Submitted to: Federal Interagency Sedimentation Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 4/4/2006
Publication Date: 4/4/2006
Citation: Leary, D., Hickey, C.J., Wren, D.G. 2006. Acoustic profiling of sediment accumulation in three small erosion control reservoirs in north Mississippi. In: Proceedings of the 8th Federal Interagency Sedimentation Conference, April 2-6, 2006, Reno, Nevada. CDROM. Interpretive Summary: Measuring the amount of sediment stored in a reservoir can be measured by collecting core samples that are used to define the depth of stored material. Acoustic techniques allow for rapid profiling that does not require the extensive lab work of core samples. However, acoustic techniques for sub-bottom profiling require the speed of sound in sediments to be assumed. In the current work, the use of an acoustic lance to directly measure the speed of sound in the field in undisturbed sediment is explored.
Technical Abstract: In Northern Mississippi, as part of a preventative erosion control program, the Yazoo-Little Tallahatchie Project (YLTP) created a system of small dams and reservoirs to regulate stream flow and to stop the movement of sediment over large distances. These structures were designed to have a lifetime of approximately 50 years, depending on water flow and sediment accumulation. As these dams and reservoirs reach their lifetime expectancy, an assessment and decisions regarding their future must be addressed. More detail on this subject is given by Wren et al.(2006). Traditional sediment coring is a time consuming and expensive approach for determining accumulated sediment volumes and sediment characteristics. The National Center for Physical Acoustics NCPA), in collaboration with the National Sedimentation laboratory (NSL), is developing acoustic methods to complement current methods of assessing sediment accumulation in these reservoirs. Three small reservoirs were chosen as the field sites. The small impoundments are approximately 4 hectares (10 acres) in area with water depths of 1–2 m and post-impoundment sediment accumulations on the order of 1m.