Submitted to: Federal Interagency Sedimentation Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/28/2001
Publication Date: N/A
Citation: Interpretive Summary: Excess clean sediment in the rivers and streams of the United States has been identified as one of the largest problems affecting the quality of the water of streams and rivers in the United States. The states of the country have been charged to write up plans to evaluate the causes of excess sediment affecting the nation's rivers and streams and to suggest remedies. These plans are termed TMDL's. The Total Maximum Daily Load (TMDL) for clean sediment of a stream or river may be defined as the maximum amount of sediment that the water body can handle without negative impacts to its designated uses. Designated use may be defined as the use that has been specified for a given river or stream. These uses may include recreation, drinking water, navigation, and supporting an unimpaired biological community. Combining the expertise of researchers at the USDA-ARS National Sedimentation Laboratory, a procedure has been developed to evaluate whether the designated uses of a stream or river have been adversely affected by excess sediment. The details of this procedure are currently being refined and verified using data collected at several experimental watersheds in northern Mississippi and in other states. Verification using data from other sites is also planned.
Technical Abstract: A national strategy is needed to develop scientifically defensible procedures to facilitate the development of Total Maximum Daily Loads (TMDL) for clean sediments in streams and rivers of the United States. A strategy is being developed which consists of 1)Determination of the stage of channel evolution of the stream; 2) Calculation of a landscape index based on data of the state of the watershed; 3) Determinations are made as to the likelihood of the stream departing from a stable condition using the stage of channel evolution and the landscape index. While preliminary results from this procedure are promising, it is still under development and needs to be verified with data from streams and rivers from the main physiogeographic provinces of the country.