Case Study: South Island Sewer Local Improvement District

Client: City of Bainbridge Island Department of Public Works Location: Bainbridge Island, WA Contact for geotechnical projects: John Peterson

Project Background & Challenges

The South Island Sewer LID consists of five separate regions where new service and conveyance systems will be installed. Conveyance destinations include both existing and new pump stations, and an existing sewer treatment plant. This project entailed two phases. Phase 1 addressed groundwater issues and areas with steep slopes, where stability and associated development impacts were assessed. It also involved researching liquefaction zones along the proposed routes and cultural issues, including historical road construction and areas of hazardous waste contamination.

Solution

As a subconsultant to Berryman & Henigar, Aspect Consulting is currently performing the geotechnical exploration for Phase 2 of the LID. The study area encompasses about 5 miles of collector system and one new pump station across the south end of Bainbridge Island.