These spatial features show the Oregon waters where Total Maximum Daily Loads (TMDLs) have been completed and approved by EPA. TMDLs that have been withdrawn, disapproved by EPA, or replaced with a newer TMDL are not shown.

A Total Maximum Daily Load (TMDL), or clean water plan, is a science-based approach to cleaning up polluted water so that it meets state water quality standards. A TMDL is a numerical value that represents the highest amount of a pollutant a surface water body can receive and still meet the standards.

The federal Clean Water Act requires states, or the U.S. Environmental Protection Agency, to develop a TMDL for each water body on the state's polluted waters list, also known as the 303(d) list (Integrated Report). The TMDL process is just one strategy used to clean up polluted waters.

The TMDL documents are available on DEQ's website: https://www.oregon.gov/deq/wq/tmdls/Pages/default.aspx