Addressing Emergency Projects Identified during Condition Assessments Can Be Challenging

Cascade Water Alliance (Cascade) provides safe, clean, and reliable water supply to seven municipalities in the Puget Sound Region (Washington). In 2009, Cascade purchased the White River Project from Puget Sound Energy (PSE) with the full expectation that the water rights could and would be converted from a hydroelectric and recreational water right to a domestic and recreational water supply. The White River Project consists of an upstream flow diversion headworks facility that diverts flow out of the White River to fill Lake Tapps and the lower conveyance system (LCS) facilities. These facilities provide flow out of the lake and drop approximately 500 feet in elevation prior to discharge back into the White River. Substantial capital improvements are necessary to convert the over 100-year old hydropower facility to a water supply project. The Project Team’s initial work has been focused on ensuring that the existing facilities can operate under conditions that the facilities were not originally designed for, as well as under a wide range of flow conditions. Condition assessment field inspections of the LCS facilities required the lake to be drawn down almost 40 feet which was a two month process alone. The inspections identified immediate rehabilitation and replacement projects that were required at the intake structure and in the discharge bay, as well as other urgent (0-1 years), near term (5 to 10 years), and future needs (25+ years).