Tacoma's Statistically Proven Approach to Stormwater Management, Tacoma, Washington

摘要

The City of Tacoma, Washington is 16,058 hectares (62 sq miles, population 200,000), ultra-urban, and has separated storm and sanitary sewer systems. Tacoma is a Phase 1 Municipal Stormwater National Pollutant Discharge Elimination System (NPDES) permitted City with a remediated Superfund Waterway located in the heart of our downtown corridor. Stormwater from 2,428 hectares (6,000 acres) of commercial, industrial and residential land discharges directly to this remediated sediment site. Through the implementation of our NPDES Permit and Superfund Consent Decree, Tacoma developed a multipronged Stormwater Management Program. Through our nationally recognized stormwater monitoring program, the City has collected sufficient data to statistically show that our stormwater management program is effective. Our Program hierarchy consists of 3 progressive elements; Source Control, Enhanced Maintenance and finally Treatment Retrofit where issues remain. This comprehensive program is a fraction of the cost of retrofitting the entire city with water quality treatment, which would cost rate payers $12-18B using current retrofit technology. This incredible expense is not currently planned for or part of our annual comprehensive Stormwater Program budget of approximately $43.6M. To make smart, sustainable decisions to solve todays problems, while anticipating future scenarios the next step is development of City-wide Watershed Planning to prioritize additional stormwater facilities and source control efforts throughout the City based on lessons learned in the Superfund Stormwater Management Program.