HomeMy WebLinkAboutD_Springbrook_Terrace_Critical_Areas_Exemption_250722_FINALDEPARTMENT OF COMMUNITY
AND ECONOMIC DEVELOPMENT
D_Springbrook_Terrace_Critical_Areas_Exemption_250722_FINAL
PLANNING DIVISION
CERTIFICATE OF EXEMPTION
FROM CRITICAL AREAS REGULATIONS
EVALUATION FORM & DECISION
DATE OF DECISION: July 22, 2025
PROJECT NUMBER: LUA25-000211, CAE
PROJECT NAME: Springbrook Terrace Water Quality Retrofit
PROJECT MANAGER: Mariah Kerrihard, Associate Planner
APPLICANT/CONTACT: Chester Bennett, City of Renton
1055 S Grady Way, Renton, WA 98057
OWNER: City of Renton
1055 S Grady Way, Renton, WA 98057
PROJECT LOCATION: APN 7941200230; Plat Lot: Tract A
PROJECT DESCRIPTION: The applicant, Chester Bennett on behalf of City of Renton Public Works Surface
Water Utility, is proposing a maintenance project for retrofitting the existing stormwater detention pond on
parcel number 7941200230, which is owned and operated by the City of Renton. The proposed
improvements would provide water quality treatment improvements for approximately 5.2 acres of
residential zoned land cover. The site is zoned Residential-4 (R-4) and is within the Talbot Community
Planning Area. The proposed stormwater detention pond facility maintenance, as described in the Project
Narrative (Attachment A) and Final Design Report (Attachment B), is to create a stormwater treatment
function which would improve water quality within the system for the existing Springbrook Terrace Pond that
discharges to a city-owned storm sewer system. That storm sewer system flows north to S 55th St, then west
along S 192nd St, where it discharges into Springbrook Creek approximately 1,600 feet (1,600’) from the pond.
The stormwater flow control function of the pond is maintained in the proposed condition with the added
benefit of stormwater treatment by using a wetpond best management practice (BMP), designed in
accordance with the City of Renton’s 2022 Surface Water Design Manual and the Washington State
Department of Ecology’s 2019 Stormwater Management Manual for Western Washington. According to the
applicant, the project would increase the pond’s volume through grading, reconfigure existing storm sewer
inlets and outlets, and install an internal Ecoblock pond divider wall and a low-permeability compacted till
liner to ensure the permanent pool necessary for wetpond treatment. As depicted in the Final Design Report
(Attachment B), comprehensive Erosion and Sediment Control (ESC) Best Management Practices (BMPs)
would be rigorously applied throughout construction to minimize impacts, prevent pollution, and ensure
disturbed areas are promptly revegetated with native species. The project is categorically exempt from SEPA
review as a maintenance activity, consistent with WAC 197-11-800(3). According to City of Renton (COR)
Maps, regulated steep slopes are mapped on site.
Docusign Envelope ID: A702932F-D2A1-4ED6-91CA-31CDF42BFB29
City of Renton Department of Community & Economic Development Certificate of Exemption From Critical Areas Regulations
Springbrook Terrace Water Quality Retrofit LUA25-000211, CAE
Permit Date: July 22, 2025 Page 2 of 4
D_Springbrook_Terrace_Critical_Areas_Exemption_250722_FINAL
SEC-TWN-R: NE 6-22-05
LEGAL DESCRIPTION:
(King County Assessor)
Springbrook Terrace Drainage
CRITICAL AREA: Regulated Slopes
CRITICAL AREAS EXEMPTION JUSTIFICATION: Pursuant to RMC 4.3.050C “Exempt, Prohibited and
Nonconforming Activities” – Maintenance, Operation, and Repair of existing Parks, Trails, Roads, Facilities,
and Utilities, and the Construction of New Trails is exempt from permit requirements within critical areas
and associated buffers in accordance with RMC 4.3.050C.3.e, within a Geological Hazard Area subject to
the following standards:
Normal and routine maintenance, operation and repair of existing parks, trails, streets, roads, rights-of-way
and associated appurtenances, facilities and utilities where no alteration or additional fill materials will be
placed other than the minimum alteration and/or fill needed to restore those facilities or to construct new
trails to meet established safety standards. The use of heavy construction equipment shall be limited to
utilities and public agencies that require this type of equipment for normal and routine maintenance and
repair of existing utility structures and rights-of-way. In every case, critical area and required buffer impacts
shall be minimized and disturbed areas shall be restored during and immediately after the use of
construction equipment.
CRITCAL AREA EXEMPTION FINDINGS: The proposed development is consistent with the following
findings pursuant to RMC section 4-3-050C.2.d:
YES i. The activity is not prohibited by this or any other provision of the Renton Municipal
Code or State or Federal law or regulation;
Staff Comments: Maintenance and repair of existing utilities are exempt activities
and are permitted within a geologic hazard area according to the City of Renton’s
Critical Areas Regulations. This decision does not exempt the applicant from any
other agency approvals needed to do the proposed work.
YES ii. The activity will be conducted using best management practices as specified by
industry standards or applicable Federal agencies or scientific principles;
Staff Comments: The scope of work details the use of best management
practices (BMPs) for stormwater treatment and erosion and sediment control,
aligning with industry standards and applicable regulations. Specifically, the
proposed wetpond design adheres to the City of Renton’s 2022 Surface Water
Design Manual (SWDM) and the Washington State Department of Ecology’s (DOE)
2019 Stormwater Management Manual for Western Washington (SWMMWW),
which are recognized regional and state standards for stormwater management
and water quality. Additionally, the comprehensive Erosion and Sediment Control
(ESC) plan outlines specific BMPs across all 13 elements, including vegetation
preservation, stabilized construction access, sediment controls (silt fence,
sediment trap, check dam, wattles), soil stabilization (temporary and permanent
seeding, mulching, nets/blankets, plastic covering), slope protection, storm drain
inlet protection, channel and outlet stabilization (quarry spalls, hydroseed,
mulch), and pollutant control measures (concrete handling, spill prevention,
Docusign Envelope ID: A702932F-D2A1-4ED6-91CA-31CDF42BFB29
City of Renton Department of Community & Economic Development Certificate of Exemption From Critical Areas Regulations
Springbrook Terrace Water Quality Retrofit LUA25-000211, CAE
Permit Date: July 22, 2025 Page 3 of 4
D_Springbrook_Terrace_Critical_Areas_Exemption_250722_FINAL
material containment). The project also incorporates a Certified Erosion and
Sediment Control Lead to ensure ongoing compliance and maintenance of these
BMPs, demonstrating a commitment to scientific principles for effective
stormwater management and environmental protection. According to the Final
Geotechnical Report (Attachment C), the slopes constructed at 3H:1V are suitable
for the proposed pond retrofit.
YES iii. Impacts are minimized and, where applicable, disturbed areas are immediately
restored;
Staff Comments: The project proposal is designed with a focus on minimizing
environmental disturbance and ensuring prompt restoration of affected areas.
This commitment is demonstrated by the strategy to limit soil disturbance
specifically to actively worked zones, covering only about 6,900 square feet, and
by designing proposed slopes (3:1 H:V or less) to avoid extensive cuts on steep
terrain. To facilitate quick recovery, final landscaping and planting are prioritized
for the earliest feasible time. Any unworked soils will be swiftly stabilized within
two (2) days during the wet season or seven (7) days in the dry season, with topsoil
and hydroseed being the chosen methods for ultimate site revegetation. Crucially,
the plan also emphasizes preserving existing natural vegetation wherever possible
to prevent erosion, and includes specific measures for managing stockpiles, such
as using wattles and temporary stabilization, to prevent them from becoming
pollution sources.
YES iv. Where water body or buffer disturbance has occurred in accordance with an
exemption during construction or other activities, revegetation with native
vegetation shall be required;
Staff Comments: No in-water work is proposed. The project has been designed to
minimize impacts by following the proposed plans for revegetation with native
vegetation. The report states that, following construction, application of topsoil
and hydroseed is the proposed restoration technique for final stabilization of soils
and revegetation. This proactive measure ensures that disturbed areas, including
those near the pond which drains to Springbrook Creek, are promptly returned to
a stable, vegetated state.
N/A v. If a hazardous material, activity, and/or facility that is exempt pursuant to this
Section has a significant or substantial potential to degrade groundwater quality,
then the Administrator may require compliance with the Wellhead Protection Area
requirements of this Section otherwise relevant to that hazardous material,
activity, and/or facility. Such determinations will be based upon site and/or
chemical-specific data.
Staff Comments: Not applicable. It is not anticipated that the proposal would
result in hazardous materials infiltrating the groundwater as the proposed work is
located outside of a Wellhead Protection Area Zone. The project proposal is
designed to maintain existing drainage patterns to the maximum extent, aligning
with best management practices for stormwater (Attachment B). The scope of
work includes construction of a wetpond, installation of low permeability
compacted till liner, groundwater monitoring well, implementation of
comprehensive pollutant control BMPs, and revegetation with native vegetation.
Docusign Envelope ID: A702932F-D2A1-4ED6-91CA-31CDF42BFB29
City of Renton Department of Community & Economic Development Certificate of Exemption From Critical Areas Regulations
Springbrook Terrace Water Quality Retrofit LUA25-000211, CAE
Permit Date: July 22, 2025 Page 4 of 4
D_Springbrook_Terrace_Critical_Areas_Exemption_250722_FINAL
DECISION: An exemption from the Critical Areas Regulations is hereby Approved.
SIGNATURE & DATE OF DECISION:
_____________________________________________ ____________________________________
Matthew Herrera, Planning Director Date
RECONSIDERATION: Within 14 days of the decision date, any party may request that the decision be
reopened by the approval body. The approval body may modify his decision if material evidence not readily
discoverable prior to the original decision is found or if he finds there was misrepresentation of fact. After
review of the reconsideration request, if the approval body finds sufficient evidence to amend the original
decision, there will be no further extension of the appeal period. Any person wishing to take further action
must file a formal appeal within the 14-day appeal time frame.
APPEALS: This administrative land use decision will become final if not appealed in writing to the
Hearing Examiner on or before 5:00 PM on August 5, 2025. An appeal of the decision must be filed within
the 14-day appeal period (RCW 43.21.C.075(3); WAC 197-11-680). Appeals must be submitted
electronically to the City Clerk at cityclerk@rentonwa.gov or delivered to City Hall 1st floor Lobby Hub
Monday through Friday. The appeal fee, normally due at the time an appeal is submitted, will be collected at
a future date if your appeal is submitted electronically. The appeal submitted in person may be paid on the
first floor in our Finance Department. Appeals to the Hearing Examiner are governed by RMC 4-8-110 and
additional information regarding the appeal process may be obtained from the City Clerk’s Office,
cityclerk@rentonwa.gov.
EXPIRATION: Two (2) years from the date of decision (date signed).
ATTACHMENTS:
Attachment A: Project Narrative
Attachment B: Final Design Report, prepared by David Evans and Associates, Inc, dated June 2025
Attachment C: Final Geotechnical Report, prepared by HWA GeoSciences Inc., dated May 2, 2025
Docusign Envelope ID: A702932F-D2A1-4ED6-91CA-31CDF42BFB29
7/22/2025 | 2:52 PM PDT