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Completed – Spring 2009

From 2006-2009 King County rebuilt ageing sewer infrastructure and provided needed capacity to protect public health, limit overflows to the Puget Sound, and to provide safe, reliable service for the next 50 years in western Shoreline.

What King County built

  • New underground storage pipe
    • A 500,000-gallon underground storage pipe that temporarily stores wastewater during large storms
    • Underground odor and flow control structures
    • About 1,000 ft of sewer pipe replaced in the streets around the park
    • Additional capacity added to the city’s stormwater detention pond
  • Boeing Creek Trunk Sewer replacement
    • Replaced about 1,200 ft of Ronald Wastewater District sewer pipe
    • Replaced about 12,000 ft of county sewer pipe
    • Replaced about 6,500 ft of water mains for Seattle Public Utilities
    • Repaved streets and widened asphalt shoulder in some areas
  • Pump station replacement
    • A new Hidden Lake Pump Station, with pumping capacity of 6.8 mgd
    • A cost-effective design that helps the building blend in with the neighborhood
    • In winter 2008, landscaping with mostly native plants completed

Project schedule

  • Construction began: summer 2006
  • Construction complete:
    • Underground storage tank in Boeing Creek Park – Fall 2007
    • Boeing Creek Trunk – Summer 2008
    • Hidden Lake Pump Station –  Spring 2009

Project map

Hidden Lake Pump Station

rsz_4208874151_c9ce9e159a_oJuly 2008 – the new pump station building exterior is now complete

View more photos on our Flickr site  .

Boeing Creek Park, Shoreline

rsz_4208724227_2ae803220c_oMay 2007 – the underground odor control structure should be completed by fall 2007

View more photos on our Flickr site  .


You can download and view documents (PDF files) using a PDF Reader.

24-hour emergency and odor reporting:

Contact West Point Treatment Plant at  206-263-3801.

Learn more about the new underground storage pipe in Boeing Creek Park and replacement of the Boeing Creek Trunk Sewer and Hidden Lake Pump Station .

The only above ground structure in Boeing Creek Park is an odor control stack disguised as a tree snag.The only above ground structure in Boeing Creek Park is an odor control stack disguised as a tree snag.

Boeing Creek Park celebration, Oct. 20, 2007


Hidden Lake service area report, May 2000. This report evaluates the existing Hidden Lake service area, pump station, and related conveyance system components. Wastewater planning for the service area is driven more by the need to address the immediate concerns of alleviating the operational difficulties at the Hidden Lake Pump Station, managing peak wet weather flows while anticipating the effects of future sewer deterioration, and controlling odor, rather than accommodating future growth.

Source: Conveyance system improvement program.


To thank Shoreline community members for their input and patience during construction of wastewater facilities in and around Boeing Creek Park, King County hosted a neighborhood celebration on Saturday, Oct. 20, 2007 in the park.

Wastewater Treatment Division and City of Shoreline staff were on hand to tell visitors about the new underground facilities in Boeing Creek Park, including a large underground wastewater storage pipe that helps safeguard the environment by limiting overflows to Puget Sound, plus an expanded city stormwater detention pond.

Visitors could also see current plans for park improvements, take a self-guided walking tour, and learn how this project protects public health and the environment.

King County and Shoreline worked with the public to design a facility that blends in with the park, including placing most structures underground and doing so in a way that avoided impacts to large trees in the park. Public access to the park was maintained during construction, providing uninterrupted access and use of most areas.

Click on the 'thumbnail' images below to view larger versions.

Displays and presentation




Self-guided tour


Project maps and diagrams


City of Shoreline stormwater detention pond



King County odor control structure, with tree snag art (exhaust stack)