Water Resources Research Act Program

Principal Investigators: Rollin H. Hotchkiss

Abstract: Reservoir operators, irrigation districts, and conservation districts in Utah need to know how much their storage reservoirs are filling with sediment. Sediment accumulation depends upon annual snowpack and runoff, but can be exacerbated dramatically following devastating fires such as seen in 2018. Determining accumulated sediment storage requires a bathymetric survey that yields information below the water surface at the time of the survey. Repeated surveys during the spring runoff period will provide data to evaluate sedimentation rates and correlations with runoff. Reservoir areas above the water surface, and especially near the inlet where much sediment collects, typically goes unmeasured. This project will combine sonar surveys with drone surveys and knit the datasets together for a complete bathymetry analysis. Areas of rapid sedimentation will be repeatedly surveyed to determine sedimentation rates. Drops in equipment prices and advances in technology allow such a cutting edge project to be executed. Data will be collected as suggested by the Utah Division of Water Resources (DWR), the U.S. Bureau of Reclamation, and the Central Utah Water Conservancy District (CUWCD). The DWR and CUWCD are providing matching funding and the Bureau is investing $80,000 in equipment for the project. Repeated surveys at the inlet of Starvation Reservoir, at a minimum, will track sediment inflows following the destructive Dollar Ridge Fire of 2018.