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ARS Home » Southeast Area » Oxford, Mississippi » National Sedimentation Laboratory » Watershed Physical Processes Research » Research » Publications at this Location » Publication #135020
Title: PHYSICS OF SUSPENED SEDIMENT TRANSPORT IN ANNAGNPS

Author
item Bingner, Ronald - Ron
item THEURER, FRED - NRCS

Submitted to: Federal Interagency Hydrologic Modeling Conference
Publication Type: Proceedings
Publication Acceptance Date: 7/28/2002
Publication Date: 7/28/2002
Citation: Bingner, R.L., Theurer, F. 2002. Physics of suspened sediment transport in AnnAGNPS [CD-ROM]. Proceedings of the 2002 Second Federal Interagency Hydrologic Modeling Conference, Las Vegas, NV, July 28-August 1, 2002. 12 pp.

Interpretive Summary: Eroded soil from agricultural fields and streams is a major source of sediment pollutants from agricultural watersheds within the United States. An accurate determination of the soil erosion from watersheds is essential in estimating the downstream impact on water quality. Technology is described in this study that has been developed and incorporated as part of a watershed model to describe the transport of sediment within the watershed system. Improved technology is needed to adequately simulate the sediment transport processes in order to provide the link between the soil erosion leaving the agricultural fields and the sediment loadings downstream in the rivers of a watershed. This technology is important to local, state, and federal watershed management planners who are required to determine and separate out the impact of non-point source pollution and channel erosion from agricultural watersheds on the impairment of rivers and streams.

Technical Abstract: The physics of suspended sediment transport as used in the continuous-simulation version of AnnAGNPS is explained. The fine sediment loading from sheet & rill erosion on agricultural lands is both a primary source of wash load within stream systems and a significant non-point source of pollutants. Fine sediment can cause deterioration of the stream system and its aquatic habitat by simply being physically deposited on the bed or intruded into the substrate as well as having an affinity for carrying attached toxic chemicals that are a problem no matter where they end up. The fundamental basis for the suspended sediment transport model is Einstein's suspended sediment transport equation that he developed in 1968 which was modified by the Agricultural Research Service for use in several of their models (single-event AGNPS, CREAMS, WEPP, etc.) to include a limiting sediment transport capacity, and then further modified & integrated within the continuous-simulation AnnAGNPS to include bed material transport.