Hidden Lake Pump station replacement and sewer improvement project

Underground storage pipe

May 2007. Workers installed a channel at the bottom of the underground storage pipe to convey normal wastewater flows. View more construction photos.

In October 2007, King County completed construction of a new 500,000-gallon underground storage pipe in Boeing Creek Park to temporarily store wastewater during large storms and help reduce overflows into Puget Sound. The pipe replaced an existing 24-inch sewer in Boeing Creek Park owned by the Ronald Wastewater District. The new sewer is 12 feet in diameter and about 640 feet long. Work on associated odor control and flow control structures continued into January 2008. The county replaced 1,000 feet of smaller pipe in the streets near the park.

The new underground storage pipe is conveying normal wastewater flows toward the Hidden Lake Pump Station. Operational testing is ongoing to accommodate system capacity. The storage pipe will be used to retain flows during operations to connect the new Hidden Lake Pump Station to the Boeing Creek Trunk Sewer.

The contractor is completing restoration around the underground odor control facility in Boeing Creek Park. Permeable pavers were installed to build a solid surface for maintenance trucks while creating a more natural appearance and allowing water to penetrate the soil beneath. The contractor has seeded the area for erosion control.

At the city's request, the county also graded the existing storm water facility to increase its capacity and then stabilized the area. The City of Shoreline plans to improve its existing storm water facility and make park improvements, using $1.1 million in funds provided by the county.