ACOUSTIC PROFILING OF SEDIMENT ACCUMULATION IN THREE SMALL EROSION CONTROL RESERVOIRS IN NORTH MISSISSIPPI

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.