152nd Westpark & NE 90th St Stormwater Improvements

Vicinity Map

Location 1: 152nd Ave NE south of NE 90th St
Location 2: NE 90th St, near 160th Ave NE

Project Phase: Construction complete

Contact: Joe O'Leary, 425-556-2723

Page Last Updated: 11/13/18


The stormwater lines in the right of way of 152nd Ave NE adjacent to Westpark Business Park are in a state of disrepair. City maintenance crews have identified these pipes for replacement based on pipe inspection video recordings. The existing corrugated metal pipes are heavily corroded and large tree roots have entered the pipes at various locations, obstructing water flow during storm events. After evaluating options for replacing the pipe, it was determined that least expensive and less obtrusive construction approach is to slip line the existing pipe with new pipe.

On NE 90th Street, east of 160th Ave NE, there is a large perforated stormwater infiltration pipe. The large pipe was designed and installed with perforations prior to the existence of the wellhead protection zone. This pipe was found to be good candidate for slip lining to ensure the integrity of the pipe. When slip lined, the pipe will no longer infiltrate untreated stormwater into the wellhead protection zone. This will also extend the service life of the pipe which is needed to provide stormwater conveyance.