Corps of Engineers' Models for TMDLs

The regulatory authority for developing and implementing Total Maximum Daily Loads (TMDLs), as required by the Clean Water Act (CWA), lies with the U.S. Environmental Protection Agency (USEPA) and the States. However, there are a number of Corps of Engineer (CE) activities which will either be affected by, or will be the subject of TMDLs. In addition, the CE is also involved in assisting the USEPA and States in the development of TMDLs. Watershed runoff and receiving water models are frequently used to evaluate TMDLs. This paper provides an overview of the TMDL process, how TMDLs may relate to the CE mission, and watershed and receiving water models used by the CE that are applicable to TMDL analysis.