HomeMy WebLinkAboutOrd. 20724COUNCIL ORDINANCE NO. 20724
AN ORDINANCE CONCERNING STORMWATER MANAGEMENT; AMENDING
SECTIONS 9.6791, 9.6792, 9.6793, AND 9.8030 OF THE EUGENE CODE,
1971; AND PROVIDING AN EFFECTIVE DATE.
ADOPTED: March 10, 2025
SIGNED: March 12, 2025
PASSED: 8:0
REJECTED:
OPPOSED:
ABSENT:
EFFECTIVE: July 1, 2025
ORDINANCE NO. 20724
AN ORDINANCE CONCERNING STORMWATER MANAGEMENT; AMENDING
SECTIONS 9.6791, 9.6792, 9.6793, AND 9.8030 OF THE EUGENE CODE, 1971;
AND PROVIDING AN EFFECTIVE DATE.
THE CITY OF EUGENE DOES ORDAIN AS FOLLOWS:
Section 1. Section 9.6791 of the Eugene Code, 1971, is amended to provide as follows:
9.6791 Stormwater — Flood Control.
(1) Purpose. The purpose of EC 9.6791 is to protect life and property from flood and drainage
hazards by maintaining the capacity of the city's stormwater conveyance system through the
establishment of flood control regulations for stormwater runoff. These standards are also
intended to ensure that urban stormwater discharged into Junction City Water Control District's
flood control system meets the assigned downstream capacity of the District's system.
(2) Applicability and Exemptions.
(a) Except as provided in EC 9.6791(2)(b), flood control standards in EC 9.6791(3) apply to
all development permit applications and land use applications.
(b) The standards in EC 9.6791(3) do not apply to development permit applications where
the proposed development will be served by a flood control facility that is a manmade
drainage system designed to accommodate stormwater run-off generated by the stormwater
basin area.
(3) Standards.
(a) Stormwater flood control facilities shall be selected, sited, designed, and constructed
according to adopted plans and policies, and in accordance with standards in EC Chapters
6 and 7, and the Stormwater Management Manual.
(b) Stormwater runoff from the development site for the applicable flood control design storm
shall be:
1. Discharged into existing stormwater flood control facilities that, considering all
developments that have received tentative or final plan approval as of the date the
applicant submits a complete application, have the capacity to handle the stormwater
runoff; or
2. Retained or detained onsite; or
3. Discharged into a new stormwater flood control facility constructed by the applicant.
Ordinance -- Page 1 of 7
(c) For development proposed within the area shown on Map 9.6791(3)(c) Special
Stormwater Flood Control Area Map, the post -development peak flow rate shall not exceed
the pre -development peak flow rate for the applicable flood control design storm unless the
applicant submits documentation from Junction City Water Control District that the proposed
flow rate is acceptable.
Section 2. Section 9.6792 of the Eugene Code, 1971, is amended to provide as follows:
9.6792 Stormwater Quality.
(1) Purpose. The purpose of EC 9.6792 is to reduce runoff pollution and mitigate the volume,
duration, time of concentration and rate of stormwater runoff from impervious surface areas.
(2) Applicability and Exemptions.
(a) Except as exempt in EC 9.6792(2)(b) or (c), the standards in EC 9.6792(3) apply to land
use applications and development permit applications that propose new or replaced
impervious surfaces.
(b) The standards in EC 9.6792(3) do not apply to land use applications or development
permit applications proposing:
1. Construction of less than 1,000 square feet of new or replaced impervious surface
within a 12-month period;
2. Replacement of impervious surface area that does not expose more than 1,000
square feet of soil (for purposes of this subsection, "soil" means: the unconsolidated
mineral or organic material on the immediate surface of the Earth that serves as a natural
medium for the growth of land plants);
3. Maintenance and/or repair activities on an existing structure, facility or other
impervious surface to prevent its decline, lapse or cessation in the use;
4. Construction of a single -unit dwelling or duplex on a lot or parcel that was created by
a land division application submitted and approved by the City between July 14, 2006,
and March 1, 2014, that is consistent with the approved land use application and the
City's stormwater quality (pollution reduction) standards in place at the time of the land
division application; or
5. Construction of new or replaced impervious surface that will be served by an existing
City approved stormwater quality facility that was designed and sized to treat the
stormwater runoff from the proposed impervious surface.
Ordinance -- Page 2 of 7
(c) The standards in EC 9.6792(3) do not apply to land use applications or development
permit applications within the S-DR Downtown Riverfront Special Area Zone. Instead, the
standards at EC 9.3155(17) apply.
(3) Standards.
(a) Stormwater quality facilities for water quality treatment shall be selected from and sited,
designed, and constructed according to the Stormwater Management Manual. The selected
stormwater quality facilities shall treat all stormwater runoff from all new or replaced
impervious surface areas, or an equivalent on -site area, that will result from the water quality
design storm.
(b) Stormwater quality facilities shall be selected based on the following priority order.
1. Infiltration shall be utilized for treatment of the water quality design storm runoff unless
one of the following site conditions exists:
a. Infiltration rates are less than 2 inches per hour;
b. Bedrock is less than 5 feet below the ground surface;
c. Groundwater elevations are less than 6 feet below the ground surface; or
d. Ground surface slopes are greater than 10%.
2. If any of the site conditions listed in subsection (3)(b)1 exist, extended filtration
(filtration through natural or engineered media) shall be utilized to treat the water quality
design storm runoff from the impervious surface areas unless:
a. The applicant submits a report that includes a site plan of the proposed
development and the required sizing of the stormwater quality facility based upon the
water quality design storm requirement showing that the development site has
insufficient land area to construct an infiltration or extended filtration facility to treat
the water quality design storm runoff without reducing the size of the proposed
development; and
b. The proposed development is otherwise consistent with all other applicable lot
and development standards.
(c) An applicant that is not required to use an infiltration or filtration system for any of the
reasons stated in (b) or (d) of this section will be subject to the Low Impact Development
component of the City's system development charge improvement fee due to the reliance on
an off -site system. In that case, the City's system development charge methodologies may
include a stormwater system development charge credit for an approved on -site mechanical
treatment facility.
Ordinance -- Page 3 of 7
(d) The standards in EC 9.6792(3)(a) and EC 9.6792(3)(b)2 may be adjusted pursuant to
EC 9.8030(24).
Section 3. Section 9.6793 of the Eugene Code, 1971, is amended to provide as follows:
9.6793 Stormwater — Flow Control (Headwaters).
(1) Purpose. The purpose of EC 9.6793 is to protect waterways in the headwaters area from the
erosive effects of increases in stormwater runoff peak flow rates and volumes resulting from
development.
(2) Applicability and Exemptions.
(a) Except as exempt under EC 9.6793(2)(b), the standards in EC 9.6793(3) apply to land
use applications and development permit applications that propose new or replaced
impervious surfaces on sites in the headwaters area that drain directly into a headwater
stream or drain into a pipe that discharges into a headwater stream.
(b) The standards in EC 9.6793(3) do not apply to:
1. Construction of less than 1,000 square feet of new or replaced impervious surface
within a 12-month period;
2. Replacement of impervious surface area that does not expose more than 1,000
square feet of soil (for purposes of this subsection, "soil' means: the unconsolidated
mineral or organic material on the immediate surface of the Earth that serves as a natural
medium for the growth of land plants);
3. Maintenance and/or repair activities taken on an existing structure, facility or other
impervious surface to prevent its decline, lapse or cessation in use; or
4. Construction of a new or replaced impervious surface that will be served by an
existing City approved stormwater flow control facility that was designed and sized to
manage stormwater runoff from the proposed impervious surface.
5. Development sites within a drainage basin for which the city has constructed or
approved a project to restore the receiving waterway, and the entire downstream system
has been designed to accommodate full build -out conditions within the drainage basin.
(3) Standards.
(a) Applications shall demonstrate, using methodology in the Stormwater Management
Manual, that peak rates of flow delivered to an existing open waterway at a point above 500
feet in elevation will not increase during storms larger than the water quality design storm
Ordinance -- Page 4 of 7
and smaller than the flood control design storm as a result of the development that is the
subject of the application;
(b) For purposes of designing the system as required by the standards in this section, the
amount of impervious surface per lot is assumed to be the maximum lot coverage allowed
for the use in the zone in which it is located, unless the applicant demonstrates otherwise.
(c) All facilities to control the rate of stormwater runoff shall be sited, designed and
constructed according to the flow control provisions and the facility design requirements set
forth in the Stormwater Management Manual. Flow control facilities must be designed using
one of the methodologies outlined in the Stormwater Management Manual.
(d) The standards in EC 9.6793(3) may be adjusted pursuant to EC 9.8030(24).
Section 4. Subsections (24)(a) and (24)(b) of Section 9.8030 of the Eugene Code,
1971, are amended to provide as follows:
9.8030 Adjustment Review —Approval Criteria.
The planning director shall approve, conditionally approve, or deny an adjustment review
application. Approval or conditional approval shall be based on compliance with the following
applicable criteria.
(24) Stormwater Quality, Flow Control, Oil Control and Source Control Standards Adjustment.
(Adjustments under this subsection are not permitted within the /CL Clear Lake Overlay Zone.)
(a) The requirement in EC 9.6792(3)(a) and EC 9.3155(17)(c)4 that selected stormwater
quality facilities shall treat all the stormwater runoff that will result from the water quality
design storm may be adjusted upon a finding that the stormwater quality facility will treat as
much of the runoff as possible; and
(b) The requirement in EC 9.6792(3)(a) and EC 9.3155(17)(c)5 that all stormwater quality
facilities be selected from and sited, designed, and constructed according to the Stormwater
Management Manual may be adjusted upon finding that all of the following requirements are
met:
1. The proposed alternative design will achieve equal, or superior, results for function
(reducing pollution), maintainability and safety, and the proposed siting does not
adversely affect structures or other properties.
2. The applicant's written description of the proposed alternative design has been
reviewed and approved by the City Engineer. The description of the proposed design
submitted for review must include all of the following information for each component
of the proposed alternative design:
Ordinance -- Page 5 of 7
a. Size, technical description, capacity, capital cost, design life, construction
process and costs, consequences of improper construction, operation and
maintenance requirements and costs;
b. Data on the effectiveness of proposed alternative technologies, if available,
including data from laboratory testing and pilot/full-scale operations, and
information regarding the operations of any full-scale installations;
c. Any other available information about the proposed design, including peer
review articles, scientific or engineering journals, and approvals from other
jurisdictions.
3. The applicant has submitted a method and schedule for monitoring the effectiveness
of the proposed design once constructed, and a schedule for its maintenance.
4. The applicant has submitted a signed statement that the applicant will replace the
alternative stormwater quality facility if the facility does not function as proposed.
(c) The requirement in EC 9.6792(3)(b)2 that extended filtration (filtration through natural or
engineered media) shall be utilized to treat the water quality design storm runoff from the
impervious surface areas may be adjusted upon a finding that:
1. An engineering report shows that, due to unique topography, a filtration system
would be unreliable or would be likely to have an adverse impact on surrounding
properties; or
2. Soil contamination would negatively impact surface water or groundwater quality if
a filtration system was used.
Section 6. Subsections (24)(c), (d), (e), and (f) of Section 9.8030 of the Eugene Code,
1971, are re -lettered to subsections (24)(d), (e), (f) and (g), respectively.
Section 6. The findings set forth in Exhibit A to this Ordinance are adopted as findings
in support of this Ordinance.
Section 7. Notwithstanding Section 32 of the Eugene Charter 2002, this Ordinance
shall take effect on July 1, 2025.
Ordinance -- Page 6 of 7
Section 8. The City Recorder, at the request of, or with the consent of the City Attorney,
is authorized to administratively correct any reference errors contained herein, or in other
provisions of the Eugene Code, 1971, to the provisions added, amended or repealed herein.
Passed by the City Council this
loth day of March, 2025
it Recorder
Ordinance -- Page 7 of 7
Approved by the Mayor this
i 'day of March, 2025
Mayor