University CSO GSI Design Project

King County is actively working to prevent heavy rains from causing combined sewer overflows (CSOs) into Portage Bay in Lake Washington. On average, six CSOs occur each year, degrading water quality in the lake. Herrera is supporting an alternatives analysis and design for what is slated to be the largest retrofit project using green stormwater infrastructure (GSI) in the region. GSI will work in conjunction with a centralized storage facility to reduce the number of CSO events to a maximum of one per year.