Improving Stormwater Quality in an Urban Watershed – Using Management and Monitoring to Prevent Recontamination of the Thea Foss Waterway

In the heart of downtown Tacoma is Thea Foss Waterway, once characterized by oil sheens, coal tar deposits and dilapidated buildings and listed as a Superfund site in 1985. In 2006, the City of Tacoma and others completed a 105 million remediation of the waterway. To ensure that the waterway remains the asset it has since become, the City of Tacoma is using source control, maintenenace, engineering, and enforcement to make a real difference in the stormwater discharged to the Waterway. To track the progress, these efforts were paired with extensive monitoring of stormwater throughout the Thea Foss Watershed. This nine-year record of actions and monitoring has been correlated, and the results are impressive. Data shows significant improvement in the quality of stormwater discharged to the waterway. This data enables Tacoma to better understand the effectiveness of individual management practices and increase the cost effectiveness of its overall stormwater program.