Total Maximum Daily Load of Sediment in the Wills Creek Watershed, Garrett and Allegany Counties, Maryland.

摘要

This document, upon approval by the U.S. Environmental Protection Agency (EPA), establishes a Total Maximum Daily Load (TMDL) for sediment in the Wills Creek watershed (basin number 02141003). Section 303(d) of the federal Clean Water Act (CWA) and the EPAs implementing regulations direct each state 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 required to either establish a TMDL of the specified substance that the waterbody can receive without violating water quality standards, or demonstrate that water quality standards are being met (CWA, 2006). The Maryland Department of the Environment (MDE) has identified the waters of Wills Creek (basin number 02141003) on the States 303(d) List submitted to the EPA by MDE as impaired by nutrients (1996), sediments (1996), pH (1998 and 2004), bacteria (2002), toxics - Cyanide (1996), and portions of the basin for impacts to biological communities (2002) (MDE, 2006a). The designated use of Wills Creek is Use IV-P (Recreational Trout Waters and Public Water Supply) for the mainstem only and Use I (Water Contact Recreation and Protection of Aquatic Life) for all other tributaries (MDE 2006a and COMAR, 2006a; 2006b). This document proposes to establish a TMDL of sediment in Wills Creek to allow for the attainment of the above mentioned designated uses. The objective of the sediment TMDL established in this document is to ensure that there will be no sediment impacts affecting aquatic health, when aquatic health is evaluated based on Marylands biocriteria (Roth et al., 2000, Roth et al., 1998 and Stribling et al., 1998), thereby establishing a sediment load that supports the Use I/IV-P designation for the Wills Creek watershed. The watershed sediment load includes the potential effects of water clarity and erosional and depositional impacts, thus accounting for all of the sediment impacts that indicate a sediment impairment per the Maryland 303(d) listing methodology (MDE, 2006b).