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United States Department of Agriculture

Agricultural Research Service

Research Project: TECHNOLOGIES FOR ASSESSING SEDIMENT MOVEMENT & THE INTEGRITY OF FLOOD CONTROL STRUCTURES, STREAMBANKS, & EARTHEN POND-LEVEES & EMBANKMENTS Title: Suspended Load

Author
item Kuhnle, Roger

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: February 1, 2012
Publication Date: March 1, 2013
Citation: Kuhnle, R.A. 2013. Suspended Load. In: Shroder, J.F. (Editor-in-Chief), Wohl, E. (Volume Editor), Treatise on Geomorphology Vol. 9, Fluvial Geomorphology, Academic Press, San Diego, CA, pp. 124-136. (Book Chapter).

Interpretive Summary: Suspended load refers to the sediment that rivers and streams carry up in the water column away from the stream bottom. Sediment in motion as suspended load is one of the major pollutants of water bodies in the US according to the Environmental Protection Agency. Excess sediment impairs the use of water for industrial and human uses and also increases the cost of treatment. Excess sediment has also been shown to have detrimental effects on aquatic plants and fish. Pollutants, including heavy minerals, pesticides, and nutrients are adsorbed to fine sediments and moved by the flow of rivers and streams as suspended load. Therefore, an understanding of where suspended sediment originates and what processes control its movement and deposition are important information needed by managers of agricultural and other watersheds. This chapter provides an up to date summary of what is known about the movement of suspended sediments by rivers and streams.

Technical Abstract: The suspended load of rivers and streams consists of the sediments that are kept in the water column by the upward components of the flow velocity. Suspended load may be divided into cohesive and non-cohesive loads which are primarily discriminated by sediment particle size. Non-cohesive sediment is generally taken as sediment with a size greater than 0.062 mm with cohesive sediments being less than 0.062 mm. Non-cohesive suspended sediment generally is transported at the capacity of the flow and is derived from the bed material of a stream and is termed part of the bed material load. Cohesive suspended sediments are generally not part of the bed material load but are part of the wash load of a stream and are transported below the capacity of the flow. An up to date account of the processes controlling the concentration of non-cohesive and cohesive sediments as suspended load will be given. The measurement, computation and estimation of suspended load will also be considered.

Last Modified: 10/21/2014
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