Abstract |
Section 303(d) of the federal Clean Water Act directs States to identify and list waters, known as water quality limited segments (WQLS), in which currently required controls of specified substances are inadequate to achieve water quality standards. For each WQLS, the State is to establish a Total Maximum Daily Load (TMDL) of the specified substances that the water can receive without violating water quality standards. Conococheague Creek was identified on the States 1996 list of WQLS as a waterbody potentially impacted by nutrients (nitrogen and phosphorus) and suspended sediments. The Creek was listed for nutrients due to historically low levels of dissolved oxygen. Recent data does not show violations of the dissolved oxygen standard in the Maryland portion of Conococheague Creek, partially because the Conococheague Wastewater Treatment Plant (WWTP) has discharged effluent of better quality and lower flow than the maximum allowed under its NPDES permit. It is suspected, however, that violations of the dissolved oxygen standard could occur in the future, if Carbonaceous Biochemical Oxygen Demand (CBOD) and Nitrogenous Biochemical Oxygen Demand (NBOD) loadings are increased. This report documents the proposed establishment of a TMDL for the Maryland portion of Conococheague Creek to maintain dissolved oxygen at levels equal to or higher than the dissolved oxygen standard. |