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Bathymetric and Sediment Accumulation of Halfway Lake, PA using Ground-Penetrating Radar

    Braught, Charles, Earth and Environmental Sciences, Susquehanna University, 514 University Ave, Selinsgrove, PA, 17870,; Lachhab, Ahmed, Susquehanna University, 514 University Ave, Selinsgrove, PA, 17870.

    Ground Penetrating Radar (GPR) has emerged as a highly effective method for waterborne subsurface investigations, providing accurate results without causing negative impacts. This study utilized GPR to survey Halfway Like, a manmade reservoir located in Mifflinburg, Pennsylvania. The investigation focused on obtaining detailed bathymetry, sub-bathymetry, and sediment volumes within the lake. A 400 MHz transceiver was employed to perform 71 survey profiles, covering the entirety reservoir. To assess the water volume and the total sediment load, contour maps of bathymetry and sub-bathymetry were generated respectively. For all surveys, a custom-designed GPR apparatus was constructed on a two-person inflatable raft, equipped with a sub-metric GPS and a 400 MHz antenna. The collected data was processed using mapping software, to generate contour maps and 3D models of the site and provide detailed information about the lakebed. In an intense literature review on radar wave velocities through saturated lakebed sediment, like that of Halfway Lake, a value of 0.0762 m/ns was found. The sediment volume was calculated to be 7897.224 m³, while water volume was calculated to be 19704.963 m³. The sedimentation rate over the last 100 years has been also estimated to be approximately 87.747 m³/year. Moreover, the survey profiles reveal the original stream channels of both Rapid Run and Halfway Run. At the point where the two stream channels originally met, the reservoir reaches its greatest depth, measuring 2.5 m. Lastly, the survey profiles display a notable difference in sediment types, with sand accumulation on the beach side and naturally occurring organic sediment in the deeper parts of the reservoir.

    GPR, Lake Bathymetry, Lacustrine deposit,