Peak Wet Weather, CSO & SSO Facilities

Henderson Pump Station and M.L. King CSO Project | Seattle, WA, US

Combined sewer overflows (CSOs) and sanitary sewer overflows (SSOs) can have adverse effects on entire communities. In addition to homes with flooded basements, beaches and other public areas may be closed as a result of health risks due to poor water quality. Federal collection system regulations and third-party lawsuits are also driving cities to examine their systems and develop comprehensive plans to manage large storm events and reduce the occurrence of CSOs and SSOs.

Investigating and reducing CSOs and SSOs means studying a city inside and out. Computer modeling of storm flows, population and land use projections and investigating thousands of miles of pipe all come into play when developing a basin plan to address the problem. HDR takes these steps to thoroughly examine all conditions, explore all options and ensure the program is a success. The end result is worth it when CSOs and SSOs are reduced by 50 to 125 percent or more, protecting the quality of a community's natural water resources and the quality of life in its neighborhoods and commercial districts.