Groundwater Storage Trends in the Great Salt Lake Basin, 2002–2024

Groundwater storage change in the Great Salt Lake Basin (GSLB) is difficult to quantify because monitoring data are uneven. We estimate groundwater storage anomalies over 2002–2024 with five methods: Gravity Recovery and Climate Experiment (GRACE) total water storage minus Global Land Data Assimilation System (GLDAS) land‐surface components (GRACE‐raw); the same with lake and reservoir storage removed (GRACE‐sw); a further correction for GRACE signal leakage, calibrated against in situ data (GRACE‐Lf); the GRACE‐assimilated GLDAS v2.2 product (GLDAS‐2.2); and an in situ reconstruction from groundwater‐level observations (GWDM). Four of the five methods show drawdowns in 2011–2016 and 2019–2022. Surface water, dominated by the Great Salt Lake, accounts for about 31% of the basin's storage signal. A leakage factor of 2.3 indicates that uncorrected GRACE captures less than half of the signal where pumping is concentrated along the Wasatch Front. Over 2011–2016, leakage‐corrected GRACE indicates a groundwater loss of 13.3 ± 7.8 km 3 and the in situ reconstruction 10.1 ± 1.8 km 3 , both consistent with an independent GPS‐based estimate of 10.9 ± 2.8 km 3 . With a calibrated leakage factor, GRACE and GLDAS data can update the basin's storage estimate as new data are released.