of Chapter IV, Section 16 of the Eugene Charter of 2002, the City Manager is designated as the administrative head of the City, and is specifically authorized to appoint and remove all employees (except as otherwise provided in the Charter), and to enforce all ordinances of the City. B. Pursuant to that authority, I have been designated as Executive Director of the City's Public Works Department. My appointment has most recently been affirmed by the City Manager's Administrative Order No. 21- 12 -10. In such capacity, I have the responsibility for supervision of the Public Works Department and its employees. C. The River Road -Santa Clara Stormwater Basin Master Plan (Basin Plan) has been developed to replace the 1990 Otak Areawide Drainage Master Plan for River Road —Santa Clara. The new Basin Plan will be included in the 2002 Stormwater Basin Master Plan as Volume VIII. The Basin Plan documents the comprehensive basin planning process and results, and provides guidance for the management of stormwater throughout the study area. This plan describes a "multiple- objective" approach (i.e., incorporating water quality, stormwater- related natural resources and flood control) to stormwater management, and is to be used by City staff for background /contextual information, for development of the City's biennial CIP, for contextual support for stormwater development standards, and for evaluating technical information about the stormwater system. However, the Basin Plan will not be used in a manner that regulates conduct or activities of the public. D. The new Basin Plan: (1) Identifies the major drainage basins and major sub -basin delineations in River Road -Santa Clara; (2) Describes the study area characteristics (existing/build -out land use, impervious surface cover, slopes, topography, soil types, drainage features, etc.); (3) Describes the flood control, water quality and stormwater- related natural resource problems and opportunities in each major basin of River Road - Santa Clara; Administrative Order - Page 1 of 2 (4) Describes the long -term (35 year) multiple objective capital improvement program for River Road -Santa Clara (including water quality, flood control and storrwater- related natural resources projects as well as stream corridor acquisitions) and stonrwater development standards that would, together and along with the other multitude of activities in the stormwater program, address the identified problems and opportunities; and (5) Compliments the adopted 2002 Storrnwater Basin Master Plans which describe the City's drainage criteria for design of stormwater system improvements. E. The drainage criteria for design of stormwater system improvements contained in the Basin Plan, and other specific information about design storm events and analysis and design methods serve as guidance to the City and the public and are neither requirements nor prohibited conduct. Now, therefore, based on the above findings, which are hereby adopted: IT IS HEREBY ORDERED THAT: 1. The River Road -Santa Clara Stormwater Basin Master Plan (Basin Plan) attached to this Order is hereby approved, and shall be utilized by staff on the Public Works Department in lieu of the 1990 Otak Areawide Drainage Master Plan for River Road —Santa Clara in evaluating development proposals. The Basin Plan shall not be used as approval criteria. 2. Copies of this Order shall be forwarded to all Public Works Department Division Managers. Dated this ' Z day of oa tv- .2012. K , rt Corey, Exec )tnment Director Public Works Dept Administrative Order - Page 2 of 2 River Road-Santa Clara Volume Vill of Vill September 2012 P vej) a i ed by: City o Eug f ene " URS Corporation Lane Council of Govevnnients Stormwater Basin Master Plan Volume VIII of VIII River Road — Santa Clara September 2012 Prepared by: City of Eugene URS Corporation Brown and Caldwell Lane Council of Governments ACKNOWLEDGEMENTS The River Road — Santa Clara Stormwater Basin Master Plan represents the culmination of a long term planning effort by a multi- agency team consisting of representatives from the City of Eugene, Lane County, URS Corporation, Brown & Caldwell Consultants, and Lane Council of Governments (LCOG). The project team would like to gratefully acknowledge the efforts of the many city, county and consultant staff that provided input for and review of this document. POLICY GUIDANCE Kurt Corey, Public Works Director Mark Schoening, City Engineer Jeff Lankston, Maintenance Division Manager Peter Ruffier, Wastewater Division Manager Johnny Medlin, Parks & Open Space Division Manager Becky Carlson, Administration Division Manager Bill Morgan, Lane County Engineer TECHNICAL GUIDANCE Angela Brown, URS Hernan Rodriguez, URS David Weatherby, URS Fred McVey, Public Works Engineering Division Peggy Keppler, Public Works Engineering Division Terry Colvin, Public Works Engineering Division Jack Long, Public Works Parks & Open Space Division Jim McLaughlin, Public Works Maintenance Division Eugene Stormwater Management Team Tim Bingham, LCOG PROJECT MANAGEMENT Krista Reininga, Brown & Caldwell Therese Walch, City of Eugene Dan Hurley, Lane County Mike Russell, Lane County MAPPING SUPPORT Cress Bates, Lane County Mike Miller, City of Eugene Bill Clingman, LCOG The information published in this report is subject to revision. Please contact the City of Eugene's Engineering Division for potential changes before proceeding with any engineering design that uses the information published herein. N:ASTORMWATER \City of EugencARR_SC Stormwater Basin Plan\2012 Document \Master_ Plan _9- 18- 12_DR-AFT Word Version.doc TABLE OF CONTENTS Executive Summary Section1 Introduction ......................................................................................... ............................1 -1 Section 2 Study Area Characteristics ............................................................. ............................... 2 -1 2.1 Location and Area ..................................................... ............................... 2 -1 2. 1.1 Regional Drainage Context ........................... ............................... 2 -1 2.1.2 City of Eugene .............................................. ............................... 2 -1 2.1.3 River Road Santa Clara Basin ....................... ............................... 2 -7 2.2 Climate ......................................................................... ............................2 -7 2.3 Land Use and Surface Cover .................................... ............................... 2 -8 2.3.1 Existing Land Use ......................................... ............................... 2 -8 2.3.2 Buildout Land Use ........................................ ............................... 2 -9 2.3.2.1 Buildout Land Use Within the UGB ........................ 2 -10 2.3.2.2 Projected Land Use Outside the UGB ..................... 2 -10 2.3.3 Surface Cover .............................................. ............................... 2 -11 2.3.3.1 Impervious Surfaces ...................... ...........................2 -11 2.3.3.2 Pervious Surfaces ...................... ............................... 2 -12 2.4 Landform, Topography, Slopes .............................. ............................... 2 -13 2.5 Surface Water Features and Drainage System ........ ............................... 2 -14 2.5.1 Waterways ....................................................... ...........................2 -14 2.5.1.1 A -1 Channel .................................. ...........................2 -14 2.5.1.2 Flat Creek .................................. ............................... 2 -14 2.5.1.3 Spring Creek ............................. ............................... 2 -15 2.5.1.4 Willamette Overflow ................ ............................... 2 -15 2.5.1.5 Highway 90 ................................... ...........................2 -16 2.5.2 Wetlands ..................................................... ............................... 2 -16 2.5.3 Public Piped Drainage System .................... ............................... 2 -16 2.5.4 Drywell Drainage System ............................... ...........................2 -17 2.5.5 Maintaining the Drainage System ............... ............................... 2 -17 2.5.6 Floodplain ................................................... ............................... 2 -17 2.6 Water Quality .......................................................... ............................... 2 -17 2.6.1 Documented Water Quality Problems ........ ............................... 2 -18 2.6.1.1 Chemical Stormwater Monitoring Data ................... 2 -18 2.6.1.2 Findings from Macroinvertebrate Sampling............ 2 -22 2.6.2 Oregon Department of Environmental Quality Water Quality Limited Designations [303(d) List] .............................. 2 -22 2.6.3 Natural and Built Conditions ...................... ............................... 2 -23 2.6.4 Conclusions ..................................................... ...........................2 -24 2.7 Rare, Threatened, and Endangered Plants, Animals, and Communities........................................................... ............................... 2 -25 2.8 Soils ............................................................................. ...........................2 -25 2.8.1 Permeability ................................................ ............................... 2 -26 2.8.2 Runoff Potential .......................................... ............................... 2 -26 2.8.3 Erodible Soils .............................................. ............................... 2 -27 N:ASTORMWATER \City of EugencARR_SC Stormwater Basin Plan\2012 Document \Master_ Plan _9- 18- 12_DR-AFT Word Version.doc i TABLE OF CONTENTS 5.1 Evaluation of Natural Resources Under Existing and Expected FutureConditions ..................................................... ............................... 5 -1 5.2 Development of the Natural Resources Strategy ...... ............................... 5 -3 5.2.1 Capital Project Alternatives .......................... ............................... 5 -4 5.2.2 Development Standard Alternatives ............. ............................... 5 -4 Section 6 Integrated Stormwater Management Strategy .............................. ............................... 6 -1 6.1 CP and Development Standard Strategies ................ ............................... 6 -1 6.2 Summary of Strategy Benefits .................................. ............................... 6 -5 6.3 Summary of Strategy Implementation and Costs ..... ............................... 6 -5 N:ASTORMWATER \City of EugencARR_SC Stormwater Basin Plan\2012 Document \Master_ Plan _9- 18- 12_DR-AFT Word Version.doc ii 2.8.4 Unstable Slopes ........................................... ............................... 2 -27 2.8.5 Hydric Soils ................................................ ............................... 2 -27 2.9 Groundwater ........................................................... ............................... 2 -28 2.10 Existing and Planned Educational Facilities ........... ............................... 2 -29 2.11 Existing and Planned Park and Recreational Facilities .......................... 2 -29 Section 3 Flood Control Evaluation ................................................................ ............................... 3 -1 3.1 Hydrologic/Hydraulic Model Development ............. ............................... 3 -1 3. 1.1 River Road Santa Clara Basin Hydrologic Data .......................... 3 -1 3.1.2 River Road Santa Clara Basin Hydraulic Data ............................ 3 -4 3.2 Model Validation Process ......................................... ............................... 3 -6 3.3 Model Results ........................................................... ............................... 3 -9 3.4 Flooding Problems Identified by the Model ........... ............................... 3 -10 3.5 Development of the Flood Management Strategy .. ............................... 3 -10 3.5.1 Capital Projects to Address Capacity Deficiencies ................... 3 -11 3.5.2 Selected Projects to Address Flows Associated with Drywell Decommissioning ......................... ............................... 3 -13 3.5.3 Selected Development Standard Alternatives ............................ 3 -15 Section 4 Water Quality Evaluation ................................................................... ............................4 -1 4.1 Regulatory Drivers Related to Water Quality ........... ............................... 4 -1 4.1.1 Stormwater Discharges to Surface Waters ... ............................... 4 -1 4.1.2 Stormwater Discharges to the Subsurface .... ............................... 4 -2 4.2 Evaluation of Existing and Expected Future Water Quality Conditions................................................................. ............................... 4 -4 4.3 Development of the Water Quality Strategy ............. ............................... 4 -7 4.3.1 Capital Project Alternatives ......................... ............................... 4 -7 4.3.2 Development Standards to Address Water Quality ................... 4 -34 Section 5 Stormwater Related Natural Resources ........................................ ............................... 5 -1 5.1 Evaluation of Natural Resources Under Existing and Expected FutureConditions ..................................................... ............................... 5 -1 5.2 Development of the Natural Resources Strategy ...... ............................... 5 -3 5.2.1 Capital Project Alternatives .......................... ............................... 5 -4 5.2.2 Development Standard Alternatives ............. ............................... 5 -4 Section 6 Integrated Stormwater Management Strategy .............................. ............................... 6 -1 6.1 CP and Development Standard Strategies ................ ............................... 6 -1 6.2 Summary of Strategy Benefits .................................. ............................... 6 -5 6.3 Summary of Strategy Implementation and Costs ..... ............................... 6 -5 N:ASTORMWATER \City of EugencARR_SC Stormwater Basin Plan\2012 Document \Master_ Plan _9- 18- 12_DR-AFT Word Version.doc ii TABLE OF CONTENTS LIST OF APPENDICES Appendix A Capital Project Fact Sheets Appendix B Hydrologic/Hydraulic Model Output Tables Appendix C Methodology for Estimating the Effective Impervious Area of Urban Watersheds Appendix D Capital Project Unit Cost Tables Appendix E Evaluation of UICs (i.e., Drywells) with Respect to High Groundwater Appendix F Rain Garden Sizing Calculations and Plan Views for Six ROW Options Appendix G Summary of Model Refinements Since the Initial 2002 Study Appendix H River Road Santa Clara Stormwater Management Strategy Development Map Appendix I Public Comments and Responses LIST OF TABLES Table 2 -1 Average Storm Event ............................................................ ............................... 2 -8 Table 2 -2 Existing Land Use — River Road Santa Clara Basin ............. ............................... 2 -9 Table 2 -3 Buildout Land Use General ................................................ ............................... 2 -10 Table 2 -4 River Road Santa Clara Basin Slope Distribution .............. ............................... 2 -13 Table 2 -5 Summary of Stormwater Quality Monitoring in Eugene .... ............................... 2 -21 Table 2 -6 Soil Permeability in the River Road Santa Clara Basin ...... ............................... 2 -26 Table 2 -7 Runoff Potential in the River Road Santa Clara Basin ....... ............................... 2 -27 Table 2 -8 Hydric Soils in River Road Santa Clara Basin ................... ............................... 2 -28 Table 3 -1 Major Hydrologic Input/Output Data for the River Road Santa Clara Storm Drainage System ...................................................... ............................... 3 -17 Table 3 -2 Hydraulic Performance of the River Road Santa Clara Storm DrainageSystem ................................................................. ............................... 3 -19 Table 3 -3 Rainfall Data Used for the Model Validation ....................... ............................... 3 -7 Table 3 -4 Model Adjustments and Associated Model Results for Node 74406 .................. 3 -8 Table 3 -5 Capacity Deficiencies Identified Through Modeling and Proposed Capital Projects to Address Them ....................................... ............................... 3 -11 Table 3 -6 Capital Project Options Selected to Address Decommissioning of Drywell .............................................................................. ............................... 3-14 Table 4 -1 Summary of Increased ROW Required for Six Different On- Street RainGarden Options ........................................................... ............................... 4 -17 Table 6 -1 Summary of Capital Project Costs and Funding ................... ............................... 6 -6 LIST OF FIGURES Figure 1 -1 Process to Develop the Integrated Stormwater Management Strategies ............. 1 -8 Figure 1 -2 CIP/Master Planning Phase Process for the River Road Santa Clara Basin........ 1 -9 Figure 2 -1 Willamette Region Location Map ......................................... ............................... 2 -3 Figure 2 -2 Basin Location Map .............................................................. ............................... 2 -5 Figure 2 -3 Average Monthly Rainfall .................................................... ............................... 2 -7 Figure 2 -4 Surface Cover in the River Road Santa Clara Basin UGB . ............................... 2 -13 Figure 2 -5 Water Quality Monitoring Sites .......................................... ............................... 2 -19 N:ASTORMWATER \City of EugencARR_SC Stormwater Basin Plan\2012 Document \Master_ Plan _9- 18- 12_DR-AFT Word Version.doc iii TABLE OF CONTENTS Figure 2 -6 Extent of Open Drainage System in the River Road Santa Clara Basin (UGB) .................................................................................... ...........................2 -24 Figure 2 -7 Extent of Area as a Percentage of the River Road Santa Clara Basin (UGB) .................................................................................... ...........................2 -24 Figure 2 -8 Extent of 100 -Year Floodway Fringe that is Vacant in the River Road SantaClara Basin ............................................................... ............................... 2 -24 Figure 3 -1 River Road Santa Clara Basin Drainage System Index Map.......... end of Section 3 Figure 3 -2 River Road Santa Clara Basin Drainage System ............................ end of Section 3 Figure 3 -3 River Road Santa Clara Basin Drainage System ............................ end of Section 3 Figure 3 -4 River Road Santa Clara Basin Drainage System ............................ end of Section 3 Figure 3 -5 River Road Santa Clara Basin Drainage System ............................ end of Section 3 Figure 3 -6 River Road Santa Clara Basin Drainage System ............................ end of Section 3 Figure 3 -7 River Road Santa Clara Basin Drainage System ............................ end of Section 3 Figure 3 -8 River Road Santa Clara Basin Drainage System ............................ end of Section 3 Figure 4 -1 Estimated Total Suspended Solids Loads Per Year in the River Road Santa ClaraBasin ( UGB) ................................................................ ............................... 4 -5 Figure 4 -2 Estimated Increases in Total Suspended Solids Loads Associated with Future Buildout in the River Road Santa Clara Basin (UGB) ............................. 4 -5 Figure 4 -3 Estimated Total Suspended Solids Loads Per Acre — Per Year in the River Road Santa Clara Basin (UGB) ............................................ ............................... 4 -6 Figure 4 -4 Comparison of Pre- and Post - Development Hydrographs .... ............................... 4 -7 Figure 4 -5 Original Green Street Concept #2 with Adjusted ROW (Plan View) ............... 4 -19 Figure 4 -6 Original Green Street Concept #2 with Adjusted ROW (Section View) ........... 4 -21 Figure 4 -7 Original Green Street Concept #4 with Adjusted ROW (Plan View) ............... 4 -23 Figure 4 -8 Original Green Street Concept #4 with Adjusted ROW (Section View) ........... 4 -25 Figure 4 -9 Original Green Street Concept #6 with Adjusted ROW (Plan View) ............... 4 -27 Figure 4 -10 Original Green Street Concept #6 with Adjusted ROW (Section View) ........... 4 -29 Figure 4 -11 Destination Considerations for Project Planning Phase ...... ............................... 4 -31 Figure 4 -12 Water Quality Protected Waterways Map .......................... ............................... 4 -36 LIST OF MAPS (Located at end of Section 2) Map 1 Existing Land Use Map 2 Projected Land Use Map 3 Surface Cover Map 4 Slope and Topography Map 5 Surface 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X O _d O ~ m U o n > N � o i 7 c o E m � c �n o � m i U N o 2 o . Nyip '0 � o(J) N o c O a °- R m o a m R . V E N 7 • .Qa m R E E N 2 y E a, C E O c U Y m E E o p N !O d U N Q U O a ±+ N a C4 > N'00 0 SECTION 1 Introduction Adoption of the City of Eugene's Comprehensive Stormwater Management Plan (CSWMP) in November 1993 marked a significant shift in the City's approach to stormwater management. In addition to drainage and flood control services, the stormwater program was expanded to include the protection and enhancement of stormwater quality and related natural resources. Since the previous Storm Drainage Master Plan (OTAK, 1990) was developed solely for the purpose of addressing drainage and flood control issues, an update of that Plan was necessary to bring it into compliance with current City policy. As a result, the City initiated a project to develop multiple - objective Stormwater Basin Master Plans. In addition to CSWMP, other locally adopted policy documents were reviewed for applicability to the Basin Master Planning effort. The following were identified for containing policies related to and supportive of protection of water quality and related natural resources: 1) Eugene /Springfield Metro Area General Plan (1987 Update) in general and, specifically, the following refinement plans: • Bethel - Danebo, 1982 • Eugene Downtown Plan, 1984 • Eugene Parks and Recreation Plan, 1989 • Jefferson/Far West, 1983 • Public Facilities and Services Plan, December 2001 • Laurel Hill, 1982 • Riverfront Park Study, 1985 • River Road Santa Clara Urban Facilities Plan, 1985 • South Hills Study, 1974 • Willakenzie Neighborhood, 1991 • Willow Creek, 1982 2) Eugene Growth Management Study, 1998 The overall goal of the Stormwater Basin Master Plans was to provide a stormwater management strategy for each basin that proactively addresses the multiple objectives of CSWMP. In addition to flood control, these multiple objectives include: • Protect and improve water quality. • Protect natural resources that provide beneficial stormwater functions. • Use best management practices that promote a green infrastructure. • Address the unique qualities of each drainage basin. • Meet federal, state, and local laws and policies (including CSWMP, the Clean Water Act, the Endangered Species Act, the Safe Drinking Water Act and State Underground Injection Control Rules — for these broader topics and other issues, please refer to Volume I). • Complement other existing stormwater best management practices (BMPs) that are part of the City's stormwater program. • Balance responsibilities community -wide. N:ASTORMWATER \City of EugencARR_SC Stormwater Basin Plan\2012 Document \Master_ Plan _9- 18- 12_DR-AFT Word Version.doc 1 -1 SECTION 1 Introduction • Provide a dynamic and flexible program that can be refined based on a changing regulatory climate. This report represents the final River Road Santa Clara Basin Plan, Volume VIII of an eight - volume set. The Initial Study Towards the Development of an Integrated Stormwater Management Strategy for the River Road Santa Clara Basin (Initial Study) was developed in 2002, and held in draft form pending resolution of inter jurisdictional issues as well as additional information gathering and analysis. In 2004, subsequent to entering into an Intergovernmental Agreement (IGA), the City of Eugene and Lane County commenced with a joint effort to finalize the Initial Study. Outreach to the River Road and Santa Clara Community Organizations was conducted periodically throughout the process. This report incorporates feedback received from these initial public outreach efforts. The City completed the other seven volumes of the Stormwater Basin Master Plan that summarize and document integrated strategies for each of the other basins in Eugene. Volume I provides an overview of the project, describes the process for developing integrated strategies, and summarizes the information that is presented in detail in the basin - specific volumes. Each of the six companion volumes covers a specific drainage basin as follows: Volume II - Amazon Creek, Volume III - Bethel IDanebo, Volume IV Laurel Hill, Volume V - Willakenzie, Volume VI - Willamette River, Volume VII - Willow Creek. This document is Volume VIII River Road Santa Clara. NOTE: It should be noted that the term basin is typically used to refer to a defined surface area that drains to a common discharge point. However, for the purposes of this study, the term basin is used to refer to a specific planning or study area. While the planning or study areas were developed based on topography and drainage patterns, they may include several discharge points, or they may exclude specific tributary areas based on convenience for planning purposes. In some cases, portions of the basin were not included in the planning area as they are managed by other jurisdictions. The basin areas as defined in this plan are also further divided into major subbasins and subbasins as described in Section 3.0. The overall process conducted to develop integrated strategies for each of the City's stormwater basins included in the Stormwater Basin Master Plans consisted of the following thirteen steps. The details regarding each of these steps are provided in Volume I of the City's Stormwater Basin Master Plans. Step 1) Compile information regarding the unique characteristics of each basin that are related to the stormwater drainage system. Step 2) Identify problems and opportunities associated with the stormwater drainage system with respect to flood control, water quality, natural resources, and maintenance. Step 3) Develop potential solutions in the form of capital projects and development standards for addressing identified problems. Step 4) Evaluate and compare potential solutions in terms of feasibility, costs, and effectiveness. Step 5) Evaluate capital projects to address problems expected under existing conditions. N:ASTORMWATER \City of EugencARR_SC Stormwater Basin Plan\2012 Document \Master_ Plan _9- 18- 12_DR-AFT Word Version.doc 1 -2 SECTION 1 Introduction Step 6) Evaluate capital projects and development standards to address problems expected as a result of future build -out. Step 7) Select an integrated stormwater management strategy based on the evaluations conducted in steps 5 and 6. Step 8) Develop a maintenance strategy for the proposed solutions. Step 9) Obtain feedback regarding integrated stormwater management strategies and the maintenance strategy from the public and refine the strategies as appropriate. Step 10) Prioritize selected capital projects for implementation and conduct a financial analysis. Step 11) Develop stormwater basin master plans to summarize the integrated stormwater management strategies including proposed capital projects and development standards. Step 12) Develop an ordinance to implement the proposed development standards. Step 13) Develop a best management practices manual to help guide developers in meeting the requirements of the development standards. The process described above for developing integrated strategies for each of the stormwater basins, including River Road Santa Clara, is outlined in Figure 1 -1. Information updates related to this plan are provided at the end of this section. The integrated basin strategy specific to the River Road -Santa Clara basin is described in the following sections. In order to complete the Initial Study for River Road Santa Clara, some additional analysis was necessary to address the unique challenges represented by the mix of City and County jurisdictional areas, the large number of sub - dividable lots and unimproved streets, and federal Safe Drinking Water Act regulations related to underground injection controls which are predominant in the basin. Thus, additional steps were needed and are outlined in Figure 1 -2. Section 2.0 of this report provides a summary of the specific characteristics in the River Road Santa Clara basin (from Step 1). Sections 3.0, 4.0, and 5.0 provide summaries of the flood control, water quality and natural resources evaluations, respectively (from Steps 2 and 3). These evaluations provide a list of identified problems, and potential solutions in the form of capital projects and development standards. Section 6.0 describes implementation of the integrated stormwater management strategy for the River Road Santa Clara basin. Information Updates (June 2012) Eugene's Stormwater Basin Plans are used for background /contextual information, development of capital improvement programming, contextual support for proposed development standards, and for evaluating technical information about the stormwater system. Since the drafting of the Stormwater Basin Master Plan for River Road -Santa Clara, several other efforts have been initiated or are planned to begin within the next year or so that have a relationship to stormwater management and in some cases further the goals of the Stormwater Basin Master Plans including for River Road — Santa Clara. This section describes these other efforts and their status. N:ASTORMWATER \City of EugencARR_SC Stormwater Basin Plan\2012 Document \Master_ Plan _9- 18- 12_DR-AFT Word Version.doc 1 -3 SECTION 1 Introduction Envision Eugene, Followed by Area Plan for River Road /Santa Clara Envision Eugene is our community's process for determining the best way to accommodate growth projected over the next 20 years. The Envision Eugene process began with abroad spectrum of community input in 2010, followed by a draft proposal and technical analysis in 2011 and draft recommendations published in March 2012. The Envision Eugene process established seven "pillars" which reflect the values of the community and serve as the foundation from which the draft recommendation emerged. Recommendations include a proposed urban growth boundary and strategies for accommodating growth. Under the pillar: "Protect, Repair and Enhance Neighborhood Livability," Strategy 4 is to: "Create neighborhood plans to address unique situations and impacts in different neighborhoods." Strategy 4b in particular is most relevant to River Road /Santa Clara: Complete area planning for the River Road and Santa Clara neighborhoods to address impacts of increasing urbanization. Base future planning efforts on previous work done under the River Road /Santa Clara Transition Project and Final Report, June 2006, and the Santa Clara -River Road Outreach and Learning (SCRROL) project, 2012. Begin this planning process immediately following local adoption of Envision Eugene. On June 13, 2012, the Eugene City Council passed the following motion which reflects the current status of the Envision Eugene process: 'Move to direct the City Manager to prepare, for a formal adoption process, planning documents to establish a new Urban Growth Boundary based on recommendations in the Technical Components Document (Attachment A), as revised, and that carry forward the pillars and strategies [emphasis added] described in the Envision Eugene Draft Proposal, March 14, 2012. " In effect, this means that the community visioning and strategy refinement phases are complete, and the formal adoption process and implementation work is underway. The adoption process will include decision - making by the Eugene City Council and the Lane County Board of Commissioners. Implementation of the area planning strategy for the River Road and Santa Clara neighborhoods, to address impacts of increasing urbanization, will begin following adoption of Envision Eugene. For additional information about Envision Eugene, including the seven pillars and related strategies, how to get involved, and up -to -date status of the process, see City's web page at www.envisioneugene.org. Eugene's Municipal Stormwater Permit Stormwater discharges from municipal stormwater systems are regulated under the federal Clean Water Act via a permit program which, in Oregon, is administered by the Oregon Department of Environmental Quality (DEQ). Eugene's National Pollution Discharge Elimination System Municipal Separate Storm Sewer Permit (or "MS4 permit ") was first issued in 1994, which prompted the City to adopt the comprehensive stormwater policy, CSWMP, described previously in Section 1. Eugene's permit was issued under Phase I of the program, and is therefore called a MS4 Phase I permit. The City's MS4 permit was re- issued in 2004, and again most recently in December 2010. The goal of the MS4 permit program is to reduce stormwater pollution and help improve the condition of the nation's water bodies. Eugene's permit is designed to reduce N:ASTORMWATER \City of EugencARR_SC Stormwater Basin Plan\2012 Document \Master_ Plan _9- 18- 12_DR-AFT Word Version.doc 1 -4 SECTION 1 Introduction pollution from Eugene's municipal stormwater system and protect and improve the water quality of our local waterways, including Amazon Creek and the Willamette River. Adaptive management to continually improve the effectiveness of the City's stormwater program and further reduce stormwater pollution is a regulatory expectation and is an on -going part of the City's stormwater program. Adaptive management coupled with the Issuance of the 2010 MS4 permit will result in additional refinements to the City's stormwater program, including in the following areas: • Stormwater Development Standards - As described in Action 4.3.2. of this plan, development standards for water quality were adopted City -wide in June 2006. Stormwater Development Standards apply to all new development and re- development that adds or replaces 1,000 square feet or more of impervious surface area. Acceptable stormwater management facility types along with siting and design criteria are included in the City's Stormwater Management Manual (SWMM). The current SWMM leaves the choice of facility type up to the applicant, as long as siting and design criteria are met. In response to the 2010 MS4 permit, Eugene's Stormwater Development Standards will need to be modified to prioritize low impact development techniques and green infrastructure facilities (for example: vegetated stormwater planters, rain gardens and swales) over mechanical treatment approaches (for example: prefabricated underground water quality treatment manholes) for managing stormwater. Making these changes will involve revising Eugene City Code and the SWMM. Draft revisions are under development for public review beginning in fall 2012, and adoption by the City Council in fall 2013. More information about the proposed Stormwater Development Standards changes will be posted on the City's web page by fall 2012. • Retrofit Strategy — Under the 2010 MS4 permit, the City is required to develop a strategy to retrofit its municipal stormwater system to further reduce pollution in runoff from existing developed areas. Over the past 20 years, Eugene has implemented many environmental restoration and stormwater system retrofit projects, developed concepts for additional retrofit projects (including via the Stormwater Basin Plans), and in a limited capacity worked with property owners to encourage retrofitting stormwater systems on private property. The City's retrofit strategy will be reviewed and refined as necessary to meet the 2010 permit conditions. Public input will be solicited on the City's retrofit strategy in approximately spring 2013. For more information and an up -to -date status on development of the City's retrofit strategy, see City's web site: http://www.eugene- or.gov. Go to Services > Stormwater > Stormwater Planning, Permits and Regulations > NPDES. Lane County's Municipal Stormwater Permit Lane County received its first MS4 permit in 2007. Lane County's permit was issued under Phase II of the program, and is therefore called a MS4 Phase II permit. The permit required Lane County to establish a stormwater program for the regulated area corresponding to the area between the city limits of Eugene and Springfield and the cities' Urban Growth Boundaries (UGB). Lane County was required to establish a stormwater program for the regulated area to address the following minimum control measures: N:ASTORMWATER \City of EugencARR_SC Stormwater Basin Plan\2012 Document \Master_ Plan _9- 18- 12_DR-AFT Word Version.doc 1 -5 SECTION 1 Introduction NPDES Six Minimum Control Measures • Public Education & Outreach • Public Involvement & Participation • Illicit Discharge & Elimination • Construction Site Stormwater Control • Post - Construction Stormwater Management • Pollution Prevention in Municipal Operations Lane County provides stormwater services in accordance with its Stormwater Management Plan (SWMP). Many of the services in the River Road -Santa Clara area are provided by the City of Eugene on behalf of Lane County through Inter - governmental Agreements (IGAs). Lane County's SWMP was updated in July of 2011 and a new Stormwater IGA with the City of Eugene was approved in December 2011. Lane County's current NPDES was to expire on December 31, 2011 but has been administratively extended by the DEQ until a new permit is negotiated and issued. Drywell Elimination Program The regulatory drivers for eliminating most or all public drywells are described in this Basin Plan in Section 4.1.2. Approximately half of the City of Eugene's publicly owned and managed drywells, and most of Lane County's owned and managed drywells, are in the River Road -Santa Clara area. At the time of this information update, the Oregon DEQ has not yet issued any WPCF permits in Oregon, with the exception of City of Portland's permit. While permit conditions are not finalized, based upon the latest draft WPCF permit template, the City of Eugene is proceeding with its strategy, described in Section 4.3 of this Plan, to eliminate public drywells. Once a permit is issued, the City will re- evaluate and refine its strategy if necessary. The County is currently prioritizing risk levels for its drywells and is reevaluating its drywell management /decommissioning strategy with regard to changes in the latest draft WPCF permit template. Where the City and County have drywells in the same area, the agencies will continue to seek ways to partner on projects for the sake of efficiency and cost - effectiveness. Capital project concepts identified in the document to address UIC decommissioning are simply starting points for the project design and implementation. Final designs are likely to differ from conceptual design concepts based on changing circumstances and additional information gathered during the design process. The South of Horn Lane UIC cluster, for example, identified on- street raingardens as the conceptual decommissioning strategy. However at this time, large - scale street improvements are not likely in the near future for this area, and other options such as individual rain gardens will need to be considered. As another example, one of the City's first UIC capital projects to be constructed (A1 -8 -UIC, Escalante, further described in the following paragraph) was conceptually identified as a piped decommissioning project. However, through the dynamic design process a more advantageous solution was developed resulting in a neighborhood vegetated swale as the final design. Capital projects Al -3 -UIC, A14-UIC (Shirley 1 &2), and Al -8 -UIC ( Escalante) were selected for implementation by the City of Eugene first because they include drywells with the least N:ASTORMWATER \City of EugencARR_SC Stormwater Basin Plan\2012 Document \Master_ Plan _9- 18- 12_DR-AFT Word Version.doc 1 -6 SECTION 1 Introduction vertical separation to seasonal high groundwater and thus pose the highest relative risk to groundwater quality. As with all capital projects when they are selected for implementation, the planning -level concepts were viewed from a more detailed perspective taking into account neighborhood input, stormwater characteristics (e.g. soil types, slopes, catchment area), system design opportunities and constraints, and cost effectiveness. Final design for both projects includes constructing a piped conveyance system which will collect the stormwater runoff from these two areas and, in each case, direct it to a neighborhood vegetated infiltration facility. In the case of the Shirley project, the infiltration facility will be located in Ferndale Park and has been designed to meet multiple objectives including consistency with park planning objectives. Designs for these two initial projects have been finalized and construction is scheduled for summer /fall 2012. For more information about the City's drywell elimination program, see City's web site: http: / /www.eugene- or.gov. Go to Departments > Public Works > Public Works Projects > Drywell Decommissioning. Street Design Standards Low impact development ( "green streets "), the Pedestrian & Bicycle Master Plan "tool box" the update of the Transportation System Plan and the Envision Eugene strategies are driving the need to review and update the City's street standards. The green street concepts developed as part of the River Road — Santa Clara Basin Plan (Figures 4 -5 through 4 -10) will be utilized inasmuch as they illustrate potential configurations for incorporating vegetated stormwater facilities that infiltrate runoff from the adjacent right of way. The Basin Plan concepts are simply meant to help inform the street design standards update, and do not, in and of themselves, translate directly to new standards. Updating the street design standards is included in the Engineering Division's FY13 work plan. N:ASTORMWATER \City of EugencARR_SC Stormwater Basin Plan\2012 Document \Master_ Plan _9- 18- 12_DR-AFT Word Version.doc 1 -7 SECTION 1 Introduction Step 1 Compile Basin Characteristics Step 2 Problem Identification (Existing & Future) Step 5 Evaluate Cps to Address Existing Problems • Flood Control • Water Quality • Natural Resources • Hydrologic Impacts • Maintenance Step 3 Identify Basin Guidelines and Potential SW Management Tools Step 4 Initial Feasibility Screening Figure 1 -1 Process to Develop the Integrated Stormwater Management Strategies Evaluate Cps to Evaluate Development Address Future Standards to Address Problems/ Future Problems/ Opportunities Opportunities Step 7 Select a Basin Strategy Step 8 Develop a Maintenance Strategy Step 9 Public Involvement Compare Cps with Development Standards • effectiveness • costs Step 12 Develop Ordinance Language Step 10 Prioritize CP Solutions for Implementation and Conduct a Financial Analysis Step 11 Develop Master Plans Step 13 Develop BMP Manual N:ASTORMWATER \City of EugencARR_SC Stormwater Basin Plan\2012 Document \Master_ Plan _9- 18- 12_DR-AFT Word Version.doc 1_8 C CD Ca in O i 0 W SECTION 2 Study Area Characteristics This section provides background information regarding the existing physical characteristics of the River Road Santa Clara basin. This information was used to assess opportunities and constraints for meeting the multiple- objective goals of this study. Specifically this section includes the following information for the River Road Santa Clara Basin: location and area; climate; land use and surface cover; land form; topography and slopes; surface water features and drainage system; water quality; rare, threatened and endangered plants, animals and communities; soils; groundwater; and recreational and educational facilities. 2.1 Location and Area 2.1.1 Regional Drainage Context Eugene is located in the western third of the Upper Willamette Drainage Basin as shown on Figure 2 -1. Drainage in the southern Willamette Valley is a combination of natural and built systems that have evolved over time. The natural system is composed of rivers, waterways, and a series of interconnected ponds and wetlands. Historically, the natural system had an extensive floodplain that typically experienced over -bank flooding every 1 -2 years. The built drainage system includes a series of dams, pipes, and waterways that were built to contain over -bank flooding, and to retain water for recreational and irrigation purposes. The primary drainage features of the Upper Willamette Drainage Basin are: Main Stem of the Willamette River, Middle Fork of the Willamette River, Coast Fork of the Willamette River, McKenzie River, Amazon Creek, Coyote Creek, and the Long Tom River. From 1940 to 1960, the U.S. Army Corps of Engineers built nine dams on this system. The cities of Cottage Grove, Creswell, and Springfield are all upstream from the City of Eugene and contribute urban runoff to the regional drainage system. Runoff from Cottage Grove, Creswell, and South Springfield flows through Eugene via the Willamette River. Approximately 4,800 acres of west Springfield's drainage area, as shown on Figure 2 -2, discharges urban runoff into the Q Street Floodway, which is within Eugene's public drainage system. Eugene's public drainage system refers to the system of stormwater facilities (i.e., pipes, ditches, open waterways) that Eugene is responsible for operating and maintaining. 2.1.2 City of Eugene The City of Eugene is currently responsible for managing the stormwater quantity, quality, and related natural resources for the drainage area within its city limits. The area outside of the City limits but within the urban growth boundary (UGB) is expected to be annexed into the city as urban development occurs. Therefore, this basin plan study includes both the current city limits and the Lane County area within the UGB. The Eugene- Springfield Metro Area General Plan (Metro Plan) boundary covers the city limits, the UGB and, in some cases, areas beyond the UGB. For the purposes of characterizing the study area in this chapter, the area covered includes the Metro Plan boundary. 0: 25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 2-1 _. _ d c 16 NMI= CL > 1>1 m M < C c 04 04 (D iTL � k 5 / � (S) cc NEE cc I SECTION 2 Study Area Characteristics 2.1.3 River Road Santa Clara Basin As shown on Figure 2 -2, the River Road Santa Clara basin forms the northwest corner of the Eugene - Springfield metropolitan area, and is generally bounded by the Willamette River on the east, the Bethel - Danebo drainage basin on the south and the Metro Plan boundary on the west and north. The basin is 10,458 acres in size with about 58 percent (6,071 acres) located within the Eugene urban growth boundary (UGB). 2.2 Climate The climate in the study area is primarily affected by humid air masses from the west and south, and infrequent influxes of cold, continental air masses from the east. As a result, the year -round climate in Eugene is moderate with relatively cool, wet winters, and warm, dry summers. Average minimum winter temperatures are in the mid -30s with extremes seldom dropping below 10 degrees Fahrenheit ( -12.2 Celsius). Average maximum summer temperatures are in the low 80's (26.7 to 28.9 Celsius) with extremes seldom exceeding 100 degrees Fahrenheit (37.8 Celsius). Snowfall constitutes only 2 percent of the annual precipitation in Eugene. Winter snow does not accumulate; however, quick snow melt can contribute to flooding problems throughout the Eugene area. The National Weather Service records rainfall information at the Mahlon Sweet Airport in Eugene. Average annual precipitation is approximately 46 inches with 86 percent occurring from October to May. Figure 2 -3 presents the average monthly rainfall distribution based on the airport's 48 -year rainfall record from 1949 -1997. Figure 2 -3 Average Monthly Rainfall w ,IAAAAAAAA�AI 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 11 -7 SECTION 2 Study Area Characteristics Table 2 -1 characterizes a typical storm event for the Eugene area based on the historic 48 -year precipitation record measured at the Eugene Airport: Table 2 -1 Average Storm Event Storm Event Parameter Average Volume 0.67 inches Duration 16.9 hours Intensity 0.042 inches per hour Since 1992, rainfall information has been recorded at six rain -gage stations within the Eugene city limits. Comparison of that data with the National Weather Service's Eugene Airport data indicates a significant difference between the two, with the airport data approximately 30 percent higher. For additional information regarding this issue, see Section 3.1.2 and Appendix A of Volume I. Historically, performance of the City's drainage system has been very good. For example, the City's system handled the February 1996 storm event with very few problems even though this event caused widespread flooding in the Willamette River Valley. 2.3 Land Use and Surface Cover The conversion from undisturbed to developed land uses can significantly affect the quantity and quality of stormwater runoff. Runoff volumes and velocities increase as impervious surface areas increase. Likewise, stormwater quality decreases due to nonpoint source pollution from roadways and urban land uses such as commercial, industrial, and residential. The purpose of this section is to describe existing land use and impervious surface conditions within the basin and to forecast changes in these conditions due to buildout of remaining vacant lands within the UGB according to Metro Plan designations. Existing land use data presented in Map 1 are based upon the current use of the property as depicted on the Land Use Parcel Data GIS layer as of January 2007. Buildout data presented in Map 2 are based on Metro Plan designations. It was assumed that 15% of the area designated as "vacant" on the 2007 Land Use Parcel Data GIS layer would be for the creation of new streets. See maps at the end of Section 2. 2.3.1 Existing Land Use As shown in Table 2 -2, the predominant land uses in the basin are: agriculture (2,949 acres); low- medium density residential (2,658 acres); industrial /airport (1,447 acres); other undeveloped land (1,326 acres); street rights -of -way (1,197 acres); commercial (3 50 acres); and schools /churches /cemeteries (187 acres). 0: 25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 11 -8 SECTION 2 Study Area Characteristics Table 2 -2 Existing Land Use — River Road Santa Clara Basin Land Use Categories Acres Percent Of Area Inside UGB Agriculture 516 4.9% Commercial 297 2.8% Communication, Utilities 47 0.5% Golf Courses 17 0.2% Government 20 0.2% Industrial 450 4.3% Low -Med. Density Residential 2,558 24.5% Med -High Density Residential 68 0.6% Other Undeveloped Land 702 6.7% Parks, Open Space, & Recreation 65 0.6% Railroad 40 0.4% Streets (R.O.W.) 1,106 10.6% Schools, Churches, & Cemetaries 187 1.8% Subtotal 6,071 58.1% Outside UGB Agriculture 2,433 23.3% Commercial 53 0.5% Communication, Utilities 6 0.1% Golf Courses 35 0.3% Government 960 9.2% Industrial 75 0.7% Low -Med. Density Residential 99 0.9% Med -High Density Residential 1 0.0% Other Undeveloped Land 608 5.8% Parks, Open Space, & Recreation 12 0.1% Railroad 10 0.1% Streets (R.O.W.) 91 0.9% Timber 3 0.0% Subtotall 4,387 41.9% Grand' Total 1 10,458 100.0% Source: LCOG 2007 Parcel File 2.3.2 Buildout Land Use The primary land use policies pertaining to the River Road Santa Clara basin are contained in the following locally adopted policy documents: • Eugene- Springfield Metro Area General Plan (1987) • River Road Santa Clara Urban Facilities Plan (1988) • Annexation and Urban Services Policy Agreement, City of Eugene and the Industrial Corridor Community Organization [ICCO,/, (April 1991) Lane County zoning applies to areas outside the UGB and City Codes apply within the UGB. Table 2 -3 summarizes the buildout land use for the River Road Santa Clara basin. 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 11 -9 SECTION 2 Study Area Characteristics 2.3.2.1 Buildout Land Use Within the UGB This area includes both the current city limits and the unincorporated UGB, totaling 6,071 acres (58% of basin). 1,217 acres are vacant and considered available for development. For the purposes of this report, the term "vacant acres" refers to lands within the UGB that are expected to develop to urban uses. As shown in Table 2 -3, land use categories with significant remaining vacant acres include: industrial and commercial - industrial mixed (641 acres), low- density residential (326 acres), medium - density residential (32 acres), and commercial and residential - commercial mixed (20 acres). 2.3.2.2 Projected Land Use Outside the UGB Forty -two percent of the River Road Santa Clara basin (4,387 acres) is located outside the UGB. All of the area outside the UGB in this basin will remain rural and land uses will be restricted to the Metro Plan designations as shown in Table 2 -3. Areas outside the UGB are not permitted to develop to urban uses and, therefore, "vacant" acres do not apply here. Table 2 -3 Buildout Land Use General General Plan Designation Total Designated Acres Vacant* (2006) for Future Urban Development Inside UGB Low-Density Residential 2,855 326 Medium-Density Residential 168 34 Commercial and Residential - Commercial Mixed Use 135 20 Industrial and Commercial - Industrial Mixed 1,459 641 Parks and Open Space 37 9 Government, Education, and Research 127 4 A hculture and Aghculture/Airport Reserve 2 0.4 Streets (R.O.W.) ** 1,288 183 Subtotal 6,071 1,217 Outside UGB Rural Residential 101 0 Low-Density Residential 0.2 0 Industrial and Commercial - Industrial Mixed 23 0 Government, Education, and Research 2,034 0 Parks and Open Space 7 0 A hculture and Aghculture/Airport Reserve 2,114 0 Outside Metro Plan Boundaiy 16 0 Streets (R.O.W.) ** 91 0 Subtotal 4,386 0 Grand Total 10,458 Source: LCOG and City of Eugene Geographic Information System, 2006 *For purposes ofthis report, vacant acres apply to lands only within the urban growth boundary. * *Notes: Streets (Right of Way). The Metro Plan does not have a "Streets" Plan designation. This amount was estimated based on the difference between total designated area and total basin size. In undeveloped areas, 15 percent of the land area was put into the Streets (Right of Way) category to account for streets that will serve future designated development. 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 2-10 SECTION 2 Study Area Characteristics 2.3.3 Surface Cover Other than precipitation, surface cover is perhaps the single most influential factor that affects the volume, quality, and velocity of stormwater runoff and the ability to treat runoff through filtration and other natural processes. Pervious surfaces are undisturbed natural areas that retain native prairie or forest vegetation or lands in developed areas that are typically covered with lawn, agricultural fields, or pasture. In both cases, water is free to infiltrate into the ground. Undisturbed natural areas provide significant beneficial stormwater functions. They help reduce the volume and velocity of runoff by facilitating infiltration of precipitation into the groundwater. Stormwater quality is best in undisturbed natural areas. The vegetative cover associated with undisturbed natural areas is also important for stabilizing steep slopes and streambanks. The infiltration capacity of undisturbed areas may be reduced during conversion to urban lawns and agricultural crops. Stormwater quality may also be impacted by lawn care and agricultural practices. Pervious surfaces in developed areas provide stormwater benefits, although to a lesser degree than undisturbed natural areas. In contrast, impervious surfaces are lands covered by hard surfaces such as rooftops, roads, and parking lots and allow little or no infiltration of water. Impervious surfaces are unable to absorb and infiltrate precipitation, which results in greater runoff volumes, higher but shorter duration peak flows, and higher concentrations of pollutants. The transition from undisturbed to developed land uses and densities involves a significant change from pervious to impervious surfaces. As a consequence, adequate facilities must be planned, constructed, and maintained to minimize drainage and flood problems and impacts to water quality and natural resources. The purpose of this section is to describe existing surface cover conditions with data current to 2007, and as they are projected to exist at buildout of the River Road Santa Clara basin urban growth boundary (UGB). 2.3.3.1 Impervious Surfaces Total impervious surface area for the study area was calculated using a set of impervious surface area factors (ISAF) that were applied to the existing and buildout land use data. To calculate total impervious surface area, the ISAF percentages were multiplied by the total land area in each of the land use categories. The ISAFs used are provided in Volume I. These factors were derived through a process that used existing developed properties in Eugene to generate typical impervious percentages. Impervious surface area for residential, commercial, and industrial land uses had previously been digitized as the basis for calculating stormwater user fees. By using this data source, the resulting ISAFs have been calibrated specific to the City of Eugene and in some cases specific to the basin. The ISAFs for land use categories that were not previously digitized were derived through review of national standards and by calculating the impervious surface area on sample sites. The amount of existing impervious surface area in the UGB portion of the River Road Santa Clara basin is estimated to be 2,277 acres or 37.5 percent of the basin's UGB area. [Note: 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 2-11 SECTION 2 Study Area Characteristics calculations for this data are available from the City of Eugene.] The majority of this impervious surface area is concentrated between Highway 99 (west) and the east boundary of the basin. Map 3 depicts the existing generalized impervious surface area in pink. Due to the map scale and data restrictions, developed lots are shown entirely in pink. These pink areas are a mix of impervious surface and pervious surfaces associated with the land use such as lawns, streetscapes, parking lot planting, and other landscaped areas. Assuming that future growth in the basin will follow conventional stormwater management drainage practices and will develop according to the land use categories depicted on the Eugene - Springfield Metro Plan designations (see Map 2), the amount of impervious acres in the UGB portion of the basin is projected to increase to 3,044 acres, or 50 percent of the basin's UGB area at buildout. [Note: calculations for this data are available from the City of Eugene.] 2.3.3.2 Pervious Surfaces Except for the impervious surface areas noted above, the rest of the basin remains in a pervious condition, consisting mostly in the form of prairie wetlands, forest, agriculture and lawns. Overall, pervious area cover is expected to decrease from the current 62.5 percent of the UGB portion of the basin (3,794 acres) to 50 percent (3027 acres) at UGB buildout. For the purposes of this report, pervious surface areas were identified and grouped into Forest Cover, Landscaping, and Other Vegetated Areas (refer to Figure 2 -4) for the following reasons: Forest Cover is highly effective in reducing runoff volumes, and in preventing erosion (e.g., reduces soil impact by slowing down the velocity of precipitation and by intercepting up to 35 percent of it before hitting the ground) and stabilizing steep slopes (established root zones). Areas were included in this category if the forested area exceeded one acre in size. One percent of the River Road Santa Clara basin is currently in forest cover and at UGB buildout, forest cover would decrease to 0 percent. Landscapin areas, including lawns, streetscape and parking lot landscaping are associated with site improvements due to urban development. This category was distinguished to highlight both its positive and potential negative impacts on stormwater resources and is included in the area shaded pink on Map 3. Positive impacts include protection of surface soils, filtration of sediments, and some infiltration (although this is reduced from pre - development conditions). The use of chemical fertilizers, pesticides, and herbicides can cause negative impacts to water quality. The amount of landscaped area in the UGB is projected to decrease from the existing 41 percent to 39 percent at UGB buildout. • Other Vegetated Areas are pervious surfaces not in forest cover or landscaping use, such as agricultural fields, pasture, vacant lots, prairie wetlands, and small clusters of trees (less than one acre). Similar to the landscaping category, these areas have both positive and negative impacts on stormwater resources. Agriculture and pasture uses can be significant contributors of pollutants in this category due to the use of chemical fertilizers, pesticides, 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 2-12 SECTION 2 Study Area Characteristics herbicides, and fecal coliform due to grazing. This category is expected to decrease from 20 percent of the UGB to 9.7 percent at UGB buildout. Figure 2 -4 compares the percentage of existing and projected surface cover for the UGB portion of the River Road Santa Clara basin. Figure 2 -4 Surface Cover in the River Road Santa Clara Basin UGB 2.4 Landform, Topography, Slopes Ninety -nine percent of the basin has slope in the 0 % -5% category. The following table is keyed to Map 4, Slope and Topography, and indicates the amount of acres affected by varying categories of slope steepness. Table 2 -4 River Road Santa Clara Basin Slone Distribution Location ' Surface Cover (UGB) Slope Distrib tion (percent 100 % ......... Slopes 0 -5% Slopes 6 -10% .::.: Slopes 16 -25% 90% Total Within UGB 80% 1 % 0% 0% �q 70% Outside UGB 99% 1% 0% 0% 0% 100% Total Basin 99% 1% 0% .� o 60 /o 100% o Pervious - Other 0 Pervious - Landscape p 50% U El Pervious - Forest 40% ■ Impervious U i■ 30% a 20% 10% 0% Existing (2007) Buildout 2.4 Landform, Topography, Slopes Ninety -nine percent of the basin has slope in the 0 % -5% category. The following table is keyed to Map 4, Slope and Topography, and indicates the amount of acres affected by varying categories of slope steepness. Table 2 -4 River Road Santa Clara Basin Slone Distribution Location ' Slope Distrib tion (percent Slopes 0 -5% Slopes 6 -10% Slopes 11 -15% Slopes 16 -25% Slopes >25% Total Within UGB 99% 1 % 0% 0% 0% 100% Outside UGB 99% 1% 0% 0% 0% 100% Total Basin 99% 1% 0% 0% 0% 100% 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 2 -13 SECTION 2 Study Area Characteristics 2.5 Surface Water Features and Drainage System This section describes the existing drainage features of the basin including the City's stormwater facilities, open waterways, and wetlands. Refer to Map 5. 2.5.1 Waterways Pre - settlement (prior to 1855) morphological conditions in the Willamette Valley reflected a network of shallow, broad swales that would often over -bank during storm events creating ponded conditions. Today, most of the drainages have been altered into narrow, deep and well - defined channels where the management objective of preventing over banking conditions has been accomplished for most small storm events. Five major drainage systems exist in this basin including: the A -1 Channel, Flat Creek, Spring Creek, Highway 99 and the Willamette Overflow (also referred to as the East Santa Clara Waterway). Generally, these open waterways run in a northerly or northwesterly direction. Historically, most of these features meandered along the valley floor before reaching the Willamette River or Long Tom River. Some of these have been altered into narrow, deep and well defined channels designed to collect and convey runoff while others remain relatively undisturbed. 2.5.1.1 A -1 Channel The A -1 Channel originates at the junction of Beltline Highway and the Northwest Expressway. It is the largest waterway in this basin flowing northwesterly about three miles through the Highway 99 Industrial Corridor. The channel is surrounded by residential use in the Santa Clara neighborhood changing to adjacent agricultural use as it leaves the UGB. The channel drains into Amazon Creek outside of the Metro Plan boundary. This channel was constructed by the Soil Conservation Service as part of the Lower Amazon and Flat Creek Watershed Improvement Projects primarily for flood control purposes. Vegetation lacks diversity along the channel contributing to poor wildlife habitat. The channel has high enhancement potential however, due to its connectivity with other waterways. The A -1 Channel is listed as a riparian resource site (refer to E60: A -1 Channel) in the adopted 2007 Goal 5 Water Resources Conservation Plan, a refinement plan to the Eugene - Springfield Metro Plan. Protections for two of three identified segments of Site E60 in the form of the Water Resources Conservation Overlay Zone (Eugene Code 9.4910) were adopted by the City of Eugene in November 2005 (effective January 1, 2006) and Lane County in December 2006 (effective January 12, 2007), including setbacks of 20 feet from top of high bank. 2.5.1.2 Flat Creek The southern portion of Flat Creek begins near the Northwest Expressway and Park Avenue and flows north towards Beltline Road. With development of Beltline Road and the Northwest Expressway, the natural Flat Creek drainage area south of Beltline Road was diverted into the A- 1 Channel, and is no longer hydrologically linked to the northern portion of Flat Creek. The southern portion of Flat Creek includes riparian resource sites E61 (Middle Flat Creek) and E69 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 2-14 SECTION 2 Study Area Characteristics (South Flat Creek). Eight of the ten identified segments of Sites E61 and E69 are protected in the form of the Water Resources Conservation Overlay Zone adopted by the City of Eugene and Lane County, including setbacks ranging from 0 to 40 feet from top of high bank. Although not hydrologically linked with the southern portion, the northern portion of Flat Creek extends from Beltline Road and continues north where it exits the Metro Plan boundary near Beacon Drive. Eventually the creek joins the Willamette River by way of Ingram Slough near the community of Monroe. Unlike the Al Channel, Flat Creek is a natural drainage feature and is identified for possible protection in the 1987 River Road Santa Clara Urban Facilities Plan (Environmental Design Element), a refinement plan to the Eugene - Springfield Metro Plan. More recently, Flat Creek is listed as a riparian resource site (refer to E59: Flat Creek) in the adopted 2007 Goal 5 Water Resources Conservation Plan, also a refinement plan to the Metro Plan. Six of seven identified segments of Site E59 are protected in the form of the Water Resources Conservation Overlay Zone adopted by the City of Eugene and Lane County, including setbacks ranging from 0 to 20 feet from top of high bank. The condition and function of Flat Creek within the UGB varies significantly with some segments relatively undisturbed and others significantly altered due to urban development property owner impacts. 2.5.1.3 Spring Creek Spring Creek is about two miles long (within the UGB) and flows south -to -north beginning just north of Greenfield Avenue. It crosses River Road near Spring Creek Drive and continues north where it eventually joins the Willamette River nearly 3 miles north of the UGB. The creek flows through Awbrey Park and is adjacent to Spring Creek Elementary School serving both a stormwater and open space function. The creek is bordered by riparian vegetation, predominately Oregon ash and Bigleaf maple. Spring Creek is identified for possible protection in the 1987 River Road Santa Clara Urban Facilities Plan (Environmental Design Element), a refinement plan to the Eugene - Springfield Metro Plan. More recently, Spring Creek is listed as a riparian resource site (refer to E58: Spring Creek) in the adopted 2007 Goal 5 Water Resources Conservation Plan, also a refinement plan to the Metro Plan. Five of six identified segments of Site E58 are protected in the form of the Water Resources Conservation Overlay Zone adopted by the City of Eugene and Lane County, including setbacks ranging from 0 to 40 feet from top of high bank. 2.5.1.4 Willamette Overflow The Willamette Overflow, also referred to as the "East Santa Clara Waterway" is a two mile long waterway located in the northeast portion of the basin and straddles the UGB. It has a relatively high wildlife value and is one of a few vegetated sloughs identified for potential protection in the River Road Santa Clara Urban Facilities Plan (Environmental Design Element), a refinement plan to the Eugene - Springfield Metro Plan. More recently, it is listed as a riparian resource site (refer to E57: East Santa Clara Waterway) in the adopted 2007 Goal 5 Water Resources Conservation Plan, also a refinement plan to the Metro Plan. Two of four identified segments of Site E57 are protected in the form of the Water Resources Conservation Overlay Zone adopted by the City of Eugene and Lane County, including setbacks ranging from 20 to 40 feet from top of high bank. 0:\25695978 Eugene RR -SC Final Basin P1an\Nlaster P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 2-15 SECTION 2 Study Area Characteristics 2.5.1.5 Highway 99 This drainage system mainly consists of a long roadside ditch along Highway 99. This ditch drains in a northwesterly direction and into the A -1 channel. The ditch is owned and maintained by the Oregon Department of Transportation. 2.5.2 Wetlands Most wetland features within the basin are associated with riparian areas adjacent to creeks and open waterways. There are also a few wetland sites located primarily near the relatively undeveloped northern and western portions of the basin outside the UGB. About 281 acres of wetlands are identified in the basin in the National Wetland Inventory (NWI) which provides basic data about the general characteristics and extent of wetlands in the nation. The NWI identifies the general boundaries of wetlands; however, in many instances actual wetland boundaries are more extensive than what is identified. About 54 percent of the NWI wetlands in the basin are located outside the UGB, and the area outside the UGB represents about 42 percent of the total basin area. A Local Wetland Inventory (LWI) was conducted in 2005, and the wetland sites evaluated for potential protection as part of the City and County's Goal 5 efforts. Several wetland sites in the River Road Santa Clara basin are identified in the adopted 2007 Goal 5 Water Resources Conservation Plan in the River Road Santa Clara basin and are protected in the form of the Water Resources Conservation Overlay Zone adopted by the City of Eugene and Lane, including setbacks ranging from 25 to 50 feet from the jurisdictional wetland boundary. The River Road Santa Clara basin also includes several open water ponds; all located in the general vicinity of the Northwest Expressway and /or Highway 99 North. These ponds are identified in the adopted 2007 Goal 5 Water Resources Conservation Plan as Site E62: Northwest Expressway Ponds. The Northwest Expressway ponds are located just south of Maxwell Road and on both the east and west sides of the Northwest Expressway. The eastern pond (Dianna's Pond) is within the River Road Santa Clara basin and is hydrologically connected with Upper (or South) Flat Creek. The pond is a former borrow pit that currently supports willow, black cottonwood, reed canary grass, rush and sedge as the predominant plant species. The southern and eastern arms of the pond have healthy riparian strips, while much of the rest of the banks are bare and eroding. 2.5.3 Public Piped Drainage System Most of the existing development in this basin occurred prior to the City of Eugene having jurisdiction over urban land use requirements and, as a consequence, this basin lacks a stormwater pipe system found in the other basins. Only 94.5 miles of stormwater pipes exist in this basin and 43 of these miles are located outside the UGB, mostly serving Mahlon Sweet Airport. The piped system located within the UGB was constructed to serve more recent development that was required to annex and develop to City of Eugene standards. See Map 5. 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 2-16 SECTION 2 Study Area Characteristics 2.5.4 Drywell Drainage System Drywells are underground structures that collect stormwater runoff which is then discharged into the ground where it mixes with the groundwater. The River Road Santa Clara stormwater basin is unique compared to other Eugene -area basins in its frequent use of drywells for managing stormwater. Approximately 22% of the River Road Santa Clara stormwater basin currently drains to drywells. This area has historically utilized drywells because it lacks a continuous stormwater system and because the flatness of the topography and the relatively high permeability of the soils are conducive to stormwater management through this method. There are 785 known drywells in the River Road Santa Clara basin. Of those drywells, 634 (81 %) are privately owned, 79 (10 %) are owned by Lane County, and 72 (9 %) are owned by the City of Eugene. Drywells come in numerous configurations which are collectively termed "Underground Injection Controls" or "UICs." 2.5.5 Maintaining the Drainage System The Lane County Public Works Department, the Junction City Water Control District, and the City of Eugene share limited maintenance responsibilities in this basin. Lane County Public Works Department is responsible for stormwater facility maintenance in the unincorporated portions of this basin. This maintenance activity is limited to drainage problems that directly affect County right -of -way, such as roadside ditches, culverts, and bridge crossings. The Junction City Water Control District is responsible for maintenance of irrigation ditches, channels and waterways within the District's boundaries, which lie in the unincorporated areas north of Eugene in the Flat Creek, A, A -1 and A -2 Channel watershed boundaries. The City is responsible for maintaining areas that have been annexed to the City. The City and County share maintenance responsibilities in this basin which results in greater efficiencies for both jurisdictions. 2.5.6 Floodplain A flood insurance study for the Federal Emergency Management Agency (FEMA) has been conducted within the River Road Santa Clara basin. As part of this study, areas subject to the 100 -year flood event have been identified. One thousand two hundred seventy acres of floodplain have been mapped within the basin. There are approximately equal acres of floodplain within and outside the UGB. Most of the broad floodplain area is associated with the Willamette River in the northeast portion of the basin just outside the UGB. Ribbons of floodplain are also located adjacent to the five primary waterways that flow through the basin. (See Map 5) More detailed floodplain studies necessary to map floodway boundaries have not been conducted for this basin. 2.6 Water Quality This section provides a description of water quality conditions in the River Road Santa Clara basin. Water quality conditions can vary dramatically depending on time of day, weather conditions, land use activities conducted in the watershed, and location in the water body. Therefore, without significant amounts of data, it is often difficult to adequately evaluate water N:ASTORMWATER \City of EugencARR_SC Stormwater Basin Plan\2012 Document \Master_ Plan _9- 18- 12_DR-AFT Word Version.doc 2 -17 SECTION 2 Study Area Characteristics quality conditions. It is even more difficult to evaluate the water quality impacts of stormwater runoff on receiving waters. Therefore, a variety of available sources of water quality - related information was reviewed in an attempt to provide a general picture of water quality conditions in the basin. The following sources of information were reviewed and are described below: • Documented water quality problems based on existing chemical data, biological data, and field observations. • Oregon Department of Environmental Quality's (DEQ's) designations of water quality limited water bodies. • Natural and built environmental conditions that influence water quality. 2.6.1 Documented Water Quality Problems The following subsections describe the water quality problems that have been documented for the River Road Santa Clara basin in terms of chemical stormwater monitoring data, macroinvertebrate sampling, and field observations. 2.6.1.1 Chemical Stormwater Monitoring Data The City collected and analyzed samples of stormwater runoff from 1992 to 1997 at 6 sampling stations in Eugene (see Figure 2 -5). The 6 sampling stations were selected to represent runoff from various land uses. In 1998, the storm event monitoring at the 6 sampling stations was discontinued and a pilot project on the A3 Channel using a basin approach to water quality monitoring was implemented. The revised monitoring plan consisted of collecting monthly composite samples at the original industrial land use station on the A3 Channel (station I1) and collecting samples at selected high source areas in the piped system on the A3 Channel. The following table provides a summary of the results collected during 1992 to 1997 from the 6 sampling stations. Table 2 -5 includes a description of the problem pollutants, typical sources of the pollutants, specific results from Eugene, and potential problems associated with the pollutants. Although none of these data were collected from within the River Road Santa Clara basin, they provide general information regarding stormwater quality in Eugene and were used in this initial study towards the development of a stormwater basin master plan. N:ASTORMWATER \City of EugencARR_SC Stormwater Basin Plan\2012 Document \Master_ Plan _9- 18- 12_DR-AFT Word Version.doc 2 -18 SECTION 2 Study Area Characteristics Table 2 -5 Summary of Stormwater Quality Monitoring in Eugene Pollutant Description Sources Eugene's Results Potential Problems Bacteria Enterococcus, Animal Wastes (droppings Results from almost all of These are commonly used Fecal coliform, and from wild /domestic the samples significantly indicators of pathogens. Fecal streptococcus animals), exceeded the DEQ standard Water contact may cause eye and Human Wastes (leaking for water quality. skin irritations and gastro- sanitary sewer pipes, and intestinal diseases if swallowed. seepage from septic tanks). Heavy Antimony Arsenic Vehicles (combustion of Cadmium, chromium, copper, Heavy metals are toxic to Metals Beryllium Cadmium fossil fuels, improper lead, nickel, and zinc were freshwater aquatic ecosystems. Chromium Copper disposal of car batteries, typically present in samples. These metals are considered to be Lead Mercury wear /tear of tires and brake the most significant toxic Nickel Selenium pads), Copper, lead, and zinc in substances which are commonly Silver Thallium Metal Corrosion, stormwater samples found in urban stormwater runoff. Zinc Pigments for Paints, frequently exceeded DEQ Solder, standards for the protection Fungicides, of aquatic life. Pesticides, Wood Preservatives Oil & A broad group of Food Wastes (animal and Two of fifty -three samples These compounds can coat the Grease pollutants including: vegetable fats from had concentrations which surface of the water limiting garbage), exceeded discharge oxygen exchange, clog fish gills, Animal fats, and Petroleum Products (gas, limitations specified for and cling to waterfowl feathers. Petroleum products. engine oil, lubricants, etc.). industrial stormwater When ingested these compounds discharges (i.e., > 10 mg /L). can be toxic to birds, animals and other aquatic life. Sediments Sediments in the water Erosion from increased Excess levels were measured Sediments cause increased are considered pollutants stream flows, at all stations. Results from turbidity, reduced prey capture for when they exceed natural Construction site runoff, the urban sampling stations sight feeding predators, clogging concentrations and Landscaping activities, in Eugene were all 40% to of gills /filters of fish and aquatic negatively affect water Agricultural activities, 70% higher than results insects, and blocked light which quality and /or beneficial Logging, from an open space (i.e., limits food production available uses of the water. All other activities where undeveloped) sampling. for fish. Sediments also the ground surface is accumulate in stream bottoms disturbed. which reduces the capacity of the stream (and hence increases the potential for flooding) and covers stream bottom habitats. Sediment also acts as a carrier of toxic pollutants such as metals and organics. Nutrients Nitrate Landscaping activities, The DEQ guidance value of Excess levels of nutrients can lead Ammonia Yard debris, 0.1 mg /L for total to eutrophication in downstream Kjeldahl Nitrogen Human wastes (leaks from phosphorus was exceeded in receiving waters. Problems Phosphorus septic tanks and sanitary 100% of the samples include surface algal scums, Orthophosphate sewers), collected. odors, reduced oxygen levels, and Animal wastes, dense mats of algae. In addition Vehicle exhausts, to water quality problems, these Agricultural activities, effects have anegative impact to Detergents (car washing), the aesthetic quality of water Food Processing bodies. Organics There are many organic Illegal dumping, Although sampling for these Most synthetic organics are highly compounds, however, the Illicit connections, compounds was limited, nine toxic to aquatic life at very low synthetic organics are of Spills, volatile organic compounds concentrations, and many are most concern and Leaks from drums and were detected (including carcinogenic (cancer causing) or include: storage tanks, one pesticide). suspected carcinogens. Diazinon Fuels Landscaping activities has been identified in many recent Solvents Agricultural activities. studies as one of the causes of Pesticides toxicity in stormwater. Herbicides. 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 2-21 SECTION 2 Study Area Characteristics Table 2 -5 continued Pollutant Descri tien Sources Eugene's Results Potential Problems Litter and Plastics, Littering, Sampling for litter and These pollutants degrade the other Paper products, Dumping, floatables was not conducted, aesthetic quality of water bodies. Floatable Yard debris, Spills. however, specific problem In addition, they contribute Debris Tires, dumping areas have been pollutants as they decompose, and Metal, identified in Eugene (see they can reduce the capacity of the Glass. notes below). water body. Excess yard debris contributes to high levels of nutrients and it reduces oxygen levels as it decomposes. Based on results from the above monitoring program and the results from state -wide monitoring efforts (ACWA, 1997), industrial and commercial land uses have been identified as significant sources of stormwater pollutants (i.e., high source areas). In the River Road Santa Clara basin, the commercial and industrial areas are in the following locations: • Along Highway 99. • Along the Northwest Expressway. • Along Prairie Rd. • In the vicinity of the Beltline, River Road intersection. 2.6.1.2 Field Observations of Water Quality Problems In addition to the information obtained from the stormwater monitoring data described above, specific water quality related problems /issues have been observed in this basin as follows: Excessive Sediment: Elevated levels of sediment have been observed in Spring Creek, potentially due to poor erosion control practices at construction sites. Tip -ups: Sediment and debris that has been observed to accumulate in tip -ups is likely getting flushed into downstream open waterways during larger storm events. Debris in the Open Waterways: Significant amounts of trash and debris are dumped into the open waterways in this basin and maintenance access is often limited for removing debris. 2.6.2 Oregon Department of Environmental Quality Water Quality Limited Designations [303(d) List] The federal Clean Water Act requires states to maintain a list of water bodies that do not meet water quality standards. These standards are established to protect beneficial uses such as drinking water, fisheries, industrial water supply, recreational, and agricultural uses. This list is called the 303(d) list based on the section of the Clean Water Act that mandates this requirement. The list is meant only as a means of identifying water quality problems and not the causes. States must monitor water quality and review available data and information to determine if the standards are being met. In Oregon, this responsibility is carried out by the Department of Environmental Quality (DEQ). If available data indicate a water body is not meeting water 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 11 -22 SECTION 2 Study Area Characteristics quality standards, and the data meet listing guidelines, DEQ must assume that the water body is water quality limited. Water bodies with no information, or information incompatible with the EPA guidelines, are not included on the 303(d) list. The 303(d) list is updated and revised every two years. Once a water body is included on the 303(d) list, DEQ is required to develop a total maximum daily load (TMDL) requirement for both point and non -point sources of the pollutants of concern. It is anticipated that DEQ will develop TMDL requirements for all designated water quality limited water bodies in the State of Oregon sometime within the next ten years. No water bodies in the River Road Santa Clara basin appear on the 303(d) list. However, two subbasins drain to the Amazon Creek and all subbasins in River Road Santa Clara eventually drain to the Upper Willamette River. Amazon Creek appears on the 303(d) list for bacteria, arsenic and lead. The Willamette River appears on the 303(d) list for bacteria, temperature and mercury. A TMDL was issued for the Willamette River basin in September 2006 for bacteria, mercury, and temperature. Lane County and the City of Eugene have each developed TMDL implementation plans outlining specific actions and programs to address water quality problems in the Willamette Basin. Lane County's plan was approved by the DEQ on June 17, 2008. The City of Eugene's plan was approved on December 23, 2008. 2.6.3 Natural and Built Conditions Evaluating the natural and built conditions that influence water quality can be useful in indirectly assessing water quality conditions in the basin. As urbanization occurs, negative impacts to the health of receiving waters result from changes in the quality of stormwater runoff. Natural features such as riparian areas, wetlands, and open drainage systems have the ability to treat stormwater pollutants, prevent waterway scour by slowing down runoff rates, settle out sediments, and protect stream banks from erosion. However, with research showing that water quality degradation occurs at relatively low levels of imperviousness (10 -20 percent), the implications of development on water quality is significant.' Figures 2 -6, 2 -7, and 2 -8 examine natural and built conditions relative to the other Eugene drainage basins. 1 Tom Schueler, et al. Site Planning, for Urban Stream Protection: The Importance oflmperviousness, 1995. 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 11 -23 SECTION 2 Study Area Characteristics Figure 2 -6 Extent of Ouen Drainage Svstem in the River Road Santa Clara Basin (UGB) Miles per Square Mile River Road Santa Mara Basin Relative to of Open Drainage System in the the Range in Other Eugene Basins (milesfsq mile) River Road Santa Clara Basin The Range in other Eugene Basins 3.0 T 0 1 2 3 4 5 Figure 2 -7 Extent of Area as a Percentaue of the River Road Santa Clara Basin (UGB) 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% Vacant land includes tax- lotted areas currently in vacant, agricultural, and timber uses. Figure 2 -8 Extent of 100 -Year Floodwav Fringe that is Vacant in the River Road Santa Clara Basin 1 44% 1 T 0% 10% 20% 30% 40% 50% 60% 70% Vacant land includes tax- lotted areas currently in vacant, agricultural, and timber uses. 2.6.4 Conclusions A summary of the above findings suggest that degraded water quality conditions exist in the River Road Santa Clara basin as follows: • Based on the analysis of stormwater runoff samples collected from Eugene and other urban areas in Oregon, the pollutants of concern that were identified are as follows: — Total Suspended Solids (TSS) — Nutrients — Heavy Metals — Bacteria — Oil and Grease • Commercial and industrial areas have shown to be the most significant contributors of specific stormwater pollutants. 0:A25695978 Eugene RR-SC Final Basin Plan \Master Plan\FINAL 2- 2010AMaster_ Plan _3 -11 -10 FINAL Word Version AW Sec 2 Corr.doc 2-24 Percent in River Road Santa Clara Basin Relative to Factors River Road The Range in other Eugene Basins Santa Clara Basin Remaining Vacant Lands* 29% T Existing Impervious Surface Area 34% T Projected Impervious Surface 51% Area T Wetlands 3% T 100 -Year Floodplain 12% T 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% Vacant land includes tax- lotted areas currently in vacant, agricultural, and timber uses. Figure 2 -8 Extent of 100 -Year Floodwav Fringe that is Vacant in the River Road Santa Clara Basin 1 44% 1 T 0% 10% 20% 30% 40% 50% 60% 70% Vacant land includes tax- lotted areas currently in vacant, agricultural, and timber uses. 2.6.4 Conclusions A summary of the above findings suggest that degraded water quality conditions exist in the River Road Santa Clara basin as follows: • Based on the analysis of stormwater runoff samples collected from Eugene and other urban areas in Oregon, the pollutants of concern that were identified are as follows: — Total Suspended Solids (TSS) — Nutrients — Heavy Metals — Bacteria — Oil and Grease • Commercial and industrial areas have shown to be the most significant contributors of specific stormwater pollutants. 0:A25695978 Eugene RR-SC Final Basin Plan \Master Plan\FINAL 2- 2010AMaster_ Plan _3 -11 -10 FINAL Word Version AW Sec 2 Corr.doc 2-24 SECTION 2 Study Area Characteristics • The extent of the open drainage system in the basin on a miles per square mile basis is in the mid -range when compared with other Eugene drainage basins. • At 34 percent, the basin currently has levels of imperviousness that are expected to degrade water quality. Projections at UGB buildout indicate that the impervious surface area will increase to 51 percent, which is the highest for all of the basins. 2.7 Rare, Threatened, and Endangered Plants, Animals, and Communities Stormwater management decisions and practices can affect rare, threatened, and endangered plant and animal species. Local populations can be reduced or even eliminated as a result of decisions to pipe a waterway, install upstream detention, or to allow significant increases in runoff due to new development. The purpose of this chapter is to describe the known rare species and communities located in the River Road Santa Clara basin so that the details of these resources can be consulted prior to any final decisions. Review of the Oregon Natural Heritage Program database reveals no records of rare plant, animal, or community observations. In March 1999, the National Marine Fisheries Service (NMFS) listed spring -run Chinook salmon as a threatened species under the Endangered Species Act (ESA). It includes all naturally spawned populations of Spring Chinook in the Clackamas River and in the Willamette River and its tributaries above Willamette Falls, Oregon. Because runoff from Eugene discharges either directly or indirectly to the Willamette River, the listing will affect the city's stormwater management program and practices. A species that is listed as threatened means it is likely to become endangered within the foreseeable future throughout all or a significant portion of its range. Protective regulations, known as 4(d) rules, have been developed that are deemed necessary and advisable to provide for the conservation of the species. These rules spell -out the take prohibitions that pertain to Spring Chinook and focus on the type of activities that are likely to lead to a "take." The City completed a review of its own processes, procedures, and development standards and identified those that may not be compatible with the 4(d) rules for potential adjustment. Lane County has established a Routine Road Maintenance Manual outlining procedures and standards for road maintenance activities designed to be compatible with the 4(d) rules. 2.8 Soils Soil characteristics are important factors in predicting the amount, rate, and quality of stormwater runoff and for selecting management measures for addressing the effects of runoff. This section describes the key soil parameters relative to stormwater issues and the distribution of those parameters in the River Road Santa Clara basin. All soils data were obtained from the USDA Soil Survey of Lane County. Refer to Tables 2 -6 to 2 -8 and Maps 6 to 10 for a description of the soil mapping units and relevant stormwater related data found in River Road Santa Clara basin. 0:A25695978 Eugene RR-SC Final Basin Plan \Master Plan\FINAL 2- 2010AMaster_ Plan _3 -11 -10 FINAL Word Version AW Sec 2 Corr.doc 2 -25 SECTION 2 Study Area Characteristics 2.8.1 Permeability Soil permeability measures the rate of water movement through the soil horizon. This factor is important in managing stormwater quantity and quality. Soils with slow permeability rates are more likely to result in higher stormwater runoff volumes than soils of high permeability. Under these conditions, larger and more extensive stormwater facilities are needed to accommodate new development where space permits. In more densely developed areas, slow permeable soils may be better suited to stormwater conveyance and storage facilities than infiltration facilities. Storage facilities could include detention ponds and treatment ponds where time is desired for settling and filtering purposes. Compared with other Eugene basins, soil permeability in the River Road Santa Clara basin within the UGB is relatively high with 81% being moderately slow and 17% being moderate to very rapid. The following table displays the distribution of soil permeability for the basin. Table 2 -6 Soil Permeability in the River Road Santa Clara Basin Location Permeability (percent) Very Moderately 'Moderate Moderately Slow Very No Data* Total Rapid Rapid Slow Slow Within 4% 3% 10 % 81% 0% 1% 1% 100% UGB Outside 8% 2% 3% 74% 3% 8% 2% 100% UGB Total 7% 3% 7% 78% 1% 1 3% 1% 100% Basin *Includes borrow pits and water features such as ponds Source: USDA Soil Survey ofLane County Area, Oregon, 1987. 2.8.2 Runoff Potential Soil groups have been rated according to their runoff potential under nonvegetated and saturated conditions without consideration of topographic conditions. Runoff potential measures a soil's capacity to permit infiltration and can be used to describe the degree of runoff expected during storm events. For example, soils rated with a low runoff potential are more likely to have high infiltration rates and, conversely, soils with a high runoff potential are more likely to have low infiltration rates. Hydrologic stormwater models often use this parameter in conjunction with slope and surface cover factors for estimating surface flows under undeveloped conditions. As shown on Map 7, the River Road Santa Clara basin within the UGB contains soil groups with runoff ratings ranging from moderately low (16 %), moderately high (71 %) to "high" (11 %). The following table displays the distribution of potential runoff qualities of the basin: 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 11 -26 SECTION 2 Study Area Characteristics Table 2 -7 Runoff Potential in the River Road Santa Clara Basin Location Medium Low Negligible No Data* Total Within UGB 80.7% 17.3% 0.5% 1.4% 100% Outside UGB 75.9% 22.5% 0.3% 1.3% 100% Total Basin 78.7% 19.5% 0.4% 1.4% 100% *Includes borrow pits and water features such as ponds Source: NRCS Soil Data, December 2006. 2.8.3 Erodible Soils Highly erodible soils have significant stormwater management implications. If not properly protected during construction and land clearing activities, erosion and sedimentation from these soils can have the following negative effects: • Reduction in the conveyance capacity of downstream stormwater facilities resulting in potential drainage and flooding problems. • Reduction or elimination of aquatic habitat and covering or destroying of spawning beds. • Water quality impacts due to pollutants that are attached to sediments. The Soil Survey ofLane County indicates soils in this basin are generally not susceptible to high levels of erosion (See Map 8). 2.8.4 Unstable Slopes Soils that are subject to slumping can present structural problems especially where extensive grading is made for roads and building pads. The Soil Survey ofLane County indicates there are no soils in this basin subject to slumping. 2.8.5 Hydric Soils Hydric soil is one of three criteria for determining the presence of wetlands; the other two being inundated or saturated soil conditions and the presence of hydrophytic vegetation. Federal and state regulations limit activities that can occur in wetlands, including the direct discharge of untreated stormwater runoff. The Oregon DEQ has not yet established such standards for discharging into wetlands. The following table displays the percentage of hydric soils found in the basin. Hydric soils areas are located almost entirely west of the Northwest Expressway corresponding to historic low lying drainage areas (See Map 9). 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 2-27 SECTION 2 Study Area Characteristics Table 2 -8 Hydric Soils in River Road Santa Clara Basin Location Hydric Soils (percent) Within UGB 11% Outside UGB 37% Total Basin 22% Source: USDA Soil Survey of Lane County Area, Oregon, 1987. 2.9 Groundwater Two aspects related to groundwater need to be given special consideration when planning for stormwater management. The first relates to the regional aquifer that underlies much of the lower Willamette Valley basin. This aquifer is the source of drinking water for rural residents and several nearby communities (i.e., Springfield, Coburg, Junction City) and has also been investigated as a potential future source of water for Eugene. For this reason, consideration needs to be given to the effects that stormwater management can have on groundwater quality and quantity. The second issue relates to depth to the water table. Map 11 shows the depth to high water table during the wet season. This information is linked to soil type and comes from the USDA Soil Survey of Lane County. During the course of the year, these elevations respond to rainfall amounts and, therefore, vary accordingly. As with hydric soil location, the Northwest Expressway is a definitive boundary where deeper water table elevations are found to the east and shallower depths to the west. As part of this study a more detailed analysis of high groundwater was conducted by reviewing well logs from the Oregon Water Resources department. The results of the evaluation showed that seasonal high groundwater levels are approximately 8 feet deep on average in this basin. A copy of study results is provided in Appendix E. With regard to the issues of aquifer protection and depth to the water table, the numerous drywells used for stormwater management in this basin present a unique environmental problem because drywells have the potential to discharge surface water pollutants directly to groundwater without sufficient treatment. Congress enacted groundwater protection rules in 1974 under the federal Safe Drinking Water Act (SDWA). The U.S. Environmental Protection Agency (EPA) administers these rules under Title 40 of the Code of Federal Regulations (CFR) Parts 144 -148. In Oregon, the EPA has delegated the regulation of groundwater protection rules to the Department of Environmental Quality (DEQ). The DEQ regulates this program for the EPA under the Oregon Administrative Rules (OAR) Chapter 340, Division 44. As part of these groundwater protection rules, DEQ specifies a minimum of 10 feet of separation between the bottom of a drywell and the seasonal high groundwater. Due to high groundwater in a large portion of the River Road Santa Clara basin, most of the UICs in this area do not meet the necessary separation criteria and cannot, therefore, be Authorized by Rule by the DEQ. Both the City of Eugene and Lane County have registered their known UICs with the DEQ and have applied for a Water Pollution Control Facility (WPCF) permit to manage the UICs until they can 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 11 -28 SECTION 2 Study Area Characteristics be authorized or decommissioned. More detail regarding these regulations and strategies for compliance are provided in Section 4.0 of this document. 2.10 Existing and Planned Educational Facilities The River Road Santa Clara basin currently has nine public schools (including two middle schools and one high school) and one private school. No additional schools are currently planned in the basin. 2.11 Existing and Planned Park and Recreational Facilities The River Road Santa Clara basin contains 69 acres of public park land spread over 13 separate park parcels (see Map 12). The two largest parks are Emerald Park (9.78 acres) and Walnut Grove (19.75). Because of its environmental, historic and social significance, Walnut Grove Park is one of the few neighborhood parks in Eugene to be maintained as a natural environment. The plan for the park, which was developed in collaboration with area neighbors, emphasizes native plant and wildlife preservation and enhancement, passive recreation, and educational opportunities. 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Smini 766 0 < C) MIN MR, M., 0 < C) -E� U _0 0 C-: 1 U) 0 z C) C:) 00 0 w 0 T ) N No w — . 0 Lu u) cr- 0 0 C� ' M E o C, t C t D C) U) w o 0 - 0 -5� 2 LO - C4 M - T 0 0 co a) w U) 0 , , o Z 2 Lu E Lu 0 o _0 o a) :� C: a) E m 2 0 M w C4 0 �� 0 (D 73 (D LO N . in 0) 0) 2 w 0 ' '- 2-' 0 co 00 00 (C; of co LU LU a) E � � o w 2- 0 �3 b - E' 8 Z-< 4 RE a m 0 oo :F 00., is ME GiLu AN c- D dj mm as I U) SECTION 3 Flood Control Euaination In order to identify flood related problems and opportunities, a flood control evaluation was completed for the drainage system in the River Road Santa Clara basin that is described in Section 2.5 and illustrated on Map 5. A computer model was used to predict capacity deficiencies in the existing storm drainage system. Section 3.1 provides a brief description of the computer model and a summary of the hydrologic and hydraulic model input data. Section 3.2 describes the model validation process, and Section 3.3 provides a description of model results. Section 3.4 provides a general description of the identified flood - related problems. Section 3.5 describes the project alternatives and development standard alternatives that were selected to address the identified flooding problems. 3.1 Hydrologic/Hydraulic Model Development To develop a flood control strategy for the River Road Santa Clara basin, a computer model was used to evaluate hydrologic /hydraulic conditions of the public storm drainage system. The storm system was evaluated under both existing and buildout land use conditions. The City of Eugene selected the XP -SWMM model software to conduct these analyses. In general, the evaluation concentrated on the conveyance capacity of the significant components of the public drainage system; typically, all storm sewer pipes with a diameter equal to or greater than 36" and the associated open waterways on the Willamette Overflow (also referred to as the East Santa Clara Waterway), Spring Creek, Flat Creek, and the A -1 Channel. The River Road Santa Clara basin drainage system, including pipes, open channels and drywells, is shown on Figures 3 -2 through 3 -8. Figure 3 -1 provides an index map that illustrates the relative locations of Figures 3 -2 through 3 -8 in the basin. Modeled drainage segments and locations of the proposed capital projects are also illustrated on Figures 3 -2 through 3 -8. The City -wide storm drainage basin planning summary in Volume I contains detailed information regarding the process and sources of information that were used for identifying flooding problems and opportunities. Section 3 of Volume I specifically includes detailed information regarding the following: • Model selection process. • Sources of model input data. • Design storm selection process. • Model calibration (note: while Volume I contains calibration information that was applied City -wide during the development of the 2002 basin plans, a separate model validation was conducted that is specific to the River Road Santa Clara basin and is described in Section 3.2 of this plan). This section of the River Road Santa Clara report provides a summary of the basin specific hydrologic and hydraulic data used in the models. 3.1.1 River Road Santa Clara Basin Hydrologic Data The original River Road Santa Clara Study was an initial study towards development of a stormwater basin master plan and was created in 2002. The Study identified a number of 0:\25695978 Eugene RR -SC Final Basin P1an\Nlaster P1an\FINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 3-1 SECTION 3 Flood Control Euaination hydrologic data gaps, specifically related to the subbasin delineations and locations of runoff nodes in the model (a runoff node is a point where runoff from a subbasin area enters the modeled system). Since the original Study was prepared, data gaps have been addressed by the City of Eugene and Lane County. Specifically, survey data collected by Lane County between October and December 2005 allowed for refinement of the original subbasin delineations and node locations in the model (described in more detail in Subsection 3.1.2 and in Appendix G). These refinements have been applied to the original model, and the following discussion summarizes the overall hydrologic input data in the refined model. Hydrologic Data Based on the Piped and Surface Water Drainage System The River Road Santa Clara basin was subdivided into five major subbasins. The major subbasin boundaries are presented in Figure 3 -1. The five major subbasins were further divided into 75 subbasins for modeling purposes. The subbasin boundaries presented on Figures 3 -2 through 3 -8 were delineated based on both topography and the piped and open channel drainage system layout. The subbasin boundaries were digitized into the City's /County's GIS so that hydrologic data could be compiled for each subbasin. Seven - character names were assigned to each subbasin. The first two characters represent a two - letter abbreviation for the major basin; in this case RS for River Road Santa Clara. The second two characters represent a two - letter abbreviation for the major subbasin. The 5 major subbasins in the River Road Santa Clara basin are as follows: Al = A -1 Channel Drainage System FC = Flat Creek Drainage System SC = Spring Creek Drainage System WO = Willamette Overflow Drainage System (also referred to as the East Santa Clara Waterway) 99 = Highway 99 The last three characters of the subbasin name consist of numbers, starting with 010 and increasing in increments of 10 for each additional subbasin. For example, the first two subbasins in the Willamette Overflow major subbasin of the River Road Santa Clara basin are RSWO010 and RSWO020. In addition, each subbasin has an associated inlet node number. The hydrologic component (i.e., RUNOFF block) of XP -SWMM was used to generate a stormwater runoff hydrograph for each subbasin. This hydrograph was routed by the hydraulic component (i.e., the EXTRAN block) of XP -SWMM to model the storm drainage system. The subbasin inlet node is the point where the subbasin hydrograph enters the storm drainage system for routing. The following parameters were required for each subbasin in the hydrology component of XP- SWMM: 1. Subbasin name or number. 2. Channel or pipe inlet node number into the storm drainage system. 3. Subbasin area (acres). 4. Hydraulically connected impervious percentage for both existing and future land use scenarios (percent). 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 3-2 SECTION 3 Flood Control Euaination 5. Average ground slope (dimensionless, ft/ft). 6. Subbasin width (feet). 7. Manning's roughness coefficient for impervious areas. 8. Manning's roughness coefficient for pervious areas. 9. Depression storage for impervious areas (inches of water over subbasin). 10. Depression storage for pervious areas (inches of water over subbasin). 11. Green -Ampt soil infiltration parameters: average capillary suction (inches), saturated hydraulic conductivity (inches /hour), and initial moisture deficit (volume air /volume voids). Table 3 -1 (provided at the back of this section) includes the major hydrologic information for each of the River Road Santa Clara subbasins. Specifically, the tables provide the information for parameters 1 - 5 listed above and the expected increase in impervious surface under future conditions. More detailed hydrologic information, including information described for parameters 1 — 11, can be found in Appendix B. The following subbasins were not included in the model for the reasons noted: • The A -1 Channel subbasins Al -000 and Al -005 were excluded from the model since they are located outside the City limits and the Urban Growth Boundary. • The Highway 99 major subbasin (including subbasins 99 -010 and 99 -020) were excluded since they drain to a roadside ditch along Highway 99N that is owned and maintained by the Oregon Department of Transportation. • Flat Creek subbasin FC -000 was excluded from the model since it is located outside the City limits and the Urban Growth Boundary. • Willamette Overflow subbasin WO -000 was excluded from the model since it is located outside the City limits and the Urban Growth Boundary. Hydrologic Data Associated with Drywell Drainage Areas After completing the subbasin delineations described above, a second step was conducted to delineate the portion of each subbasin where runoff is draining to drywells as opposed to the piped or surface conveyance system. Section 2.5.4 provides a description of the drywells in the River Road Santa Clara basin including 79 County wells, 72 City wells, and approximately 634 private drywells. At the time that this exercise was conducted, the GIS system for drywells was still under development and somewhat incomplete. Therefore, the delineation of drywell drainage areas included a subset (or approximately 759) of the total 785 drywells. For each subbasin that included some portion of area draining to drywells, the subbasin was subdivided into these two areas, and the hydrologic information described above (e.g., inlet node number, subbasin area, impervious percentage, etc.) was generated for both the subset of the subbasin draining to the drywells and the subset of the subbasin draining to the piped or surface conveyance system. The purpose of delineating these drywell areas individually was to simulate the effect of drywells in the hydrology portion of the XP -SWMM model and on the runoff calculations. In order to develop a model that would simulate the infiltration characteristics associated with drywells, the drywells were modeled as storage nodes that would store runoff generated up to the 5 -year, 25 -hour (3.6 inches) storm event. This was based upon the City's design criteria for 0:A25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 3-3 SECTION 3 Flood Control Euaination public drywells which includes that they serve an area no greater than 40 acres and infiltrate all of the runoff up to a 5 -year, 24 -hour event. In the model, when the capacity of the storage node was reached, the areas draining to drywells would begin to contribute additional runoff to the piped and surface water drainage system. The drywell storage nodes were sized using an iterative trial and error process until the 5 -year, 24 -hour event filled the storage volume but did not contribute runoff flows to the piped and surface stormwater drainage system. As a result, two hydrologic modeling scenarios were developed for the River Road Santa Clara Basin: 1) One model scenario was developed that did not account for the infiltration associated with existing drywells. 2) The second model scenario was developed to account for the infiltration associated with existing drywells. The purpose of developing both model scenarios was to evaluate the impacts that the drywells were having on the capacity of the piped and surface drainage system during the various design events. Decommissioning of the public drywells in this basin is ultimately required (see Section 4.0 for a summary of relevant requirements). Therefore, comparing the results from the two model scenarios provided useful information in order to better understand how decommissioning will impact the system and planned capital projects in terms of capacity and sizing. 3.1.2 River Road Santa Clara Basin Hydraulic Data The primary purpose of the modeling was to evaluate the capacity of the existing storm drainage system. The evaluation of the storm drainage system included a hydraulic analysis of the major storm pipes, culverts, and open channels, which convey stormwater discharges. The original River Road Santa Clara Basin Plan, created in 2002, identified a number of hydraulic data gaps due to the multi jurisdictional ownership of the drainage system and the lack of a comprehensive data set for the overall drainage system, a result of the multi jurisdictional ownership. Data gaps have since been addressed by the City of Eugene and Lane County. Specifically, survey data collected by Lane County between October and December 2005 allowed for refinement of the piped and open channel segments of the drainage system (described further in this section and in Appendix G). These refinements have been applied to the original model, and the following parameters (i.e., model input data) were compiled for each pipe, culvert or open channel section: 1. Conduit name. 2. Upstream node number. 3. Downstream node number. 4. Conduit size (diameter for pipes and culverts; cross - section dimensions for open channels) 5. Conduit length. 6. Conduit material for pipes and culverts. 7. Upstream and downstream invert elevations. 8. Upstream and downstream ground surface elevations. 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 3-4 SECTION 3 Flood Control Euaination 9. Channel roughness coefficients (for open channels). For the River Road Santa Clara basin, the model was used to evaluate the capacity of approximately 160 open waterway and pipe segments under existing and future land use conditions. Table 3 -2 (provided at the back of this section) provides the major hydraulic information for each of the modeled conduits in the 4 major subbasins evaluated within the River Road Santa Clara basin. Specifically, the table provides the information for parameters 1 — 6 listed above, in addition to the drainage area for each conduit, the relevant design storm, and the model results for the relevant design storm. Model results are presented in terms of peak flows and maximum water surface elevations. The results for all storm events that were run through the models (i.e., 10 -year, 25 -year, 50 -year, and 100 -year storms) can be found in Appendix B. As discussed previously, due to the multi jurisdictional ownership of the drainage system, the City did not have a comprehensive data set on the drainage system in this basin at the time the original River Road Santa Clara Basin Plan was completed. Since the original Plan was completed in 2002, the City and County partnered to develop this revised Plan, and the following areas were surveyed and updated in the original model, resulting in a more refined hydrologic and hydraulic data set and a more refined modeled system. A more detailed summary of major changes made to the model is provided in Appendix G. The refined model results were used for design of the capital projects described in Section 3.5. Willamette Overflow major subbasin: — A large elevation difference was noted between the inlet and outlet pipes to the manhole at node 58287, located east of River Road and north of Division on Figure 3 -7. Hydraulic conditions at this location were field verified and surveyed. — The pipe system that conveys stormwater from Beltline Road to the Willamette Overflow drainage system, as shown on Figure 3 -7, appeared to include pipes with a diameter equal to or greater than 36 inches, which would ordinarily be included in the model, but insufficient data were initially available for these pipes. Hydraulic conditions at this location were field verified and surveyed. — Field crews noted that fill had been placed in the open waterway between Division and Hunsaker, which blocks the waterway except under high flow conditions. This fill was not reflected in the original survey data so a revised survey of this open channel segment was conducted. • Flat Creek major subbasin: — The hydrologic connection of subbasin FC -070 and Flat Creek was field verified. • A -I Channel major subbasin: — Hydraulic conditions in the pipe system along Irving Road that conveys stormwater to the A -1 Channel, shown on Figure 3 -7, were unclear, and therefore the system was field verified and surveyed. — Drainage patterns in the A -1 Channel major subbasin, south of Beltline Road on Figures 3 -7 and 3 -8 were unclear. A number of drywells may result in less area that is directly connected with the A -1 channel. Hydrologic conditions at this location were field verified. 0:\25695978 Eugene RR -SC Final Basin P1an\Nlaster P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 3-5 SECTION 3 Flood Control Euaination — The open waterway profile of the A -1 Channel between Bushnell Lane East and Irving Road (node 72730 to node 72797) on Figure 3 -7 was unknown, and therefore the system was field verified and surveyed. — Conditions of the western tributary of the A -1 Channel from node 72102 to 71215, shown on Figure 3 -5, were unclear, and therefore the system was field verified and surveyed. 3.2 Model Validation Process As described previously, an initial model calibration was applied City -wide during the development of the 2002 basin plans. However, a separate model validation was conducted specific to the River Road Santa Clara basin because of the unique conditions of the basin associated with fairly high permeability soils and the use of drywells to handle some of the drainage. In addition, photos from a large storm event were available from within the basin for use in validating the model. Flow monitoring data were not available for a calibration process; therefore, a model validation process was conducted based on photos and observed freeboard elevations provided by the City. The information was provided from the Willamette Overflow subbasin in the Willamette Overflow Waterway at Lone Oak Way (node 74406) for three days of rainfall in 2005: December 28 30 and 31 Validation of the model was based on comparisons between model - simulated water surface elevations at node 74406 (converted to freeboard elevations) and the freeboard observed during the rainfall event(s), as provided below. To start, the base hydrologic /hydraulic model that was used for the model validation process assumed that the drywells in the Willamette Overflow Basin were functioning as they were designed to infiltrate all of the runoff from the 5 -year, 24 hour design storm (model scenario 2 from subsection 3.1.1). Another assumption in the base model was that the impervious percentages were equal to the mapped impervious percentages areas as opposed to using effective impervious percentage areas. The comparison between simulated and observed freeboard elevations revealed that the model - simulated freeboard was less than the observed freeboard (i.e. the model was conservative as it was simulating higher water surface elevations and hence, lower freeboards). Model parameters were adjusted in an attempt to reduce the differences between model - simulated and observed freeboard. These adjustments to the model input parameters were applied to the entire Willamette Overflow subbasin model, and the model was run for the period from December 27, 2005 to January 3, 2006 using real rainfall data. A summary of the daily rainfall depths that were used in the model validation is provided in Table 3 -3 below. Several additional model runs were conducted to evaluate the model's sensitivity to changes in input parameters. The results of these sensitivity analyses indicated that the impervious percentage area was the most sensitive model input parameter. 0:\25695978 Eugene RR -SC Final Basin P1an\Nlaster P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 3-6 SECTION 3 Flood Control Euaination Table 3 -3 Rainfall Data Used for the Model Validation Date Daily Rainfall Total (inches) Validation Conducted for Day? (Y/N) December 27, 2005 1.25 N December 28, 2005 0.88 Y December 29, 2005 0.17 N December 30, 2005 2.56 Y December 31, 2005 0.94 Y January 1, 2006 0.16 N January 2, 2006 0.37 N January 3, 2006 0.12 N Total: 6.45 Several combinations of model adjustments were evaluated to obtain the best match to observed conditions (i.e., to reduce differences between simulated and observed freeboard). The model adjustments that were evaluated during the model validation process are shown in Table 3 -4. The best results (i.e., closest to observed data) were obtained when the model input parameters were adjusted to reflect the use of effective impervious percentage areas instead of mapped impervious percentage areas (i.e., lowering the impervious percentages). Effective impervious percentage areas were estimated based on Roger Sutherland's paper (provided as Appendix C) titled Methodology for Estimating the Effective Impervious Area of Urban Watersheds (1995). His method includes five different equations for estimating the effective impervious area from mapped impervious area. The five equations are based on how directly connected the mapped impervious areas are to the piped storm drainage system. Equation #1 (below) was used to calculate effective impervious area for the purpose of conducting this model validation. Average subbasins which are predominately sewered with curbs and gutters, have no infiltration facilities, and the residential rooftops are not directly connected to the drainage system: Effective Imp. % 0.1 * (Mapped Imp. %) ­ Although the use of equation #1 (for average connected basins) and associated revised impervious surface estimates resulted in somewhat better model results (i.e., closest to observed data), the drainage area upstream of the calibration site was determined to be all curb and gutter, and the impervious area was estimated to be mostly connected. As the calibration data came from only one point in the basin, and as it was observed as opposed to measured, it was decided that it would be better to use the more realistic input parameters and err on the conservative side (i.e., model - simulated flows higher than observed flows). The entire River Road Santa Clara basin varies with respect to whether streets have curb and gutter, but without better calibration data the variations were not taken into account with the equation used to calculate effective impervious surface and thus accounted for in the model. In other words, one consistent equation was used to convert mapped impervious areas to effective impervious areas for the entire basin. 0: 25695978 Eugene RR -SC Final Basin P1an\Nlaster P1an\FINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 3-7 SECTION 3 Flood Control Eualnation Therefore, the following model adjustments were recommended that are shown as shaded in Table 3 -4. Table 3 -4 Model Adjustments and Associated Model Results for Node 74406 * For Average Connected Impervious Areas: Effective imp. % = 0.1 * (Mapped Imp. %) (equation # I - Appendix C) ** For Low Connected Impervious Areas: Effective imp.% = 0.04 * (Mapped Imp. %) (equation # 4 - Appendix C) 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 3-8 Storm Observed Simulated Alternative Model Adjustments Difference (ft) Event Date Freeboard (ft) Freeboard (ft) No initial Changes 12/28/2005 5.00 3.20 1.80 1 No initial Changes 12/30/2005 9.00 4.47 4.53 No initial Changes 12/31/2005 6.00 3.03 2.97 I mp. % Reduced using Average Formula* 12/28/2005 5.00 3.57 1.43 2 mp. '/o educed using Average Formula* 12/30/2005 9.00 5.75 3.25 mp. % Reduced using Average Formula* 12/31/2005 6.00 3.11 2.89 I mp. % Reduced using Low Formula* * 12/28/2005 5.00 4.20 0.80 3 Imp. % Reduced using Low Formula* * 12/30/2005 9.00 6.17 2.83 I mp. % Reduced using Low Formula* * 12/31/2005 6.00 3.17 2.83 Saturated Hydraulic Conductivity Increase by 12/28/2005 5.00 3.20 1.80 0% Saturated Hydraulic Conductivity Increase by 4 12/30/2005 9.00 4.47 4.53 Saturated Hydraulic Conductivity Increase by 12/31/2005 6.00 3.03 2.97 0% Basin width decrease by 50% 12/28/2005 5.00 3.20 1.80 5 Basin width decrease by 50% 12/30/2005 9.00 4.47 4.53 Basin width decrease by 50% 12/31/2005 6.00 3.03 2.97 Model includes only non Drywell areas 12/28/2005 5.00 3.20 1.80 Model includes only non Drywell areas 6 12/30/2005 9.00 4.47 4.53 Model includes only non Drywell areas 12/31/2005 6.00 3.06 2.94 Model includes only non Drywell areas with I mp. Reduced by Average Formula* 12/28/2005 5.00 3.57 1.43 Model includes only non Drywell areas with 7 I mp. Reduced by Average Formula* 12/30/2005 9.00 5.75 3.25 Model includes only non Drywell areas with ,Imp. Reduced by Average Formula* 12/31/2005 6.00 3.14 2.86 Model includes only non - Drywell areas with I mp. Reduced by Low Formula ** 12/28/2005 5.00 4.20 0.80 Model includes only non - Drywell areas with 8 I mp. Reduced by Low Formula ** 12/30/2005 9.00 6.17 2.83 Model includes only non - Drywell areas with mp. Reduced by Low Formula ** 12/31/2005 6.00 3.17 2.83 * For Average Connected Impervious Areas: Effective imp. % = 0.1 * (Mapped Imp. %) (equation # I - Appendix C) ** For Low Connected Impervious Areas: Effective imp.% = 0.04 * (Mapped Imp. %) (equation # 4 - Appendix C) 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 3-8 SECTION 3 Flood Control Euaination Based on the above information, the City and County agreed to move ahead with the #2 model adjustments from Table 3 -4, which included reducing mapped impervious percentage areas using Equation #1. These model adjustments were applied basin -wide to the A -1 Channel, Spring Creek, Flat Creek, and the Willamette Overflow major subbasins. 3.3 Model Results As described in Section 3.1 of Volume I (City -wide Study Methodology and Summary), models were run for the selected design storms, and model output was produced for peak flows and water surface elevations for both existing and future conditions. These results were used to identify capacity deficiencies in the system. Surcharging was considered to be acceptable and problems were only identified if the models indicated that water was exiting the system and onto the streets. For this basin, model results were produced for existing and future conditions for two scenarios as described in subsection 3.1.1: 1) the model scenario did not account for infiltration from the existing drywells in the model simulation; and 2) the model scenario did account for existing drywells in the model simulation. Given new rules related to stormwater discharges to drywells (under the Safe Drinking Water Act), decommissioning of the public drywells in this basin will ultimately be required (with the possibility of some exceptions depending on confirmed groundwater levels). Therefore, the model scenario without the incorporation of drywells was used to evaluate the capacity of the drainage system when public drywells are ultimately decommissioned. It should be noted that private drywells are under the authority of the Oregon Department of Environmental Quality (ODEQ) and any decommissioning associated with private drywells (if required) would be directed by ODEQ. Of the 785 drywells in the basin, 634 (81 %) are privately owned, 79 (10 %) are owned by Lane County, and 72 (9 %) are owned by the City of Eugene. Section 4.0 of this plan provides more detail regarding the Safe Drinking Water Act and associated DEQ requirements for stormwater discharges to drywells. As mentioned in Section 3. 1, the model simulation that accounted for drywells was based on an incomplete dataset at the time and included a portion (approximately 759) of the total 785 drywells. It was anticipated that the modeling results would show that the existing drywells are providing some relief with respect to capacity deficiencies. However, the comparison of model results between both scenarios (with and without drywells) for the 10 -year and 25 -year design events did not show significant differences with respect to identified flooding problems. Based on a more detailed review of the results, it was assumed that this occurred for the following two reasons: 1. The drywells were only designed to infiltrate runoff from up to the 5 -year storm event and the design events modeled to identify flooding issues were the 10 -year and 25 -year events. The accommodation of the flows from the 5 -year storm had minimal impacts with respect to flows from the larger storms when comparing the two model scenarios. 2. Only 22% of the total modeled drainage area was estimated to be draining to drywells (following this analysis, the number was updated to 25 %). Therefore, the majority of the drainage area was already accommodated via the pipe and surface storm drainage system and not highly impacted by infiltration associated with drywells for the larger storms. 0:\25695978 Eugene RR -SC Final Basin P1an\Nlaster P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 3-9 SECTION 3 Flood Control Euaination Because the drywells were not shown to provide significant benefits with respect to resolving capacity deficiencies for the larger storms; and given that the public drywells will eventually need to be decommissioned; and given that the City and County do not have authority over the private drywells, a decision was made to continue with the flood control evaluation and the identification of capital projects using the model that did not include the infiltration of runoff associated with existing drywells. The hydraulic model results are summarized by conduit in Table 3 -2 for the system design storm, and full model results are provided in Appendix B. 3.4 Flooding Problems Identified by the Model This section provides a general description of model - identified flooding problems. The model results are summarized in Table 3 -2 and include both peak flows and water surface elevations for the relevant design storm under both existing and buildout conditions. The last columns in the table indicate the design event and land use condition when certain conduits are expected to be deficient and the associated capital project that addresses the deficiency (discussed in more detail in Section 3.5). For pipe segments and roadway crossings, surcharging was considered to be acceptable, and flooding problems were only identified if the models predicted water getting out of the system and into the streets. For open waterways, deficiencies were identified when the depth of the design flow was predicted to exceed the tops of the channel banks. In general, very few flooding problems were identified in the River Road Santa Clara basin. Specifically, one flooding problem is expected to occur in the Flat Creek drainage system during existing land use conditions. Nineteen open channel and 17 pipe segments were identified as deficient for their respective design storms in the remaining three drainage systems (i.e., A -1 Channel, Spring Creek, and Willamette Overflow). Eighteen of the 19 open channel segments and eleven of the 17 pipe segments are expected to be deficient under existing land use conditions. Additionally, one open channel and six pipe segments are expected to be deficient under buildout conditions. Each of these problems is listed in Section 3.5 in association with the proposed capital project to address the problem. In addition to flooding problems associated with predicted capacity deficiencies, decommissioning of drywells would result in the need for an alternative drainage system to handle or convey the 5- year flows that are currently discharging to drywells. Management strategies to address this issue are described in Section 3.5 and 3.6 as well. 3.5 Development of the Flood Management Strategy As shown in the stormwater basin master planning process flow chart in Figure 1 -1, Step 1 included a compilation of basin characteristics. These basin characteristics are summarized in Section 2.0 of this document. Step 2 in the process includes problem identification under both existing and future land use conditions, focusing on the major components of the public drainage system. These results are provided in Section 3.4 above. The next step includes the development of potential stormwater management tools (i.e., capital projects or development standards) to address the identified problems. This section describes the capital project and development standard alternatives that were considered to address the identified flooding problems. 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 3-10 SECTION 3 Flood Control Euaination 3.5.1 Capital Projects to Address Capacity Deficiencies All flooding problems (i.e., capacity deficiencies) identified through modeling and proposed capital projects (CPs) to address these problems are referenced in Table 3 -2 and presented in Table 3 -5. Prior to this study, design standards for flood protection levels in Eugene were based on the previous storm drainage master plan (OTAK 1990). The 1990 plan includes varying degrees of protection depending on the size of the drainage area, type of system (open channel or pipe), and type of roadway (local collector vs. major arterial). Depending upon these factors, the standards for designing CIPs ranged from the 5 -year to the 50 -year recurrence interval storm. For this plan, the City elected to retain the flood protection levels listed in the 1990 plan with the exception that the minimum level of protection would be the 10 -year as opposed to the 5 -year storm (see Section 3.1.4, Table 3 -1 of Volume 1 for exceptions). Flooding problems were identified for the open waterways and the pipe system and CIPs were developed based on the relevant design storm as listed in Table 3 -2. A flooding problem was identified for an open waterway if the water depth exceeded the top of bank elevation. For the pipe system, surcharging was allowed, however, if the water entered the street a flooding problem was identified. In all, 10 flood control CPs focused on existing culvert replacement and upsizing of the culverts are proposed. Two CPs are proposed that include regrading of the existing channel to improve conveyance capacity. Three CPs are associated with providing storage to relieve predicted capacity issues and one CP is associated with additional survey efforts. Table 3 -5 Capacity Deficiencies Identified Through Modeling and Proposed Capital Projects to Address Them Selected Flood Controlapital' elected Flood Control Capital Conduits Addressed with Capital Project Name Project Descri tion Project Al Channel AM Regrade the existing open channel RSA1090B, RSA1090CI and C2, segment (RSA1090B) from node and RSA1090D 72789 to 78790 (18'). Al -2 Upsize and replace the existing 36" RSA1090A, RSA1090B, CMP culvert (RSA1090A) with a RSA1090CI and C2, and 48" CMP culvert. RSA1090D Al -3 Construct storage facilities at nodes RSA1090A, RSA1090B, 72782 and 72102 to provide a total RSA1090CI and C2, RSA1090D, of 85 acre -ft of storage. RSA1090E1, E2, and E3, RSA1090F, RSA1080B, RSA1060H, RSA1060M, RSA10600, RSA1060Q, RSA I060U, RSA 1100B.1, RSA1100C, RSA1100D.1, RSA1100E, RSA1100F.1, RSA 1100G, RSA I100H, and RSA 1100K Al -4 Upsize and replace the existing 24" RSA I100I.1, RSA 1100J, CMP culvert (RSA11001) with a 36" RSA1110A1 and A2 CMP culvert. 0: 25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 3-11 SECTION 3 Flood Control Eualnation Selected Flood Control Capital Selected Flood Control Capital' Conduits Addressed with Capital Project Name Project Description Project AI -5 Upsize and replace the existing 3- RSA1090E1, E2, and E3, 24" CMP culverts (RSA1090E) with RSA1090F, RSA1100B.1, a 2' x 8' box culvert. RSA1100C, RSA1100D.1, RSA1100E, RSA1100F.1, RSA 1100G, and RSA 1100K AI -6 Upsize and replace the existing 24" RSA1060U, RSA108013, CMP culvert (RSA1060L) with a 2' RSA1090A.1, RSA1060M, x 4' box culvert. RSA1060Q and RSA1060U AI -7 Upsize and replace the existing 18" RSA1060H, RSA1060U, and 24" CSP culverts (RSA1060G) RSA108013, RSA1090A.1 with a 2' x 4.5' box culvert. AI -8 Install a storage CP at nodes 72725 RSA 116013, RSA 11601), and 59020 to provide approximately RSA I160F, RSA I160H 135 acre -ft of storage. AI -9 Conduct survey of open channel RSA 11601), RSA I160H, segments RSA1080B Flat Creek FC -1 Upsize and replace the existing 3- RSFCO50E 12" CSP culverts (RSFCO50D) with a 1.5' x 5.0' box culvert. Spring Creek SC -1 Upsize and replace the existing 2- RSSC040B 30" CSP culverts (RSSCO50B) with a 12' long pedestrian bridge. Willamette Overflow WO -1 Upsize and replace the existing 18" RSWO070D.1, RSWO070E CMP culvert (RSWO070D) with a 66" CSP culvert. WO -2 Upsize and replace the existing 36" RSWO110B.1, RSWO110C.I CSP culvert (RSWOI10A) with a 60" CSP culvert. WO -3 Upsize and replace the existing 48" RSWO090A, RSWO090Aa, CSP culvert (RSWO080A) with a RSWO090B, RSWO090C, 66" CSP culvert. RSWO090F, RSWO090H WO -4 Regrade the existing open channel RSWO090A, RSWO090Aa, segments (RSWO090Aa, RSWO090B, RSWO090C, RSWO090B, RSWO090C, and RSWO090F, RSWO090H RSWO090D) from node 74405 to 78833 (724'). WO -5 Install a storage CP at node 77703 to RSWO070D.1, RSWO070E, provide approximately 124 acre -ft of RSWO090A, RSWO090Aa, storage. RSWO090B, RSWO090C, RSWO090F, RSWO090H, RSWO110B.1, RSWO110C.I For more detail regarding each of these projects, capital project fact sheets are provided in Appendix A. 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 3-12 SECTION 3 Flood Control Euaination 3.5.2 Selected Projects to Address Flows Associated With Drywell Decommissioning As stated previously, DEQ is expected to require decommissioning of all the public drywells in the basin (more detail is provided in Section 4.0). As a result, alternative systems will be necessary to handle the flows (up to the 5 -year, 24 hour design event) that were previously handled through drywells. The drywell drainage areas were reviewed, and three project options were developed to handle the flows from these areas as follows: 1) Piped Option — If the drywell is located in close proximity to an existing storm drainage pipe and the pipe has the capacity to handle the flow, a new piped system would be constructed as necessary to route the drywell flows to the existing piped system. 2) Surface Infiltration/Rain Garden Option — If the drywell is located in an area where flow is not able to be routed to an existing piped system, flows would be routed to an area where a vegetated infiltration /rain garden type facility would be constructed to handle flows. Infiltration of municipal stormwater runoff that occurs through the ground surface as opposed to the subsurface is not regulated under the Safe Drinking Water Act. 3) On- Street Rain Garden Option — In areas where street improvements are planned, right -of- way plans /cross - sections that include street side rain gardens for the storage and infiltration of runoff could be used to handle flows from the right -of -way (ROW). For this option, properties adjacent to the R.O.W. would be required to deal with their individual drainage on -site in accordance with requirements for stormwater in the City of Eugene Code (Chapter 9, Section 9.6791(3)). Many of the drywells are concentrated in various portions of the basin. Therefore, prior to selecting an option for the individual drywells, drywells located in close proximity to each other where flows were proposed to be managed in accordance with the same option as defined above, were grouped into drywell "clusters ". This grouping of drywells was conducted because some of the management options could be applied and constructed in a manner to address a "cluster" of drywells. A total of 39 drywell clusters were delineated, as illustrated on the Stormwater Management Strategy Development map in Appendix H and listed in Table 3 -6 below. Table 3- 6 also lists the CPs associated with each drywell cluster to address decommissioning of the drywells. A capital project fact sheet including a map, estimated costs, and conceptual design assumptions is provided for each of these projects in Appendix A, and the location of each of these projects is also shown in Figures 3 -2 through 3 -8. The project options were selected for each cluster to maximize water quality benefits while addressing the flows associated with decommissioning. See Section 4.0 — Water Quality Evaluation for more detail regarding the development of each of these projects. 0:A25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 3-13 SECTION 3 Flood Control Eualnation Table 3 -6 Capital Project Options Selected to Address Decommissioning of Drywells (UICs)* CP/ Cluster Number # of County Drywells 'Addressed b the CP of City Drywells Addressed by the CP CP Project Option Selected CPI Cluster Name Willamette Overflow Major Subbasin WO -I -UIC 2 Piped Green UIC Cluster WO -2 -UIC 4 Rain Garden/Infiltration Facility Corliss/ Carol n/ Onyx UIC Cluster WO -3 -UIC 4 6 Rain Garden/Infiltration Facility Autumn, Ross, Moore /Oak UIC Cluster WO -4 -UIC 1 Piped Taz UIC WO -5 -UIC 3 Rain Garden/Infiltration Facility Silver Meadows UIC Cluster WO -6 -UIC 3 Piped Poplar UIC Cluster WO -7 -UIC 1 Piped Kendra UIC WO -8 -UIC 1 1 Piped Kent UIC Cluster WO -9 -UIC 1 Rain Garden/Infiltration Facility Ba wood UIC WO -10 -UIC 1 Rain Garden/Infiltration Facility Greenwood UIC WO -1I -UIC 1 I Rain Garden/Infiltration Facility Warrington UIC A -1 Channel Major Subbasin' Al -1 -UIC Al -2 -UIC 7 Piped Crocker 1 and 2 UIC Cluster Al -3 -UIC Al -4 -UIC 10 Piped Shirley 1 and 2 UIC Cluster Al -5 -UIC 4 Piped Hamilton UIC Cluster Al -6 -UIC 2 Piped Bushnell UIC Cluster Al -7 -UIC 8 14 Rain Garden/Infiltration Facility Anderson UIC Cluster Al -8 -UIC 4 Rain Garden/Infiltration Facility Escalante UIC Cluster Al -9 -UIC 1 Piped Greenleaf UIC Cluster Al -10 -UIC 4 Rain Garden/Infiltration Facility Grove UIC Cluster Al -11 -UIC 3 Rain Garden/Infiltration Facility Exeter UIC Cluster Al -12 -UIC 1 Rain Garden/Infiltration Facility Brentwood UIC Cluster Al -13 -UIC 2 Piped Korbel UIC Cluster Al -14 -UIC 1 Rain Garden/Infiltration Facility Howard UIC Al -15 -UIC 26 1 On -Street Rain Gardens South of Horn Lane UIC Cluster S' rin Creek Major Subbasin SC -I -UIC SC -2 -UIC SC -3 -UIC 2 3 Piped Zinnia 1, 2, and 3 UIC Cluster SC -4 -UIC 1 Piped Countryside Cluster SC -5 -UIC 1 3 Piped Lodenquai UIC Cluster SC -6 -UIC 2 Rain Garden/Infiltration Facility Byron UIC Cluster SC -7 -UIC 1 I Rain Garden/Infiltration Facility Stark UIC Cluster SC -8 -UIC 2 1 Rain Garden/Infiltration Facility Castrey UIC Cluster SC -9 -UIC 2 1 Rain Garden/Infiltration Facility Calumet UIC Cluster 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 3-14 SECTION 3 Flood Control Euaination Total Drywells: 79 72 * In the regulatory context, drywells are referred to as Underground Injection Controls (UICs). The terms drywell and UIC are used interchangeably in this document. 3.5.3 Selected Development Standard Alternatives As part of the Storm Drainage Master Plans that were completed in 2002, detailed analyses were conducted with regards to the potential implementation of development standards to address identified flooding issues (i.e., capacity deficiencies). For each of the basins, the estimated costs to address flooding problems through public capital projects was compared with the estimated costs to address flooding problems through a combination of both capital projects and the implementation of on -site controls required for private development. As a result of these analyses, development standards to address capacity deficiencies (through on -site controls for private development) were not selected for implementation (see Section 3.3 of the Eugene Stormwater Basin Master Plan, Volumes II -VII for more information). The reason for this decision was that most of the identified flooding problems were anticipated to occur as a result of existing developed conditions. While future development would exacerbate some of the problems, a capital project would already be required to address existing condition flooding, and increasing the size of the capital project to address flows from future development was more cost effective than requiring developers to address the issue through on -site storage requirements. For this basin, the conclusions from this previous analysis were assumed to apply. Note: It should be noted that in the City and County, stormwater system improvements are currently designed to meet conveyance design criteria based upon the size of the drainage area and the type of system (closed or open) being improved. Conveyance design criteria will still apply to new development and re- development, to provide the appropriate level of protection from the risk of flooding and a consistent level of service city -wide. See Eugene Stormwater Basin Master Plan, Volume I Sections 3.1.4 and 4.3.2 for more information. 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 3-15 # of # of City County CP/ Cluster Number Drywells Drywells CP Project Option Selected CP/ Cluster Name 'Addressed Addressed b the CP by the CP Flat Creek Major Su basin FC -I -UIC FC -2 -UIC FC -3 -UIC 12 Rain Garden/Infiltration Facility Willowbrook 1, 2, and 3 UIC Cluster FC -4 -UIC 5 Rain Garden/Infiltration Facility Maesner UIC Cluster Total Drywells: 79 72 * In the regulatory context, drywells are referred to as Underground Injection Controls (UICs). The terms drywell and UIC are used interchangeably in this document. 3.5.3 Selected Development Standard Alternatives As part of the Storm Drainage Master Plans that were completed in 2002, detailed analyses were conducted with regards to the potential implementation of development standards to address identified flooding issues (i.e., capacity deficiencies). For each of the basins, the estimated costs to address flooding problems through public capital projects was compared with the estimated costs to address flooding problems through a combination of both capital projects and the implementation of on -site controls required for private development. As a result of these analyses, development standards to address capacity deficiencies (through on -site controls for private development) were not selected for implementation (see Section 3.3 of the Eugene Stormwater Basin Master Plan, Volumes II -VII for more information). The reason for this decision was that most of the identified flooding problems were anticipated to occur as a result of existing developed conditions. While future development would exacerbate some of the problems, a capital project would already be required to address existing condition flooding, and increasing the size of the capital project to address flows from future development was more cost effective than requiring developers to address the issue through on -site storage requirements. For this basin, the conclusions from this previous analysis were assumed to apply. Note: It should be noted that in the City and County, stormwater system improvements are currently designed to meet conveyance design criteria based upon the size of the drainage area and the type of system (closed or open) being improved. 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N H U a U U a U U i� 4 U U i� U i� a U n a U n a 0 c y d - � - � c - � - � cz c c c c c - � - � - � cyyd -_ � 't c - '� 1 U /� U U /� U U /� /� /� /� /� U U U H U H U M N N Ol Ol Ol 00 l� l� 1 10 Vl Vl 00 00 00 00 00 00 00 00 00 O O O O O O O O O O a ol � O 0 0 0 O 0 0 O 7-i O O M M M Cl 00 00 00 00 l� 110 110 In Uj a al 00 00 00 00 00 00 00 CD 00 O O O O O O O O O O O 0 0 0 O 00 0 0 0 0 0 0 0 0 0 00 0 0 0 0 O D 0 O D W V w W H .7 3� w w w w w w A o 0 0 0 0 0 A O 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 Si A oc O �I •� CD oc CD 00 CD 00 00 00 00 00 00 Do 00 00 00 00 Do 00 00 a� a m s m a m s m O ol M M M M M m M m m M m M m M M m m M M m M m M M M M M m Si O a+ O 00 CD 00 CD 00 CD 00 CD 00 CD oc� CD 00 oc CD oc� CD 00 oc CD �� 00 00 a 00 s 00 a 00 s 00 a 00 u � y .� oc oc oc oc oc oc� oc oc� oc a Do a s a s O O yE .7 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 a 3 W M M M M M M M M M M M M M M M M M M y am, y O O ol ol CD O O O W O bA +� Ol 00 00 00 M M M N N N W A � 00 M Ni Do vl bA N ,--i N Vl Vl N D U U £ H U a U a a bA � c yy d H c yy d H c yy d H c yy d H cyyd H � c H ct � c H = '� U � _ '� U ct � N U U 00 00 M M M --i Vl Vl Vl Vl 00 00 O O 00 00 O 00 O O N N M M M M M 00 00 00 00 00 00 00 00 00 M M 00 l� cz y�i C of ol ol ol of a O of O O O O O O, p u } , A f E !!! . o \\j\ \— o }{)\ ; _ 4\\ t \ \ , 2 .2 \ \\\\� � u } , A } \ {o . o o ;! ;— 4\\ \ \ , 2 .2 \ \ \ \ \ \ \\ \ �\\ Cm) u } , A } \ {o . \ \ / u } , A SECTION 4 water Quality Eualuatiou While a very general characterization of water quality in this basin is described in Section 2.6, this section includes discussion of water quality in more detail. Section 4.1 starts off by providing detailed information related to regulatory drivers associated with water quality in the basin. Section 4.2 provides a description and results of the processes that were used to evaluate water quality with respect to both surface and groundwater discharges. And, finally, Section 4.3 describes the capital project alternatives and development standards that were considered and selected to address the identified water quality issues. 4.1 Regulatory Drivers Related to Water Quality Two federal acts, the Clean Water Act (CWA) and the Safe Drinking Water Act (SDWA), regulate the discharge of urban stormwater runoff. The CWA regulates discharges of urban stormwater to surface waters, and the SDWA regulates the discharges of urban stormwater to the subsurface or groundwaters. This section describes each of these regulatory drivers with respect to stormwater management in the River Road Santa Clara basin. 4.1.1 Stormwater Discharges to Surface Waters In the early 1990s, the Federal Clean Water Act required municipalities with populations greater than 100,000 to apply for and obtain a National Pollutant Discharge Elimination System ( NPDES) permit for their stormwater discharges. In Oregon, this program was delegated to the Oregon Department of Environmental Quality (DEQ). Asa result, DEQ directed jurisdictions in six Oregon urban areas to apply for and obtain a Phase I municipal NPDES stormwater permit. The City of Eugene was one of the jurisdictions required to obtain a Phase I permit. In December 1999, EPA adopted rules to implement "Phase II" of the stormwater program. Phase II expanded the stormwater permitting program to include smaller communities located in U.S. census - defined urban areas. Lane County was included as one of the smaller jurisdictions required to obtain a Phase II MS4 NPDES permit. The City of Eugene obtained its first Phase I permit in November, 1994; and Lane County received its Phase 11 permit in January, 2007. In the River Road Santa Clara Stormwater Basin, Lane County's Phase II MS4 NPDES permit covers the areas inside the UGB not covered by the City of Eugene's Phase I NPDES permit. The municipal NPDES stormwater permits initially required municipalities to perform a review of their stormwater systems including mapping, outfall inventories, and for the Phase I communities, monitoring of stormwater quality. Based on the results of this review, jurisdictions were then required to develop a Stormwater Management Plan (SWMP). The SWMPs were required to include specific categories of Best Management Practices (BMPs) that should be implemented to reduce the discharge of pollutants to the "maximum extent practicable ". Categories of BMPs included those that addressed public education, public involvement, elimination of illicit discharges, construction site erosion controls, post - construction development standards, and operations and maintenance practices. In addition, the Phase I permits require municipalities to look for opportunities to retrofit their existing systems to address water quality. The development of this basin plan represents one of the City's BMPs that is identified and listed in their required SWMP. The basin plan also represents a BMP in Lane County's SWMP. 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 4-1 SECTION 4 water Quality Eualuatiou The other Clean Water Act program related to urban stormwater discharges is the total maximum daily load (TMDL) program. The Oregon Department of Environmental Quality (DEQ) has the responsibility for developing water quality standards that protect beneficial uses of rivers, streams, lakes, and estuaries. Once standards are established, the state monitors water quality and reviews available data and information to determine if these standards are being met and water is protected. Section 303(d) of the Federal Clean Water Act requires each state to develop a list of water bodies that do not meet the standards. The list serves as a guide for developing and implementing watershed pollution reduction plans to achieve water quality standards and protect beneficial uses. These watershed pollution reduction plans are referred to as TMDLs. With respect to the River Road Santa Clara basin, the tributaries in the basin eventually drain to the Willamette River, and the Willamette River has an established TMDL for bacteria, mercury, and temperature. The City and the County have both submitted and obtained DEQ approval on their TMDL implementation plans (see Section 2.6.2). This basin plan and the water quality management measures proposed in Section 4.3 were developed with these regulatory drivers in mind and will help the City and County move in the direction of reducing pollutant loads, improving water quality, and supporting compliance with these regulations. 4.1.2 Stormwater Discharges to the Subsurface (i.e., through drywells) As described in Section 2.5.4, a portion of stormwater runoff in the basin discharges to the subsurface through the use of drywells. Over the years, drywells have been a management strategy of choice for dealing with drainage in the River Road Santa Clara basin largely due to the flat topography, highly permeable soil conditions, and lack of a continuous storm drainage system. In the regulatory context, these drywells are referred to as Underground Injection Controls (UICs). Injection of water below ground, particularly to underground sources of drinking water, is strictly regulated under the Safe Drinking Water Act (SDWA). Injection systems fall into five classes (Class IN). Class V is reserved for small injection systems, including stormwater disposal systems such as drywells. As with the CWA, implementation of the SDWA has been delegated to the Oregon Department of Environmental Quality (DEQ). Infiltration has become increasingly more attractive as a management practice for addressing surface water quality concerns. Therefore, DEQ is concerned that stormwater disposal in underground systems will become more highly utilized. DEQ promulgated new state rules in 2001 to implement the SDWA. One of DEQ's intents in promulgating the new rules was to see that all stormwater management entities exercise the same care with respect to stormwater discharged to the ground that they do with stormwater discharged to surface waters under the NPDES permitting program. The 2001 rules require stormwater management entities to evaluate the quality of water disposed of in all facilities that have a "subsurface fluid distribution system ", including dry wells /sumps and infiltration trenches. The program also requires comprehensive stormwater management plans that address: 1) the need for and effectiveness of pre- treatment before injection; 2) spill prevention and control measures designed to minimize immediate harm to underlying aquifers; 3) systematic monitoring and record keeping; and, 4) system performance evaluation. DEQ representatives noted that there are long- standing regulations against groundwater contamination, and that the 2001 UIC program rules were designed to assist stormwater managers in complying with these regulations. 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1an\FINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 4 -2 SECTION 4 Water Quality Eualuatiou As part of the process to implement the new rules, DEQ required UIC systems (i.e., drywells) to be registered with DEQ by December 31, 1999 (with amnesty for public systems until December 31, 2000). Stormwater UICs are prohibited unless they can be shown to meet criteria for being regarded as "exempt ", "authorized by rule ", or "authorized by a permit ". These three categories of allowable stormwater UICs are described in more detail as follows: Exempt — Stormwater UICs that are exempt include single residential roof drains and footing drains receiving only rainwater. Authorized by Rule — Municipalities may apply to have stormwater UICs "rule authorized" if the following criteria are met: a) No other waste is mixed with the stormwater. b) Stormwater runoff is minimized. c) No other disposal option is appropriate. An appropriate method shall protect groundwater quality and may consider management of surface water quality and watershed health issues. d) No domestic drinking water supply wells are present within 500 feet. e) No public drinking water supply wells are present within 500 feet or the 2 year time -of- travel whichever is more protective. f) No soil or groundwater contamination is present. g) The wells are not deeper than 100 feet and they do not discharge into groundwater or below the highest seasonal groundwater level. h) A confinement barrier or a natural or engineered filtration medium is present between the base of the injection system and the highest seasonal groundwater level and prevents contaminants from reaching groundwater, or the owner or operator implements best management practices that prevent drainage into the injection system in the event of an accidental spill. (DEQ has suggested that they would like to see 10 feet of separation between the bottom of the drywell and the high groundwater). i) Design and operation prevents accidental or illicit disposal and temporary blocking is available. Authorized by Permit - Municipalities may apply to have their stormwater UICs covered by a water pollution control facilities (WPCF) permit. If UICs are not exempt or can not be rule authorized, the permit would provide a mechanism for the municipality to work with DEQ to develop a plan for these UICs, which could include retrofitting the UICs so that they meet "rule authorization" criteria or developing a plan for decommissioning UICs that can not be rule authorized. A WPCF permit would likely include significant requirements for monitoring. The County evaluated their public drywells and had them registered with DEQ by December, 2001. The City evaluated their public drywells and had them registered with DEQ by November 2001. None of the City or County public drywells met the criteria for being exempt. An initial study conducted by the City as part of the UIC registration process also showed that only 16 (of 78) wells were not likely to be rule authorizable. However, based on more recent DEQ 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 4-3 SECTION 4 water Quality Eualuatiou clarification /interpretation of rules with respect to criteria for separation distance to groundwater, it is unlikely that any of the drywells in the basin will meet criteria for rule authorization based on criteria g) and h) from above. An evaluation of the City and County drywells with respect to high groundwater and the presence of a filtration medium between the drywell bottom and the high groundwater was conducted for this basin plan and is provided in Appendix E. Seasonal high groundwater levels were found to be close to the surface in this basin (i.e., approximately 8 feet deep on average). Based on this evaluation, there are several drywells that are expected to be discharging directly to high groundwater, and there were not any drywells where a distance of 10 feet was expected between the bottom of the drywell and the high groundwater level. Therefore, it is likely that most or all of the County and City drywells will eventually require decommissioning. Both the County and City have applied for a WPCF permit with DEQ. A plan to decommission the drywells will be a part of the permit. The decommissioning plan will be based on the management alternatives evaluated and selected as part of this storm drainage master plan and as provided in Section 4.3. As decommissioning projects are being implemented, if further groundwater investigations reveal opportunities to rule authorize drywells, retaining and /or retrofitting selected drywells may be considered. As mentioned previously in Section 3, private drywells are under the authority of DEQ and any decommissioning associated with private drywells (if required) would be directed by DEQ. 4.2 Evaluation of Existing and Expected Future Water Quality Conditions This section describes water quality conditions in the basin in terms of both pollutant loads and stream stability issues. Pollutant Loads To supplement the general water quality information provided in Section 2.6, pollutant loads for total suspended solids (TSS) were calculated for this basin. Although TSS has not been shown to directly relate to all other pollutants, it was used as a general indicator of other pollutants for the purposes of making relative comparisons. The relative values of the TSS load were used to evaluate the impact of drywells on water quality, as drywells infiltrate runoff resulting in a net pollutant load reduction, and to highlight those land uses and drainage areas that appear to contribute the largest pollutant load to receiving waters. The values were also used to evaluate the relative contribution and increase in pollutant loads expected from future development. The methods used to estimate pollutant loads are described in Volume I, Section 3.2. The pollutant load estimates for the River Road Santa Clara basin are summarized in Figures 4 -1 through 4 -3 below. As mentioned in Section 2.6, these results are based on stormwater quality monitoring conducted in the City of Eugene. Although none of these data were collected from within the River Road Santa Clara Basin, they provide general information regarding stormwater quality in Eugene and were used in identifying a stormwater management strategy for this basin. The pollutant load estimates are based on the following assumptions: 1) new development would occur without the inclusion of water quality best management practices (consistent assumption used for the other basins, enabling comparison of pollutant estimates between basins): 2) during an average year, all flows from drywells (and, hence pollutant loads) would be infiltrated and would not discharge to surface waters; 3) all drywells were assumed to be located in residential areas; and 4) decommissioning of all drywells would result in those discharges 0:25695978 Eugene RR -SC Final Basin P1an\Master P1an\FINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 4 -4 SECTION 4 Water Quality Evaluation being transferred, untreated, to surface waters. In general, pollutant loads in the River Road Santa Clara basin (based on 2007 land use data) could potentially increase by up to 85% as a result of future development and drywell decommissioning, if treatment and /or other forms of infiltration are not provided for flows associated with drywell decommissioning. Figure 4 -1 Estimated Total Suspended Solids Loads Per Year in the River Road Santa Clara Basin (UGB) Estimated TSS Pounds Per Year in 1,000 River Road Santa Clara Basin Relative to the >Range ;,of the River Road Santa Clara Basin Pounds > TSS Pounds Per Year in Other Eugene Basins From Existing Development 1,403 (assuming drywells in place and functioning) 20 Potential Increase from Development 740 + of Vacant Land 85 Potential Increase from Drywell 434 :♦ Decommissioning Total Buildout 2,597 1,000 2, 3,000 4,000 5,000 Figure 4 -2 Estimated Increases in Total Suspended Solids Loads Associated with Future Buildout in the River Road Santa Clara Basin (within the UGB) Percentage 1 25 50 75 100 125 0:A25695978 Eugene RR -SC Final Basin PlanVMaster Plan \FINAL 2- 2010AMaster Plan 3 -11 -10 FINAL Word Version AW Sec 2 Corr.doc 4-5 River Road Santa Clara Basin Relative to the Range of Estimated Increase in TSS Loads Percent Increase in TSS Loading in Other Eugene Basins Potential Increase from Future 54 Development Potential Increase from Drywell 20 Decommissioning Total Potential Increase 85 Percentage 1 25 50 75 100 125 0:A25695978 Eugene RR -SC Final Basin PlanVMaster Plan \FINAL 2- 2010AMaster Plan 3 -11 -10 FINAL Word Version AW Sec 2 Corr.doc 4-5 SECTION 4 Water Quality Evaluation Figure 4 -3 Estimated Total Suspended Solids Loads Per Acre - Per Year in the River Road Santa Clara Basin (within the UGB) Estimated TSS Pounds Pounds River Road Santa Clara Basin Relative to the Range of TSS Pounds Per Acre Per Year in the per Acre Per Acre Per Year in Other Eugene Basins River Road Santa Clara per Year Basin Existing Development 231 Potential Increase from 126 Development of Vacant Land Potential Increse from 71 Drywell Decommissioning Total Buildout 428 100 200 300 400 500 600 700 Note: The pollutant load estimates are based on the following assumptions: 1) new development would occur without the inclusion of water quality best management practices: 2) during an average year, all flows from drywells (and, hence pollutant loads) would be infiltrated and would not discharge to surface waters; 3) all drywells were assumed to be located in residential areas; and 4) decommissioning of drywells would result in those discharges being transferred, untreated, to surface waters. Stream Stabili In addition to pollutant loads discharged to surface waters, an additional water quality issue is streambank erosion. As urbanization occurs, changes to the natural hydrology of an area are inevitable. Hydrologic changes associated with development include both an increase in the volume of runoff and an increase in the peak rate of runoff, as illustrated by the storm hydrograph comparison shown in Figure 4 -4. These changes occur in response to site clearing, grading, and the addition of impervious surfaces and maintained landscapes. In addition to hydrologic changes associated with urbanization, activities within and adjacent to waterways such as vegetation removal, construction of retaining walls, weirs, fences, bridges and other features, can affect stream stability and, ultimately, water quality. Collectively, these activities can produce the following impacts to stream corridors: • An increase in streambank and streambed erosion; • Increased deposition of newly eroded debris and sediment, which reduces flood conveyance capacity; • Damage to riparian habitat; • Reduced streamflows during the dry season as a result of reduced infiltration and hence groundwater recharge; • Increased water temperatures in the summer due to reduced and hence more shallow streamflows; and • Increased maintenance needs and liabilities. 0:A25695978 Eugene RR -SC Final Basin PlanVMaster Plan \FINAL2- 2010AMaster Plan 3 -11 -10 FINAL Word Version AW Sec 2 Corr.doc A —L SECTION 4 water Quality Eualuatiou Figure 4 -4 Comparison of Pre and Post - Development Hydrographs While some of the waterways in River Road Santa Clara remain relatively undisturbed, many of these conditions have been observed in the basin. Many of the open channel systems in this basin are also lacking vegetated buffers, which is likely impacting stream temperatures. Section 4.3 provides a description of the water quality strategy developed to address both the potential increases in pollutant loads and stream stability issues. 4.3 Development of the Water Quality Strategy As shown in the stormwater basin master planning process flow chart (Figure 1 -1), Step 1 included a compilation of basin characteristics. These basin characteristics are summarized in Section 2.0 of this document. Step 2 in the process included problem identification under both existing and future land use conditions. The results of this step for water quality are provided in Sections 4.1 and 4.2 above. The next steps included the development of potential stormwater management tools (i.e., capital projects or development standards) to address the identified problems. This section describes the capital projects (CPs) and development standards that were considered to address the identified water quality problems. 4.3.1 Capital Project Alternatives Identifying potential CPs to address water quality concerns is very different from identifying CPs to address flooding issues. With respect to flooding, specific capacity deficiencies are identified through modeling and CPs are proposed to address those deficiencies. With respect to water quality, pollutant discharges associated with urban runoff are ubiquitous. When the city -wide basin planning project was initiated, the focus of developing CP alternatives for water quality was on identifying the best opportunity areas for the siting of water quality CPs in developed areas that would not be affected by stormwater development standards except over the very long 0: 25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 4 -7 SECTION 4 water Quality Eualuatiou term through re- development, and developed areas with high pollutant source land uses such as commercial and industrial uses. This effort included identifying areas with the following characteristics: 1) largely developed areas with little remaining vacant land; 2) densely developed high pollutant source areas; 3) sufficient space available for a surface water quality facility; 4) the space that was available is publicly owned or vacant and potentially available for purchase; and 5) the location could potentially be used to construct a CP that addresses objectives in addition to water quality control (i.e., flood control, natural resources enhancement, recreation, education). Given the differences in the River Road Santa Clara basin when compared to the other basins (i.e., the mix of County /City jurisdiction and the significant presence of drywells), the identification of water quality CPs was conducted somewhat differently from the previous basins. The development of water quality CPs was predominantly focused on water quality projects that could be implemented to deal with increases in runoff and pollutant loads associated with the decommissioning of public drywells. Approximately 151 public drywells (79 County and 72 City) will need to be decommissioned to comply with DEQ's UIC rules. Decommissioning of the drywells is expected to be a significant undertaking. Therefore CPs were developed to address the water quality objectives in parallel with the decommissioning effort, especially since the potential decommissioning of public drywells could result in a significant increase in pollutant loads to the surface water system (see Figure 4 -2). These proposed CPs are described below under "Water Quality CPs Associated with UIC Decommissioning." Additional water quality CPs were also developed to specifically target high pollutant source areas and stream stability problems that were described in Subsection 4.2 above. These proposed CPs are described below under "Other Water Quality CPs." Water Quality CPs Associated with UIC Decommissioning As described in Section 3.0, drywells located in close proximity to each other were grouped into drywell "clusters ". This grouping of drywells was conducted because some of the decommissioning options could be applied and constructed in a manner to address a "cluster ", as opposed to individual drywells. A total of 39 drywell clusters were identified. The drywell clusters are illustrated on the Stormwater Management Strategy Development map in Appendix H, and listed in Table 3 -6, and the location of each of these clusters is also shown in Figures 3 -2 through 3 -8. As a result of the decommissioning of drywells, alternative systems will be necessary to handle the flows (up to the 5 -year, 24 hour design event) that are currently being handled through drywells. CP options were selected for each drywell cluster with the intent of maximizing water quality benefits while addressing increases in flows from a flood control and conveyance standpoint. As described in Section 3.0, three project options were developed to handle the flows from these drywell drainage areas: 1) construct pipes to handle flows and route them to the nearest storm piped system — provide structural pre- treatment as part of the pipe retrofit (Pipe and Pre -treat Option); 2) direct drainage to a neighborhood -scale surface infiltration /rain garden facility for storage and infiltration (Surface Infiltration/Rain Garden Option); or 3) construct on- street rain gardens to handle right -of -way drainage as local street improvements are made (On- Street Rain Garden Option for Local Streets). 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 4 -8 SECTION 4 water Quality Eualuatiou More detail regarding each of these three options and the methods that were used for developing the CP conceptual designs and costs is provided as follows: 1) Pipe and Pre -treat Option — All of the drywell clusters were reviewed in terms of selecting the best option for dealing with drainage resulting from decommissioning. Some of the drywells were located in very close proximity to an existing storm drainage pipe and directing the drainage to that pipe appeared to be the most cost - effective option. This option was selected for the following 16 drywell clusters (the list includes the CP IDs that were assigned). It should be noted that this is a planning level analysis and while preliminary invert elevations were confirmed, the project level engineering analysis and design will need to confirm the viability of piped options for decommissioning. Willamette Overflow Subbasin WO -I -UIC: Green UIC Cluster W04-UIC: Taz UIC Cluster WO -6 -UIC: Poplar UIC Cluster WO -7 -UIC: Kendra UIC Cluster WO -8 -UIC: Kent UIC Cluster A1- Channel Subbasin Al-1-UIC: Crocker 1 UIC Cluster Al -3 -UIC: Shirley 1 UIC Cluster Al -5 -UIC: Hamilton UIC Cluster Al -6 -UIC: Bushnell UIC Cluster Al -9 -UIC: Greenleaf UIC Cluster Al -13 -UIC: Korbel UIC Cluster Spring Creek Subbasin SC -I -UIC: Zinnia lUIC Cluster SC -2 -UIC: Zinnia 2 UIC Cluster SC -4 -UIC: Countryside UIC SC -5 -UIC: Lodenquai UIC Cluster Flat Creek Subbasin FC -2 -UIC: Willowbrook 2 UIC Cluster There were two methods used for developing conceptual pretreatment and pipe designs for this category of CPs. The first, and more simple method was used if the drywell or drywells were located in close proximity to an existing pipe system and within the delineated drainage subbasin for that piped system. Given that the XP -SWMM hydrologic model to estimate future flows was already run assuming no drywells (see Section 3.0), the hydrologic results from the model already included flows from the area that would be associated with drywell decommissioning. Therefore, the calculations that were performed to size the pretreatment and pipe system included 1) delineation of the sub - drainage area associated with the drywell; 2) estimation of flow from the sub - drainage area using the Rational Method; and 3) estimation of a pretreatment 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 4 -9 SECTION 4 water Quality Eualuatiou system size and pipe size (using Manning's equation) based on the calculated flow rate. In some cases, more detailed information was desired regarding the proposed pipe size and length. In these cases, a new pipe was actually included in the XP -SWMM model and iterative model runs were conducted to size the pipe as opposed to using the Rationale Method and Manning's equation. See the design assumptions section of each CP fact sheet in Appendix A for specific sizing methods for each individual CP. The second method was used if routing of the drywell drainage area to the closest piped system would require a re- delineation of the existing subbasin boundaries. In other words, including a new pipe in the system would result in redirecting some flows into a different subbasin. In these cases, the drywell drainage area was delineated and subtracted from the existing subbasin and moved to the new subbasin that would incorporate the drainage. The model was then run to ensure that capacity would be available to handle the new drainage. Then, either the Rational Method/Manning's Equation, or if more detail was desired, an XP -SWMM model simulation was conducted to size the pretreatment system and pipe. The CP fact sheets for each of these projects are provided in Appendix A. Construction and retrofit of the piped system provides an opportunity to provide for water quality treatment. Costs of the proposed pretreatment systems (i.e., underground structural devices to provide water quality treatment) are also included along with costs of the proposed pipe systems. 2) Surface Infiltration/Rain Garden Option — Given the flat topography and long distance to the closest piped system for some of the drywell clusters, alternative options were needed to address the decommissioning of drywell clusters in areas north of Horn Lane, where street improvements were not likely to occur in the near future. For these drywell clusters, the proposed option was to route the flows to an area where a neighborhood -scale vegetated infiltration /rain garden type facility could be constructed to handle flows. It should be noted that infiltration of municipal stormwater runoff that occurs through the surface of the ground as opposed to the subsurface is not considered to be a UIC and is therefore not regulated under the Safe Drinking Water Act. For the modeling conducted and described in Section 3.0, drainage areas were initially delineated for the drywells that were included in the system at the time. The system included the 79 County wells, 46 of the 72 City wells, and 634 private wells. The system (drywell database) was under development and thus 26 of the existing City drywells were not included in this drywell drainage area delineation. These drywell drainage areas that were delineated represented areas draining to multiple drywells (i.e., clusters). Individual drywell drainage areas were not delineated. Based on this information, an average drainage area per drywell was estimated to be 2.70 acres. As drainage areas were only calculated for some of the drywell clusters, use of the average drainage area per drywell allowed for conceptual sizing, design and cost estimating for neighborhood - scale infiltration /rain garden facilities or CPs for all clusters on a normalized basis. Detail regarding the steps conducted to size the rain garden facilities for each cluster is provided as follows: 0:\25695978 Eugene RR -SC Final Basin P1an\Nlaster P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 4-10 SECTION 4 Water Quality Eualuatiou Step 1) Determine the number of drywells in the cluster. Example: Number ofDrywells in Cluster: 10 Step 2) A drainage area for each drywell cluster needing a surface infiltration/ rain garden CP was estimated based on the number of drywells in the cluster and assuming a 2.70 acre drainage area per drywell. Example: Drainage Area Per Drywell: 2.7 acres Total Drainage Area for Example Drywell Cluster: 10 x 2.7 27 acres Step 3) Given the number of drywell clusters and the level of uncertainty associated with the defined drainage areas for each drywell cluster, site - specific rain garden designs (as described above for the on- street, rain garden option) were not developed. Instead, using one of the ROW rain garden configurations (from one of the initial on- street rain garden options), the total drainage area associated with one "rain garden unit" was determined to be 1.12 acres. Step 4) Given the total drainage area for the drywell cluster, and the drainage area accommodated by one rain garden unit, the number of rain garden units required for treatment of the drywell cluster was estimated. Example: # of Rain Garden Units Req'd: 27 acres =1.12 acres 24 Rain Garden Units Step 5) The on- street rain gardens were sized to treat only the ROW area within the drainage area. This represented approximately 19% of the entire unit drainage area or 0.21 acres of the 1.12 acres. It was assumed that drainage from the remaining portion of the drainage area would be treated on -site. The rain gardens within one "rain garden unit" were designed to be 12" deep with 3:1 horizontal to vertical side slopes. The 5 -year, 24 hour design storm runoff volume from the ROW that would have to be managed by a rain garden was calculated to be approximately 2,120 cubic feet. Assuming a single, rectangular rain garden, the required surface area to manage the required volume of runoff from the 0.21 acres of ROW per rain garden unit is approximately 2,854 square feet. As a result, the rain garden total surface area required to treat runoff from the drywell cluster was estimated. Example: Rain Garden Surface Area Per Rain Garden Unit: 2, 854 ft2 Total Surface Area Req'd: 24 Rain Garden Units x 2,854 ft2 68, 496ft2 (or 1.6 acres) Step 6) Finally, assuming each rain garden unit has 2,854 square feet of rain garden, and that construction of one square foot of rain garden (with native soils) is approximately $8.00 (for non - engineered soils), the average cost of rain garden 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 4-11 SECTION 4 Water Quality Eualuatiou construction per drywell cluster was estimated. It should be noted that the installation of these neighborhood -scale rain gardens could also require land acquisition. The CP cost estimates for neighborhood -scale rain gardens do not include the piping that could potentially be necessary (in addition to the street gutter system) to route flows to the rain garden. Example: 68, 496ft2 x $8/ft2 $547,968 Note: If the actual ROW in the drainage area represents a higher or lower percentage of the drainage basin, the rain garden sizes would be somewhat higher or lower. In addition, if engineered soils are used, a cost estimate of $29 /square foot should be used (see Appendix D for unit cost tables). These methods for sizing rain gardens that are described above are rough estimates made for conceptual planning purposes. This neighborhood scale surface infiltration facility /rain garden option was selected for the following 22 drywell clusters (the list includes the CP IDs that were assigned): Willamette Overflow Subbasin WO -2 -UIC Corliss/ Carolyn/ Onyx UIC Cluster WO -3 -UIC Autumn, Ross, Moore /Oak UIC Cluster WO -5 -UIC Silver Meadows UIC Cluster WO -9 -UIC Baywood UIC Cluster WO -10 -UIC Greenwood UIC Cluster WO -1I -UIC Warrington UIC Cluster Al- Channel Subbasin Al -2 -UIC Crocker 2 UIC Cluster A14-UIC Shirley 2 UIC Cluster Al -7 -UIC Anderson UIC Cluster Al -8 -UIC Escalante UIC Cluster Al -10 -UIC Grove UIC Cluster Al-11-UIC Exeter UIC Cluster Al -12 -UIC Brentwood UIC Cluster Al-14-UIC Howard UIC Cluster Spring Creek Major Subbasin SC -3 -UIC Zinnia 3 UIC Cluster SC -6 -UIC Byron UIC Cluster SC -7 -UIC Stark UIC Cluster SC -8 -UIC Castrey UIC Cluster SC -9 -UIC Calumet UIC Cluster Flat Creek Major Subbasin FC -I -UIC Willowbrook 1 UIC Cluster FC -3 -UIC Willowbrook 3 UIC Cluster FC -4 -UIC Maesner UIC Cluster 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 4-12 SECTION 4 water Quality Eualuatiou A CP fact sheet for each of these projects is included in Appendix A. It should be noted that at the time of writing of this report, Lane county funding for CPs has not been identified. 3) On- Street Rain Garden Option for Local Streets — The South of Horn Lane drywell cluster includes a relatively large area with many drywells (26 County wells and 1 City well). Almost the entire area within the River Road Santa Clara basin and south of Horn Lane is drained through the use of drywells and informal surface infiltration, except for the area adjacent to and including River Road which is drained through a piped system. In addition, this area reflects a mix of County and City jurisdiction (sometimes on a lot -to -lot basis). As redevelopment and street improvements occur in this area, it is likely that City annexations will also occur. For this area, constructing pretreatment systems and pipes to discharge to the nearest surface drainage was considered to be infeasible due to the flat topography and lack of available capacity in the downstream system. The decommissioning option that was selected for this drywell cluster was to construct street side rain gardens for the storage and infiltration of runoff as local street improvements occur. For this option, individual properties adjacent to the right of way (ROW) would be required to manage their drainage on -site, in accordance with requirements for stormwater in the City of Eugene Code (Chapter 9, Section 9.6791(3)), and the street side rain gardens would be constructed to handle all runoff from the ROW (for a five -year design storm). Six different concept options were evaluated in terms of providing street side rain gardens for handling drainage from local streets. Each option assumes a base 45 -foot ROW width and various initial raingarden configurations. The six initial options were evaluated to determine the amount of additional ROW that would be required to accommodate runoff from the ROW during the 5 -year design storm. The six initial options are described according to the following: 1. Shed Cross - Section, Reduced Parking Bays One Side, Sidewalk Opposite Side 2. Shed Cross - Section, Parking Bays One Side, Sidewalk Opposite Side 3. Crown Cross - Section, Reduced Parking Bays One Side, Sidewalk Opposite Side 4. Shed Cross - Section, On- Street Parking, Sidewalk One Side 5. Crown Cross - Section, On- Street Parking, Sidewalk Both Sides 6. Crown Cross - Section, On- Street Parking, Sidewalk One Side Figures illustrating these six initial options are provided in Appendix F. Each option was evaluated as one ROW unit, which includes four 50 -foot wide residential lots on each side of the street and a base ROW width of 45 feet. For each option, the pervious and impervious areas associated with the ROW were computed, and the Santa Barbara Urban Hydrograph method was used to estimate the volume of runoff that would need to be accommodated by the rain gardens for a 5 -year, 24 -hour design storm of 3.6" using an SCS Type IA rainfall distribution. Rain garden sizing was based on guidance from Eugene's manual (Eugene's Stormwater Management Manual, 2006) for a rain garden facility. The rain gardens were assumed to be 12" deep with a 3:1 horizontal to vertical sideslope. By comparing the volume of runoff generated during the 5 -year design storm with the volume of storage associated with the initial rain garden configurations, the initial rain garden configuration did not accommodate all of the volume of runoff as necessary. Therefore, the additional ROW width 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 4 -13 SECTION 4 water Quality Eualuatiou that would allow for expansion of the initial rain gardens to accommodate the total volume of runoff was determined. As the addition of ROW would also result in the addition of contributing area and runoff to the rain gardens, an iterative sizing process was conducted until the size of the rain gardens would also handle the increases in runoff associated with the expanding ROW. The results of this process and the associated increases in ROW width are summarized in Table 4 -1 below for each of the six options. As a result of this evaluation process and attempts to minimize the required ROW width, Concepts #2, #4, and #6 were selected for potential future implementation. Concepts #1, #3, and #5 were eliminated from further consideration for the following reasons: Concept #1 — This ROW option was eliminated, as providing sidewalk directly adjacent to the street is not optimal from a safety standpoint. Concept #3 — This ROW option was eliminated due to the significant amount of additional ROW width that would be required to accommodate a rain garden that would be large enough to manage the runoff from the ROW during the 5 -year event. Concept #5 — This ROW option was also eliminated due to the significant amount of additional ROW that would be required. Final renderings of the three selected local street concepts (both plan views and cross - section views) including the required ROW widths are provided in Figures 4 -5 through 4 -10. CP Al -15 -UIC includes the development of street -side rain gardens, and it was selected to address drywell decommissioning for the drywell cluster south of Horn Lane. This project will provide water quality benefits in terms of preventing a significant increase in pollutant loads and hydrologic impacts that would be associated with decommissioning of drywells and routing discharges to surface waters. It should be noted that, while these street -side rain garden concept options for local street improvements were developed to address UIC decommissioning needs, these options are envisioned to be employed for various circumstances beyond UIC - related projects. Implementing the street -side rain garden concepts will require first making some changes to the City's Local Street Plan under a separate process subsequent to completion of the River Road Santa Clara Basin Plan. A decision flowchart was developed as part of this basin planning process, to illustrate the approach to managing stormwater runoff from sites, and where the street -side rain garden approach could be employed. In the broad sense, the approach to managing stormwater runoff from a site, and the potential application of the street -side rain garden concept options, will depend on whether a project is public or private, whether it is for an arterial or collector street, and whether it is for infill or new development. A decision flow chart for the project planning phase, to show where the new local street concepts could be employed, is provided in Figure 4 -11. During the conceptual development of CP Al -15 -UIC, for decommissioning drywells south of Horn Lane, a timeline mandate for decommissioning was not known. It was assumed that UIC decommissioning could occur over a decades -long timeframe that could allow for decommissioning to occur in association with street improvements in annexed areas. The Department of Environmental Quality (DEQ) has more recently indicated that decommissioning 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 4 -14 SECTION 4 Water Quality Eualuatiou of all non - compliant UICs will be required in a shorter timeframe — one that will likely require UICs in this area to be decommissioned using individual or clustered Surface Infiltration / Rain - Gardens (Option #2). Due to budget and time concerns for completing this document, The City of Eugene and Lane County have elected not redo the analysis on this UIC cluster at this time. 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 4-15 0 a 0 W d i mr O_ CD W O Y L I� 4 �i O .n G 0 o b ro -o b � 3 p O O � 0-0 O C P. 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The pollutant loads evaluation showed that commercial and industrial land uses discharge relatively higher pollutant loads when compared to residential and open land uses. Therefore, a list of projects was developed to retrofit the piped systems in these high source areas to include structural water quality facilities such as sedimentation manholes and select proprietary stormwater treatment devices that incorporate filtration to reduce the pollutant load. As part of the basin planning process, a City -wide annual budget line item was included to construct these types of projects. RRSC -1 - Citywide Annual Budget Line Item — Stream Bank Stabilization: This proposed project alternative includes using bioengineering techniques to stabilize the creek bank at locations where problems have been observed or are expected to occur as a result of future development. RRSC -2 - Citywide Annual Budget Line Item — High Source Areas: Single or multiple facilities may be appropriate for these high source areas, and the facilities should be selected and designed to treat the particular pollutant of concern based on specific site conditions. The following ten potential locations for these retrofits were identified: Willamette Overflow major subbasin 1) Node 68485 18" diameter pipe that runs south along River Road 2) Nodes 58315, 58314, 58313 and 58312 27" diameter pipe that runs east along Division Avenue 3) Nodes 72406 and 66531 24" diameter pipe that runs east along Division Avenue 4) Node 58319 12" diameter pipe along Division Avenue 5) Node 67014 15" diameter pipe south of Beltline Road Spring Creek major subbasin 1) 48" pipe east of River Road, north of River Loop 2, south of Swain Lane Flat Creek major subbasin 1) Nodes 72206, 72210, 72215, 72218, 72223 24" diameter pipe south of Irvington Drive 2) Node 72321 18" diameter pipe along Zinfandel Lane 3) Node 72326 10" diameter pipe along Napa Valley Lane A -1 major subbasin 1) Nodes 59020, 59021 54" diameter pipe that runs west along Maxwell between Bushnell Ln. and N. Park Ave. 0:A25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 4-33 SECTION 4 water Quality Eualuatiou RRSC -3 - Citywide Annual Budget Line Item - Outfall Stabilization: This proposed project alternative would include identification and retrofit of storm drainage system outfalls, which are creating localized erosion and bank stability problems. 4.3.2 Development Standards to Address Water Quality Stormwater Development Standards Potential development standards were considered for addressing water quality problems as part of the 2002 City -wide basin master planning efforts. As a result, development standards for water quality were adopted City -wide in June 2006. The Stormwater Development Standards include regulations for locating, designing, constructing, and maintaining water quality facilities for new development and significant re- development. These standards apply within the city limits and to properties within the urban growth boundary (UGB) that develop and annex to the City. Eugene developed a Stormwater Management Manual (July 2006) to assist developers with the design, operations, and maintenance of approved stormwater facilities. Eugene's Stormwater Management Manual is a modified version of Portland's Stormwater Management Manual. The Portland Stormwater Management Manual was reviewed and edited for accuracy and consistency with the City of Eugene's regulatory structure and to reflect policies and the Stormwater Department Advisory Committee's recommendations for a water quality design storm (i.e. 1.4 inches for volume -based analyses, 0.22 in /hr for in -line flow -based systems and 0.13 in /hr for off -line flow -based systems), flow controls, and maintenance responsibilities for public and private facilities. The Eugene Stormwater Management Manual provides developers and design professionals with specific tools to meet the City's requirements for reducing the impacts of stormwater runoff quantity and pollution resulting from new development. The Manual is to provide guidance for developers subject to the stormwater development standards adopted by City ordinance. As an extension of stormwater development standards adoption, in September, 2008, the Eugene City Council reviewed and directed efforts to increase use of Low Impact Development practices for stormwater management through administrative adjustments, additional integration of LID practices with other initiatives, development of proposals for land use code amendments, and development of proposals for other program enhancements. Implementation of the stormwater development standards is underway, including a 2008 update to the Stormwater Management Manual, plan review and inspection of private water quality facilities, and the incorporation of water quality facilities into public capital improvement project design. Following up from 2008 City Council direction related to increasing the use of LID practices, specific administrative adjustments, incentives and other LID- related actions are being identified and prioritized for implementation. Water Quality Protected Waterways Waterway protections for addressing water quality problems were also considered as part of the 2002 City -wide basin master planning efforts. In June 2006, the City initiated a proposal for protecting waterways for water quality purposes. Under the initial (2006) proposal, nearly 90 miles of waterways were proposed for protection, including 75 -foot setback areas along each 0: 25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 4 -34 SECTION 4 water Quality Eualuatiou side of the waterways. The waterways originally identified for protection were determined to have a direct relationship to those that are on the State of Oregon's 303(d) list as water quality impaired. A public outreach process on the initial proposal was conducted including an open house where affected property owners, interested persons, and the general public attended and provided feedback. As a result of the issues raised, significant revisions were made to the proposal. The revised proposal would apply protections only to the original waterways of concern that have no existing protections under Goal 5 wildlife habitat regulations (Water Resources Conservation Overlay Zone, referred to in Section 2.5.1). The revised proposal recognized the significant incidental water quality protection already provided by the Goal 5/Water Resources Overlay Zone, and became a proposal to "fill the gaps" in protection on a system of waterways that are water quality impaired. In March 2009, the Eugene City Council adopted the Water Quality Overlay Zone requirements, the revised waterway protection proposal, and the adopted regulations became effective on June 10, 2009. Approximately 13.5 miles of waterways are protected by the Water Quality Overlay Zone, including: 40 -foot setbacks on each side of certain headwater streams (measured from the centerline of the waterway) and 25 -foot setbacks on each side of all other specifically identified waterways (measured from the top of high bank). More specifically, the regulations: Establish a Water Quality Overlay Zone and related water quality protection measures; Apply the new zone to specifically identified lots within the Eugene city limits that contain or are adjacent to waterways identified for protection on the Water Quality Protected Waterways map; and Identify certain properties outside the city limits (inside the urban growth boundary) that contain or are adjacent to Water Quality Protected Waterways, and that will be rezoned to apply the Water Quality Overlay Zone upon annexation to the City of Eugene if and when annexation occurs. Figure 4 -12 provides an overview of the City's waterway protections, and the specifically identified Water Quality Protected Waterways. Some of the waterways affected by the new Water Quality Overlay Zone are located in the River Road Santa Clara basin, including portions of the Upper Flat Creek and tributaries to the Al Channel. 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 4-35 SECTION 4 Water Quality Eualuatiou Figure 4 -12 Postscript Note to Section 4.0: It should be noted that this basin stormwater management strategy was intended to focus on water quality management tools in the form of development standards and CPs. To comply with their respective National Pollutant Discharge Elimination System (NPDES) permits for stormwater discharges, both the City and the County have also been implementing a significant number of other stormwater quality management practices that will supplement this strategy and help to reduce the discharge of pollutants in stormwater. In addition to the proposed CPs and the City of Eugene's stormwater development standards implemented in 2006, these include BMPs under the following general categories: • Illicit Discharge Detection and Elimination • Operations and Maintenance and Good Housekeeping (e.g., street sweeping, catch basin cleaning, vegetation management, spill prevention and response) • Public Education and Outreach • Public Participation and Involvement • Planning and Administration (e.g. basin planning, data management) • Construction Site Management Controls 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 4-36 SECTION 5 Stormwater Related Natural Resources For purposes of the basin planning process, the term "natural resources" pertains specifically to the City's open waterways drainage system and the characteristics of it that provide or assist in providing beneficial stormwater functions such as: storm conveyance, flood storage, water quality preservation or treatment, aquatic and riparian habitat, and water temperature controls. These natural resources include the primary waterway corridors of Eugene and adjoining riparian and wetland areas, and headwater streams and wetlands. These characteristics are described in Section 2.0 of this report. Section 5.1 describes the evaluation process used for the other six stormwater basins in Eugene, and partially completed for this River Road Santa Clara basin plan. Section 5.1 also describes the basin - specific problems and opportunities identified under existing and expected future conditions. A description of existing waterway protection measures, other related efforts underway, and gaps in stormwater related natural resources data is also included. Section 5.2 describes the alternatives selected for addressing these problems and opportunities. 5.1 Evaluation of Natural Resources Under Existing and Expected Future Conditions The following provides the objectives, methods, and results of the stormwater related natural resources evaluation for the River Road Santa Clara basin. ectives of the evaluation • Determine the extent of the open waterway drainage system that should be protected for beneficial stormwater functions. • Determine where existing protection policies apply and where gaps exist. • Determine where restoration efforts should be targeted to improve stormwater functions. • Determine where intervention efforts are needed to correct streambank stability problems. • Determine what other efforts are underway which may ultimately provide protection consistent with stormwater program objectives. Methods used to conduct the evaluation Several methods were used to conduct the natural resources evaluation for the River Road Santa Clara basin including the following: The following information was compiled and reviewed to assess the location, condition, and function of the River Road Santa Clara Basin waterway system. Most of the data were contained in the City's geographic information system (GIS): — Open waterway drainage system. — Draft inventory of the Eugene - Springfield Metropolitan Plan Natural Resources Study. — FEMA floodway and floodplain areas. — National wetland inventory. — Soil Survey of Lane County Area, Oregon (1987), Natural Resources Conservation Service. — Historic photos, hydric soils — to help reconstruct the historic drainage system (i.e., pre - settlement). — Areas with stormwater pipe system. 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 5-1 SECTION 5 Stormwater Related Natural Resources - 1999 aerial photography of the River Road Santa Clara Basin. • Site visits to collect and verify GIS information about select portions of the waterway system including location, size, condition, and function. For the site visits that were conducted, functions were evaluated using a modified version of the Oregon Freshwater Assessment Methodology (OFWAM). This method was modified to focus on the stormwater related benefits of natural resources. • Eugene Public Works Department engineering and maintenance staff were interviewed as to their knowledge of the system. • Property owners provided site specific information at public workshops and through other contacts. • Policy plans were reviewed to determine where and how waterways were protected in the River Road Santa Clara Basin. • Other City of Eugene and Metro area staff were consulted to identify other on -going efforts which may ultimately provide protection for waterways consistent with stormwater program objectives. Results of the evaluation The results are provided below in terms of both existing conditions and expected future conditions. Existing Waterway System Conditions: • Urbanization within the River Road Santa Clara basin has caused significant changes to the open waterway systems. • There are about 48 miles of remaining open waterways in the basin, the majority of which are now protected through either FEMA Floodway restrictions, the City's Water Resources Conservation Overlay Zone (adopted in November 2005), or the City's Water Quality Overlay Zone (adopted in March 2009). • While some of the remaining waterways are large conveyance channels characterized by a trapezoidal shape with moderate riparian functions, three of the basins waterways (Flat Creek, Spring Creek and the East Santa Clara Waterway) are somewhat more naturally configured with meanders and riparian vegetation. • Significant channels include the Highway 99 Roadside Channel, Al Channel, A2 Channel, North Beltline Floodway, Spring Creek, Flat Creek and the East Santa Clara Waterway. • Efforts to protect, rehabilitate and /or restore the East Santa Clara waterway and its floodplain functions have occurred in the northern portion of the basin. Expected Future Waterway System Conditions: • Future conditions for some "privately owned and maintained" waterways would be expected to deteriorate without specific waterway protection policies and measures in this basin. • Future conditions of "publicly owned and /or maintained" waterways are expected to remain the same or improve over existing conditions due to the City's commitment to environmentally friendly maintenance practices and increasing level of responsibility for managing the open waterway systems. 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 5 -2 SECTION 5 Stormwater Related Natural Resources The remainder of this section provides additional context for the stormwater related natural resources evaluation: Existing Protection Measures • The Water Resources Conservation Overlay Zone (EC 9.4900) applies to waterways within the basin with significant natural resources habitat. The Water Resources Overlay Zone, while primarily aimed at protecting natural resources habitat, provides significant incidental water quality protection for these waterways. • The Waterside Protection Overlay Zone (EC 9.4700) applies within the West Eugene Wetlands Plan boundary and provides protection for channels, setbacks and contiguous riparian areas. The West Eugene Wetlands boundary does not extend into the River Road Santa Clara basin. • The Natural Resource Zone (EC 9.2500) is intended to protect outstanding natural resource areas in adopted plans (EC 9.2500). It currently does not apply to any specific property in the River Road Santa Clara basinbut could be used in the future as a waterway protection tool. • The Planned Unit Development (EC 9.8300) provisions contain specific approval criteria for protecting significant natural resources. These criteria are to be balanced with other policy needs and standards and, therefore, offer some but no consistent protection standards for waterways. • Site Review (EC 9.8425) provisions contain approval criteria that could be used for waterways protection if specifically identified for protection. • The Water Quality Overlay Zone (EC 9.4770), adopted in March 2009 provides increased protection of waterways with water quality functions and a significant relationship to waterways listed as impaired under the federal Clean Water Act (see subsection 4.3.2 for more detail). Other Related On -going Efforts • Endangered Species /Salmon program developed strategies for responding to the January 2001 listing of spring Chinook salmon. Strategies include incentives and regulatory measures for protection and restoration of salmon habitat in Eugene. Strategy options for Council consideration were developed. Data Gaps • There is little data as to existing aquatic habitat and species condition in the River Road Santa Clara basin waterways. This data would not only help further inform the condition of the waterways, but would also allow for better evaluation of the effects of any future capital improvements to these waterways. 5.2 Development of the Natural Resources Strategy As shown in the stormwater basin master planning process flow chart in Figure 1 -1, Step 1 included a compilation of basin characteristics. These basin characteristics are summarized in Section 2.0 of this document. Step 2 in the process included problem identification under both existing and future land use conditions. The results of this step for natural resources are described in Section 5.1. The next step included the development of potential stormwater 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 5 -3 SECTION 5 Stormwater Related Natural Resources management tools (i.e., capital projects or development standards) to address the identified problems and opportunities. Development of these stormwater management tools was the result of an all -day basin assessment meeting, attended by a large multi - disciplinary group of people including staff with experience in water quality, engineering, maintenance, natural resources, planning, and groundwater resources, and a half -day multi - disciplinary meeting focused on underground injection controls. In both instances, preliminary ideas were developed based on the goals and objectives of the project. This section describes the capital projects and development standards that were considered to address the identified stormwater - related natural resource problems and opportunities. 5.2.1 Capital Project Alternatives The following capital projects were considered that would address stormwater related natural resources problems and opportunities: RRSC — 4 - Stream Corridor Acquisition — Stream corridors and specific sites with relatively high stormwater values which are also at risk of future development would be identified for acquisition. The following corridor (shown on Figure 3 -6) was identified for acquisition in the River Road Santa Clara Basin, in the 2000 Stream Corridor Acquisition Study: Willamette Overflow, also referred to as the East Santa Clara Waterway. *RRSC — 1 - Citywide Annual Budget Line Item — Streambank Stabilization — This would be an annual budget line item for identifying and implementing streambank stabilization projects to help streams adjust to increased runoff volumes while limiting negative impacts associated with downcutting, sedimentation, and erosion. Where appropriate, bioengineering techniques would be used. *RRSC — 3 - Citywide Annual Budget Line Item — Outfall Stabilization — This would be an annual budget line item for identifying and retrofitting storm drainage system outfalls which are creating localized erosion and bank stability problems. * These two CPs were also listed in the water quality section (subsection 4.3.1). It should be noted that Lane County is limited by Road Fund constraints and by the inability to spend money outside of the County road right -of -way. In addition, at the time of writing of this report, Lane County funding for CPs has not been identified. 5.2.2 Development Standards Alternatives The following development standards were considered for addressing identified stormwater related natural resources problems and opportunities in the River Road Santa Clara basin. • Water Quality Waterway Protections — Using this approach, criteria would be established for identifying waterways of significance to protect for their water quality functions. See Section 4.3.2 for more detail about the Water Quality Protected Waterways. 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 5-4 SECTION 5 Stormwater Related Natural Resources Require BMPs to reduce pollutants associated with stormwater runoff from new development and significant redevelopment — This standard would require new development and significant redevelopment to control the quality of stormwater runoff by selecting, designing, constructing, and maintaining a water quality facility. It also emphasizes techniques to address impacts to open channels associated with increased quantities of runoff This standard is covered in Section 4.3.2 of this plan. 0:25695978 Eugene RR -SC Final Basin P1an\Master P1an\FINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 5-5 SECTION 6 Integrated Stormwater Management Strategy The purpose of this section is to summarize the flood control, water quality, and stormwater related natural resource elements of the integrated stormwater management strategy for the River Road Santa Clara basin as they were presented in Sections 3.0, 4.0, and 5.0 respectively. The capital project elements of the stormwater management strategy are shown on Figures 3 -2 through 3 -8. These CPs and development standard strategies are summarized in subsection 6.1. Subsection 6.2 provides a summary of strategy benefits and subsection 6.3 provides a summary of strategy implementation and costs. 6.1 CP and Development Standard Strategies Flood Control Strate2y Two categories of flood control capital projects were identified for implementation. The first category of flood control CPs were identified to address predicted capacity deficiencies. These projects are listed as follows: Al -1: Open Channel Improvements: Regrade the existing open channel segment (RSA1090B) from node 72789 to 78790 (18'). Al -2: Flood Control (Culvert Replacement) at Irving Road and Gent Road: Upsize and replace the existing 36" CMP culvert (RSA1090A) with a 48" CMP culvert. Al -3: Flood Control (Storage) at Prairie Road and Beltline Road: Construct storage facilities at nodes 72782 and 72102 to provide a total of 85 acre -ft of storage. Al -4: Flood Control (Culvert Replacement) at Prairie Road and Beltline Road: Upsize and replace the existing 24" CMP culvert (RSA1100I) with a 36" CMP culvert. Al -5: Flood Control (Culvert Replacement) South of Irving Road: Upsize and replace the existing 3 -24" CMP culverts (RSA1090E) with a 2' x 8' box culvert. Al -6: Flood Control (Culvert Replacement) at Carol Avenue: Upsize and replace the existing 24" CMP culvert (RSA1060L) with a 2' x 4' box culvert. Al -7: Flood Control (Culvert Replacement) at Kelso Street: Upsize and replace the existing 18" and 24" CSP culverts (RSA1060G) with a 2' x 4.5' box culvert. Al -8: Flood Control (Storage) at Maxwell Road West of N. Park Avenue: Construct storage facilities at nodes 72725 and 59020 to provide a total of approximately 135 acre -ft of storage. Al -9: Al Channel Survey: Conduct survey of open channel segments to identify available storage above the top of banks. FC -1: Flood Control (Culvert Replacement) at Calla Street: Upsize and replace the existing 3 -12" CSP culverts (RSFCO50D) with a 1.5' x 5.0' box culvert. SC -1: Flood Control (Culvert Replacement) at Katy Lane: Upsize and replace the two existing 30" CSP culverts (RSSCO50B) with a 12' long pedestrian bridge. WO -1: Flood Control (Culvert Replacement) East of Azalea Dr.: Upsize and replace the existing 18" CMP culvert (RSWO070D) with a 66" CSP culvert. WO -2: Flood Control (Culvert Replacement) East of Edgewood Dr.: Upsize and replace the existing 36" CSP culvert (RSWO110A) with a 60" CSP culvert. WO -3: Flood Control (Culvert Replacement) East of Yvonne St.: Upsize and replace the existing 48" CSP culvert (RSWO080A) with a 66" CSP culvert. 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 6-1 SECTION 6 Integrated Stormwater Management Strategy WO -4: Open Channel Improvements: Regrade the existing open channel segments (RSWO090Aa, RSWO09013, RSWO090C, and RSWO090D) from node 74405 to 78833 (724'). WO -5: Flood Control (Storage) at River Ave.: Construct a storage facility at node 77703 to provide approximately 124 acre -ft of storage. The second category of flood control capital projects were identified to address new flows to the system that would result from the decommissioning of public drywells. As these projects have a significant water quality component, and to avoid duplication, these CPs are listed below under the water quality strategy. Water Quality Strategy Capital Projects: Two categories of water quality capital projects were identified for implementation. The first category of water quality CPs was identified to prevent water quality impacts that would be associated with the decommissioning of drywells. If not addressed, these impacts would include an increase in pollutant loads and impacts to the stream channels associated with the increased flows. The projects to address /prevent these impacts are listed as follows: WO- I -UIC: Green UIC Cluster Pipe and Pre -treat WO -2 -UIC: Corliss/ Carolyn/ Onyx UIC Cluster Rain Garden WO -3 -UIC: Autumn, Ross, Moore /Oak UIC Cluster Rain Garden WO -4 -UIC: Taz UIC Cluster Pipe and Pre -treat WO -5 -UIC: Silver Meadows UIC Cluster Rain Garden WO -6 -UIC: Poplar UIC Cluster Pipe and Pre -treat WO -7 -UIC: Kendra UIC Cluster Pipe and Pre -treat WO -8 -UIC: Kent UIC Cluster Pipe and Pre -treat WO -9 -UIC: Baywood UIC Cluster Rain Garden WO -10 -UIC: Greenwood UIC Cluster Rain Garden WO -1 I -UIC: Warrington UIC Cluster Rain Garden Al -1 -UIC: Crocker 1 UIC Cluster Pipe and Pre -treat Al -2 UIC: Crocker 2 UIC Cluster Rain Garden Al -3 -UIC: Shirley 1 UIC Cluster Pipe and Pre -treat Al -4 -UIC: Shirley 2 UIC Cluster Rain Garden Al -5 -UIC: Hamilton UIC Cluster Pipe and Pre -treat Al -6 -UIC: Bushnell UIC Cluster Pipe and Pre -treat Al -7 -UIC: Anderson UIC Cluster Rain Garden Al -8 -UIC: Escalante UIC Cluster Rain Garden Al -9 -UIC: Greenleaf UIC Cluster Pipe and Pre -treat Al -10 -UIC: Grove UIC Cluster Rain Garden Al -11 -UIC: Exeter UIC Cluster Rain Garden Al -12 -UIC: Brentwood UIC Cluster Rain Garden Al -13 -UIC: Korbel UIC Cluster Pipe and Pre -treat Al -14 -UIC: Howard UIC Cluster Rain Garden Al -15 -UIC: South of Horn Lane UIC Cluster Street -Side Rain Gardens 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 6 -2 SECTION 6 Integrated Stormwater Management Strategy SC -I -UIC: Zinnia 1 UIC Clusters Pipe and Pre -treat SC -2 -UIC: Zinnia 2 UIC Clusters Pipe and Pre -treat SC -3 -UIC: Zinnia 3 UIC Cluster Rain Garden SC -4 -UIC: Countryside UIC Pipe and Pre -treat SC -5 -UIC: Lodenquai UIC Cluster Pipe and Pre -treat SC -6 -UIC: Byron UIC Cluster Rain Garden SC -7 -UIC: Stark UIC Cluster Rain Garden SC -8 -UIC: Castrey UIC Cluster Rain Garden SC -9 -UIC: Calumet UIC Cluster Rain Garden FC -I -UIC: Willowbrook 1 UIC Cluster Rain Garden FC -3 -UIC: Willowbrook 3 UIC Cluster Rain Garden FC -2 -UIC: Willowbrook 2 UIC Cluster Pipe and Pre -treat FC -4 -UIC: Maesner UIC Cluster Rain Garden The second category of water quality capital projects includes line items in the City's annual budget towards the construction of projects to address stream bank stabilization, the reduction of existing pollutant loads, and outfall stabilization. The three capital projects under this category are as follows: RRSC -1 Stream Bank Stabilization — Use bioengineering techniques to stabilize the creek bank at locations where problems have been observed or are expected to occur as a result of future development. RRSC -2 Structural Facilities to Reduce Pollutant Loads in High Source Areas — The following ten locations were identified as potential sites for locating underground structural water quality facilities: 1) Node 68485 - 18" diameter pipe that runs south along River Road 2) Nodes 58315, 58314, 58313 and 58312 - 27" diameter pipe that runs east along Division Avenue 3) Nodes 72406 and 66531 - 24" diameter pipe that runs east along Division Avenue 4) Node 58319 - 12" diameter pipe along Division Avenue 5) Node 67014 - 15" diameter pipe south of Beltline Road 6) 48" pipe east of River Road, north of River Loop 2, south of Swain Lane 7) Nodes 72206, 72210, 72215, 72218, 72223 - 24" diameter pipe south of Irvington Drive 8) Node 72321 - 18" diameter pipe along Zinfandel Lane 9) Node 72326 - 10" diameter pipe along Napa Valley Lane. 10) Nodes 59020, 59021 - 54" diameter pipe that runs west along Maxwell between Bushnell Ln. and N. Park Ave. RRSC -3 Outfall Stabilization — Identify and retrofit storm drainage system outfalls which are creating localized erosion and bank stability problems. 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 6 -3 SECTION 6 Integrated Stormwater Management Strategy Development Standards: Potential development standards were considered for addressing water quality problems associated with future development as part of the 2002 City -wide basin master planning efforts. As a result, development standards for water quality were adopted City -wide in June 2006. These standards apply within the city limits and to properties within the urban growth boundary (UGB) that develop and annex to the City. These standards require developers to implement water quality best management practices to treat runoff from their sites. In addition, following up from 2008 City Council direction related to increasing the use of LID practices, specific administrative adjustments, incentives and other LID- related actions are being identified and prioritized for implementation. On- Street Rain Garden Concept Options for Local Streets: Street -side rain garden concept options for local street improvements were developed to address UIC decommissioning needs as described in Section 4.3.1. However, these options are envisioned to be employed for various circumstances beyond UIC - related projects. Implementing the street -side rain garden concepts will require modifications to the City's Local Street Plan under a separate process subsequent to completion of the River Road Santa Clara Basin Plan. Water Quality Protected Waterways Ordinance: New regulations went into effect on June 10, 2009 that provides protection of approximately 13.5 miles of waterways through the use of a Water Quality Overlay Zone. The new regulations fill gaps in protections on a set of waterways of significance to water quality, and acknowledge the significant incidental water quality protection already provided by the Goal 5 Water Resources Overlay Zone. Natural Resources Management Strategy The proposed strategy, similar to the strategy for the six other stormwater basins in Eugene, is focused on the protection and enhancement of open waterways for their stormwater functions and benefits. The strategy includes both a capital project and development standards component. Capital Projects: Three capital projects have been identified for implementation in River Road Santa Clara as follows: RRSC — 4 - Stream Corridor Acquisitions: Acquire the Willamette Overflow, also referred to as the East Santa Clara Waterway Corridor. Capital projects RRSC — 1 — Streambank Stabilization and RRSC — 3 — Outfall Stabilization will also provide natural resource benefits. These projects were listed as part of the water quality strategy and are not listed separately here to minimize duplication. Development Standards: Part of the strategy includes support for existing waterway protection standards (i.e., Water Resources Conservation Overlay Zone, Natural Resource Zone, Planned Unit Development provisions, Site Review provisions as applicable). Another part of the strategy involves coordinating with other related on -going efforts (NR Study, ESA) to ensure that, ultimately, the stormwater functions and benefits of stream corridors are protected. Lastly, waterway protection will occur under the implementation of the June, 2009 ordinance that will include a Water Quality Overlay Zone (this is included above under the water quality strategy). 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 6 -4 SECTION 6 Integrated Stormwater Management Strategy Multiple Obiective Stormwater Capital Improvement Program It should be noted that, in general, all stormwater capital projects, will consider flood control, water quality and natural resources protection and enhancement as project objectives when feasible and appropriate. All stormwater capital projects will conform to adopted code requirements for private development, including stormwater quality standards. 6.2 Summary of Strategy Benefits The River Road Santa Clara integrated strategy, when finalized and implemented, is expected to provide the following benefits: 1. Provide the required level of flood protection basin -wide through capital projects. 2. Reduce existing pollutant loads through capital projects. 3. Reduce the potential for increased pollutant loads and erosive impacts to stream channels that would be associated with increased flows from drywell decommissioning. 4. Reduce pollutant loads associated with new developments through development standards. 5. Identify, protect and manage significant open waterways for their beneficial stormwater functions. 6. Address compliance issues associated with the Clean Water Act and Safe Drinking Water Act. 6.3 Summary of Strategy Implementation and Costs For a description of implementation of water quality and stormwater related natural resources standards, refer to Volume I — Citywide Basin Master Plan Report. This section provides a summary of the estimated costs for each of the capital projects in the River Road Santa Clara Basin. It also describes the approach for capital project implementation. The list of capital projects in Table 6 -1 is a summary of the full list of projects identified from the basin planning process, and includes planning level cost estimates. Appendix A contains a more detailed fact sheet for each capital project, which includes a description of the project and assumptions made for purposes of estimating costs. Unit cost tables utilized for these estimates are provided in Appendix D. The actual cost split for each project between the City and Lane County will be determined on a project -by- project basis, and was not estimated as a part of this planning process. At the time of completion of this report, there is no identified funding mechanism in the County to pay for the County's portion of the capital improvement projects identified in this basin plan. The City will fund its portion of the projects identified in this basin plan primarily through a combination of stormwater user fees and systems development charges. 0: 25695978 Eugene RR -SC Final Basin P1an\Master P1anTINAL 2- 2010\Master_Plan 3- 11- 10_FINAL_ Word _Version.doc 6 -5 SECTION 6 Integrated Stormwater Management Strategy With respect to implementation of City of Eugene capital projects, the City will use its recently updated 2009 stormwater capital project prioritization criteria for initial prioritization of stormwater projects. Projects listed in the River Road Santa Clara Basin Plan will be added to the full list of City public projects, and then will be scored and ranked using the prioritization criteria. An overall prioritized project list will be established, from which an initial sub -set of projects will be selected for future six -year capital improvement program (CIP) development and review process. The CIP forecasts the City's capital needs over a six -year period based on various City- adopted long -range plans, goals and policies. Development of the City's CIP is typically a nine -month process, beginning in August of even - numbered years and ending the following spring with adoption by City Council. Following adoption of the CIP, the projects become the basis for preparation of the upcoming fiscal year's capital budget. The capital budget is submitted to the Budget Committee in the spring of each year following the CIP process, and adopted by the City Council in June. Projects in the second fiscal year of the CIP become the basis of the subsequent fiscal year's capital budget. The final list of projects identified in the CIP for implementation may be different than the initial list as a result of input from the CIP public involvement and budget adoption process. Table 6 -1 Summary of Capital Project Costs and Funding Capital Project Identification Total Estimated Capital Project Implementation Implementation A -1 Channel Al -1— Al Open Channel Improvements $7,500 Al -2 — Culvert Replacement at Irving Road and Gent Road $131,400 Al -3 — Storage at Prairie Road and Beltline Road $12,160,200 Al -4 — Culvert Replacement at Prairie Road and Beltline Road $18,400 Al -5 — Culvert Replacement South of Irving Road $26,400 Al -6 — Culvert Replacement at Carol Avenue $21,600 Al -7 — Culvert Replacement at Kelso Street $16,600 Al -8 — Storage at Maxwell Road $16,879,800 Al -9 — Al Channel Survey $50,000 Al -1 -UIC — Pipe and Pre -treat Crocker 1 UIC Cluster $530,000 Al -2 -UIC — Rain Garden Crocker 2 UIC Cluster $271,200 Al -3 -UIC — Pipe and Pre -treat Shirley 1 UIC Cluster $777,200 Al -4 -UIC — Rain Garden Shirley 2 UIC Cluster $1,070,600 1 Total estimated capital project implementation cost includes construction, site acquisition (if applicable), and engineering and administrative costs. 2 Reflects a baseline cost estimate for planning purposes only and is not included in the unit cost tables (Appendix D) nor CP fact sheets (Appendix A). 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1an\FINAL 2- 2010\Master_Plan 3-11-10 FINAL Word Version AW Sec 2 Corr.doc 6-1 SECTION 6 Integrated Stormwater Management Strategy Capital Project Identification Total Estimated Capital Project Implementation Cost Al -5 -UIC — Pipe and Pre -treat Hamilton UIC Cluster $540,600 Al -6 -UIC — Pipe and Pre -treat Bushnell UIC Cluster $197,400 Al -7 -UIC Rain Garden Anderson UIC Cluster $2,936,000 Al -8 -UIC Rain Garden Escalante UIC Cluster $537,700 Al -9 -UIC — Pipe and Pre -treat Greenleaf UIC Cluster $111,600 Al -10 -UIC — Rain Garden Grove UIC Cluster $537,700 Al -11 -UIC — Rain Garden Exeter UIC Cluster $404,400 Al -12 -UIC — Rain Garden Brentwood UIC Cluster $138,000 Al -13 -UIC — Pipe and Pre -treat Korbel UIC Cluster $140,400 Al -14 -UIC — Rain Garden Howard UIC Cluster $138,000 Al -15 -UIC — South of Horn Lane Street -side Rain Gardens $3,600,900 Subtotal: $41,243,600 Flat Creek FC -1 - Flat Creek Flood Control at Calla Street $13,400 FC -I -UIC — UIC Decommissioning Willowbrook 1 UIC Cluster $404,400 FC -2 -UIC — UIC Decommissioning Willowbrook 2 UIC Cluster $135,300 FC -3 -UIC — UIC Decommissioning Willowbrook 3 UIC Cluster $937,400 FC -4 -UIC — UIC Decommissioning Maesner UIC Cluster $670,900 Subtotal: $2,161,400 River Road Santa Clara RRSC -1 — River Road Santa Clara Streambank Stabilization - RRSC -2 — Water Quality Facilities for High Source Areas - RRSC -3 — River Road Santa Clara Outfall Stabilization - RRSC -4 — River Road Santa Clara Stream Corridor Acquisition - Subtotal: - Spring Creek SC -1— Spring Creek Flood Control at Katy Lane $18,000 SC- I -UIC — UIC Decommissioning Zinnia 1 UIC Cluster $249,000 SC -2 -UIC — UIC Decommissioning Zinnia 2 UIC Cluster $263,400 SC -3 -UIC — UIC Decommissioning Zinnia 3 UIC Cluster $271,200 SC -4 -UIC — UIC Decommissioning Countryside UIC Cluster $436,000 SC -5 -UIC — UIC Decommissioning Lodenquai UIC Cluster $423,100 SC -6 -UIC — UIC Decommissioning Byron UIC Cluster $271,200 SC -7 -UIC — UIC Decommissioning Stark UIC Cluster $138,000 SC -8 -UIC — UIC Decommissioning Castrey UIC Cluster $271,200 SC -9 -UIC — UIC Decommissioning Calumet UIC Cluster $271,200 Subtotal: $2,612,300 Willamette Overflow WO -1 — Willamette Overflow Flood Control East of Azalea Dr. $145,600 0:A25695978 Eugene RR -SC Final Basin P1an\Master P1an\FINAL 2- 2010\Master_Plan 3-11-10 FINAL Word Version AW Sec 2 Corr.doc 6-7 SECTION 6 Integrated Stormwater Management Strategy Footnote to Summary of Strategy Implementation and Costs: Public outreach conducted in October 2009 included comments regarding the size and scope of the flood control capital projects based upon the basin planning modeling and recommended by the RR -SC Plan. The current model is the best fit based upon the best available information and professional engineering judgment, and is likely somewhat conservative for reasons notes in Section 3 as well as the degree of "informal" infiltration in the RR -SC basin. Resource and data limitations inherently limit the level of detail and resolution of the model, and further model refinement would not be appropriate in the absence of better data and additional resources to refine the model. The City and County believe that further refinement to the model based upon measured flow data would be beneficial to confirm capacity issues on the major system related to the larger capacity enhancement and storage CPs. Installation of a flow meter is planned in the RR -SC basin, and would realistically precede detailed design and implementation of these larger CPs. 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1an\FINAL 2- 2010\Master_Plan 3-11-10 FINAL Word Version AW Sec 2 Corr.doc < —O Capital Project Identification Total Estimated Capital Project Implementation Cost WO -2 — Willamette Overflow Flood Control East of Edgewood Dr. $22,500 WO -3 — Willamette Overflow Flood Control East of Yvonne St. $27,800 WO -4 — Willamette Overflow Open Channel Improvements $521,200 WO -5 — Willamette Overflow Flood Control (Storage) at River Avenue $15,630,200 WO- I -UIC — UIC Decommissioning Green UIC Cluster $111,000 WO -2 -UIC — Cluster UIC Decommissioning Corliss /Carolyn/Onyx UIC $537,700 WO -3 -UIC — Cluster UIC Decommissioning Autumn/Ross/Moore -Oak UIC $1,337,100 WO -4 -UIC — UIC Decommissioning Taz UIC Cluster $124,500 WO -5 -UIC — UIC Decommissioning Silver Meadows UIC Cluster $404,400 WO -6 -UIC — UIC Decommissioning Poplar UIC Cluster $390,600 WO -7 -UIC — UIC Decommissioning Kendra UIC Cluster $75,600 WO -8 -UIC — UIC Decommissioning Kent UIC Cluster $397,000 WO -9 -UIC — UIC Decommissioning Baywood UIC Cluster $138,000 WO -10 -UIC — UIC Decommissioning Greenwood UIC Cluster $138,000 WO -1I -UIC — UIC Decommissioning Warrington UIC Cluster $138,000 Subtotal: $20,139,200 TOTAL: $66,156 Footnote to Summary of Strategy Implementation and Costs: Public outreach conducted in October 2009 included comments regarding the size and scope of the flood control capital projects based upon the basin planning modeling and recommended by the RR -SC Plan. The current model is the best fit based upon the best available information and professional engineering judgment, and is likely somewhat conservative for reasons notes in Section 3 as well as the degree of "informal" infiltration in the RR -SC basin. Resource and data limitations inherently limit the level of detail and resolution of the model, and further model refinement would not be appropriate in the absence of better data and additional resources to refine the model. The City and County believe that further refinement to the model based upon measured flow data would be beneficial to confirm capacity issues on the major system related to the larger capacity enhancement and storage CPs. Installation of a flow meter is planned in the RR -SC basin, and would realistically precede detailed design and implementation of these larger CPs. 0:\25695978 Eugene RR -SC Final Basin P1an\Master P1an\FINAL 2- 2010\Master_Plan 3-11-10 FINAL Word Version AW Sec 2 Corr.doc < —O APPENDIX A CAPITAL PROJECT FACT SHEETS r .... _,, ,..fie. �.- _` -- , b i i u ,.. _.._..,� ,.,. � I L_ - r ' / i I. III I II III qq I I I I I I I I I I I I I V I r _ li I n1 .:. �._. �_ �.. i- .. � .. :�. _ �.`... -:� -.. ;..; .. . - -.. — —.. _ —_ _� i � ' i _ .__. .. - - - - - �� ,e ,, � � i � - �� � � — — — — -. -..- ... -. .: � _tee. - ...> _ _ -. _x ... .. - ,. .:.� .- . ,. V ,.. ,..., .. �.., :. ......, �.�. - ..p - ;'r i 1 _ m — _ _ — — i — _ -: — - _ _ - , -. S q:; it ,. - n } r . _, .. - _ _ - - _ c; _ �... I I _.. .:A:��:. _ ... -_ _ _ __ _ - _ -_ - .. -.. 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APPENDIX B HYDROLOGIC /HYDRAULIC MODEL OUTPUT TABLES H I-a Qi H 0) w O X O N r 9 � -- co H 07 X a Q Q R O � 00 00 00 00 00 N �O 00 00 �O 00 O� O� M O� ti O W 00 V� 00 00 ti W 00 00 00 �D ti W 00 M 00 M O 00 R � O L 9 R Qi G O L "o d c L G O L o � o� •�m�N� �o� `R �^.o `^. �o oo `R `^.o �o o�� 0�0�4 R V 7 G , L' E O O O O O O O O O O O O O O O O O O O O O O O O O O O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 O p Cy L S L 7 O O O O O O O O O O O O O O O O O O O O O O O O O O O O O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 O O O O O O O O O O O O O O O O O O O O O O O O O O O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 G � L O O O O O O O O O O O O O O O O O O O O O O O O O O O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 W c Pa c U R L O � 7 y O O O O O O O O O O O O O O O O O O O O O O O O O O O 0 0 0 0 0 0 0 0 0 0 0 0 0 I. O O O O O O O O O O O O O O O O O O O O O O O O O O O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 h a '2� �mmom�mN�� L ,� N 0 0 0 0 0 c�N� 0 0 0 0 0 0 0 0 �N 0 0 0 0 room 0 0 0 0 0 0 oo 0 0 0 0 N 0 0 0 0 0 0 0 Noce 0 0 0 0 0 0O 0 0 0 0 . . 0 0 . 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 h G W ci ci��o o�om�o�o��oo ci oo oo �n m� cio o� o�m000 oomm oo m�nomci a °' moo r.m� oo��n Nr.mm� ��n �o r.o oo oo Nan r.mm r. oo r.� o�ooN r. oo r. o�o��n o� F 7 � �� � ci vi vi oi��oo of of vio oo vi o,-:o of vim000 otN cim cn mcn oo �d ci �d E G W ~ a p 9 �o min oom� o� r. m oo or. oa r. �n��o N�o o�m�r. ooNm 000 oar. o�oo� Noo r. m�NN R� v�,�����oo R��o R °' o L R N 0000m�o�mmooNC�mNr. N N oO r.�mN OOO L �o N v, ono N o� m N Lov,00�v, R room oo �o v, H Z - ----------- .......... r r r r r r r r r r r r N r N N r r N r r - r r R R R O R O R O R y R O oU UCJUUUU °UUUUUUU d P4 V V P4 V V V P, P, V V] V V V V V V V V V V V V V V V V V L V P4 V V P4 P V V P, V V L V] ; V] V] V] V] V] V] a a a 0) w O X O N r 9 � -- co H 07 X a Q Q H I-a Qi H 0) w O X O N r 9 � -- co H 07 X a Q Q L 000r. ammma�v,�aoa000r. O1 R � O L 9 R Qi G O L s,�^�+'�+ mmmm mmm�ma mmmmmmmm "o d c L G O R Zs a R V 7 G s 0 0 0 0 O O O O O O O O O O O O O O O O O p Cy L S L 7 O O O O O O O O O O O O O O O O O O O O X 0 0 0 0 O O O O O O O O O O O O O O O O G � W c Pa c U R L O � N N N N N N N N N N N N N N N N N N N N 7 y 0 0 0 0 O O O O O O O O O O O O O O O O I. O O O O O O O O O O O O O O O O O O O O G 's r.a�v, oo r.a�ao�o�m�0000mm ��"mc�c�� �aa�v�imm �nmmmaa h a a m act aaoao m L. � 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 s 0 h G W T i T ' HT m� a V 6 9 � °' R w R ... M M T ;" V V b F 7 O Q m b ~ a p 9 y °' mmm m�m o�r.om o �oo o�m��n �o� o � h 3 �aoo o l� om�v, v, r.mmm ° 'Z oO o N Loo R oo oo oo o�o�0000�mm� H N N N � HIT N N - -- - W v, - � R G a 0) w O X O N r 9 � -- co H 07 X a Q Q z 0 H A z O U U �I A z a �W A� F+H O� a a W o A O I � I U I� O a A x m O X O N to N -0 c co m X c N Q Q Q s, O O � i." 0 U � � O a N w N s � N $� CC � CC O S. I "O O O U � O a N � N U O N . CC CC � O � i." 4 r x x C1 N C1 M IO C � I C x C1 x CC S.i CC .ti i FBI i i i i i i i i i i i i i i i i i i i i i i i i i i i m O X O N to N -0 c co m X c N Q Q Q z 0 H A z O U U �I A z a �W A � H O� a a W o A O I � I U O a A x rn O X O N to N -0 c co m X c Q Q Q s, O O � i." 0 U � •� O a N S. M N O O v'� M w N s � CC � N � CC � CC O So •'O O O U So 't M M O M CO C� O N M — — — a N Cl O c , c , O Ic 't N x N O�'t r— 't O N N N W � � N U � $y O � CO — l- W) 01 l- O N � N --� --� --� N M �--i �--� �--� �--i �--� �--� �--� M �--� N N N �--� 01 � N IX O O � N M �--� �--� �--� U � � ^ •� `� y U M l� N 01 CO N N W) 01 CO -t ~ - M x -t C1 .`�. x V) x r- O S.i r•• �--i N't O O N v'� M O 4 O fd V'� CO M M V� V� V� CO Ic C1 N N CO CC CC CC U O U M O 00 O O l— -t -t N O O l� v'� 01 O 01 O O M O � CO v� "o v� O O O� O l� O O � N CO N CO N CO N CO O 01 01 CO O H z �, IO N N C� IO IO N N N N C� C� C� C� M M N CO 01 =% � �wwwwwww �vnvnvnvnv)v)v)v)v)v)v) rn O X O N to N -0 c co m X c Q Q Q z 0 �I H �I A z 0 U H w� ["I U �I A z NN A !� o N a W W o A O I � I U I� O W A x L N E E II II o�U) Z N rn O X O N to N -0 c co m X c a� Q Q Q s, O O i." 0 U � � O a N S. w U N a N O S. "O O O U � � O C � a N bA • O CO � � v'� � � � O � W � � W N N N v') N . CC CC �I O CO O r- Ic CO N � O l- IO v) 4 v') C� O O d o o 0 0 0 0 0 0 0 0 0 CO O� �z 333333333 xxxxxxxxx L N E E II II o�U) Z N rn O X O N to N -0 c co m X c a� Q Q Q � M P � F 0) w O X O Q N W 9 0] x a Q Q b O CO CO O (J �O �O CO O� CO CO O O ti (J M M M M M CO CO O CO CO CO O� O� O� L m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m aJ m m mmm m m m m m m m m mmm mmm m m m m m m m m m m m m m m � � �o N �o �o �o �o � - o v, ' v, v, �o �o � o �o o N N N N N ri � 0 06 06 06 06 06 00 mmm mmm m m m m m m m m m m m m m m v' �o000mm N� � m 0 0 moyo oNN m m m Nam N N m m m m m m G R L vi �d of of ci �d �d 00 0y 00 0y 0 ddd 0 N N m N m N m N - mmm - - d - 00 d d 00 00 d d 00 00 00 d d d • k L rW R � m � � � N �n m � m m � o ,-. m o � � ' m � � ' � � � � b b b b b b b b- - - F - - - N- - - m m m m m = N mmm m m m mmm mm m m m m m m m m m m m m m m m m m -- - r m r - m m - - m m - - - m m m W � m m mmm m m m m m m m m mmm mmm � L ✓y � �O O� (J �O �O CO O� O� CO CO O� O r. (J (J (J (J (J t� CO CO t� CO CO CO CO CO CO min m mmmmm m m m m m m m mmmmmm m m m m m m m m m m m m m m L N R 3 m m m N N N m . . N N N N N N i x + d mH dddx - d m m m --- m d m m m m m m m m m m m m m m N m m m N O 00 00 00 � 0 r. ci ci ci ci ci 00 r 00 00 00 00 00 00 mmmmmmm m mmm m m mmm m d d d d d d d d d d d d d d d d ci �i N N N 0 06 06 N N vi r: 0 " m 0 �i N m ri M d d d M d M d M d M 7 W v m m m m d m m m d m m m m d m m mmm d d d m d d d m d m d m d m R 0 R i+ 9 N � R Y I-a N Qi G y r/� • � mN�� o�m� o m� N L R 0 e .y o NNNN r. r. r. NNNNN N N N NN r. r. r. r. A � c s A m o D o m N o 0 0 0 9 O c�c� c�---- O -- - - - od0. d It 0.w'UQ `� �dddd dd d dd d d ddddd d d d dd d d d d 0) w O X O Q N W 9 0] x a Q Q � M P � F 0) w O X O Q N W 9 CO '' 07 x a Q Q L � oy q m oy oy m m oy oy m m oy oy m m oy 0 m m m 0 0 m m m m 0 0 m m m m 0 0 m m m m 0 0 m m m m 0 06 m m m 06 m 0y oy m mmm rd of mmm of of m m m of m m of of m m m m � m m m m m m m m m m m m m m m m m m m m m m m mmm m m m m m m ,-. ,-. m TF ri m ri m T ri m m m m o � m m m m m - m m m - m m - - m m - - m m - - m m m m m m m m mmm m mmm m m m m m m m m m m m m 9 G R L a y . . . . . . . . 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L R 9 � O � R Y I-a N Qi G r/� y W v+ N L R O Q � c s � a a � ' J ' J ' J ' J ' J ' J ' J ' J ' 2 � o � 3 . o � 3 . o � 3 . o � 3 . o � 3 . o � 3 . o � 3 . o � 3 . o � 3 . o J� o J� J� o A o 0 0 0 9 O - - - - - - - - - 0) w O X O Q N W 9 CO '' 07 x a Q Q � M P � F 0) w O X O Q N W 9 CO '' 07 x a C N Q m m m m mmm m m m m m m m m m m mmm m m m m m m m m m m m O � � m m m m mmm m m m m m m m m m m mmm m m m m m m m m m m m o r. r. �n o� 0 0 o ' N N �o �o �o m m m m m m mmm m � � � � �n � ' m I F m m cn m cn m m m m m 06 m 06 m 06 m 06 0 m O� �O F �O m m m m m m m m m m m m m m m m m m � m m m m mmm m m m m m m m m m m mmm m m m m m m m m m m m 9 G R L m mm m mmm m mm m m m m mm m mmm m m m mm � �� � d .9 k L rW R m r. m N m o� m m � x i m r. N r. r. r. N m r. � o m m N m I F m m m m m m o� �O o� �O 1 7 m m m m m m m m m m m m m m m m m G m W � m m m m mmm m m m m m m m m m m mmm m m m m m m m m m m � L m �n m m m m mmm m m m m m m m m m m mmm m m m m m m m m m m m L N R v' m m 1 m m dd m m H m m m m m m m m m m m m m H m m o m v' m mm m m m c�i c�i c�i m m m �o �o o0 00 00 o0 00 0� o0 0� .7 m m m m mm m mmm m m m m m m m m m m mmm m m m m m m m m m m m � ,d o6 of o6 of o of of N cn of of of of o of ,-. N N N cn �i v; ,-. 06 of cn R � A m m m m m mmm m m m m m m m m m m mmm m m m m m m m m m m m N do� d omo m m omo m d omo m m o mmm o o omo m m m m m m m m R 0 L R 9 � O � L y R I-a N Qi G r/� y W :+ N N L R - - c e A � c s � � � � � � CJ � � CJ � CJ CJ � � CJ � � � CJ CJ CJ j� � � CJ i� � � CJ i� CJ � � � � � � � m � 9 O d 1 m, x r. x 0) w O X O Q N W 9 CO '' 07 x a C N Q � M a P � F 0) w O X O Q N W 9 m x a Q Q m m m m m m ddd m m m m m m m m m m m m m m m m m m m m m m m m m mmm m m m m m m m m m m m m m m m m m m m "P � o �n �n m r. r. m m m M m m � � N r V� r m m m m m m m m m m m m m m m m m m m m m � m m m m m m mmm m m m m m m m m m m m m m m m m m m m 9 G R L y3 m m m dd d mmm d dd d dd d d dd m m m dd d d dd k R L e O �° �° O �° °� N °� N � °� � ° � h N m N M m m T i � m v� W m = N m m M m m m m m m m m m m m m m m m G m m m m m m mmm m m m m m m m m m m m m m m m m m m m W � � L L ✓� 7 F r (J (J ti M M M m �n L N m m m m m m mmm m m m m m m m m m m m m m m m m m m m R v, N N °� � � � � � � � � � � � � � I m M m M mm M M d d � d M �� M M �; M �;� M M � M � M �� M M � M � M � M �� M M � M � M m � M M Y ~ � d N d N d r. M dd M d � M ddd � � d � V� dd CO d V� CO dd CO d CO d CO CO dd CO d CO d CO d CO CO dd CO d CO d CO CO dd R 1 m d d d d d ddd d d d d d d d d d d d d d d d d d M m v, °� m m � v, ,-. N o I H k M i d- 1 - i d d ddd d d d d d d d d d d d d and R I CO CO O d m m O l I O m N - 1 7 7 1 m 0 r. r. m m m r. r. m c� 0 L R i+ 9 N � O � L I-a Qi G r/� O O O CO V� V� I CO C O �° k Y O O O O CO CO CO m r. r O N L R ^✓^ N r. 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NoN mN o�N 7 mmm mmmm mmm mmm m mmm mm mmm mmm mmm r. m MM r m m m MM L R 0 0 G R � m o, m m m 0 dt c�c� m N °c� "- c� � N o N � � , d 9 , O - O N � V 5 3 � L 'w R R N a L oo 0 wN L R ^✓' �p O d O O O CO CO O M N N N O N N O vi N vi N O N M O N O O Ix I b N I O x x R Q CO CO CO CO �O �O �O O� CO CO " H A � c s � a h 9 O _ o § N Q o Q o o o 0 o a o o 0 0 0 0 0 0 0 0 0 o o a o o o 0 0 d d d d v v v v v v v P v d v v d v v v v d v v d 0) w O X O Q N W 9 07 X a C N Q Q F-1 Pa I-a Qi F 0) w O X O Q N W 9 07 X a C N Q Q L A R 00 M 00 00 M M 00 00 M M 00 M 00 M M 00 M 00 M O I� W m W 00 m m 00 00 m m 00 m 00 m m 00 m 00 m 0 9 y O � � o o m m m m m m o o G R L G A o0 00 00 00 00 00 m 00 m 00 m 00 00 w L m m m m m m m L R m m m ' m m �o �n N � 00 00 vi 00 o0 00 00 (J 00 00 O M M M W � A o0 00 00 00 00 00 00 R h L R 7 R N 3 L A dO� m� o I 1H, o m I I m m x I m x 1 m x m N N o t� o � o0 m 0o m m m m m m m m m m o0 m 00 m R 0 0 G R O 9 O � V 5 O 4 -a o o m m m o m W R R N a L L � 7 i W N L R 0 R Q 00 O� 00 O� 00 00 Pr R � a 9 G R h R G h 0) w O X O Q N W 9 07 X a C N Q Q APPENDIX C METHODOLOGY FOR ESTIMATING THE EFFECTIVE IMPERVIOUS AREA OF URBAN WATERSHEDS lu w •�v `:ti- - :!-sue.•: - f ^•>�, mar ���:. ... .._.. rv: .. _�" _�- — _ �� '� yA I 1 _ . ... ... .Z� .. S ICr- -�:rx. %I�:= x].x,�� •..:� -.- . ��;. ,, _ ;ems:: - - - ._�. <•w... -.. _ _ �`; , •� - -� = ,1�::::.�.:; _�: d��^ �'��= ;off• "�.4,' � �1 �.:.. �i`�`:•�; �r „�7:: � �.:.��:�:�.: �':y� rte.; ,.�ni:; :xy:�. y i ; � ., :.:.. _ yA I 1 _ . ... ... .Z� .. S ICr- -�:rx. %I�:= x].x,�� •..:� -.- . ��;. ,, _ ;ems:: - - - ._�. <•w... -.. _ _ �`; , •� - -� = ,1�::::.�.:; _�: d��^ �'��= ;off• "�.4,' 77 , ._.,�, �• .. �, APPENDIX D CAPITAL PROJECT UNIT COST TABLES APPENDIX D Eugene Basin Planning Unit Cost Tables for Estimating Capital Project (CP) Costs August 2009 INTRODUCTION The following tables provide the unit costs and back -up documentation associated with material and construction costs for various drainage system components. The purpose of these tables is to provide general guidance with respect to CP costs and to allow for cost comparisons between CPs. These unit costs are based on original and refined unit costs used for the Eugene Master Plan in 1999 with a 15% increase to all original unit costs to reflect current conditions (2007). These increased costs are only applicable to the scale of projects in the City's preliminary storm system CP list. They are not applicable to projects that are of a much smaller or larger scale than those preliminary CPs. Tables 1 through 4 — Tables 1 through 4 provide estimated capital /construction costs for each CP type (e.g., pipe installation, open channel improvements, and detention and water quality facilities). Table 1 provides cost estimates for all of the CP types except for pipes and structural water quality treatment systems (i.e., CONTECH Storm Filter). Table 2 provides cost estimates for drainage pipe, based on pipe size and depth of cover. Table 3 provides detailed back -up information regarding estimated construction costs for drainage pipe installation. Table 4 provides cost estimates for five different sized structural water quality facilities (i.e., CONTECH Storm Filter). For many of the CPs in Table 1 and the pipe costs in Table 2, the unit cost must be multiplied by a quantity such as acre -feet, square yards, or lineal feet to estimate the total capital cost for that CP. Tables 5 through 7 — Tables 5 through 7 provide the back -up information that was used to estimate the unit costs for CP types listed in Table 1. Table 5 provides unit costs for the various elements that comprise each CP (e.g., labor, excavation, etc.). Table 6 provides the quantities of each element that comprise the CPs (e.g., 1 hour of labor, 6 cubic yards of excavation, etc.). Table 7 provides the detailed back -up capital /construction cost information for each CP type based on Tables 5 and 6. (Note: a revision was made to the Natural Resource Enhancement and Open Waterway Improvement Construction unit costs November 2001. Seethe addendum following this summary, prior to the tables.) Table 8 — Table 8 provides the estimated maintenance costs for each CP type. For many of the CPs, the maintenance cost must be multiplied by a unit such as acre -feet or square yards in order to come up with the total estimated maintenance cost. Estimated maintenance costs have been calculated and reported for flood control CPs. A maintenance cost is not provided for capital projects to increase the pipe sizes based on the assumption that maintenance of piped systems typically includes catch basin /manhole cleaning I:A 945042m\ task0300 Asdmps \vol=cl\appendixg.doc and that this cleaning is already being conducted for the existing piped system. A general maintenance cost is provided for water quality CPs (CONTECH StormFilter and raingardens), based on personal communication (emails and phone calls). Table 9 — Table 9 provides the detailed back -up information for estimating the maintenance costs for each CP type except for increased pipe sizes and raingardens. Tables 1, 2, 4, and 8 were used to estimate capital and maintenance costs that are provided in the draft CP fact sheets. Tables 3, 5, 6, 7 and 9 are only provided to show back -up for information presented in Tables 1, 2, 4, and 8. I:A 945042m\ task0300 Asdmps \vol=cl\appendixg.doc 2 November 1, 2001 Addendum to Natural Resource Enhancement and Open Waterway Improvement Construction Unit Costs As requested by the City, URS has reviewed and recommended revisions to the construction activity /material unit costs developed for the Storm Drainage Master Planning project for open channel improvements (Types 1 and 2), natural resource enhancement, and natural resource revegetation. The distinction between these project types for basin planning was as follows: • Open channel improvements (Type 1) — Modify existing channels. Construction activities and materials included traffic control, excavation (0 to 10 foot bottom width, 4 to 6 foot depth, 3:1 side slopes), hydroseed, and erosion protection at inlets and outlets. • Open channel improvements (Type 2) — Modify existing channels. Construction activities and materials included the same elements as for Type 1 except channel excavation was increased to a 10 to 20 foot bottom width and 6 to 10 foot depth. • Natural resource enhancement — Plant additional vegetation. • Natural resource revegetation — Remove invasive vegetation, grade and revegetate. For each of these project types, overall unit costs were developed based on unit costs for construction activities and materials including: traffic control, general excavation, hydroseeding, trees and shrubs, riprap, and erosion control. In this letter, we revised our unit costs for the project construction activities and materials based on a review of bid tabulations from two recently completed enhancement projects in Eugene (i.e., the 1135 and ACE projects), the Longfellow Creek Habitat Improvement Project in Seattle, Washington, the Oregon Department of Transportation Historical Bid Price Listings, and the RS Means 2000 Heavy Construction Cost Data book. This letter report includes a description of how the specific construction activities /materials unit costs were revised, a discussion of how recommended unit costs were identified, a recommended new unit cost for natural resource enhancement, and a recommendation for computing construction costs for open waterway improvements. Unit Costs Compiled from Other Projects /Sources Table 1 presents the unit costs from the above mentioned projects and sources for each of the appropriate construction activities /materials. Clearing and grubbing, and grading were added to the list of construction activities and materials because it is likely that with most natural resource enhancement projects some clearing and grubbing of invasive vegetation or dead trees will be necessary and that regrading of the top soil will also be necessary. The range of unit costs, which can be compared with the existing basin planning unit costs, is provided in Table 1. From this range, we developed new recommended unit costs to be used for the construction activities /materials elements of the project types. For those elements that had unit costs from more than two projects /sources (i.e., general excavation, hydroseeding, trees, shrubs, and riprap) the average of the unit costs was recommended. For elements that had only two sources (i.e., clearing and grubbing, grading, and erosion control), the numbers were compared with the existing basin planning costs and an average was taken of all three. The recommended unit costs (rounded up to the nearest dollar) are presented in Table 1. 3 Natural Resource Enhancement The natural resource enhancement and natural resource revegetation project types were combined into one type of improvement "natural resource enhancement ". For earlier basin planning, natural resource enhancement included planting of trees /shrubs only, while natural resource revegetation included general excavation, hydroseeding, planting trees /shrubs, and erosion control. During this review it was determined that it would be unlikely that a capital project would include only tree /shrub planting, and that if the natural resources of an area were designated to be enhanced, that enhancement would likely include some clearing and grubbing, grading, hydroseeding, planting trees /shrubs and erosion control. Clearing and grubbing, and grading were added because it is likely that with most natural resource enhancement projects some clearing and grubbing of invasive vegetation or dead trees would be necessary and that regrading of the top soil would also be necessary. For a strictly natural resource enhancement project (i.e., no channel modifications) it is unlikely that much excavation would be necessary, therefore excavation was removed from the cost estimate. The construction activities /materials that comprise natural resource enhancement now include clearing and grubbing, grading, hydroseeding, planting trees /shrubs, and erosion control. The original basin planning costs for natural resource enhancement and natural resource revegetation were $10 /square yard (SY) and $49 /SY respectively. After combining the two types of projects into one type, natural resource enhancement, the new recommended unit cost is $13 /SY, as presented in the table below. Natural Resource Enhancement Unit Cost Construction Activity/Material Units Unit Costs Units Unit Costs Comments Clearing and Grubbing AC $4,300 SY $0.90 Grading CY $5 SY $5 Assume a maximum depth of 1 foot to be regraded. H droseed AC $3,200 SY $0.66 Trees /Shrubs EA $120/$36 SY $6 Assume trees planted at 20 -foot spacing on- center (O.C.) and shrubs planted at 10 feet O.C. Erosion Control AC $3,800 SY $0.62 Total for Natural Resource Enhancement SY $13 Although the construction activity and material unit costs for clearing and grubbing, hydroseed and erosion control increased, they are being applied on a square yard basis. Therefore, these increases did not have much impact on the unit cost for natural resource enhancement. The greatest factor that led to the decrease in the unit cost for natural resource enhancement is the modification to the quantity of trees /shrubs per square yard. In the calculations for the basin planning costs, the quantity of trees /shrubs was 0.5 each per SY, which corresponds to a tree /shrub planted approximately every 4 feet O.C. During this review, it was determined that a more appropriate spacing for shrubs would be every 8 feet O.C. and every 20 feet O.C. for trees. For example, on a 100 foot long, 25 foot wide buffer the revised spacing would allow for planting of either 12 trees at a unit cost of $120 /tree or 52 shrubs at a unit cost of $36 /shrub, while the original basin planning allowed approximately 139 trees /shrubs to be planted. On a M square yard basis, the basin planning costs for trees /shrubs as part of natural resource enhancement were approximately $25 /SY, while the recommended unit costs would be approximately $6 /SY for either trees or shrubs. Another significant factor in the decrease of the natural resource enhancement unit cost was the quantity of erosion control per SY in the basin planning quantity tables. The basin planning quantity tables indicated that 0.008 acres (38.7 SY) of erosion control would be applied every SY. It appears that this quantity was an error and that the correct quantity for erosion control per SY would be 0.0002 AC (1 SY) per SY. Open Waterway Improvements Before this review, open channel improvements were divided into two different types (i.e., Type 1 and Type 2). Both the Type 1 and Type 2 improvements included traffic control, excavation, hydroseeding, trees and shrubs, riprap, and erosion control. The estimated construction costs per unit were based on lineal feet. During this review, it was determined that there was a need to determine quantities for each open waterway improvement project specifically, rather than rely on general quantities for the various construction activities /materials. The quantities that are input into the cost tables have a significant impact on the overall cost of open waterway improvements. The quantity of excavation, the area to be hydroseeded and the area disturbed for which erosion control would be needed vary greatly between projects. Therefore, we are not recommending a general construction unit cost for open waterway improvements. We are recommending that each project be evaluated individually and that costs are developed based on the recommended unit costs for construction activities and materials provided in Table 1. In addition, if each open waterway improvement project is evaluated individually there is no longer a need for two different types of improvements. Therefore, we recommend that these improvements be combined into one category. TABLE 1 STORMWATER FACILITIES ESTIMATED CONSTRUCTION COSTS PER UNIT Stormwater Facility Type Unit S/Unie "` i +z Description of Stormwater Facility Construction Activities Trash Rack Inlet (Type 1) EA $5,940 Cone shaped rebar cage bolted to an inlet structure (manhole or vault), inlet protection (riprap, geotextile fabric), clearing of invasive vegetation, grading and revegetation . Trash Rack Inlet (Type 2) EA $9,970 Steel trash rack approximately 15 It wide and 4 It high placed in the channel with concrete foundation walls on both banks. Also includes inlet protection, clearing of invasive vegetation, grading and revegetation. Garbage and Debris Removal CY $120 Hand collected debris not requiring mechanical means to lift, hauled in 10 CY truck to disposal. Sediment Removal CY $250 Removal of sediment from channels and culverts with heavy equipment. Includes hydroseeding for revegetation. Streambank Stabilization SY $90 Grading, geotextile, toe reinforcement, revegetation and erosion control. Open Channel Improvements (Type 1) LF $350 Traffic control, excavation (0 tol 0 It bottom width, 4 to 6 It depth, 3:1 side slopes), hydroseed, erosion protection at inlet and outlet Modification of existing channel. Open Channel Improvements (Type 2P LF $730 Same as above except 10 to 20 It bottom width, 6 to 10 It depth. Dry Extended Pond Ac -Ft $59,700 Gravel access road (25 It long x 12 It width), clearing & grubbing, excavation (3 It depth), grading, erosion protection at inlet & outlet, hydroseed, trees & shrubs, safety fence, erosion control. Wet Extended Pond Ac -Ft $59,700 Gravel access road (25 It long x 12 It width), clearing & grubbing, excavation (3 -6 It depth), grading, erosion protection at inlet & outlet, hydroseed, trees & shrubs, safety fence, erosion control. No lining has been included. Stormwater Marsh/Wetland AC $88,300 Gravel access road (25 It long x 12 It width), grading (1 -2 It depth, no removal from site), erosion protection at inlet & outlet, hydroseed, vegetation and erosion control. Flood Control Facility Ac -Ft $59,700 Gravel access road (25 It long x 12 It width), clearing & grubbing, excavation (3 It depth), grading, erosion protection at inlet & outlet, hydroseed, trees & shrubs, safety fence, erosion control. Outfall Protection EA $7,670 Precast concrete outlet structure, erosion protection, geotextile fabric, clearing of vegetation around structure, grading and revegetation. Vegetated Swale LF $17 Traffic control, clearing & grubbing, excavation (4ft bottom width, 2 It depth, 4:1 side slopes), hydroseed, erosion protection at inlet and outlet Infiltration Trench LF $50 Clearing & grubbing, excavation (2ft bottom width, 4 It depth), geotextile fabric, 4 " -8" perforated pipe, drain rock, and hydroseed. Natural Resource Enhancemene -3 SY $10 Add additional vegetation Natural Resource Revegetation SY $56 Remove invasive vegetation, grade and revegetate. Recreational Trail SF $5 Clearing & grubbing, grading (up to 1 It depth), erosion control, cedar shavings. Does not include storm drainage, signage, benches or other recreational amenities. Raingarden - Native Soils N -5 SF $8 Includes installation of plants. Does not include grading, curb work, and sod installation outside of garden area. Rain garden - Engineered Soils N -6 g g SF $29 Includes installation of plants, bed amendment with engineered soils), and underdrain piping. P ( g ) P P g. Does not include grading, curb work, and sod installation outside of garden area. Note 1: The costs in this table reflect an update of the original Table 1 prepared in 1999. It is based on a 2007 update that included an accross the board increase of 15% to all unit costs in Table 7. It also includes the inclusion of geotextile fabric for both types of open channel improvements (see update to Table 7). Note 2: Construction costs presented in this table are planning level estimates. They are reflective of average facilities constructed under typical conditions. Each facility will vary depending on site conditions, the size and number of facilities constructed, and depending on the local construction market at the time of bidding. Contingencies should be reflected for budgeting purposes based on the variety of possible conditions. Note 3: For purposes of calculating costs, these 2 categories have been combined and called Natural Resource Enhancement (use $13 /sy) see attached addendum dated 11 /01. This $13 /sy should be updated to $15 /sq based on the 15% increase being applied for a 2007 update. Note 4: The cost presented here for TYPE II channel improvements of $730 reflects a 2007 accross the board update of +15% to the costs in the 1999 tables. However, due to several years experience with this type of project and an expectation of economies of scale (e.g., wider bottom width, deeper excavation, but same start up /mobilization/erosion control costs, etc.), an amount of $600/LF is now used as the unit cost here. Note 5: Native soil mingarden cost estimates are assumed for 2007 and were provided by David Dods at URS (Overland Park, Kansas) , email dated 9 -21 -2007 and approved by Eugene and Lane County staff. See attached email. Note 6: Engineered soil raingarden cost estimates are estimated for 2007, based on information provided by David Dods at URS (Overland Park, Kansas) , email dated 9 -21 -2007, and information provided by the City of Portland (phone call with City 8- 10 -09). The two costs provided ($24 /sf from Kansas City and $34 /sf from Portland) were averaged to take into account the fact that the Kansas City estimate was assumed to be on the low side when compared to typical costs in Eugene, and the City of Portlands estimate was on the high side given that it reflected 2009 costs as opposed to 2007. To be consistent with the other unit costs in these tables, unit costs should reflect 2007 estimates. Reference: Table 1 summarizes data in Table 7. Table 5 (Unit Cost) x Table 6 (Quantities) = Table 7 (Unit Cost per CIP Type) H � 0 W H Z F� 0 N � � F+I W L� H L� W vi O ,r cz O N cz cz N Li O O N �I �I Z O F"r Q U F ct N ,r O P" H N � N cz O u 7-r c u U "r•" N cz O 0 U � O O CZ O c Y bb cz cz i c c U O � U O � O N O � N U N C � y H C N C � , U CZ Y O a CZ � O C � � O F cd cz N cd U cz cz u cz Y U N Vi 7-r 7-r N O cct O ,r U � T O N fi r" cz cz - Z P� cz ti W P4 O O O O � 69 69 69 69 al O O O O 00 �O M � 69 69 69 69 69 69 69 69 O O O O 69 69 69 69 O O O O O vi O �O 69 69 69 69 O O O w O vi O O O � O al O 69 69 69 69 in S in O b0 � O A O N� 69 69 69 69 •�+ N N N M M � O O O O O 69 69 69 69 O M O O O O N 69 69 69 DO rl t N N � W v O v A i, O vi O ,r cz O N cz cz N Li O O N �I �I Z O F"r Q U F ct N ,r O P" H N � N cz O u 7-r c u U "r•" N cz O 0 U � O O CZ O c Y bb cz cz i c c U O � U O � O N O � N U N C � y H C N C � , U CZ Y O a CZ � O C � � O F cd cz N cd U cz cz u cz Y U N Vi 7-r 7-r N O cct O ,r U � T O N fi r" cz cz - Z P� cz ti W P4 TABLE 3 STORMWATER FACILITIES ESTIMATED CONSTRUCTION COSTS FOR STORM DRAIN INSTALLATION IN IMPROVED AREAS BACK UP INFORMATION Storm Drain Pipe Construction Cost per Linear Foot Diameter inch Depth of Cover (ft) 18 24 30 36 42 48 54 60 66 72 84 96 Sub Task Pipe + Bed (ft) 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7.5 8.5 Width (ft) 3 4 5 6 7 8 9 10 11 12 14 16 Bedding (ft) 0.1 0.1 0.2 0.2 0.3 0.3 0.3 0.4 0.4 0.4 0.5 0.6 Shoring (If) $ 10.34 $12.42 $14.90 1 $17.88 $21.46 1 $25.75 $30.90 $30.90 $37.09 $44.51 1 $53.41 $64.09 Excavation (CY) $ 11.50 $11.50 $11.50 $11.50 $11.50 $11.50 $11.50 $11.50 $11.50 $11.50 $11.50 $11.50 Backfill and Air Tamped Compaction (CY) $ 17.25 $17.25 $17.25 $17.25 $17.25 $17.25 $17.25 $17.25 $17.25 $17.25 $17.25 $17.25 Piping (If) $ 15.00 $29.33 $59.80 $79.35 $90.85 $108.10 $131.10 $154.10 $204.70 $203.55 $304.75 $379.50 Pavement Restoration $ 6.40 $8.54 $10.67 $12.81 $14.94 $17.08 $19.21 $21.35 $23.48 $25.62 $29.89 $34.16 Traffic Control $ 20.91 $23.00 $25.30 $27.83 $30.61 $33.67 $37.04 $40.75 $44.82 $49.30 $54.23 $59.66 Stream Management $ 12.54 $14.38 $16.53 $19.01 $21.86 $25.14 $28.91 $33.25 $38.24 $43.97 $50.57 $58.15 Cover CY 2 -5 0.7 1.1 1.5 1.9 2.3 2.8 3.3 3.9 4.5 5.1 6.5 8.0 5 -10 1.4 1.9 2.4 3.0 3.6 4.3 5.0 5.7 6.5 7.3 9.1 11.0 10 -15 1.9 2.6 3.3 4.1 4.9 5.8 6.7 7.6 8.6 9.6 11.7 13.9 15 -20 2.3 3.3 4.3 5.2 6.2 7.3 8.3 9.4 10.6 11.8 1 14.3 16.9 2 -5 $90.32 $124.60 $174.80 $216.19 $251.81 $295.67 $348.00 $397.15 $482.17 $518.89 $684.19 $830.56 5 -10 $110.44 $145.90 $201.42 $248.13 $289.08 $338.26 $395.92 $450.39 $540.73 $582.78 $758.72 $915.74 10 -15 $124.82 $167.20 $228.04 $280.08 $326.35 $380.85 $443.83 $503.63 $599.30 $646.67 $833.26 $1,000.93 15 -20 $136.32 $188.49 $254.66 $312.02 $363.62 $423.45 $491.75 $556.87 $657.86 $710.56 $907.80 $1,086.11 Note 1: The costs in this table reflect an update of the original table prepared in 1999. The 2007 update includes a 15% increase to all unit costs. Note 2: Construction costs presented in this table are planning level estimates. These estimated costs include minor stream management, traffic control costs associated with typical in- stream culvert projects, average utility relocation and pavement restoration costs in improved areas. Utility easement or other land acquisition costs are excluded. Information presented in this table is summarized in Table 2 (costs in Table 2 are rounded to the nearest $10). TABLE 4 STORMWATER FACILITIES ESTIMATED CONSTRUCTION COSTS FOR WATER QUALITY STRUCTURES Device /Model Total Installed Cost Number of Cartridges Compost Storm Filter (CSF) Function: Primarily metals uptake and oil & grease removal. Commonly used with sediment manhole CSF 8x6 $58,500 6 CSF 8x6 $70,000 11 CSF 12x6 $73,280 11 CSF 16x8 $138,560 33 CSF 16x8 $157,000 39 Note 1: StormFilter costs were provided by Contech Stormwater Solutions (email to URS dated 10 -24 -2007, email attached). If other proprietary treatment systems are proposed, costs for other facilities will be updated. Note 2: Construction costs presented in this table are planning level estimates. Costs represent installation of average facilities under typical conditions. Estimates reflect vaults installed in public right of way, in an existing residential paved street, with average utility conflicts and restoration costs. TABLE 5 STORMWATER FACILITIES CONSTRUCTION COST ESTIMATE BACK -UP INFORMATION Construction Activity/Materials Units $/Unit Manual Labor Labor -Hr $35 Traffic Control Labor -Hr $32 Gravel Access Road SF $4.37 Clearing & Grubbing AC $2,300 General Excavation CY $17 Grading CY $6 Inlet Cone & Structure EA $4,025 Trash Rack Structure EA $8,050 Pond Outlet EA $5,750 Curb & Gutter LF $14 Hydroseed AC $2,300 Trees & Shrubs EA $58 Geotextile Fabric SY $2.01 Rip Rap TN $69 Chain Link Fence LF $20 Erosion Control AC $2,300 Drain Rock CY $30 Crushed Rock CY $25 Truck Haul (Disposal) CY $21 Perforated Drain Pipe LF $30 Cedar Savings CY $25 Note 1: The above costs (originally prepared in 1999) were updated in 2007 with an across the board increase of 15 %. Note 2: The above are representative unit costs based on information collected from bid tabulation sheets from two years (1997 -1999) in the Eugene, Lebanon and Portland areas. These costs are representative of average conditions and assume that the CP projects are competitively bid. Unit costs include materials and installation. Actual construction cost will vary with site conditions and local factors at time of bidding. Unit cost for trees assumes bare root stock with temporary water for 2 -3 years. Note 3: With respect to Natural Resource Enhancement and Open Waterway Improvement Construction Costs (not included in this table), unit costs were revised (Nov. 2001) for clearing & grubbing, hydroseeding, trees & shrubs, and erosion control. See attached addendum. Reference: Table 5 (Unit Cost) x Table 6 (Quantities) = Table 7 (Unit Cost per CIP Type) w h a w GG w ai O F PM L Ieuol;eaaaag w o 0 0 o 0 0 ;uaMaauegug N aaanosag IeanjuN ° �UOjJUJ;4taeag 0 0 0 0 aaanosan Ir. 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U H cd N cd M N a� o H� n � O O U U L � aHH W . r I� V w GG w F W F O U � y � ct 0 0 U s. U U � T � O U O U N U y r3 O OU w � w O w r U O s. T bA cC tiy+. U CI�i R C C C 0 � 3 o w o 0 s CL 'O w 00 t a � h G U ^� O • U � w U N E O U � 0 0 o o c c� + c� y , A Si Si Si i N i i N i i N i 00 O CD 01 O O O 01 O h O 00 O 00 M O h O M rn w w w w U U U o O oO w 0 o O v v � O N C.i �' •v � a .:i y Cn '�' ' u' y �C o o ow O U � y � ct 0 0 U s. U U � T � O U O U N U y r3 O OU w � w O w r U O s. T bA cC tiy+. U CI�i R C C C 0 � 3 o w o 0 s CL 'O w 00 t a � h TABLE 9 STORMWATER FACILITIES ESTIMATED ANNUAL MAINTENANCE COSTS Frequency Effort/Time Equip. /Time Times/Year Lb -Hr $ @ $46/hr Hours $/hr Rate $ Total Comments Trash Rack Inlet (Type 1 & 2) Emergency Response 10 1 $ 460.00 0 $ - $ - Inspect & Clean In1eU0utlet 4 4 $ 736.00 2 $ 172.50 $ 1,380.00 Vactor Truck & Operator Routine Repair $ - $ - $ - Maintain Vegetation 4 2 $ 368.00 2 $ 11.50 $ 92.00 Mower, Weedeater, Etc. Disposal Costs 4 $ 46.00 $ - $ Subtotals $ 1,610.00 $ 1,472.00 Total Estimate Annual Maintenance $ 3,082.00 Open Channel (Type 1 & 2) Inspect Vegetation & Sediment Loading 2 1 $ 92.00 0 $ - $ Maintain Vegetation $ - $ - $ - Remove Debris /Garbage 4 2 $ 368.00 0 $ - $ - Remove Sediment 1 8 $ 368.00 4 $ 345.00 $ 1,380.00 Tractor Shovel, 10 CY Dump & Operators Disposal Costs 1 $ 920.00 $ - $ - Assumes 10 CY/Year Inspect Slopes 2 1 $ 92.00 0 $ - $ - Repair Slopes (On Going Activity) $ 575.00 0 $ - $ Annual Misc. Cost Subtotals $ 2,415.00 $ 1,380.00 Total Estimate Annual Maintenance $ 3,795.00 Dry Extended Pond Inspect & Clean In1eU0utlet 4 4 $ 736.00 2 $ 172.50 $ 1,380.00 Vactor Truck & Operator Inspect Vegetation 2 1 $ 92.00 0 $ - $ - Remove Debris /Garbage 4 2 $ 368.00 0 $ - $ - Maintain Vegetation 4 4 $ 736.00 4 $ 11.50 $ 184.00 Mower, Weedeater, Etc. Inspect Sediment Loading 2 1 $ 92.00 0 $ - $ - Remove Sediment 0.5 12 $ 276.00 6 $ 345.00 $ 1,035.00 Tractor Shovel, 10 CY Dump & Operators Disposal Costs 0.5 $ 920.00 $ - $ - Assumes 10 CY Every Two Years Inspect slopes 2 1 $ 92.00 0 $ - $ - Repair Slopes (On Going Activity) $ 575.00 $ - $ Annual Misc. Cost Subtotals $ 3,88700 $ 2,599.00 Total Estimate Annual Maintenance $ 6,486.00 Wet Extended Pond Inspect & Clean In1eU0utlet 4 4 $ 736.00 2 $ 172.50 $ 1,380.00 Vactor Truck & Operator Inspect Vegetation 2 1 $ 92.00 0 $ - $ - Remove Debris /Garbage 4 2 $ 368.00 0 $ - $ - Maintain Vegetation 4 4 $ 736.00 4 $ 11.50 $ 184.00 Mower, Weedeater, Etc. Inspect Sediment Loading 2 1 $ 92.00 0 $ - $ - Remove Sediment 0.5 12 $ 276.00 6 $ 345.00 $ 1,035.00 Tractor Shovel, 10 CY Dump & Operators Disposal Costs 0.5 $ 460.00 $ - $ - Assumes 10 CY Every TwoYears Inspect slopes 2 1 $ 92.00 0 $ - $ - Repair Slopes $ 575.00 $ - $ Annual Misc. Cost Subtotals $ 3,427.00 $ 2,599.00 Total Estimate Annual Maintenance $ 6,026.00 Flood Control Facility Inspect & Clean In1eU0utlet 4 2 $ 368.00 2 $ 172.50 $ 1,380.00 Vactor Truck & Operator Inspect Vegetation 2 1 $ 92.00 0 $ - $ - Remove Debris /Garbage 4 1 $ 184.00 0 $ - $ - Maintain Vegetation 4 4 $ 736.00 4 $ 11.50 $ 184.00 Mower, Weedeater, Etc. Inspect Sediment Loading 2 1 $ 92.00 0 $ - $ - Remove Sediment 0.5 8 $ 184.00 4 $ 345.00 $ 690.00 Tractor Shovel, 10 CY Dump & Operators Disposal Costs 0.5 $ 230.00 $ - Assumes 5 CY Every two Years Inspect slopes 2 1 $ 92.00 0 $ - $ - Slope Repair (On Going Activity) $ 575.00 $ - $ Annual Misc. Cost Subtotals $ 2,553.00 $ 2,254.00 Total Estimate Annual Maintenance $ 4,80200 Stormwater Marsh/Wetland Inspect & Clean In1eU0utlet 4 4 $ 736.00 2 $ 172.50 $ 1,380.00 Vactor Truck & Operator Inspect Vegetation 2 1 $ 92.00 0 $ - $ - Remove Debris /Garbage 2 2 $ 184.00 0 $ - $ - Maintain Vegetation 4 4 $ 736.00 4 $ 11.50 $ 184.00 Mower, Weedeater, Etc. Subtotals $ 1,748.00 $ 1,564.00 Total Estimate Annual Maintenance $ 3,312.00 Vegetated Swale Inspect & Clean In1eU0utlet 4 2 $ 368.00 1 $ 172.50 $ 690.00 Vactor Truck & Operator Remove Debris /Garbage 2 2 $ 184.00 0 $ - $ - Maintain Vegetation 4 4 $ 736.00 4 $ 11.50 $ 184.00 Mower, Weedeater, Etc. Inspect Sediment Loading 2 1 $ 92.00 0 $ - $ - Remove Sediment/Regrade 1 8 $ 368.00 4 $ 345.00 $ 1,380.00 Tractor Shovel, 10 CY Dump & Operators Disposal Costs 1 $ 92.00 $ - $ Assumes 2 CY Per Year Subtotals $ 1,840.00 $ 2,254.00 Total Estimate Annual Maintenance $ 4,094.00 Frequency Effort/Time Equip. /Time Times/Year Lb -Hr $ @ $40/hr Hours $/hr Rate $ Total Comments Infiltration Trench Inspect & Clean In1eU0utlet 4 4 $ 736.00 2 $ 172.50 $ 1,380.00 Vactor Truck & Operator Remove Debris /Garbage 2 2 $ 184.00 0 $ - $ - InspectSedimentLoading 2 2 $ 184.00 0 $ - $ - Remove Sediment 0.3 8 $ 110.40 4 $ 86.25 $ 103.50 Water Truck (Flush fines) & Operator Disposal Costs 0.3 $ 28.75 $ - $ Assumes 2 CY Every Three Years Subtotals $ 1,214.40 $ 1,483.50 Total Estimate Annual Maintenance $ 2,69290 Water Quality Structures Remove Debris /Garbage 2 2 $ 184.00 0 $ - $ - InspectSedimentLoading 2 2 $ 184.00 0 $ - $ - Remove Sediment 0.3 8 $ 110.40 4 $ 172.50 $ 690.00 Vactor Truck & Operator Disposal Costs 4 $ 276.00 $ - $ Assumes 3 CY a Year Subtotals $ 478.40 $ 690.00 Total Estimate Annual Maintenance $ 1,168.40 Natural Resource Enhancement Inspect Vegetation 1 1 $ 46.00 0 $ - $ - Routine Repair $ 230.00 $ - $ - Annual Misc. Cost Remove Debris /Garbage 2 4 $ 368.00 0 $ - $ Subtotals $ 644.00 $ - Total Estimate Annual Maintenance $ 644.00 Natural Resource Revegetation Inspect Vegetation 2 2 $ 184.00 0 $ - $ - Routine Repair $ 460.00 $ - $ - Annual Misc. Cost Remove Debris /Garbage 2 4 $ 368.00 0 $ - $ Subtotals $ 1,012.00 $ - Total Estimate Annual Maintenance $ 1,012.00 Recreational Trail Inspect Vegetation 2 2 $ 184.00 0 $ - $ - Remove Debris /Garbage 4 4 $ 736.00 0 $ - $ - Maintain Vegetation 2 12 $ 1,104.00 12 $ 11.50 $ 276.00 Mower, Weedeater, Etc. Subtotals $ 2,024.00 $ 276.00 Total Estimate Annual Maintenance $ 2,300.00 Note: Labor rate of $40/hr from the original table produced in 1999 was updated with an increase of 15% to $46/hr in 2007. The original information was based on information provided by the Unified Sewerage Agency of WasMngton County (now Clean Water Services). Labor for maintenance activities was assumed to be City maintenance staff averaged for maintenance and supervisor effort Effort shown includes travel time and office documentation time. This table also reflects a 2007 update of of +15% to the unit costs for equipment, disposal, and slope repair. Reference: Table 9 information is summarized in Table 8. "Simescu, Andreea" ' <SimescuA @contech- cpi.com> 10/24/2007 01:59 PM History: Angela, To <Angela_Brown @URSCorp.com> cc bcc Subject RE: Cost estimates for various size Stormfilter units � This message has been replied to and forwarded. Here are the designs available soon: 8X6 w/ 11 cartridges $35,000 8X16 w/ 39 cartridges $78,500 Let me know if you need anything else. Andreea Simescu, E.I. Stormwater Designer CONTECH Stormwater Solutions Inc. 11835 NE Glenn Widing Dr., Portland, OR 97220 Tel: 503.258.3138 Toll free: 800.548.4667 x138 simescua(a contech- cpi.com contechstormwater.com Fax: 800.561.1271 From: Angela_Brown @URSCorp.com [ mailto :Angela_Brown @URSCorp.com] Sent: Tuesday, October 23, 2007 4:15 PM To: Simescu, Andreea Cc: Krista_Reininga @URSCorp.com Subject: RE: Cost estimates for various size Stormfilter units Ili Andrea - Thanks for the cost information. If you guys are proposing additional designs of the vaults to hold more cartridges, please send me those costs and sizes as well. We are in the process of writing up the costs now and the entire update to the plan should be done in Dec/ Jan so the more information we can pull together now, the better. Thanks! Angela Angela Brown, PE URS Corporation 111 SW Columbia Suite 1500 Portland, OR 97201 Phone: (503) 478 -2762 Email: angela_brown @urscorp,com This e -mail and any attachments are confidential. Vyou receive this message in error or are not the "Simescu, Andreea" To <Angela_Brown @URSCorp.com> <SimescuA @contech- cpi.com> cc 10/23/2007 04:07 PM bcc Subject RE: Cost estimates for various size Stormfilter units History: 4;n This message has been replied to. Hi Angela, Sorry I am just getting back to you on this. Here is the updated pricing: - 6X8 w/6 cartridges $29,250 - 6X12 w/11 cartridges $36,640 - 8X16 w/33 cartridges $69,280 The 8X18 design can hold 33 cartridges (same as the 8X16). We are coming up with some new designs in November that will have integrated inlet and outlet sumps and you will be able to fit more cartridges in each size. I can give you that information as well but the vaults are not available yet. Please let me know if you need to have that now or later. Thank you. Andreea Simescu, E.I. Stormwater Designer CONTECH Stormwater Solutions Inc. 11835 NE Glenn Widing Dr., Portland, OR 97220 Tel: 503.258.3138 Toll free: 800.548.4667 x138 Fax: 800.561.1271 simescua@contech- cpi.com contechstormwater.com From: Angela_Brown @URSCorp.com [ mailto :Angela_Brown @URSCorp.com] Sent: Monday, October 22, 2007 4:16 PM To: Simescu, Andreea Cc: Krista_Reininga @URSCorp.com Subject: Cost estimates for various size Stormfilter units Hi Andrea - Im working on updating the unit cost tables for a Master Plan that we (URS) previously completed in 1999 for the City of Eugene. The compost StormFilters were referenced and I am hoping you would be able to help me with some updated costs for some various standard sizes (I realize that you have the manhole and cast in place units, but I think we will stick with just the vault systems for right now). In the original cost estimate, we assumed full number of cartridges (operating at 15 gpm) per size facility. The depth is assumed to be 8'. The standard sizes previously referenced are: 6x8, 6x12, 8x12, 8x14, 8x16, 8x18 I know that some of these sizes no longer exist, so we will only reference those sizes that are currently used. Hopefully you will be able to help. Thanks in advance and let me know if you need any more information Thanks Angela Angela Brown, PE David Dods /OveriandPark/URSCorp To Krista Reininga /Portland /URSCorp @URSCORP 09/21/2007 12:34 PM cc Angela Brown /Portland /URSCorp @URSCORP bcc Subject Re: rain garden costsEl History: E�> This message has been forwarded. Rusty in Minnesota says he builds streetside raingardens with replaced soils and an underdrain for $7 - $8lsquare foot. The qualifiers: • Most of the plants that go in them are plugs • the edging is the black plastic stuff • No walls around the gardens • The underdrain is a pipe wrapped in a filter fabric sock. He does not use a gravel layer For KC, I estimated that same price ($7/SF) for gardens that use native soils and no underdrains. A garden with replaced soils and underdrains might run $15 - 25 /square foot. I don't have a high degree of confidence in the latter number because we just have not built that many here yet. My calculations are attached. If you need to put together a pretty good cost estimate for your project, could help you come up with the line items to be included. But the unit costs would have to come from your area. nlj Raingarden construction cost est, 09.21.07.xls Best wishes, David This e -mail and any attachments are confidential. If you receive this message in error or are not the intended recipient, you should not retain, distribute, disclose or use any of this information and you should destroy the e-mail and any attachments or copies. Krista Rein inga /Portland /URSCorp Krista Rein i nga/Portland/URSCo rp To David Dods /OverlandPark/URSCorp @URSCORP 09/20/2007 03:36 PM cc Angela Brown lPortlandlURSCorp @URSCorp Subject rain garden costs Hi David, For our Eugene project, we are developing capital improvement program costs. Do you have any kind of table or anything already prepared that would show the range in rain garden costs in terms of construction and then also maintenance? Thanks, Krista History: Hi Angela, To "' Angel a_Brown @URSCorp.com "' <Ange la_B rown@ U RS Corp. com> cc bcc Subject RE: Raingarden Maintenance Costs ,1�9 This message has been replied to and forwarded. My slide from the ACWA conference is a little (or a lot) confusing. The anticipated $5001year maintenance cost for NE Holladay Street is wholly contributed to the rain gardens, as we're not planning on sweeping the porous pavement portion any more than the 10- timeslyear we already sweep standard streets in Gresham. The 3 rain gardens total about 500 square -feet in size, so you can say we anticipate the annual maintenance cost to be around $1/square-foot. On top of the annual maintenance cost, we anticipate needing to spend $1,500 or $31sf every 10 years for a larger -scale rehab. As a disclaimer, the costs I've presented are still very rough guesses, as we don't have very many public rain gardens or porous pavements and the ones we do have are relatively new. So far, we have not spent any time or money maintaining the public street rain gardens at NE Holladay (2.5 years old). They continue to look very nice and are performing well, and it's unclear about how much maintenance the adjacent property owners are taking on if any. We also are not spending any more maintaining our porous pavement streets than we do on standard ones. The City of Gresham already sweeps streets 10 times per year on average, which has been sufficient to prevent clogging of the porous systems. At some point in time maybe 5 -10 years out, I do anticipate having to do some type of maintenance to the streetside rain gardens, such as removal of some accumulated sediment, replanting and remulching. A better source of rain garden maintenance data is Henry Stevens with the City of Portland BES, The policy in place while I was there relied on the adjacent property owner for routine maintenance, but I believe they have since changed to perform more functions as a city. Hope this helps. Steve Fancher Watershed Division Manager City of Gresham, DES 503- 618 -2583 steve. fancher @greshamoregon.gov From: Angela_ Brown @URSCorp.com [ mailto :Angela_Brown @URSCorp.com] Sent: Monday, August 03, 2009 10,37 AM To: Fancher, Steve Subject: Raingarden Maintenance Costs f1i Steve - "Fancher, Steve" Steve .Fancher @greshemoregon.gov> 08/03/2009 01:58 PM lm working with Krista Reininga on a Stormwater Basin Plan for Eugene where we are proposing raingardens to manage runoff generated after UICs are decommissioned. 1 was wondering if you have any maintenance cost APPENDIX E EVALUATION OF UICS WITH RESPECT TO HIGH GROUNDWATER EVALUATION OF DEQ RULE AUTHORIZATION CRITERION G FOR SANTA CLARA STORMWATER BASIN DRY WELLS INTRODUCTION In 1974, the U.S. Environmental Protection Agency (EPA) enacted the Underground Injection Control (UIC) program under the Safe Drinking Water Act. The Oregon Department of Environmental Quality (DEQ) was delegated primacy in Oregon by the EPA in 1984, and re- authorized in 1991. DEQ regulates the program under Oregon Administrative Rules (OAR) Chapter 340, Division 44. The intent of the UIC program is to protect groundwater quality by regulating the injection of fluids into the ground. Dry wells area type of injection system installed and used by the City of Eugene and Lane County to manage stormwater runoff from roads, parking lots, roofs, and other impervious surfaces by injecting the stormwater into the ground. Dry wells are regulated by the DEQ UIC program. DEQ developed a set of criteria, known as "rule authorization criteria" to assess whether use of an injection system is authorizable by DEQ. The criteria define certain conditions that must be met in order for the injection system to be authorizable. Criterion G specifies the condition that a dry well shall not discharge directly into groundwater or below the highest seasonal groundwater level. This technical memorandum presents the methods, results, and conclusions for assessing whether dry wells within the Santa Clara Stormwater Basin (SCSB) have a reasonable likelihood of discharging to groundwater. PROJECT LOCATION AND DRY WELL DESCRIPTION The SCSB is located in the northern portion of the City of Eugene, primarily with Sections 1 through 16, 23, and 24 in Township 17 South, Range 4 West, in Lane County, Oregon. Dry wells are typically constructed as approximately 4- foot - diameter perforated concrete pipes installed vertically within the ground. Installation steps typically include excavation of a pit, placement of the dry well pipe into the pit, and backfilling of the pit with drain rock. The depths of the dry wells are typically in the range of 10 to 15 feet. Stormwater catch basins collect stormwater runoff from curbs and gutters, and convey the stormwater to the dry wells via drainpipes. Less commonly the dry well may contain a perforated lid through which stormwater may directly discharge to the dry well. METHODS The Oregon Water Resources Department (OWRD) maintains a database of water wells installed within the state of Oregon. The database consists of copies of "well logs ", which are forms completed by well installers (drillers) to record pertinent data regarding well location, method of well construction, and hydrogeologic observations such as the water level. To assess the depth to groundwater in the SCSB, the well log database was searched to identify well logs within the township, range, and sections described above that contained useful water level information. RESULTS A search of the OWRD well log database resulted in 1,447 well log records, of which 1,187 records contained water level information. The water levels for these 1,187 records ranged from 0.7 to 230 feet below ground surface (bgs), and spanned the time from 1914 to 2006. Of these, only seven records contained water levels that were below 50 feet bgs. The mean water level for all 1,187 records was 11.6 feet bgs. Figure 1 is a time -sorted plot of the 1,187 water level records. To further assess the water levels, the water level for each record was plotted as a function of well completion depth. Of the 1,187 records with useful water level information, only 1,027 records also contained completion depth information. Figure 2 presents a plot of the water level as a function of well completion depth. Well completion depths ranged from seven to 390 feet bgs. The plot shows a slight downward trend, indicating that deeper water levels are more commonly associated with deeper wells. The comparison of water level to well depth is important because the dry wells within the SCSB are typically installed at shallow depths (about 10 to 15 feet). To accurately estimate the water level at these shallow depths, it is best to use water level information for water wells that are installed at similar depths. Wells that are installed at greater depths may have corresponding water levels that are not representative of shallow conditions (i.e., depths at which dry wells are installed). Therefore, a subset of the 1,187 records was created by selecting records for wells with completion depths of 20 feet or less. This resulted in 286 records. The mean water level for the 286 records was 9.4 feet bgs. Figure 3 is a time -sorted plot of the 286 water level records. Finally, water levels are also a function of climate and are known to fluctuate throughout the year as a function of seasonal rainfall. In the Eugene area, the highest water levels typically occur during the February through May time period. To estimate the highest seasonal groundwater level within the SCSB, a subset of the 286 shallow well records was created by selecting records for the months of February through May. This resulted in 105 records. The mean water level for the 105 records is 8.1 feet. Of these 105 records, 19 of them (or approximately 18 %) had water levels that were 5 feet or shallower. CONCLUSIONS The OWRD well log database was searched to obtain historic water level information for water wells within the SCSB. The information was used to assess whether dry wells within the SCSB have a reasonable likelihood of discharging directly into groundwater or below the highest seasonal groundwater level. The following conclusions are based on the evaluation of the well log database: The mean water level for 1,187 wells with completion depths of seven to 390 feet bgs is 11.6 feet bgs. 2. The mean water level for 286 wells with completion depths of 20 feet or less is 9.4 feet bgs. 3. The mean water level during the wettest part of the year for wells with completion depths of 20 feet or less is 8.1 feet and 18% of these water depths were five feet or less. 4. Dry wells within the SCSB have a reasonable likelihood of discharging directly to groundwater or below the highest seasonal groundwater level. 2 N L O V NN� LPL ti Qo r r L (1) U) W L o � w 0 / V O t CL (1) 0 ...:.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 ,N ♦ ♦ • N ♦ NN ♦ =i w ♦ N ♦ N N J M O O O O O O LO O LO O LO T- T- N N (aae puno.if molaq Zeal) Jana JOIBM rn O O N ti LO O O 00 N O T- 9- �Z 00 N W W, Z Iq LO rn 0 T rn N ti N O 00 LO V O 00 0) t CL D c O Q E O U Q N O W c O � V LL - LL m N cv 90 . Q O r .7 Q Q J L Q m t CL a� D O N CL O U L O O O O O O LO O LO O N (aoejjns punoa6 molaq }aal) Iana aa}eM . ..................... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... o O N O ♦ ♦N ♦ ♦♦ 0 ♦ ♦ ♦ N ♦ ♦ _ ♦ ♦♦ ♦ ♦ ♦ � ♦ ♦ ♦ O ♦ j ♦ _ ♦ • ♦♦ ♦♦ ♦ �_ ♦ (7 N N L O Q O LO N_ LO ♦ O N N M ♦ ♦ ♦ ♦ LO • • rn E O H - ♦ ♦ L cv ! ♦ O L ♦ Q ♦ � 0 r O Q 0 ♦ ♦ ♦ ♦ ♦ co (Y) r O ( ♦ J L cu ♦ N O O N 'IT O 00 O N 'IT O 00 O N N 0 (aae puno.i6 molaq Zeal) Iana JOIBM APPENDIX F RAIN GARDEN SIZING CALCULATIONS AND PLAN VIEWS FOR SIX ROW OPTIONS 0 O O M — M rl W Ln U � o m m U U UOw a I� '. \, W 3'Jtl Itltld V J \\S\ \ \ \\ IF O \ \\ r O i Cf) Un Cn i z O O u LU o Q) 0 U w 2 �k H a w U z O U H w w H z w w O O M - M rl W Ln IN U � o m U r^ � VJ m \g ...., .� ° O O U i Cn 7� cn N �\ o \�\ b `o A `W" ���o� a� a� O u Cn O o W N d W U z O U H w w H z w w 0 O M — M rl W �'y U U.) o c I \Rl 0-) o� <I 0 m N 3z 3 a i I I i &> O i � N i TS 30ANIVSa CIL o U ' z cn I � LU ._ Ln cn o O ce � U LU Z Cn O � U O M u o �* d W U Z O U H w w H Z w w ce u �° 0 O O M — M rl W +'y U � o U U O od— ¢ a� - 3� c3 I C � I 3�vryiva o � I m I I � I � I I I o � U I � o �o G o U � U � � D H a w U Z O U H w w cn H Z w w C7 O O M - M rl W +'y U L o B E We- 03 Umm w ttm� 3 8 p 3 in �\ I o A� � N L a ]� 0 n \\ 3]4 Nrot10 I o O cn D u ._ Cn o I � � c LU y) O L, O m o U U D Z O L U C/� LO H d W U Z O U H w w H z w w C7 O O M - M rl W +'y U � o a �Q m � Q � U KKK 3y 0 \ � \ m O A\ 30vrvroaa ' \� cn \ \\ cn a, G oo Ln o U v >� Z � > O � K O U U *� a w U Z O U H w w H Z w w C7 APPENDIX G SUMMARY OF MODEL REFINEMENTS SINCE THE INITIAL 2002 STUDY To: Therese Walch From: Hernan Rodriguez, PE and Krista Reininga, PE. Date: April 10, 2007 Subj ect: River Road Santa Clara Model Changes As requested by the City, URS has updated the XP -SWMM models developed for the River Road Santa Clara Stormwater Master Plan project (August 2002). Models were updated using survey data collected by Lane County between October and December 2005. Areas surveyed for updating the models were identified in Section 3.0 of the current draft basin plan (August 2002) and during a June 21, 2005 meeting and in a memo to the City from URS dated August 25, 2005. Once the survey was completed, the original subbasin delineations were refined to account for new information. In addition, drainage basins for UIC areas were delineated. The model was then run to simulate conditions both with and without UICs in place. This was done to get an initial idea of whether decommissioning of all UICs would result in additional flooding issues. The purpose of this memo is to summarize the following: • changes to the original model based on new survey information; • changes to the model based on updated subbasin delineations; • methods for modeling UICs; and • results from modeling conditions both with and without UICs. HYDRAULIC CHANGES The following changes were made, based on the new survey data collected between October and December 2005, when updating each subbasin model: Flat Creek Subbasin • Model segment RSFCO20E from node 72765 to 72764 was divided into 3 segments to incorporate the culvert under Hilo Dr. (node 75697 to 75698) that was not included in the original model. The new segment names are RSFCO20Da, RSFCO20Db, and RSFCO20E. • Model segment RSFCO50A from node 72244 to 72799 was divided into 5 segments to incorporate 2 culverts that were not included in the original model. The new segment names are RSFCO50A, RSFCO50B, RSFCO50C, RSFCO50D, and RSFCO50E. Spring Creek Subbasin • Model segment RSSCOIOD from node 85033a to 72012 was divided into 3 segments to incorporate a culvert not included in the original model. The new segment names are RSSC010D, RSSCOlODa, and RSSCOlODb. 1 • Segment RSSC040B from node 72006 to 72007 was updated with a new length, invert, and rim elevations obtained from the new survey data. • Model segment RSSC100B from node 72002 to 72770 was divided into 3 segments to incorporate a culvert not included in the original model. The new segment names are RSSC100B, RSSC100C, and RSSC100D. Willamette Overflow Subbasin • Anew segment RSWO140 from node 77703 to 58311 was added to the model to extend the model farther upstream to incorporate a 54 -inch pipe segment upstream of node 58311 that was not included in the original model. • Node 58289 was renamed to 58310 to match the node number from the survey data and the GIS layer. • Data for segments RSWO110A, RSWO110B, RSWO110C, RSWO040C, RSWO090B, RSWO090C, RSWO090D, RSWO090E, RSWO090F, RSWO090G, RSWO090H, RSWO080A, were updated according to survey information related to lengths and elevations. • Segment RSWO090A was divided into 2 segments, segment RSWO090A and RSWO090Aa, since new survey data was collected for these segments individually. • Segments RSWO070E, RSWO070F, RSWO070G, and RSWO070H were renamed to RSWO070B, RSWO070C, RSWO070D, and RSWO070E respectively because old segment names RSWO070A, RSWO070B, RSWO070C, and RSWO070D were combined into one segment (RSWO070A) in the new survey data. These segments were updated with new invert elevation and cross - section information obtained from new survey data. • Segments RSWO060B, RSWO060A, RSWO050C, RSWO050B, RSWO050A, and RSWO040C were updated based on new survey information for lengths and elevations. A -1 Channel Subbasin • Segments RSA1100L, RSA1100K, RSA1100G, RSA1100F, RSA1100E, RSA1100D, RSA1100C, RSA1100B, RSA1100A, RSA1090G, RSA1090F, RSA1090E, RSA1090D, RSA1090C, RSA1090B, RSA1090A, RSA1080B, RSA1080A, RSA1060U, RSA1060J, RSA1060I, RSA1060H, RSA1060G, RSA1060C, RSA1010A, RSA1030B, RSAl230A, RSA1160F, RSA1160E, RSA1160D, RSA1160C, RSA1160B, RSA1160A, RSA1150B were updated based on survey information for lengths and elevations. • Segment RSA1060S from node 71209 to 71210 was divided into 2 segments to incorporate a 36x72 -inch CMP culvert that was included in the new survey but not 2 included in the original model. The new segment names are RSA1060S and RSA1060Sa. • Segment RSA1060F from node 71214 to 71215 was divided into 2 segments to incorporate a 48 -inch CMP culvert that was included in the survey but not included in the original model. The new segment names are RSA1060F and RSA1060Fa. • Segment RSA1030D from node 73395 to 73394 was divided into 3 segments to incorporate the culvert under Auction Ct. that was not included in the original model. The new segment names are RSA 103OD, RSA 1030Da and RSA 1030Db. • Node numbers for segment RSAI 160H were changed from 72727 -72728 to 71941 -71940 to match node numbers from the GIS layer. HYDROLOGY CHANGES The following changes were made with respect to updating subbasin delineations, as a result of the new survey data: Flat Creek Subbasin • A runoff node was moved from node 72244 to 75659 according to the new basin delineation. A -1 Channel Subbasin • Subbasin RSA1 -020 was added at node 72757 according to the new basin delineation. • Subbasin RSA1 -070 was moved from node 72740 to 72742 according to the new basin delineation. MODELING METHODOLOGY TO ACCOUNT FOR UICs A separate XP- SVOvIM model was developed for each of the four subbasins in the River Road Santa Clara major basin. The following four models were developed for each of the four subbasins: • Existing conditions model without UICs; • Existing conditions model with UICs; • Future conditions model without UICs; and • Future conditions model with UICs 3 Existing Conditions Model without UICs This model was developed to represent existing conditions of the stormwater system without modeling the effects of UICs. All runoff from subbasins with UICs was assumed to drain into the piped and surface stormwater drainage system without infiltrating into the existing UICs. Existing Conditions with UICs This model was developed to represent existing conditions of the stormwater system while modeling the effects of the UICs. UICs were assumed to infiltrate runoff from up to the 5 -year storm event (3.6 inches). UICs were modeled as storage nodes that store runoff up to the 5 -year storm event. When the capacity of the storage node is reached (5 -year event) the subbasins with UICs begin contributing all additional runoff flows to the piped and surface stormwater drainage system. The storage nodes were sized using an iterative trial and error process until the 5 -year event filled the storage volume but did not contribute runoff flows to the piped and surface stormwater drainage system. Future Conditions Model without UICs This model was developed to represent future development conditions of the stormwater system without modeling the effects of the UICs. All runoff from subbasins with UICs was assumed to drain into the piped and surface stormwater drainage system without infiltrating into the existing UICs. Future Conditions with UICs This model was developed to represent future development conditions of the stormwater system while modeling the effects of the UICs. UICs were assumed to infiltrate runoff from up to the 5- year storm event (3.6 inches). UICs were modeled as storage nodes that store runoff up to the 5 -year storm event. When the capacity of the storage node is reached (5 -year event) the subbasins with UICs begin contributing all additional runoff flows to the piped and surface stormwater drainage system. The storage nodes were sized using an iterative trial and error process until the 5 -year event filled the storage volume but did not contribute additional runoff flows to the piped and surface stormwater drainage system. Results of Modeling Conditions Both With and Without UICs While it was anticipated that existing UICs might relieve some flooding issues, the comparison of model results between the models with and without UICs for the design storms required by the City (10 -year and 25 -year storm event) did not show significant differences with respect to flooding problems. It is assumed that this was the case for the following reasons: Ii 1. The UICs were only assumed to infiltrate runoff up to the 5 -year storm event and the design events modeled were the 10 and 25 -year events. Hence, the accommodation of the 5 -year storm was overwhelmed by the larger storms; and 2. Only 20% of the total drainage area was assumed to be area draining to UICs. Hence the majority of the drainage area is accommodated via the pipe and surface drainage system only. Following the development of the XP -SWMM models for each subbasin (with and without UICs) it was discovered that the GIS maps only included the 86 Lane County dry wells and not the 72 Eugene dry wells. A decision was made not to update the basin delineations to include the Eugene UICs, as resources were limited to conduct an additional analysis. In addition, it was decided that the model without the UICs would be used to design conceptual flood control CIPs, in order to be conservative and to account for the fact that UICs may need to be decommissioned in the future to address UIC regulatory requirements under the Safe Drinking Water Act. Therefore, results of an updated analysis to include the Eugene dry wells in addition to the Lane County dry wells already included in the model would not provide significant additional value. 5 APPENDIX H RIVER ROAD SANTA CLARA STORMWATER MANAGEMENT STRATEGY DEVELOPMENT MAP .PV ilia m P Rilmal , 1 11 ,1 W ftli V soma'! ill -NEI UL P YI APPENDIX I PUBLIC COMMENTS AND RESPONSES Comments on the River Road / Santa Clara Stormwater Basin Master Plan from the Santa Clara Community Organization. Therese Walch Eugene Public Works 99 E. Broadway, Suite 400 Eugene, OR 97401 October 23, 2009 This basin master plan for River Rd/Santa Clara is an opportunity to use all the "tools" in the toolbox to best protect the open waterways, maximize storm water conveyance through these channels, and accommodate future densification without sacrificing what makes the RR/SC neighborhoods unique. While this plan touts some new ideas in the use of rain- gardens both along streets and in neighborhoods, it misses the mark in recognizing the existing natural infrastructure and prioritizing its protection and enhancement. The cost of manufactured infrastructure that degrades over time versus the protection of existing natural infrastructure that improves over time is not something we can afford, and is not the wisest use of what we have. This plan falls short of its aspirations to "provide a management strategy for storm water that reflects the uniqueness of the RR/SC basin ". Our hydrology is not what makes us unique. The forms and patterns created by heritage trees, waterways, prime soils, agricultural operations, significant populations of both urban and rural and county and city residents and all they bring to their neighborhood is what makes us unique. Without taking into account these factors, this plan has no chance to meet its goal of planning reflecting that uniqueness. The major difference between this basin and others throughout the city is our lack of storm water infrastructure and our extensive network of open waterways. These waterways, both large and small, are the infrastructure that makes development possible. They are also our primary defense from flooding. To date, many of the "lesser" waterways in our area have not been mapped and merit no level of protection from filling by development. These swales and watercourses, not wet much of the time, are what protect the existing older development from high water events. As larger lots on these swales are divided and infrll development happens, the swales are not identified as part of a complete stormwater system and are instead deemed "depressions" in otherwise developable land and filled. There is no recourse for the existing residents along what was a continuous watercourse that now ends at their property line. The neighbor's fill has increased their risk of inundation. There is a need for these watercourses to be mapped and protected from filling. Developers in our area view them as impediments to the "clean slate" they like to use when mapping their subdivision. We see them as an opportunity for the developer to design around their own use of them to accommodate the increase in stormwater their development will ultimately bring while maintaining the natural infrastructure that protects all of Santa Clara and River Rd. In this way, there is a direct benefit for the developer to use them and save on manufactured infrastructure costs. To date our basin has a total impervious surface area of approximately 37.5 %, and is projected in this plan to reach 51% at buildout. This will be the highest projected percentage of impervious surface of any of the city's basin areas. This plan highlights how impervious surface area affects both water quality and flood control profoundly. Water quality: Research shows that "water quality degradation occurs at relatively low levels of imperviousness (10 -20 %), so the implications of development on water quality are significant" (p.2 -23). Flood control: The computer model used to predict water levels did not match actual observed levels. Model parameters were adjusted to try and make the model more closely resemble actual conditions. Then several "additional model runs were conducted to evaluate the model's sensitivity to changes in input parameters. The results of these sensitivity analyses indicated that the impervious percentage area was the most sensitive model input parameter. "(p. 3 -6) So, with impervious surface percentage being the most influential variable, this basin projected to have the greatest impervious area, and our necessary reliance on infiltration and open waterways for stormwater conveyance, alternative development standards to require on -site storage and infiltration of stormwater makes sense. The unique set of circumstances in the RR/SC basin (lack of piped infrastructure, reliance on infiltration and open waterways, highly permeable soils) requires a solution that protects and enhances our natural drainage. Section 2: study area characteristics Both the city and the county have differing development standards for floodplain development and floodway development, however, "more detailed floodplain studies necessary to map floodway boundaries have not been conducted for this basin" (p.2 -17). Without these delineations, development is allowed to encroach on waterways in detrimental ways. We need development standards that will allow our natural infrastructure to meet our needs. Section 3: flood control evaluation Data collected for the computer modeling in this section was collected over an eight day period and validated for only three of those days in only one location. The effects of the resulting modeling did not match observed conditions and the data was subsequently "adjusted" to try and match real events. This is not a comprehensive data set upon which to draw conclusions for an entire basin, design major capital projects and form a course of action. In looking at table 3 -2, which details the hydraulic performance of RR/SC under present conditions and notes capacity issues for 10, 25, 50 and 100 year storms, there is no data listed for WO -005 from node 72088 continuing downstream to the end of the basin boundary. This section of the WO experienced significant flooding in the Feb. 1996 event. Stormwater rose from the storm drains to inundate the street over the curbs. In relating this to public works multiple times over the last few years in relation to ongoing development on this section of the WO, we were told that in high water events the sheer quantity of water in the Willamette River causes the WO to back up and not be able to drain into the Willamette. This anomaly is not reflected in the planning along the WO, or in the computer model which projects waterway capacity in high water events. The 1996 high water was deemed a "25 year" storm event, yet this section of the WO rose to the 374 -375 foot level, close to the" 100 year flood" level. I am concerned that this computer modeling will not reflect actual conditions. Drywells in our area were designed to accommodate a five year event. Current code requires stormwater systems to accommodate a ten year event. When rainfall exceeds the five year event, drywells become ineffective and the water is instead infiltrated where it falls, in roadside swales, in "remnanf 'waterways and identified open waterways. The data presented here shows that there are very few flooding problems associated with existing development in both the 10 and 25 year storms, yet the plan, in section 3.5.1 proposes 16 major capital projects associated with existing and future modeled capacity problems. Section 3.5.2 proposes an additional thirty-some projects associated with drywell decommissioning and rain gardens along all streets south of Horn Lane in River Rd. The modeling for future problems was done with the assumption that the drywells would be decommissioned. If that is so, how are these two lists not redundant and creating capacity for the same stormwater twice? The data presented (few capacity issues, disparity between modeled and observed conditions, ineffectiveness of drywells in carrying capacity) is not complete or compelling in light of the proposed capital projects. Plans for the other basins, completed in 2002, did not incorporate development standard alternatives. "The reason for this decision was that most of the identified flooding problems were anticipated to occur as a result of existing developed conditions. While future development would exacerbate some of the problems, a capital project to address flows from future development was more cost effective than requiring developers to address the issue through on -site storage requirements. For this basin, the conclusions from this previous analysis were assumed to apply" (p. 3 -15). The RR/SC basin plan was delayed for the last seven years in part because this basin is significantly different than the other basins. The challenges we face and the opportunities we have require us to problem solve differently than we did in the other basins. The last quote, however, clearly states that there was no analysis of the value of development standard alternatives in light of our circumstances and whether or not they are an appropriate tool for RR/SC. The data provided shows that there are few capacity issues related to existing development but that capacity will need to be expanded to accommodate expected buildout scenarios. This possibility cries out for the use of development standards to avoid costly capital projects and to meet the goals of the neighborhoods for livable communities. The required use of low impact development standards (LIDS), pervious pavement in all roads, parking lots and driveways, and on -site storage and infiltration of all storm water would go a long way toward meeting the goals for water quality and flood control for new development without staggeringly expensive capital projects. Section 4: water quality evaluation The water quality evaluation for the RR/SC basin is based on incomplete data. All water quality collection sites were located in other basins and pollution estimates were extrapolated from measured levels of total suspended solids (TSS) even though "TSS has not been shown to directly relate to all other pollutants ". The estimated percentage increase in TSS loads (as a measure of pollution) for our basin, according to fig. 4 -2, is approximately 20% due to decommissioning of drywells, but 55% due to future development. These figures suggest that future development will be far more deleterious to our water quality than the effects of decommissioning drywells. However, this plan proposes no development standards for future development to address this situation. Conventional wisdom is that storm water directly injected to the water table via drywells pollutes the groundwater and that runoff directly piped to open waterways pollutes the surface water. We agree with those premises, but do not come to the same action plan for the basin based on the collected information. Instead of trying to collect and treat storm water on a municipal scale without adequate mechanical infrastructure and piping, a dispersed system of infiltration based on development standards that prioritize non - mechanical infiltration of storm water, on site infiltration, and post development flows not exceeding pre - development conditions would accomplish both capacity and quality issues. Greater dividends will be reaped through addressing future development impacts before they are manifest than creating oversized capital projects for decommissioning drywells that will also hopefully meet the needs for future capacity. Pollutant load estimates in this plan are built on an assumption that "new development would occur without the inclusion of water quality BMPs ". However, new stormwater standards require the pretreatment of storm water using BMPs in PUDs and subdivisions and the stormwater code updates should require the same of all new development. The idea that "decommissioning of all drywells would result in those discharges being transferred, untreated, to surface waters" presupposes that the water otherwise captured by drywells will be sent to open waterways. The water presently collected in drywells could surface infiltrate, as happens informally everywhere throughout our basin presently. If this were the case, it would not be transported to surface waters untreated, but treat itself in our native soils through infiltration. The proposed rain garden street designs and the accompanying assumption that streets in our area will be widened at the time of "improvement" have not been publicly discussed. Adopting a menu of options that change a 25 foot road bed to a 50 foot roadway without public process or input will create undue amounts of tension and dissent within our neighborhoods. Experiences with context sensitive street designs and the ongoing discussions around costs to the adjacent property owners for these "improvements" need to be rolled out to our community with adequate opportunity for participation, questioning, and processing by the residents. Ironically, all of the proposed street options create more impervious surface than presently exists. Are we not then creating the problem so that we can engineer a solution instead of valuing our narrower roadbeds which do an admirable job of transporting us and reducing runoff? Many communities around the world are adopting the use of narrower streets, shared streets and other more innovative solutions that encourage the use of alternative modes of transport while reducing the paving footprint, preserving urban canopy and vegetation, and improving neighborhood livability. Section 5: stormwater related natural resources As mentioned in the beginning, the top -tier priority for stormwater related natural resources in our basin would be the mapping, protection, and enhancement of all our "lesser" waterways that are not accounted for through Goal 5, WR, WP and WQ overlays. The progress of changes to and implementation of LID standards in the code is unclear to us, but the required use of them within our basin makes functional, fiscal, and environmental sense. Doing all we can to minimize the need for large scale centralized infrastructure will allow us to grow and develop at a rate that the neighborhood can support. In closing, this plan outlines a wide array of costly capital projects designed to meet capacity and quality issues that have been identified based on incomplete data. Instead of forging ahead with a hope that this will be good enough, we would like to see us really look at all the possible tools to meet our needs. New development can and should retain and infiltrate all its stormwater on site. This is done in other communities with both new development and redevelopment and with retrofits for existing development. Responsibility for the effects of our own impacts should rest with each of us. In this way we can begin to build neighborhoods that meet the needs of their residents and minimize the need for costly capital projects that invariably need maintenance and replacement over time. Thank you for your consideration, Jerry Finigan, Chair SCCO Kate Perle, executive board SCCO Kelly Burke, executive board SCCO Rod Graves, executive board SCCO Timothy Foelker, executive board SCCO Cathy Lesiak, member SCCO Karen Lawrence, member SCCO Comments on the River Road / Santa Clara Stormwater Basin Master Plan from the River Road Community Organization. October 23, 2009 Dear Therese, These comments are submitted on behalf three members of the RRCO Executive Board. There has not been time to share the information in the Basin Plan with RRCO's full board or membership or the broader neighborhood during this comment period, nor have we been able to solicit feedback or take any kind of vote on its content. Overall, we are very disappointed that the proposed Basin Plan does not assess or recommend low impact development (LID) standards for our neighborhood -- standards to reduce the percentage of impervious surface and development footprints, protect well- draining native soils and "country- style" drainage systems, and protect large trees. It also does not discuss downspout disconnects or rainwater catchment systems, topics raised by RRCO members at past meetings about the Basin Plan. LID standards are desirable not only for stormwater management, but also to protect neighborhood character and broader environmental values. RRCO and residents of our area have been asking for such standards for many years - -during the Transition Project meetings and other processes and venues. As noted in the Executive Summary, each drainage basin offers unique conditions and opportunities for implementing development standards. Yet this plan ignores previous public input, and does not use this opportunity to propose unique or specific low impact development standards for this basin. We are also disappointed that neither this Plan nor existing City -wide stormwater standards (whether for private development or public capital projects) require on -site infiltration to the maximum extent feasible, as is required in Portland, nor require non - structural best management practices first, before use of engineered facilities. We are also very concerned that the proposed local street designs - -with sidewalks, wider lanes or parking bays, and on- street rain gardens - -are much wider and pave much more land than our existing local streets. Such streets would dramatically alter the character of our neighborhood, lead to loss of large trees and landscaping, and likely involve costly assessments to adjacent property owners. We believe that they would also encourage faster driving and greatly reduce the effective pedestrian zone relative to our existing "shared space" streets. There must be less expensive and intrusive ways to manage stormwater runoff from our streets. More options need to be evaluated (shared space and skinny streets, pervious /porous surfacing), and the public needs much more opportunity for involvement in designs for our local streets. Section 3: Flood Control Evaluation 3.2 -3.4 Model validation, results, and flooding problems This plan compares model results with actual conditions at just one point during one 3 -day rainy period. This does not seem like enough data to validate a model over the entire basin. Also, the model results at this one point do not correlate well with actual observed conditions, even after "adjustments " -- actual drainage is considerably better than predicted by the model. It seems that more work is needed to truly validate the model, or it may lead to over - predicting flooding problems and over - sizing of stormwater facilities. Also, simulations were done that showed that drywells do not provide significant drainage benefits in larger storms, even if they are carrying the full flow they are sized to handle (from a five -year storm). And even without the drywells being included, the overall model shows very few flooding problems even during the larger (10- and 25 -year) storms. This aspect of the modelling does seem to match some of our observations about what happens to roadway runoff during a rainstorm. Water infiltrates quickly into roadside drainage swales, and some of it also pools at low points in the street or areas where the drainage areas along the right of way have been compacted or paved. Eventually this water just evaporates. Certainly areas right near the drywells do drain into those for a short time during and after rainstorms, but it seems that even without the drywells, water flows have many places to drain away naturally into roadside swales, and soils are permeable enough to drain quickly. More could be done to educate property owners and residents about the function of the roadside swales, and to intervene to correct minor drainage problems in areas where water pooling does occur. 3.5.1 Capital projects Capacity deficiencies (e.g, areas of potential flooding) in the system are identified through modelling, and 16 specific capital projects are recommended to add more capacity to provide varying levels of flood protection for various sizes of rainstorms. However, as above, it seems that these projects might be over - sized, given that the model seems to overestimate flooding problems. It seems important to refine the model until its results more closely match observed reality before designing capital projects, some of which are extremely expensive. 3.5.2 Drywell decommissioning projects Supposedly the capital projects above will handle all modelled and observed flooding problems throughout the system. Also, the modelling results and on- street observations suggest that existing drywells may not be contributing much to the overall drainage of our area. Given this, is it really necessary to add additional capacity to replace the lost capacity of drywells? Isn't this just redundant capacity that will be largely superfluous to controlling flooding, just as the drywells are now? Certainly the capacity in existing roadside swales needs to be preserved, but it seems that capacity arguably is sufficient as long as pavement width of roadways is not widened (since there is very little flooding now). The assumption that local streets will be widened at the time of "improvement," with added paving width for driving, parking and sidewalks, is something that has not had a proper public airing. These assumptions also do not seem to be the best choices in terms of stormwater management. In our opinion, the local street designs summarized in Table 4 -1 are unnecessarily wide, with too much new paving and too much deference to facilitating cars. Many neighbors have expressed interest in narrower, pedestrian- oriented "shared street" or "woonerf" street models (and currently our local streets function in much this way), yet none of the proposed designs reflects such a model. The models that are proposed all include a separate new sidewalk, which arguably is not necessary or desirable for local streets in most of our neighborhood. The models also propose either widening existing travel lanes for cars, or adding separate parking bays. Adding all this pavement is detrimental to stormwater goals, as well as to neighborhood livability and other environmental goals. And it seems to be contributing to the need for extra -wide engineered rain gardens to infiltrate the induced new runoff In any case, the wide "footprints" of the new roadways (2.5 - 3 times wider than current paving widths) would have a huge impact on neighborhood character (front yards, landscaping and existing large trees). The design of residential streets, together with the amount and speed of traffic they carry, contributes significantly to a sense of community, neighborhood feeling, and perceptions of safety and comfort. At the least, affected residents need much more say before any street designs are adopted as guidelines. Residents also need to be fully informed at the outset about their responsibility for costs of road improvements, and the relative costs of various design options. The potential costs and impacts on neighborhood character are significant. Residents should have the opportunity to evaluate and compare some "shared street" options without sidewalks, and some narrower driving lane and on- street parking options. Some communities and guidelines are now suggesting and installing roadways as narrow as 14 feet wide for two -way traffic (18 feet of "drive- able" surface counting edge treatments). Also, permeable pavement options need to be considered. The use of permeable paving could reduce roadway runoff and help filter out pollutants, reducing or eliminating the need for additional stormwater facilities. Residents are also interested in "context sensitive" designs that preserve existing large trees, something that also has value for stormwater management. 3.5.3 Development standards This section states that flood control development standards were not selected for implementation in other Basin plans completed in 2002, for various reasons. The text also notes that detailed cost comparisons were done in conjunction with the other Basin Plans, showing that it was more cost effective to use public capital improvements, not a combination of public improvements and requirements on developers to address on -site storage. It is not explained why the same conclusions from other Basin Plans, or the rather dated cost analyses, are assumed to apply to our RR -SC Basin today. It is also not clear how total costs of public capital projects can (or should) be compared with costs to private developers. At the least, more explanation is needed to justify why these earlier data and conclusions are relevant to the RR -SC Basin and this Basin Plan. The text notes that many flooding problems in other basins are caused by "existing developed conditions ", and concludes that these problems need to be addressed by new (public) capital projects (instead of new development standards). It seems that other conclusions are equally reasonable. If existing (private) development causes flooding, then doesn't this suggest that development standards DO need to change to prevent similar flooding problems in the future? Also, shouldn't private property owners be required to address existing problems on their property, rather than new public projects having to be sized to handle their runoff? Portland's Stormwater code encourages, and in some cases, requires stormwater retrofit projects for private property. Eugene's could do the same. In any case, at least parts of the RR -SC Basin are significantly different than other Basins. Many areas in our neighborhood rely more on on -site stormwater infiltration and (non - structural) natural infiltration. We also have a relatively high groundwater table, and many people have and use irrigation wells. Current City -wide stormwater standards allow, but do not encourage or prioritize dispersed, on -site stormwater management. City stormwater codes also do not require protection of natural hydrology, nor offer enough non - structural choices for accomplishing on -site infiltration. We do not believe that existing City -wide stormwater standards or programs to encourage LID practices are sufficient to protect natural drainage, groundwater recharge, or surface water flows needed to maintain stream ecology in our area. Surface water flows (Flat Creek, Spring Creek) have already been altered by existing development. Also, if projected total impervious surface in the Basin could be reduced via new development standards, it seems that would reduce the few modelled and observed flooding problems throughout the system and allow some of the proposed public (flood control) capital projects to be smaller in size. Here are some of the low impact development standards or methods that we think need to be required or promoted in our Basin, and that need to be evaluated in this Basin Plan: * prioritization of on -site infiltration (as in Portland) * prioritization of non - structural Best Management Practices, including * Cluster development, * Minimize soil compaction, * Minimize total disturbed area, * Protect natural flow pathways, * Protect riparian buffers, * Protect and enhance sensitive areas and native vegetation, * Reduce impervious surfaces, * Disconnect impervious surfaces /downspouts, * Rainwater catchment/harvesting. * Split flow infiltration methods that preserve predevelopment stormwater flows in terms of rate, quality, frequency, duration, and volume, and thus more closely mimic natural systems. This is important for groundwater recharge, and preservation of surface water flow and natural channels and landscapes. Section 4: Water Quality Evaluation 4.2 Evaluation of existing and expected future water quality conditions The pollutant load estimates seem based on very shaky assumptions. First, no actual data was collected from our Basin about pollution levels, but data from other areas of Eugene was used to estimate it. Second, pollutant loads for Total Suspended Solids (TSS) were used as a general indicator of other pollutants, though "TSS has not been shown to directly relate to all other pollutants ". Third, when computing pollutant loads, decommissioning of drywells is assumed to result in 100% of those discharges being transferred, untreated, to surface waters. This seems like a very high estimate given the discontinuous nature of our drainage system, and the relatively high permeability of soils. In any case, it is unclear how these questionable pollution estimates are even used - -they don't seem to be driving particular actions or sizing of treatment facilities. On pg. 4 -5, the Plan does conclude that "pollutant loads in the RR -SC basin could potentially increase by up to 85% as a result of future development and drywell decommissioning, if treatment and /or other forms of infiltration are not provided for flows associated with drywell decommissioning." But in fact, Figures 4 -1 through 4 -3 show that the treatment of flows associated with drywell decommissioning would handle only a small part of the additional pollution that is projected--and this is the case even with the seemingly very exaggerated assumption about pollution that will be re- directed from drywells. In fact, the data presented show that most of the projected future pollution will be from new development. Thus, "treatment and infiltration of the flows associated with drywell decommissioning" appears to be NOT very helpful at reducing the potential 85% increase in pollution that is mainly from other sources. Instead, it seems that development standards to address pollution from private development would be more effective, and the logical top priority for this Plan. The sentence would be less misleading if it said "pollutant loads in the RR- SC basin could potentially increase by up to 85% as a result of future development, if treatment and /or other forms of infiltration are not provided for flows associated with future development." 4.3.1 Capital projects alternatives We understand that the existing drywells in our area are considered potential sources of pollution to groundwater, and that they need to be decommissioned to meet federal and state laws. However, not much else is very clear or convincing in this section about how (surface water) pollution will be addressed in our Basin, or what pollutants are of concern, or how the Basin Plan contributes to solving identified problems. In particular, it is not clear why rain gardens in conjunction with drywell decommissioning ought to be such a major focus. As above, the data is not convincing that decommissioning drywells will lead to significant additional surface water pollution that needs to be addressed near the sites of those drywells. As in our comments on Section 3, we have many concerns about the proposed local street designs with sidewalks and rain gardens. In terms of water quality, narrower "shared space" designs that do not include a separate sidewalk, and that use pervious pavement to reduce effective impervious area of the roadway, would be better choices for protecting water quality. 4.3.2. Development standards to address water quality Water quality development standards in the City stormwater manual may be sufficient to address water quality issues for new development in our Basin, unless significant types or amounts of new development (smaller and single - family units ?) are exempted from the standards. Also, we are not aware of what particular changes are being proposed for the update underway, nor what particular ways to encourage LID might be proposed under separate LID initiatives. However, there are many other low impact development standards that protect water quality that the City could consider, including those we listed above in our comments on section 3.5.3. Some of these may be lower in cost, more effective, and serve other beneficial functions besides just protecting water quality. We think additional low impact development standards should be encouraged or required for the RR- SC basin, to protect water quality and other values. As for preventing stream bank erosion, the Eugene Water Quality Protected Waterways ordinance and WQ overlay zone requirements are a good first step for protecting waterway segments that run through certain identified properties that are within City jurisdiction. However, Lane County needs to adopt similar protections that apply to waterway segments running through unannexed properties within the UGB. These waterways- - including segments of Upper Flat Creek and tributaries of the Al channel - -need protection whether or not the properties annex to the City. Section 5: Stormwater Related Natural Resources 5.2.2 Development Standards Alternatives As above, Lane County needs to adopt protections similar to those in the City's Water Quality Waterways ordinance, to protect waterway segments that pass through properties that are in Lane County jurisdiction now, and whether or not they are ever annexed to the City. Also, more protections are needed to prevent fill of waterways, even small ones, and whether or not such fill is done in the context of "development ". And low impact development standards, as listed in our comments on section 3.5.3, are needed to help ensure groundwater recharge and to help retain more natural stream flow in waterways such as Flat Creek and Spring Creek. Perhaps it is not feasible to consider more stream corridor acquisition for segments of Flat Creek or other waterways in our neighborhood, but it does seem that more could be done to educate property owners and the community about the natural values of even small waterways, and to encourage their protection and restoration. Section 6: Summary Overall, it seems that the data in this document show that the rain garden projects proposed as part of the drywell decommissioning are not needed for flood control. Also, the data is not convincing that they are needed for pollution control. If they were constructed, of course, they'd perform some of these functions. But they will replace swales that already perform these same functions, seemingly well. Does decommissioning the drywells really need to be linked to proposals for new sidewalks and wider streets and replacing our existing drainage swales? If necessary, the swales probably could be "spot renovated" with much less cost and disruption to our neighborhood character and landscape. Section 6.3 says that the proposed capital projects will be funded primarily through stormwater user fees and systems development charges. But does this include the costs of all the local street "improvements" that are proposed in conjunction with the drywell decommissioning? If not, and if the full street improvements are going to occur at the same time as the decommissionings (and assessments charged to local property owners), then this needs to be explained. Sincerely, Becky Riley Jolene Siemsen (co- chair) Marilyn Mohr (RRCO board members) City of Eugene & Lane County response to SSCO & RRCO October 2009 comments. Date: February 23, 2010 LANE To: Jerry Finigan (Chair), Santa Clara Community Organization Becky Riley & Jolene Siemsen (Co- Chair), River Road Community Organization From: Therese Walch, City of Eugene Public Works Dan Hurley, Lane County Public Works Thank you for the offering your comments and input on the draft River Road -Santa Clara (RR- SC) Stormwater Basin Plan. We sincerely appreciate the time and attention you have given to reviewing this document and the proposed stormwater management strategies. We have considered your comments carefully, consulted with other staff and managers in our respective organizations, and offer the following responses. We reiterate first the purpose of the stormwater basin planning, and what we understand to be the main themes of your comments. Following that, responses are provided by topic area, and include references to the community organization's comments (Attachments A and B We are looking forward to meeting with you to discuss these responses in more detail. Please see the last page of this letter for contact information if you need to reach us in the meantime. PURPOSE OF STORMWA TER BASIN PLANNING The purpose of the basin planning is to develop a stormwater management strategy that takes into consideration the unique stormwater- related characteristics of each basin, carries out established local policies, complies with federal and state regulations, and reflects input from stakeholders including residents of the basin. As with the City's six other basin plans, the RR- SC Plan describes a "multiple- objective" approach (i.e. incorporating water quality, stormwater- related natural resources and flood control) to stormwater management that reflects the problems and opportunities within the RR -SC basin. It is to be used by City and County staff for background /contextual information, for development of the City's (and County's, in this case) capital improvement programming, for contextual support for development standards, and for evaluating technical information about the stormwater system. It is intended to be complementary with the other activities conducted within the City and County's stormwater programs. The Basin Plans are not used by the City or County in a manner that regulates the conduct or activities of the public. 1 Attachment A: Santa Clara Community Organization comments (Letter to Therese Walch from Kate Perle, on behalf of Jerry Finnigan (Chair), Kate Perle, Kelly Burke, Rod Graves, Timothy Foelker, Cathy Lesiak, and Karen Lawrence, October 23, 2009), annotated to include comment numbers: "SC -XX." 2 Attachment B: River Road Community Organization comments (E -mail to Therese Walch from Becky Riley, on behalf of Becky Riley, Jolene Siemsen (Co- Chair), Marilyn Mohr, and Carleen Reilly (Co- Chair), October 26, 2009), annotated to including comment numbers: "RR -XX." RR -SC Stormwater Basin Plan Comments Pg. 1 of 17 OVERARCHING THEME OF PUBLIC COMMENT An overarching theme of the comments from the River Road Community Organization (RRCO) and Santa Clara Community Organization (SCCO) is that the basin plan strategies do not address the uniqueness of the basin, reflected in its "heritage trees, waterways, prime soils, agricultural operations, significant populations of both urban and rural and county and city residents" and that the plan misses the mark in prioritizing the protection and enhancement of the basin's existing natural infrastructure [SC -1] While the RR -SC Plan does not go as far, prescriptively, as the community organizations desire, the unique stormwater - related characteristics of the basin were significant factors in the development of strategies for River Road — Santa Clara. The strategies reflected in the basin plan, complimented by city -wide efforts including new initiatives implemented since the 2002 adoption of the other six stormwater basin plans, go a long way towards achieving the desired outcomes we heard expressed by the community groups, and reflect significant accomplishments in moving away from single- focused flood control stormwater management to multiple- objective stormwater management as conveyed in the City's stormwater policies. The mechanisms for achieving the outcomes with respect to development standards are not as prescriptive as the community organization's comments indicate they would like to see, but reflect the City's policy decisions aimed at balancing prescriptive -ness, incentives, and choice. Some factors such as the preservation of heritage trees and the protection of agricultural uses for example simply reside outside of the purview of the basin planning process. We offer the following as examples of stormwater management strategies that address the RR -SC basin's unique characteristics: • New local green street design concepts were developed that utilize rain gardens, surface infiltration, and on -site stormwater management for adjoining properties as opposed to a traditional curb /gutter /piped street improvement. These green street design concepts were developed specifically to address the problems and opportunities related to stormwater management in RR -SC including the lack of a consistent stormwater system, very flat topography, well- draining soils, mixed jurisdictional areas, significant extent of vacant and "underdeveloped" properties, large number of unimproved streets, and federal regulatory limitations on the use of drywells for stormwater destination. Once incorporated into the City's Local Street Plan, these green street design concepts may be used city -wide as appropriate. • Public underground injection controls (UICs), or drywells in RR -SC that do not meet Safe Drinking Water Act regulations, primarily due to the shallow groundwater conditions in the basin, will be replaced, many with vegetated surface infiltration facilities (i.e. rain gardens). s SC = Santa Clara Community Organization comment, on annotated Attachment A. RR -SC Stormwater Basin Plan Comments Pg.2 of 17 • Water quality retrofit projects were identified for specific locations in RR -SC to address high pollutant land uses in built -out areas developed prior to the enactment of Stormwater Development Standards. • Capital projects were identified to address flooding problems on the major stormwater system that were identified by the RR -SC system model under existing and future development conditions. Capital projects will be incorporated into the City's larger list of capital projects, and prioritized in accordance with capital improvement program (CIP) project prioritization criteria. • Support for implementation of Stormwater Development Standards to address the quality of runoff from new development and re- development (Note: Stormwater Development Standards were instituted in 2006 for development inside city limits). The standards include incentives for impervious surface area reduction techniques, and a range of green infrastructure options for meeting the stormwater requirements including rain gardens, filter strips, vegetated swales, and green roofs. • Support for increased implementation of green infrastructure and low impact development (LID) practices through potential administrative adjustments, integration of LID practices with other initiatives, land use code amendments and other program enhancements. (Note: City Council direction on implementing LID was provided at a January 17, 2007 worksession on "Green Infrastructure and Low Impact Development" and a September 17, 2008 follow up work session). Support for protecting certain waterways with a strong relationship to those considered water quality impaired by the State of Oregon, and not otherwise protected, including segments of waterways in RR -SC: Flat Creek, Spring Creek, and the East Santa Clara Waterway (Note: The City's /WQ Water Quality Overlay Zone was enacted in 2009 and applies to certain properties within the Eugene city limits including in RR -SC. It also applies to certain properties outside city limits and inside the urban growth boundary, (UGB) but only upon annexation). The /WQ Overlay Zone compliments other waterway protections previously adopted by the City and County (namely, Goal 5) to protect wetlands and wildlife habitat. The City of Eugene and Lane County have worked closely together on the basin planning and will continue to collaborate to implement the RR -SC Plan, within the respective agency's funding constraints. RR -SC Stormwater Basin Plan Comments Pg.3 of 17 COMMENTS AND RESPONSES BY TOPIC AREA Topic; Protection of Natural Functions of Waterways Map all waterways, and protect them from filling. County should adopt IWQ inside UGB, outside city limits. [SC -21, [SC -141, [RR -14] [RR -15,1 Waterways are very important components of the RR -SC stormwater system, as is the case in each of Eugene's six other stormwater basins. Evidence of the importance of waterways to the City's stormwater system is Policy 1.1 of the Comprehensive Stormwater Management Plan (CSWMP, adopted by City Council in 1993) which states: Incorporate the beneficial functions (flood control, stormwater conveyance, water quality treatment) of natural resources into the City's storm drainage system. In total, the City and County have applied land use /zoning regulations to a system of local waterways inside the urban growth boundary (approximately 100 miles in length) which meet federal and state requirements and local policies related to water quality and natural resources. The City recently applied waterway protections to 13.5 miles of waterways in the form of the /WQ Water Quality Overlay Zone, adopted by City Council in March 2009. Prior to that, in 2005 and 2006, the City Council and the Board of County Commissioners each adopted a /WR Water Resources Overlay Zone that protects waterways within the Eugene UGB for their significant habitat value. Prior to that, in 1995, the City Council adopted waterside setback ordinances (/WB Wetland Buffer Overlay Zone, /WP Waterside Protection Overlay Zone) in the west Eugene wetlands area to protect wetlands and waterways in west Eugene. A fact sheet describing local waterway protections through land use and zoning overlays is included in this response to comments. Additional waterway protections through land use and zoning regulations are not under consideration by the City at this time or in the foreseeable future. Lane County is constrained by resources to enforce greater protections of minor waterways. However it is presently establishing a working group in conjunction with watershed councils and other interested parties to analyze and make recommended changes to the County's riparian protection ordinance applicable outside of the urban growth boundary. While significant waterway protection has been achieved over the last decade through local land use regulation, the protections do not apply to all waterways. Smaller waterways may be categorized as wetlands and may therefore be protected to some degree by federal and state wetland fill regulations. 4 RR = River Road Community Organization comment, on annotated Attachment B. RR -SC Stormwater Basin Plan Comments PgA of 17 Educate property owners and residents about the function of roadside swales and small waterways. [RR -51 Lane County and the City of Eugene currently partner on stormwater education activities inside the Urban Growth Boundary (UGB) as part of the City /County Stormwater Intergovernmental Agreement related to the City of Eugene's National Pollutant Discharge Elimination System ( NPDES) Phase I permit and Lane County's NPDES Phase 11 Permit. Under the agreement, a Stormwater Connections newsletter is mailed directly to all city and county residents inside the urban growth boundary. Articles have been included in the Stormwater Connections newsletter (Spring 2005, Spring 2007 issues) related to the importance of ditches and swales and the adverse impacts to them of dumping debris and filling. An article is being drafted for inclusion in the Spring 2010 issue related to this topic, and additional articles will be considered for future additions. The City and County are always open to input about newsletter topics and public outreach strategies in general, and encourage residents to contact Kathy Eva, Eugene's Stormwater Information Specialist at: 541- 682 -2739. Citizens in both jurisdictions are encouraged to contact the City of Eugene Maintenance Division ( #541- 682 -4800) or County Road Maintenance Department ( #541- 682 -6901) to identify areas where water pooling occurs and to assist in identifying possibilities for correcting minor drainage problems. City and County have different floodplain development standards. More detailed delineations are needed to prevent encroachment on waterways. [SC -51 The City and County participate in the National Flood Insurance Program (NFIP) program. The Federal Emergency Management Agency (FEMA) is tasked with creating floodplain maps for the entire country; the City has adopted the most recent flood maps provided by FEMA. For financial and practical reasons FEMA has devoted more attention to urban areas that are at risk of flooding, and to larger streams and rivers. Detailed studies have been conducted for two waterways in the Eugene area: the Willamette River and Amazon Creek. As with rural areas and smaller tributaries across the country, the smaller waterways in Eugene have had floodplain boundaries determined using approximate methods; these areas are known as `approximate A Zones.' Santa Clara has many small approximate A Zones. It is not anticipated that FEMA will perform a detailed hydrological analysis for Eugene's approximate A Zones in the foreseeable future. The City and Lane County have adopted floodplain development regulations that apply in their respective jurisdictional areas. The Lane County and City of Eugene floodplain regulations are similar as both are intended to meet Code of Federal Regulation standards for participation with the NFIP, and state mandates. Under a 1987 Intergovernmental Agreement, authority for land use and building permit review within the urban growth boundary including areas outside Eugene city limits is conveyed to the City (with some exceptions, e.g. for the Airport and the RR -SC Stormwater Basin Plan Comments Pg.5 of 17 Lane County Fairgrounds). Development in approximate A Zones is required to meet the same City and County development standards as those in areas where detailed studies have been conducted, with just a few differences. Where detailed studies have been conducted, the hundred year water surface elevation is determined by FEMA (the expected water surface elevation corresponding to a statistical flooding event that has a one percent chance of occurring in any given year), and a floodway is designated. For approximate A Zones, the best available data from an authoritative source is used where possible to determine the 100 -year water surface elevation, and when good data is not available the applicant is responsible for determining the 100 -year elevation using a FEMA approved method, which is then evaluated by City staff. Larger developments, such as subdivisions over five acres or fifty lots are required to provide detailed hydrological analyses. Floodplain development regulations are the same in either case (detailed study areas vs. approximate A Zone areas) except that approximate A Zone areas do not have designated floodways. Floodways are intended to remain unobstructed to convey floodwaters out of our community, are typically associated with high velocity flows, and have significant encroachment provisions. The City and County floodplain development standards would not significantly change as a result of a detailed floodplain analysis in areas now designated as approximate A Zones, with the exception of floodway development prohibitions. However, for the City of Eugene, regulations regarding watercourse alterations at Eugene Code Section 9.6707 protect the flood carrying capacity of some rivers and streams that have no designated floodway. Other regulations often apply to development within the floodplain such as federal and state wetland regulations, and local natural resource and water quality waterway protections. Topic; Development Standards /Low Impact Development No development standards proposed in the Basin Plan for future development. Instead of collecting and treating stormwater on a municipal scale, maximize on -site infiltration, and require that post - development flows equal pre - development flows for new development. Require prioritization of non - structural BMPs over engineered facilities. Basin plan does not assess or recommend LID standards. Require low impact development standards [RR -11, [RR -21, [SC -101, [SC -141 The RR -SC Plan supports the implementation of city -wide Stormwater Development Standards, for much the same reasons they were proposed by the other 2002 basin plans: mainly, that on- site stormwater controls are the most cost - effective way to deal with the water quality impacts of new development. Municipal -scale collection and treatment of stormwater is not being proposed. Retrofitting the existing municipal system through capital projects is another element of the city -wide water quality strategy, but it is more targeted to collection /treatment in high pollutant source areas and opportunistic restoration /rehabilitation of the open and piped system to incorporate water quality features, and is not wholesale collection and treatment. RR -SC Stormwater Basin Plan Comments Pg.6 of 17 City -wide Stormwater Development Standards, enacted in 2006, include requirements for: destination, pollution reduction, oil controls, source controls, and flow controls for the headwaters area (for water quality). These requirements apply to properties inside city limits as well as any properties annexed to the city from the urban growth boundary. Stormwater destination requirements were already in place in 2006 and apply to all development, for the purposes of providing adequate stormwater conveyance and appropriate levels of flood control. The water quality requirements added in 2006 (pollution reduction, oil controls, source controls, and headwater flow controls) apply to new development and re- development that add or replace 1,000 square feet of impervious surface area or more. The City's code prescribes the basic design standards (flood control design storm and water quality design storm) that must be met and references the Stormwater Management Manual for acceptable facility options and detailed siting criteria and design requirements for each facility. The City does not dictate the type of facilities or stormwater management method that must be used to meet the flood control and water quality requirements, but rather provides the "tools" or best management practices to facilitate green infrastructure /low impact development (LID) practices. Facility options in the Stormwater Management Manual include those that allow onsite management of stormwater including ecoroofs and roof gardens, pervious pavement, stormwater planters, tree credits, swales, filter strips, soakage trenches, infiltration sumps, drywells and rain gardens. Financial incentives in the form of lower systems development charges and stormwater user fees are provided for certain techniques (pervious pavement, eco- roofs, contained planters, and tree credits) that reduce impervious surface areas. These techniques also results in smaller water quality facilities for treating runoff from the remaining impervious area. Beyond the stormwater development standards code and manual, the City has produced and distributed brochures (e.g. "Planters with a Purpose "), conducted outreach and trainings for the design community, and is setting an example for the community through its public capital improvement projects. In addition to supporting the Stormwater Development Standards, the RR -SC Plan supports following through on direction provided by the Eugene City Council related to LID. At a January 17, 2007 worksession ( "Green Infrastructure and Low Impact Development "), Council directed staff to conduct a review of the Eugene Code and administrative policies and procedures to identify barriers and regulatory or incentive -based approaches to increase the use of LID practices. At a follow -up September 17, 2008 worksession ( "Low Impact Development - Results of Review "), Council directed staff to further increase implementation of LID practices. This work is underway, beginning with identifying specific administrative adjustments, incentives, and other LID- related actions or implementation. 5 Eugene Code Section 9.6790- 9.6797 RR -SC Stormwater Basin Plan Comments Pg.7 of 17 An assessment of the types of facilities constructed in the past year in Eugene shows that a proportionally higher number of green infrastructure/LID 6 facilities over mechanical treatment facilities are being implemented by private development. More specifically, for the period of time from July 1, 2008 through June 30, 2009: • Of the 124 land use applications reviewed for stormwater development standards purposes, three times as many proposals incorporated green infrastructure/LID facilities, as compared to those that incorporated mechanical water quality treatment facilities (90 vs. 34, respectively). • With respect to residential building permits issued, 54 of the 55 incorporated green infrastructure /LID facilities, and one incorporated mechanical treatment. • With respect to commercial building permits issued, 35 of the 69 incorporated green infrastructure /LID facilities (including: 2 filtration planters; 6 vegetated swales; 9 grassy swale; 7 vegetated filter strips; 5 rain gardens; 2 soakage trenches; and 4 pervious pavers), and 34 incorporated mechanical treatment facilities. In summary, the City's approach to regulating stormwater management is a combination prescriptive- choice- incentive -based approach. The Stormwater Development Standards and Stormwater Management Manual prescribe the basic requirements, offer a range of choices including many green infrastructure /LID choices to suit a wide range of site - specific conditions, and incentivize the preferred choices through financial and other means. The owner /developer must meet the stormwater development standards, and is allowed to make choices in terms of stormwater facility type utilized, suitable for each individual property. The City provides outreach and training, and sets an example through its capital projects. In addition, the City is actively working to identify additional incentives and reduce or eliminate barriers to implementing LID, in accordance with City Council direction. The outcome of this approach is that the vast majority of residential developments and a slight majority of commercial /industrial developments are choosing green infrastructure /LID facilities. The City will continue to seek ways to further increase the use of these facilities. 6 Green infrastructure facilities for purposes of the City's categorization include vegetated swales, filter strips, and rain gardens, which are all pervious in nature. Soakage trenches are infiltration facilities, therefore pervious by design, but are not vegetated. Therefore, soakage trenches are considered LID facilities, but not green infrastructure as the term is commonly used. Mechanical facilities are not pervious in nature. RR -SC Stormwater Basin Plan Comments Pg.8 of 17 Development standards to address pollution from private development would be more effective than treatment and infiltration of flows associated with drywell decommissioning and therefore should be a higher priority. [RR -121 Both are important and necessary aspects of the stormwater management strategy for RR -SC and are not mutually exclusive actions. Stormwater Development Standards are necessary for meeting the Clean Water Act and associated municipal stormwater permits issued to the City of Eugene (National Pollution Discharge Elimination System, or "NPDES" Phase I permit) and Lane County (NPDES Phase II permit). As described above, the City's stormwater development standards apply to properties inside city limits as well as any properties annexed to the city from the urban growth boundary. These standards address the water quality impacts from new development and re- development sites within city limits. Addressing existing UICs that must be decommissioned for lack of separation to high groundwater levels is also necessary to meet Safe Drinking Water Act regulations (see Department of Environmental Quality, or DEQ, web site for more information about UIC regulations and pending permits for municipalities utilizing UICs: ham: / /www.deq. state .or.us /wq /uic /permits.htm Providing treatment and conveyance for stormwater currently directed to certain UICs is necessary to address the potential water quality impacts to surface water (of surfacing water currently directed to sub - surface — for UICs decommissioned utilizing a piped system) and groundwater (to provide treatment of water directed to sub - surface, prior to reaching groundwater — for UICs decommissioned utilizing rain gardens). Reduce projected impervious surface area via development standards, and as a result CPs would be smaller in size. Requiring low impact development standards, pervious pavement for all roads, parking lots and driveways, and on -site storage and infiltration of all stormwater would reduce the size of capital projects. [SC -91 [RR -101 As described in responses above, the City provides incentives for certain best management practices (e.g. pervious pavement, eco- roofs, contained planters, and tree credits) through lower systems development charges and user fees, and through impervious surface area reduction in sizing stormwater facilities. The City encourages, but does not require, green infrastructure/LID facilities over structural engineered facilities. The majority of residential developments, and slightly more than half of the commercial developments over the past year have chosen to use green infrastructure /LID facilities. Follow through on Eugene City Council direction to further increase implementation of LID is underway. It is anticipated that all of these efforts will reduce the total impervious surface area in the RR -SC basin and throughout the City, as compared to traditional development. However, development standards and incentives affect only the areas undergoing development and re- development, and must be considered in the context of the large amount of existing impervious area not affected by the development standards. RR -SC Stormwater Basin Plan Comments Pg.9 of 17 Most proposed flood control capital projects were identified to address problems predicted to occur by the model developed for the major system, for larger storm events, based upon assumed impervious surface area percentages. The City acknowledges that the assumed impervious surface area percentages used in the model are inherently slightly conservative, as they do not reflect assumptions about the degree to which impervious surface area will be reduces through incentives, however it is the City's, County's and consulting engineer's best professional judgment that slight conservatism is appropriate in the assessment of the major flood control elements of the system for purposes of identifying potential flooding problems and capital project needs. It is very important to realize, however, that during capital project design, in advance of any capital project construction, a more detailed storm drainage study is conducted which delineates the drainage areas, impervious areas, and runoff volumes to a greater level of detail than is done in the master planning process and would refine the size of flood control facilities. Justify why flood control standards do not pencil out compared to flood control capital projects for this basin. [SC -91, [RR -91 As with the other stormwater basins, most of the identified flooding problems in RR -SC were anticipated to occur as a result of existing developed conditions. While future development would exacerbate some of the problems, a capital project would already be required to address existing condition flooding. Implementing on -site storage requirements for new development would not address the majority of capacity - related problems as identified by the model. Require on -site storage and infiltration for all new development. [SC -41, [SC -91, [RR -21 As described above, the method for managing stormwater is not prescribed, but acceptable choices are provided in the Stormwater Management Manual. The appropriate destination method is site - specific and depends on a number of factors including soil type, slopes, and availability of public and private infrastructure. While on -site storage and infiltration is not explicitly required, certain circumstances prevalent in the RR -SC basin would in effect necessitate on -site retention /infiltration, for example: o Development sites in any area of the City where a public stormwater system does not exist and extension from the public system is not planned. Figure 4 -11 (Project Planning Phase) in the draft basin plan illustrates this situation, which reflects inherent constraints in some areas of the RR -SC basin (as well as other areas within the City, but less so) for piping stormwater off -site. The decision making process reflected in the figure conveys the City's strategy to allow for use of capacity where there is capacity in an existing piped system, and for connection to an existing piped system if it is feasible and there is capacity in the downstream receiving system. Given the RR -SC basin's inherent constraints (including discontinuous stormwater system, flat topography, mixed jurisdictional areas, RR -SC Stormwater Basin Plan Comments Pg.10 of 17 funding constraints), however, extending the piped system wholesale throughout RR -SC is not feasible nor is it the City's plan to do so. As shown on the figure, new development or infill development, if not located on an improved street that drains to a piped system, will need to assess the feasibility of constructing a piped system (including downstream connection and capacity constraints), and if not feasible or desirable, then the developer would need to select an approved alternative for managing stormwater on -site. Modifications to Figure 4 -11 will be made to reflect more clearly that on -site stormwater management (including volume controls) would be necessary under these circumstances. o Future situation, assuming new local "green street" design concepts are incorporated into the City's Local Street Plan (through a separate process). The local green street design concepts, which are envisioned to be alternatives to current local street standards, as proposed, assume that the linear rain gardens are sized for right of way runoff only, therefore development sites adjacent to a green streets would by necessity need to manage stormwater on -site (including volume controls). The green streets concepts could be employed on new local streets, or in a re- development situation. Permeable pavement options need to be considered [RR -81 Most street improvements will occur in response to development and most likely only in areas annexed by the City of Eugene. Permeable pavement has been used by the City on a pilot project basis, and is an accepted stormwater impervious surface reduction technique as long as it meets design criteria, but is not acceptable yet for use in the right of way. It should be acknowledged that such pavements accompany a higher construction cost and may be limited in their functionality without significant maintenance to prevent pore clogging. Permeable pavements are not recommended for sites with a likelihood of high oil and grease concentrations, which would include streets with a high number of average daily trips (> 1,000). Topic; Impervious Surface Area (ISA) RR -SC highest ISA percentages compared to other basins. [SC -31 The amount of impervious surface area (ISA) will increase as vacant or "underdeveloped" (meaning, not yet developed to Metro Plan designation and related densities) properties are developed. The basin plans estimate the future, or "buildout" ISA by assuming properties will be developed in accordance with the Metro Plan designations, and utilizes average ISA percentages by generalized land use categories, and the area of each land use category. The buildout ISA for the RR -SC basin is projected to be 50% (plan page 2 -12), an increase from the 2006 ISA of 37.5 %. The increase in ISA can be partly attributed to the relatively significant amount of vacant industrial area (326 acres as of 2006) within the basin. The estimated average RR -SC Stormwater Basin Plan Comments Pg. l l of 17 ISA for industrial land use is 60 %, as compared to 35% for low density residential land use (see Volume I, Appendix B for ISA factors by land use category), which significantly increases the overall basin buildout ISA. Overall, however, the buildout ISA for RR -SC is similar to that projected for the other basins: Bethel - Danebo (increases from 35% in 2006 to 50% at buildout), Willakenzie (37% in 2006 to 47% at buildout), Amazon (33% to 44 %), Willamette River (40% to 44 %), Laurel Hill (20% to 43 %), and Willow Creek (14% to 42 %). As with the other basins, now that stormwater development standards are in place (since mid - 2006), it is expected that the actual buildout ISA will be lower than the 50% calculated since the ISA factors used in the calculations assume buildout using traditional development practices. As described previously, this is appropriately conservative for use in modeling the major stormwater system for purposes of ensuring adequate conveyance and flood control. Topic; Underground Injection Controls or UICs (Drywells) It seems that rain garden projects proposed for drywell decommissioning are not needed for flood control, and may not be needed for pollution control either. Is it necessary to replace the lost capacity of drywells since they do not appear to have much of an effect on the overall drainage of the area? Instead of conveying UIC runoff to surface waterways (as part of decommissioning), infiltrate. [RR -7j, [RR -16j, [SC -121 Existing UICs must be decommissioned to meet Safe Drinking Water Act regulations. These facilities manage stormwater runoff primarily generated by impervious surfaces in the existing rights of way with an average contributing area of approximately 2.7 acres per drywell. There are approximately 150 total in RR -SC, with roughly equal numbers owned and managed by Eugene and Lane County. The County and the City must provide alternative means to convey the runoff currently managed by the existing drywells to meet the City and County's goals and policies related to flood control and water quality protection, and to remain in compliance with Oregon Drainage Law. Surface infiltration via rain gardens will be employed in decommissioning isolated drywells where there is no piped system with capacity nearby to connect to. In addition to managing the runoff for flood control, rain gardens provide the added benefit of surface water treatment and groundwater recharge. For the instances where there is capacity in the municipal system and the system is in close enough proximity for connection, the RR -SC plan assumes the runoff originally going to the drywell will be directed to the municipal system. In that case, pre- treatment of runoff utilizing a structural water quality facility prior to discharging to the municipal system will be incorporated. RR -SC Stormwater Basin Plan Comments Pg.12 of 17 Why are rain gardens in conjunction with drywell decommissioning such a major focus? []?R -121 Due to the discontinuous nature of the stormwater conveyance in this Basin, it was considered impractical to extend new piping to each of the drywells to be decommissioned. Rain gardens are proposed as an alternative solution for isolated drywells or clusters of drywells that are of considerable distance from an existing stormwater pipe and for which no piped extension is planned. Does drywell decommissioning need to be linked to proposals for new sidewalks, wider streets, replacing existing drainage swales? Could existing swales be "spot renovated" instead? [RR -171 Decommissioning of drywells is not necessarily linked to proposals for street improvements. Staff acknowledges that the RR -SC Plan conveys that impression, and will clarify the strategy in that regard. It is most likely that the regulatory timeline for decommissioning drywells will require action by the City and County on all drywells within the next 10 -12 years, necessitating the construction of isolated rain gardens and piped connections to the existing system — depending on the specific circumstances for each drywell. In the case of an isolated UIC decommissioned via a rain garden, the rain garden could be configured longitudinally, oriented parallel to the street and coincident with the existing swale(s) if the swale could be engineered to function adequately to infiltrate the City's flood control design storm. Adequate surface area and infiltration rates in a rain garden must be achieved in order to handle the flows currently being managed by a drywell. Where local street improvements occur in the next 10 -12 years, and if the street improvement is in an area with several public drywells to be commissioned, it makes sense to consider incorporating the management of the roadway runoff via rain gardens into the plan to decommission the UICs. Topic; Local Green Street Design Concepts • Would add too much new impervious area, alter character of the neighborhood, and result in loss of street trees and other vegetation. Would involve costly assessments; who pays? Need more discussion and public review before implemented [SC -131, [RR -31, UMA Staff's objective in developing the local green street concept drawings was to provide alternatives to traditional "improved" local street sections (which include curbs, gutters, pipes). The green street concepts address problems and opportunities inherent in a discontinuous stormwater system, rapidly draining soils, flat topography, and shallow groundwater. They also incorporate feedback received from the RR -SC community groups on maintaining narrower streets and utilizing green infrastructure. The concepts are intended to be used as a starting point RR -SC Stormwater Basin Plan Comments Pg.13 of 17 for future discussions and a separate public process which will take into account other non - stormwater related concerns before they are implemented. The green street concepts, once finalized, would most likely be utilized in areas annexed to the City of Eugene. Generally speaking, with respect to financing, if a local street improvement is developer driven, it would be paid for by the developer. If it is initiated by the property owners through the formation of a local improvement district, it would be paid for by assessments to the abutting property owners. The UIC decommissioning elements (e.g. rain gardens and appurtenances) would most likely be funded by the City's stormwater utility fund capital improvement budget. Improvements to arterials and collectors streets may follow the City's "context sensitive" collaborative design process which incorporates significant opportunities for public input on road design, stormwater management, preservation of trees, funding options, and safety. Topic; Modeling and Capital Projects Modeled and observed conditions do not match up. Model does not extend far enough. Limited data upon which the model was based and the adjustment of the model to fit observed conditions [model calibration] is inadequate as the basis for major capital projects, and may result in oversized capital projects. [RR -4], [RR -6], [SC -41, [SC -61, [SC -7j The stormwater model used to evaluate the capacity of the public drainage system is a generalized representation of the system. Calibrating the model to match measured or observed conditions is an iterative process involving adjusting certain variables (within realistic ranges) and comparing results, adjusting again, and comparing results, until a best fit is obtained. The computer model for the RR -SC basin planning evaluated the capacity of approximately 160 open waterway and pipe segments under existing and future land use conditions. The models were updated using survey data collected by Lane County between October and December 2005. The model was validated and adjusted in response to historic photos and observed freeboard elevations provided by the City and through comparison of actual conditions at the Willamette Overflow using real rainfall data for the period from December 27, 2005 to January 3, 2006. Through the RR -SC model calibration process, the impervious surface area percentages were modified to reflect "effective impervious area" as opposed to mapped impervious area. This adjustment is realistic because of the relatively disconnected nature of the stormwater system in RR -SC, but it is still somewhat conservative (as evidenced by the fact that the surface water elevations predicted by the model are somewhat higher than observed values). See page 3 -7 of the basin plan for a more detailed discussion of the adjustment to ISA factors, and rationale. The current model is the best fit based upon best available information and professional engineering judgment of the engineering consultants, and the City's engineering staff. It is acknowledged that further refinement to the model based upon measured flow data would be RR -SC Stormwater Basin Plan Comments Pg.14 of 17 beneficial to confirm capacity issues on the major system. Therefore, installation of a flow meter in the Basin has been added to the capital project list. The capacity - related capital projects resulting from the modeling will be added to the City's long -term stormwater capital improvement needs. The City's project list (including all stormwater project needs, city -wide) is significantly larger than the budget available, and by necessity a prioritization process is used to identify the highest priority projects for implementation. Prioritization criteria include whether a flooding problem is observed vs. predicted by modeling, which is where the large stormwater projects referred to in the comment would not rise to the top in the foreseeable future. Flow data and model refinement will realistically precede implementation of these capital projects. In effect, these projects are placeholders for potential capital investment in the future to maintain system capacity, and are based upon the best available information and professional engineering judgment. Individual stormwater facility capital projects will be assessed using additional data prior to final design and construction to ensure proper sizing. The County does not currently have funding for stormwater related capital projects. As the County develops funding for such projects, prioritization will be assigned in a manner similar. With respect to the extent of the model, basin planning stormwater models were generally limited due to budget and resource constraints to the larger system (pipes 36- inches and larger, and larger waterways), generally inside city limits. The RR -SC basin plan model goes beyond the modeling in other basins in that it extends, for the most part, through the mix of jurisdictional areas to the urban growth boundary. The Willamette Overflow downstream from node 72088 was not included in the model because most of it is on the edge of the UGB, with some located outside the UGB, and is located downstream from subbasin WO -000 which lies entirely outside of the UGB. It appears redundant to create capacity with facilities to replace drywells and construct large flood control capital projects. [SC -81 The City's Stormwater Development Standards require stormwater systems (pipes or drywells) serving less than 40 acres to be designed for a 5 -year storm. Open channel systems serving less than 40 acres and all systems serving 40 acres up to 640 acres must be designed for a 10 -year storm, except for culverts and bridges for arterial streets which must be designed for a 25 -year storm. The modeling for future (build -out) conditions reflects that the existing drywells do not manage a volume of runoff significant enough to affect capacity needs of the major system. In other words, whether under existing conditions or future buildout conditions, the existing public drywells do not have a significant effect on the major system conveyance needs. The decommissioning of drywells is not driving the capacity - related capital projects. What is driving the capacity related projects is a set of constraints on the major system (for example, on the RR -SC Stormwater Basin Plan Comments Pg.15 of 17 upper Al system) that are predicted by the model for the larger contributing area under existing (2006) conditions, and exacerbated by future development. Topic; Pollutant Estimates Pollutant load estimates are not based upon basin - specific water quality data. Question use of TSS as an indicator. Question assumption regarding contribution of runoff from decommissioned UICs. [SC -101, [RR -111 Although there is limited data on water quality in the Basin, the pollutant load estimates point to the need to address expected increases in pollutants from added impervious surfaces, and provide a means by which pollutant estimates can be compared between basins and contrasted between existing and future build -out conditions. Estimating pollutant loads helps in identifying locations for water quality capital projects. For example, RRSC -2, Water Quality Facilities for High Source Areas, includes specific high pollutant source locations for water quality retrofit facilities. The pollutant load estimates also support the implementation of Stormwater Development Standards and support continuation of the other complimentary best management practices conducted in the City and County's stormwater programs. Estimating pollutant loads from runoff being surfaced by decommissioning drywells supports the strategy for decommissioning drywells via rain gardens or pipe connections with pre- treatment, so as not to adversely affect downstream surface water quality. With regards to the use of total suspended solids (TSS) as an indicator of pollutant, TSS was used in the basin plans as a surrogate for the suite of pollutants typically associated with stormwater (specifically, sediment, nutrients, heavy metals). This is a common approach, utilized by other large municipalities in the state of Oregon. The TSS amounts are approximations based upon pollutant loading data used by the Phase I municipalities in Oregon. Estimates assume no water quality BMPs for future development. Estimates assume all runoff from decommissioned drywells will be transferred untreated to surface waters. [RR -101, [SC -111 Agree. The pollutant load estimates are based upon pollutant loading concentrations used by Phase I municipalities in Oregon, and the comment is correct in that the loadings assume no water quality BMPs. The pollutant load estimates were generated for illustrative and comparative purposes (e.g. identifying high pollutant source areas within a basin, comparing basin loads), and staff thought it important to use the same approach as for the other stormwater basins completed in 2002. The City is collaborating with other Phase I municipalities and professionals across the country to compile and utilize effectiveness data for stormwater management facilities so as to better estimate pollutant loadings from urban areas utilizing these facilities. RR -SC Stormwater Basin Plan Comments Pg.16 of 17 STAFF CONTACT INFORMATION Therese Walch, P.E., Water Resources Manager City of Eugene Public Works Department 99 E. Broadway, Suite 400 Eugene, OR 97401 Tel: 541- 682 -5549 E -mail: therese.walch @ci.eugene.or.us Dan Hurley, P.E. Senior Engineering Associate Lane County Public Works Department 3100 E. 17th Avenue Eugene, Oregon 97403 Tel: 541- 682 -3811 / Cell: 541- 954 -1935 E -mail: damel.hurley @co.lane.or.us ATTACHMENTS Attachment A: Santa Clara Community Organization comments Attachment B: River Road Community Organization comments Fact Sheet: Protecting Water Quality and Wildlife Habitat in Eugene RR -SC Stormwater Basin Plan Comments Pg.17 of 17 Additional comments received from the Santa Clara Community Organization. Therese Walch and Dan Hurley March 10, 2010 City of Eugene and Lane County Re: Comments to accompany RR/SC basin plan Therese and Dan, We thank you for meeting with us to review your comments to our criticisms regarding the RR/SC storm water basin master plan. Your offer to include a last set of comments generated by that meeting to accompany the proposal to the various elected officials is appreciated. We reiterate that the uniqueness of our basin is not adequately reflected in the proposed plan strategies and refer you to the SCCO comments of Oct 23, 2009 that highlight some of our challenges and our need for development standards to help address these problems. No other basin is categorized by our blend of high water table, lack of storm water infrastructure, fertile well- draining soils, and reliance on open waterways for the vast majority of storm water conveyance. Our proximity to the Willamette River makes us particularly flood -prone and heightens our focus on the importance of all open waterways within our neighborhood. As stressed in our comments, the protection and enhancement of these watercourses is pivotal in averting widespread flooding. Staff comments point to the myriad of overlays and protective measures applied to date. We appreciate these measures, but reiterate that they leave out vital watercourses that are part of our naturally occurring system. Our storm water system is akin to the human circulatory system, and the existing protections apply only to the arteries leaving the veins and capillaries unprotected. The system can not function effectively for the entire body of Santa Clara without adequate mapping and protection of our "lesser" waterways. The protection and enhancement of these create an existing storm water infrastructure that can accommodate development without capital projects. (See Santa Clara Community Organization comments dated Oct. 23, 2009) Staff uses the terms green infrastructure and low impact development throughout the basin plan, but doesn't differentiate between man-made engineered infrastructure (even "green" infrastructure) and naturally occurring infrastructure. Our neighborhood is riddled with swales, sloughs, channels and waterways that are naturally occurring infrastructure. These serve the long time residents as flood control measures. When they are obliterated by infill development, they are replaced on the development site by something that only serves the storm water needs of the infill, not the rest of the residents along what used to be a continuous storm water system. This places the existing residents at much greater risk of inundation. We would like the basin plan to prioritize the protection and enhancement of naturally occurring infrastructure which can continue to serve the existing residents as well as accommodate infill development. Finally, we urge the adoption of low impact development standards coupled with post development runoff not exceeding pre - development levels for this basin as a primary means to achieve both storm water quantity and quality goals. These measures make long -term economic and ecological sense. Let these neighborhoods be the trial ground for these principles and create a model which can inform development throughout the watershed. Sincerely, Jerry Finigan and executive board of the Santa Clara Community Organization 4 = M11 , 1 1 7, 17", 71M i rvj Ll �il 4 77 7 77 ll--,�7,��-�! 1 Mal te LIM .. ..... ..... . . . . . 1 ............. 11- �7 MEE;R W ........... Amm 'e;;. A -M O l wl � . . . . . . . . ----------- . . . . . . . . . . 7 .5..'. -S : ug T17 7171 P,� �Ml E y . . . . . . . . . ... ;7,T. Ic ■ EL ■ ase u m •ti L i t _ n - 6 u NO ■ ' mwmW=vL . , r 1 • L J ■ ' c } r ' ti Ic ■ ■ ' z ;. .. Lane County Board of Commissioners April 27, 2010 Page 2 3. How will potential urban pollution be addressed and be prevented from entering the District's ditches? Our late arrival on the scene of the Master Plan results from the continuation of a communication problem that exists between the City of Eugene, Lane County and the District. The District has not been directly includcd in the drafting of the storm water basin planning document and first learned of its existence last month. The District did not directly participate in the drafting of the document even though, on at least two occasions, the District has requested, in writing, that the city and the county communicate with it on matters regarding development of land in the northern River Road/Santa Clara area that is within the boundary of the District. In 2002 and again in 2005 we sent written requests to the city and the county asking that both governmental entities improve communication with the District prior to further development within the northern River Road /Santa Clara area. Copies of the letters containing the District's requests are attached to this correspondence for inclusion in the record of this proceeding. On December 17, 2002 we requested: "... that you assign the appropriate persons within the affected divisions of Lane County Public Works (Surveyor, Building and Planning) to contact and work with us to establish a process that provides a determination of future maintenance responsibility prior to the approval of any planning or building action for property within the subject area. Specifically we suggest that, at a minimum, the process provide the District an opportunity to respond to any application for subdivision or partition of land within the subject area and following that response, for Lane County to place the necessary conditions or restrictions (e,g., C,C &Rs) on the subdivision or partition to ensure that maintenance of the ditches continues after residential development has occurred. We note that the same type of process should be in place regarding any subdivision or partitioning of property in the area north of Beacon Drive and the Urban Growth Boundary that includes either of the subject channels." On that same date we made the same request to the City of Eugene. The District has not received a response to its 2002 correspondence. In response to a City of Eugene ordinance withdrawing property from the District in 2005, the District again requested that the city communicate with it prior to development of the subject area. The District has received no response to that request. Lane County Board of Commissioners April 27, 2010 Page 3 The District maintains a system of agricultural drainage ditches that extend from the Amazon Channel in west Eugene to the City of Monroe. The District's boundary and its ditch system overlap the City of Eugene's Urban Growth Boundary between Beltline Road and Beacon Drive. Essentially, the District eventually receives all of the city's storm water from that area. The District's A -1 Channel and its F Channel are located in that area. The District's system was developed over 40 years ago to partiall drain a c , ultural lands in the area between Eugene and the City of Monroe. The District operates and maintains its system pursuant to numerous easements across private property. The District's system was developed to serve flooded agricultural lands —it was not developed to receive water discharges from the impervious surfaces of urban lands and urban uses. The District's system was developed to drain flood waters from agricultural lands and was engineered to limit inundation of those lands to several days in duration —it was not engineered to immediately remove all storm water from those agricultural lands. The District's system has no additional capacity to handle storm water fiom impervious surfaces of urban land that exceed historical pre - development flow rates. The impact of discharging storm water from urban lands into the District's system is exacerbated by the development of residential subdivisions over lands that contain the ditches. In the case of the southern end of the two channels between Beltline Road and Beacon Drive, the District is prevented from performing any function on them in areas of residential development. The construction of fences and other residential development serves as a barrier to District efforts to maintain the channels for the five flow of flood and irrigation waters. The Lynnbrook 11 subdivision is a perfect example of such a situation. Even though C,C &Rs were recorded with the subdivision, many property owners have not provided any maintenance effort and, in some cases, have actually placed structures and vegetation, including trees, within the ditches. Back yard fences prevent the District from any access to the ditches for maintenance purposes. Out of concern about encroaching urban development from both the cities of Eugene and Junction City, the District retained the services of EGR & Associates, Inc. ( "EGR "), to conduct a capacity study of that portion of the Flat Creek basin that contains the F, F -2 and F -2 -a Channels (the area closest to Eugene on the south, Junction City on the north and including the site of the planned State of Oregon hospital and corrections facilities). EGR concluded that the District's system of flood control ditches is at capacity during significant rainfall events. It also concluded that high water tables throughout the area limited the amount of storm water absorbed by soil. Concluding that the District's ditch system has no additional capacity for post - development storm water discharges from newly - developed urban land, EGR recommended to the District that it promulgate policies to apply to requests from urban development for the discharge of post - development flow rates of storm water into the District's system. Those policies were adopted by the District's Board of Directors and are as follows: 1. For properties within the Flat Creek basin, post - developed storm water flow rates shall be regulated for the 2 -year through 50- Lane County Board of Commissioners April 27, 2010 Page 4 year, 24 -hour, rainfall events. Rainfall events in excess of the 50- year, 24 -hour, storm will not be regulated, 2. The allowable post - developed flow rate, for each regulated recurrence interval, shall be limited to the greater of: a. A flow rate equal to 0.116 cfs per acre, or b. Historic pre - development flow rates considering any constraints up to the point of connection with the District's system. The Master Plan does not adequately address the three issues presented earlier in this response. The Master Plan does not adequately recognize and implement the District's policies regarding the discharge of storm water from developed urban lands. The District requests that before adoption of the Master Plan the participating jurisdictions work with the District to modify the Master Plan to address the District's issues and to recognize and implement its policies regarding those issues. At a minimum, and for example, the following sections of the Master Plan should be modified: Section 2.5.1 Waterways needs to be modified to accurately describe the District's system of ditches and the capacity of those ditches to move water from the area (particularly the A -1 Channel and Flat Creek); Section 2.5.5 needs to be modified to accurately describe the District's system, its capacity and existing flow rates (and the implementation of District policies regarding the same); Section 3.1 needs to be modified to incorporate the District's hydrologic and hydraulic information regarding its capacity and both pre - development and post - development flow rates. In conclusion, the District requests a simple acknowledgement by Lane County and the City of Eugene that it is an agricultural flood control district whose system of ditches does not have the capacity to absorb additional water from newly - developed urban lands and uses. In concert with that acknowledgement, the District requests that the Master Plan reflect those facts and that the Master Plan include the District's policies regarding storm water discharge from newly- developed urban land and uses. m•!t.«! ± City of Eugene response to the Junction City Water Control District Public Works Engineering City of Eugene 99 East Broadway, Suite 400 Eugene, Oregon 97401 (541) 682 -5291 (541) 682 -8410 FAX September 22, 2010 Steve Cornacchia Junction City Water Control District 95282 Hwy 99 E Junction City, OR 97448 Re: Eugene Stormwater Basin Master Plan — River Road /Santa Clara Junction City Water Control District Dear Mr. Cornacchia, Thank you for your interest and that of the Junction City Water Control District in the River Road — Santa Clara Stormwater Basin Master Plan. We appreciate the District's input reflected in your letter to the Lane County Board of Commissioners provided at their March 31, 2010 work session on the topic. We would like to take this opportunity to respond to the issues that you raised. In particular, you expressed thoughts and concerns about the referral of development proposals to the District, waterway maintenance and the free flow of water, receiving stream capacity, and the water quality of urban discharges to District streams. As a courtesy, we would be happy to include you in the referral process for development proposals for properties that drain to District waterways. To assist us in ensuring that we have the area delineated as you desire, please provide me with a map showing the boundaries of the area(s) for which you would like referrals. The District's comments will then be reviewed in the context of the City of Eugene's requirements and policies. Regarding responsibility for maintenance of waterways on properties annexed to the City that may have a District easement, these waterways would fall under City of Eugene maintenance policies and practices upon annexation. The City would determine, on a case by case basis, whether we would have an interest in acquiring any existing easements. You expressed concern about the construction of fences and other obstructions in waterways upstream from District waterways, and a desire to keep these waterways free flowing. Significant progress has been made by the City (and County) in regards to development regulations in and adjacent to waterways. With adoption of the /WR Water Resources Conservation Overlay Zone in 2005, and the /WQ Water Quality Overlay Zone in 2009, the City prohibits the construction of fences and structures in and immediately adjacent to certain waterways including Flat Creek and the Al Channel — which are of the most concern by the District. The capacity of receiving streams is of interest to the City. We reviewed the EGR report ( "South Highway 99 Stormwater Feasibility Analysis," November 9, 2009) referenced in your letter, but were unable to see how the report's conclusions correlated with specific capacity constraints at the urban growth boundary since the geographic area of primary interest and assessment in the report is quite a bit further north, nearer to Junction City. We would be glad to review any additional information pertinent to the area that you could provide, within the context of City code and policies. The quality of water going into receiving streams is also of interest to us. The City implements a stormwater program under its National Pollution Discharge Elimination System ( NPDES) Phase I municipal stormwater permit to protect and improve water quality. The City's stormwater program includes public education and outreach, erosion prevention, illicit discharge detection and removal, spill response, street sweeping, catching basin cleaning, leaf pick -up, volunteer programs to restore streams and plant trees, regulatory waterway protections, and water quality capital improvement projects. Since the adoption of stormwater development standards in 2006, developments adding or replacing 1,000 square feet of impervious area or more are required to meet pollution reduction requirements. As with other municipalities across the state and country, our stormwater program continues to evolve. On the horizon for the City of Eugene are efforts to further prioritize low impact development, infiltration, and on- site retention of stormwater runoff. If the District has any pertinent information regarding the quality of water going into District streams, we would be happy to review that information within the. context of our NPDES permit and City policies. Thank you again for your interest in the River Road — Santa Clara Basin Plan. Sincerely, Therese Walch, P.E. Water Resources Manager City of Eugene Public Works Department ............. Letter of support from the Santa Clara Community Organization following edits made in September 2012. SANTA CLARA COMMUNITY ORGANIZATION established 1977 To Lane County Commissioners; October 4, 2012 As Board Members of the Santa Clara Community Organization, we would like to give you an update on our continued involvement in the crafting of the River Road /Santa Clara Stormwater Basin Master Plan. When the plan was last brought to the County Board in March of 2010, your Board received letters from members of the Santa Clara And River Road organizations identifying shortcomings in the plan. Since that time, we have continued to work with both the City and County as they modified and finalized the Plan. Attempts to address the identified shortcomings were made including edits to Section 1 and through other City processes. We appreciate that our concerns were heard and issues were clarified. We understand this plan is a blueprint that can guide future work. We look forward to our continued involvement as our community plans for the future. The Santa Clara Community Organization is now supportive of the plan as edited. The SCCO Board members would like you to know that we now endorse the plan. Sincerely, Santa Clara Community Organization Board Jerry Finigan, Chair a local voice in government Letter of support from the River Road Community Organization following edits made in September 2012. HURLEY Daniel M From: Jon Belcher Ubelcher @efn.org] Sent: Tuesday, October 09, 2012 2:17 PM To: HANDY Rob M; BOZIEVICH Jay K; LEIKEN Sid W; SORENSON Pete; STEWART Faye H Cc: HURLEY Daniel M; WALCH Therese; Bev Barr; REILLY CARLEEN (LCOG List); BELCHER JON (LCOG List); Kate Kelly; Kira Lehman; Michael Lambros; NEFF Ray (SMTP); Tuula Rebhahn ; Will Dixon Subject: River Road Community Organization Letter of Support for River Raod /Santa Clara Stormwater Basin Master Plan We wish to thank both Daniel Hurley and Therese Walsh for their assistance and cooperation during our involvement in developing the River Road /Santa Clara Stormwater Basin Master Plan. The following letter was unanimously passed at last night's River Road Community Organization meeting with 22 neighbors participating: To Lane County Commissioners; October 8, 2012 we would like to give you an update on our continued involvement in the crafting of the River Road /Santa Clara Stormwater Basin Master Plan. When the plan was last brought to the County Board in March of 2010, your Board received letters from members of the Santa Clara And River Road organizations identifying shortcomings in the plan. Since that time, we have continued to work with both the City and County as they modified and finalized the Plan. Attempts to address the identified shortcomings were made including edits to Section 1 and through other City processes. We appreciate that our concerns were heard and issues were clarified. We understand this plan is a blueprint that can guide future work. we look forward to our continued involvement as our community plans for the future. The River Road Community Organization is now supportive of the plan as edited and we now endorse the plan. Sincerely, River Road Community Organization /signed /signed Carleen Reilly Jon Belcher River Road Community Organization Co- chairs Jon Belcher (jbelcher(a�efn. org) 1