As of February 2020
We are beginning work to improve stormwater drainage along 10th Avenue NE between NE 175th Street and NE 165th Street. Due to funding challenges, this project has been on hold since 2016. Long-delayed funding from the Washington State Department of Ecology has become available and the project has resumed.
We are currently working on:
- Selection of a consultant team to complete design
- Starting preliminary design (by spring 2020)
Completed work includes:
- Preliminary studies
- Memorandum - 10th Avenue NE From NE 165th Street to NE 175th Street Roadway Drainage Review (2014)
- Technical Memorandum – Flooding at NE 175th Street and 10th Avenue NE (2018)
- Memorandum – Solution Concept Development for Flooding at NE 175th Street and 10th Avenue NE (2018)
- Thornton Creek Watershed Plan (2009)
Overview and History
Storm runoff on 10th Avenue NE between NE 175th Street and NE 165th Street flows to a ditch and pipe system on the west side. The ditches are shallow and flat and many of the pipes are too small or sloped the wrong way. During large rain events, storm runoff can overwhelm the system. This can lead to excess stormwater collecting within the roadway, shoulder, driveways, and some private properties. This system flows into Little’s Creek near NE 165th Street and 11th Avenue NE.
A poorly-draining ditch along 10th Avenue NE south of NE 170th Street.
This project will fix the drainage system along 10th Avenue NE between NE 165th Street and NE 175th Street. Work will focus on installing wider and deeper ditches and better pipes. Ditch upgrades will include new plantings and soil layers to filter stormwater and encourage it to soak into the ground.
Allowing runoff to soak into the ground is one alternative to just sending it away within a pipe. If this drainage issue was fixed by only increasing flows, this would increase stormwater flows into nearby Little’s Creek. Stormwater runoff from roadways is dirty and scours away the creek during storms. Little’s Creek already has problems with pollution and erosion from runoff, and increasing flows makes things worse. We want to try a solution at this location which will both fix the drainage problem while protecting the creek.
Exact improvements are to be determined. We will be asking for input from neighbors, the general public, and other interested parties.
Project pre-design and design will be largely funded by a Restored Green Retrofit Incentive Grant from the Washington State Department of Ecology.