ESTIMATING GROUNDWATER INFLOWS TO GREAT SALT LAKE

Estimating Groundwater Inflows to Great Salt Lake

Great Salt Lake (GSL) is the largest saline lake in the Western Hemisphere and the eighth largest in the world. It plays a vital role in the region's ecosystem and economy. (Utah Department of Natural Resources, 2023). Groundwater discharge to GSL is difficult to quantify but represents a potentially significant source of water to the lake’s overall water budget. Understanding groundwater inflows to GSL is very important due to the recent low lake levels. Previous estimates from water budget residuals suggested about 3% groundwater inflow to GSL (Waddell, M. and Barton, J. D., 1980). Recent studies suggested about 10% of total groundwater inflows to GSL via geochemical modelling (Bunce, 2022) and GIS-based analyses (Zamora and Inkenbrandt, 2024). The large uncertainty in groundwater inflow estimates, along with recent studies including stream chemistry (Godsey et al., 2009), groundwater modeling (Masbruch et al., 2016), streamflow modeling (Brooks et al., 2021), and stream hydrograph analysis (Wolf et al., 2023) all suggest that the amount of groundwater entering GSL has been underestimated. This highlights the need for independent direct measurements of groundwater inflows to GSL, which is important to improve our understanding of groundwater flow dynamics within GSL catchment area. Such work will help provide more accurate estimates of total groundwater inflows, addressing the large uncertainties and underestimation in groundwater estimates in GSL water budget. In this talk, we will present hydraulic head gradients, conductivities from slug tests, and salinity profiles from cores collected on the GSL playa along the Antelope Island Causeway and Farmington Bay.