Location: Watershed Physical Processes Research
2019 Annual Report
Accomplishments
1. Geophysical information in support of dam and levee inspections. The University of Mississippi, in collaboration with ARS researchers in Oxford, Mississippi, USDA-NRCS, and Mississippi Department of Environmental Quality (MDEQ), has been studying the added value of incorporating geophysical information into dam and levee assessments. In two case studies, geophysical investigations have provided valuable information about subsurface characteristics important to the assessments. In a seepage study of Carroll County Dam, a high hazard dam located in northwest Mississippi, the dam was affected by moderate seepage and sand boil formations. Results from geophysical surveys indicated that seepage was most likely taking place through a small lens of silty sand imbedded within a clay layer below the dam that was not properly sealed during construction. In a second case study, ground penetrating radar (GPR) measurements were conducted to investigate possible void formation in support of an assessment of the concrete emergency spillway at Big Sand Watershed Structure Y-32-12, located in North Carrollton, Mississippi. An integrated interpretation of the entire survey did not support the presence of voids below the concrete slabs. Geophysical surveys provide information about the subsurface and below structural components of dams that are not accessible during visual inspection. This added geophysical information is allowing for more confident assessments of watershed structures.
