Identifying Reaches for Additional Measurement or Seepage Studies in Utah’s Great Salt Lake Basin

To understand where additional measurement infrastructure or additional seepage studies are needed in the Great Salt Lake (GSL) basin, we conducted reach scale flow balances across five water years to preliminarily characterize gains and losses and then compared results to historical seepage studies in the basin. We looked at a total of 26 reaches that met selection criteria and summarized reach features (e.g., tributaries, diversions, measurement status) to highlight where measurement infrastructure is present and where it is lacking. Using this method, we found most reaches analyzed to be consistently gaining in the GSL basin with no discernable trend across water years. When compared to historical studies, reach scale flow balances generally overestimated potential gains or losses which was expected as the influence of individual sources (ungaged surface water vs. groundwater) can not be parsed using this method. Despite the simplicity of these methods, places for further investigation were highlighted including reaches with a high number of ungaged features, locations where additional streamgaging may be desired to break up longer reaches, and reaches which are relatively well gaged but see substantial changes in flow between upstream and downstream gages. These areas provide preliminary indications of where future seepage studies may be most beneficial.