The Great Salt Lake Water Level is Becoming Less Resilient to Climate Change

Climate change and water diversions are putting the Great Salt Lake (GSL) at risk. Projections indicate a continued decrease in the GSL water surface elevation (WSE) would lead to several catastrophic consequences. An aspect of the GSL dynamics gaining importance, and not addressed in past studies, is how resilient the lake WSE will be to increasing diversions from contributing rivers, intensifying drought conditions, and more frequent hydrologic deficits caused by climate change. The objectives of the present study were to: (1) examine the impacts of historical drought and development on the GSL resilience and (2) determine future WSE resilience under a range of hydroclimate and development scenarios. The historical resilience was analyzed considering three periods with different development conditions: (1) less developed (1901–1950); (2) moderately developed (1951–2000); (3) highly developed (2001–2020). Furthermore, a range of hydroclimate and development conditions were introduced into a system dynamics-based water management model to simulate the future GSL WSE and corresponding resilience. The historical analysis showed a significant decline in resilience (45.4%) during the highly developed period compared with the moderately developed period. Future scenarios of climate change and development revealed that the mean GSL WSE for the 2021–2050 period may drop by 0.93 m, while the resilience reduces by 30%, and 38% using RCP4.5 and RCP8.5 scenarios when compared to the less and medium developed historical periods respectively. This research provides insight for the State of Utah Department of Natural Resources and stakeholders to inform water management policies and GSL adaptive management strategies.