USING UAVS TO INVESTIGATE GROUNDWATER AND SURFACE WATER INTERACTIONS WITHIN UTAH LAKE, UTAH VIA THERMAL SENSORS

Utah Lake is a shallow Great Basin lake located in northern Utah. The region is currently exhibiting extreme drought coupled with rapid economic growth. Groundwater sources are being asked to meet the water shortages and to provide water for this rapid growth. Current water budget and isotope studies estimate that between 21-72% of the water that enters the lake originated from a groundwater source but there is minimal understanding of how groundwater interacts with the lake and its surrounding water bodies. Our team is investigating the effectiveness of identifying groundwater and surface water interactions by utilizing thermal imaging cameras from small unmanned aerial vehicles (UAVs). A Matrice 210 V2 UAV was utilized with a Zenmuse X5s 15 mm (30 mm equivalent) visible (RGB) camera and a Zenmuse XT2 R thermal imager. The researchers have collected both RGB and thermal imagery from multiple areas around the lake to identify cold water springs. Orthomosaics of the imagery were collected during different seasons to see how the surface and groundwater interactions change over time. In the analysis numerous technical errors and limitations of our sensors were determined and natural variations that create false positives/negatives were identified (i.e., temperature density differences, reflectance and shadowing of water bodies, changes of air temperatures...). The technique still has proven useful to obtain high resolution orthomosaics of the sites and provide a much more detailed understanding of how springs migrate as water levels in the lake rise and fall. Coupling the imagery with flow measurements at the sites have been useful to quantify how streams change from losing to gaining streams. As we continue to use these sensors to research the surface and groundwater interactions, we hope that we will get a better understanding of how the groundwater interacts with our surface waters and how to better utilize groundwater resources in the region.