Hydrology
Over a century of streamflow monitoring from the seven main sub-catchments draining the Central Wasatch indicate that mean annual water yield ranges from 18% to 63% with higher water yield from colder, wetter, steeper catchments (Gelderloos, 2018; Jamison, 2020; Wolf, 2020). Hydrochemical observations from U.S. Geology Survey (USGS) baseline network indicate that most of this surface water discharge has had extensive interaction with the subsurface (Godsey et al., 2009). The evidence that snowmelt drives both surface water discharge and groundwater recharge has led to extensive focus on surface water-groundwater interactions using a suite of tracers (Manning & Solomon, 2004; Manning et al., 2005). These studies demonstrate that mountain block recharge is large, driven by snowmelt, and that regional groundwaters are dominated by modern water with apparent3H/3He ages of 5 to 50 years. Younger waters are found close to the mountain front. Recent findings that snowmelt is decreasing due to long-term warming (Jamison, 2020) while proceeding more rapidly due to episodic dust deposition (Skiles et al., 2018) suggest that historical patterns in recharge and streamflow are unlikely to predict future water supply. These results have important implications for drinking water supply given that winter montane precipitation is an important source for tap water in the Salt Lake Valley (Jameel et al., 2016; 2018).