Water/Wastewater

North Mercer Island Interceptor and Enatai Interceptor Upgrade 1 Alliance  was contracted to produce a base map for engineering design through preliminary design and final design for the replacement of the North Mercer Island and Enatai sewer pipelines. The project included the design of approximately 16,000 feet of wastewater pipelines from the

Lake Hills Trunk / NW Lake Sammamish Interceptor Sewer Upgrade This project involved replacing the Lake Hills Trunk with a new pipeline, repairing the existing NW Lake Sammamish Interceptor, and constructing a new parallel pipe to the NW Lake Sammamish Interceptor to increase system reliability and add capacity. The 1 Alliance is

Chambers Creek Wastewater Treatment Plant Expansion The Chambers Creek Wastewater Treatment Plant underwent expansion to continue meeting the wastewater treatment and collection needs of the growing population. The project focused on increasing sewer capacity, repairing and replacing infrastructure, and implementing new technologies that help protect the environment. The 1 Alliance survey team

Elliott Bay Seawall The Elliott Bay Seawall project focused on constructing a replacement seawall to protect the City’s critical infrastructure and utilities against storm damage and shoreline erosion and enhancing the habitat throughout the area. The project consists of constructing a new earthquake-resistant system that will support the street and right-of-way, provide