Evaluating Surface Water Movement and Measurement near Great Salt Lake

This analysis evaluated surface water movement and measurement infrastructure near Great Salt Lake (GSL) to facilitate a better understanding of current surface water hydrology and inform future measurement infrastructure needs throughout GSL's ecosystem. This information is needed to support diverse objectives. In this study, we (1) comprehensively documented surface water movement and measurement infrastructure throughout GSL's ecosystem via diagrams and geospatial datasets. With this information in a centralized location, we were able to (2) qualitatively and quantitatively characterize the timing and magnitude of unmeasured points of inflow to GSL’s Intermediate Area, a portion of GSL's ecosystem that was previously data-poor. Using this dataset and others, we (3) evaluated different methods for estimating surface inflow to GSL’s Peripheral Wetlands, Intermediate Area, and Water Body. This work fills a gap in our understanding of how different methods for estimating surface water inflow to these regions vary (Utah Division of Water Resources, 2023). Finally, we used information from this study collectively to (4) identify potential pathways for delivering water dedicated to various point locations within portions of GSL's ecosystem where a designated pathway had not been previously determined due to ambiguity surrounding surface water movement.

We developed 46 flow balance diagrams to comprehensively document surface water movement, measurement infrastructure, water control structures, points of interest, and wells/springs throughout GSL's ecosystem in a uniform format. Where flow information has historically been sparse, we characterized the timing and relative magnitude of unmeasured points of potential inflow by consulting local experts and taking flow measurements in three distinctive periods between July 2024 to May 2025, highlighting presently ungaged but consistently larger inflows. To offer insight into potential differences between inflow quantities at different boundaries within GSL's ecosystem, we evaluated five methods of estimating inflow using time series information from gages and/or periodic field measurements. Results show variability across season.

Because surface water movement near GSL was previously not well understood, the potential pathways to deliver water dedicated to the beneficial use of GSL from the Weber and Jordan River sub-basins were unknown. Stakeholders identified 14 direct and 39 indirect pathways for delivering water dedicated to the beneficial use of GSL as well as highlighted various challenges associated with each pathway including canal capacities, storage needs, physical infrastructure needs (including measurement infrastructure), management goals, as well as the influence of the timing and quantity of deliveries.

Collectively, this report provides greater insight into the surface hydrology of GSL's ecosystem by comprehensively identifying surface flows and collating measurement infrastructure information into a single resource. Qualitative and quantitative data describing the timing and magnitude of inflows highlight locations that could be monitored to better understand the influence of wetland management practices on inflows to GSL. Evaluating methods of estimating surface inflow to different boundaries within GSL's ecosystem emphasizes the need to further investigate how water travels throughout GSL's ecosystem and the factors that influence surface hydrology near GSL.