Section 303(d) of the Clean Water Act requires states, territories, and authorized tribes to list impaired waters and develop total maximum daily loads (TMDLs) for impaired waterbodies. A TMDL establishes the maximum amount of a pollutant allowed in a waterbody and serves as the starting point or planning tool for restoring water quality (EPA). ODOT developed a statewide TMDL Implementation Plan to provide consistency in its highway management practices in all TMDL watersheds.