Total Maximum Daily Loads (TMDLs) and the 303(d) List of Impaired Water Bodies

Total Maximum Daily Loads (TMDLs) are action plans to restore clean water. Section 303(d) of the federal Clean Water Act requires that states identify water bodies -- bays, rivers, streams, creeks, and coastal areas -- that do not meet water quality standards, and the pollutants that impair them. TMDLs examine the water quality problems, identify sources of pollutants, and specify actions that create solutions. They are adopted by the Regional Water Board as amendments to our Region's Basin Plan. For more information about TMDLs, click here.

Within our region, the 2008 303(d) list includes more than 270 listings in 88 water bodies. Water Board staff are currently developing TMDL projects to address more than 160 of these listings. (One TMDL may address multiple listings. For example, the Diazinon/Pesticide Toxicity TMDL for urban creeks addressed more than 30 impaired creeks or creek segments.)

Completed TMDL Projects: Napa River Pathogens San Francisco Bay Mercury Sonoma Creek Pathogens Tomales Bay Pathogens Urban Creeks Pesticide Toxicity Walker Creek Mercury TMDL Projects Awaiting Approval from Waterboards and US EPA: Guadalupe River Watershed Mercury Richardson Bay Pathogens San Francisco Bay PCBs Sonoma Creek Sediment TMDL Projects in Development: Lagunitas Creek Sediment Pacifica beaches, San Pedro Creek Pathogens Napa River Sediment Napa River Nutrients North San Francisco Bay Selenium San Francisquito Creek Sediment Butano and Pescadero Creeks Sediment Sonoma Creek Nutrients Tomales Bay Mercury Tomales Bay Siltation/Sediment Walker Creek Sediment

Click on the map above to view a larger image.