Abstract |
Section 303(d) of the federal Clean Water Act (the Act) directs States to identify and list waters, known as water quality limited segments (WQLSs), in which current required controls of a specified substance are inadequate to achieve water quality standards. For each WQLS, the State is to establish a Total Maximum Daily Load (TMDL) of the specified substance that the water body can receive without violating water quality standards. The Lower Wicomico River was identified on the States 1996 list of WQLSs as impaired by nutrients (nitrogen and phosphorus). Subsequent investigation determined that nitrogen, phosphorus, and biochemical oxygen demand are the dominant causes of high algal levels and low dissolved oxygen concentrations. This report proposes the establishment of TMDLs for the Lower Wicomico River: one for nitrogen, one for phosphorus, and one for biochemical oxygen demand (BOD). Once the TMDLs are approved by the United States Environmental Protection Agency (EPA) they will be incorporated into the States Continuing Planning Process, pursuant to Section 303(e) of the Act. In the future, the established TMDLs will support point and nonpoint source control measures needed to restore water quality in the Lower Wicomico River. |