The Clean Water Act requires states to submit TMDLs to EPA for approval. Also, if a state does not develop the TMDL, the Clean Water Act states that EPA must do so. To support this goal, states must adopt water quality standards. Water quality standards are state regulations which have two components. The first component is a use, such as warm water fishes or recreation.
States determine the uses supported by each of their waters.
The second component relates to the instream conditions necessary to protect the uses. These conditions or criteria are physical, chemical or biological characteristics, such as temperature, the minimum concentration of dissolved oxygen, and the maximum concentrations of toxic pollutants. If criteria are being exceeded, the uses are not being met, and the water is said to be violating water quality standards. The main stem of West Branch Brandywine Creek, Business Route 30 in Coatesville to Confluence of Buck Run was determined to be impaired because excessive levels of PCB and chlordane were found in fish tissue, resulting in a fish consumption advisory. The plan includes a calculation of the loading for both PCB and chlordane that will meet the water quality objectives.