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Development of Bacteria and Benthic Total Maximum Daily Loads
Author(s) -
Benham Brian L.,
Brannan Kevin M.,
Yagow Gene,
Zeckoski Rebecca W.,
Dillaha Theo A.,
Mostaghimi Saied,
Wynn Jeff W.
Publication year - 2005
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2004.0414
Subject(s) - total maximum daily load , environmental science , watershed , clean water act , nonpoint source pollution , water quality , hydrology (agriculture) , benthic zone , watershed management , environmental engineering , water resource management , computer science , engineering , ecology , geotechnical engineering , machine learning , biology
Two total maximum daily load (TMDL) studies were performed for Linville Creek in Rockingham County, Virginia, to address bacterial and benthic impairments. The TMDL program is an integrated watershed management approach required by the Clean Water Act. This paper describes the procedures used by the Center for TMDL and Watershed Studies at Virginia Tech to develop the Linville Creek TMDLs and discusses the key lessons learned from and the ramifications of the procedures used in these and other similar TMDL studies. The bacterial impairment TMDL was developed using the Hydrological Simulation Program—Fortran (HSPF). Fecal coliform loads were estimated through an intensive source characterization process. The benthic impairment TMDL was developed using the Generalized Watershed Loading Function (GWLF) model and the reference watershed approach. The bacterial TMDL allocation scenario requires a 100% reduction in cattle manure direct‐deposits to the stream, a 96% reduction in nonpoint‐source loadings to the land surface, and a 95% reduction in wildlife direct‐deposits to the stream. Sediment was identified as the primary benthic stressor. The TMDL allocation scenario for the benthic impairment requires an overall reduction of 12.3% of the existing sediment loads. Despite the many drawbacks associated with using watershed‐scale models like HSPF and GWLF to develop TMDLs, the detailed watershed and pollutant‐source characterization required to use these and similar models creates information that stakeholders need to select appropriate corrective measures to address the cause of the water quality impairment when implementing the TMDL.