The Ballard Basin projects combine Green Stormwater Infrastructure (GSI), also known as natural drainage, and future underground storage to control approximately six million gallons of sewage and stormwater. Currently overflows into the Ship Canal and Salmon Bay happen after as little as one-tenth of an inch of rain. Natural drainage opportunities within Ballard include rain gardens, landscaped areas that allow stormwater to soak into the ground.
Ballard Natural Drainage – this project constructed raingardens along several streets to help reduce sewage overflows by keeping stormwater out of the sewer system. Runoff is diverted into swales with special soil to slow and filter the stormwater. Performance monitoring of the swales completed in 2011 began in fall 2012.