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United States Department of Agriculture

Agricultural Research Service

Title: Automatic Measurement of Bed Height Records in a Gravel-Bed Stream

Authors
item Kuhnle, Roger
item Derrow, Robert - UNIVERSITY OF MISSISSIPPI

Submitted to: Agroacoustics Symposium
Publication Type: Proceedings
Publication Acceptance Date: March 6, 1999
Publication Date: N/A

Interpretive Summary: Knowing the rate of movement of sediment through agricultural watersheds is important for a variety of reasons. The rate of sediment movement represents the net erosion of the land surface and is an indicator of problem spots in the watershed. Controlling excessive erosion is critical for managing agricultural lands for sustainable use in an environmentally friendly manner. Knowing the height and shape of the surface of the stream bottom is a critical variable for accurate determinations of sediment movement and erosion rates. This information is also critical for determining the height of flood waves. In this study an acoustic distance measuring device, developed in cooperation with researchers from the National Center for Physical Acoustics, University of Mississippi, was used to measure time records of the height of the stream bottom during flow events. This type of information is very rare for streams with sand and gravel. This information will be used to refine and improve current sediment rate prediction methods.

Technical Abstract: An automatic acoustic pulse-echo distance measuring device (Field SedBed Monitor) was developed to collect bed height records in the Goodwin Creek Experimental Watershed. The bed material at the study site is composed of a mixture of sand and gravel with a median size of 8.3 mm. Using bed height records collected by the Field SedBed Monitor, bed forms were found for nearly all flows when the bed sediment was in motion. Bed form periods, heights, and lengths were found to not be a function of flow strength. This was attributed to the limited range of flows under which data was collected.

Last Modified: 9/22/2014
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