HomeMy WebLinkAboutPN_250507_Springbrook Terrace Project Narrative City of Renton
Public Works Surface Water Utility
Springbrook Terrace Water Quality Improvements Retrofit Page 1 of 2
Project Narrative & Scope
Project Name: Springbrook Terrace Water Quality Retrofit
Project Manager: Chester Bennett
Design Consultant: David Evans and Associates
Date: 05/07/2025
Project Narrative & Scope
Objective
This project is retrofitting the existing stormwater detention pond on parcel number 794120-0230 which
is owned and operated by the City of Renton (the City). The improvements will provide water quality
treatment improvements for approximately 5.2 acres of single-family residential zoning land cover. The
project is located in the southwest area of Renton known as the Snake Hill/Springbrook Terrace
neighborhood, see Figure 1 on the following page.
Background
The City completed a 2021 Stormwater Facility Retrofit Study authored by WSP and funded by the
Department of Ecology which identified and ranked 49 facilities owned and operated by the City that
would benefit from retrofit projects. The Springbrook Terrace detention pond facility, on parcel 794120-
0230, ranked in the top five and a preliminary concept plan was developed. In October 2022 the City
prepared and presented the project to Ecology to fund the project design, and it was chosen for award
in June 2023.
The existing detention pond facility (GIS Asset #111354) was installed in 1985 as part of the Springbrook
Terrace Plat development and provides flow control for runoff discharge but was not designed to
provide water quality treatment. The facility is approximately 1,600-ft upstream of the major receiving
waterbody Upper Springbrook Creek that is classified as a non-fish bearing water body (however fish has
been observed in this creek), is tributary to the Black River watershed, and is listed on the 303(d) list.
Project Timeline
September 2024 30% Design (Completed)
December 2024 60% Design (Completed)
April 2025 Design Report submitted to Department of Ecology (Completed)
June 2025 Department of Ecology Comments / Approval Letter (In process)
September 2025 90% Design Completed
July 2026 Department of Ecology Construction Funding Application
February 2027 Bid Documents Finalized
Summer 2027 Construction
Parameters
Due to site constraints and feasibility considerations full Basic Water Quality Treatment is unlikely to be
achieved per the 2019 Washington State Department of Ecology Stormwater Management Manual for
Western Washington. Hence the project will provide partial basic treatment and maximize the water
quality treatment benefit achievable within the footprint of the pond. The improvements will maintain
or improve the existing flow control design parameters within the footprint of the existing facility.
City of Renton
Public Works Surface Water Utility
Springbrook Terrace Water Quality Improvements Retrofit Page 2 of 2
Project Narrative & Scope
Figure 1 - Area Map