Saline pans are environments with evaporite crusts, high-salinity surface and groundwater brines, and low topographic gradients. These characteristics make them sensitive to diverse hydrological processes. The Bonneville Salt Flats, a valued and changing saline pan, was investigated to identify saline pan hydrology responses to diurnal to seasonal cycles. Seasonal changes in evaporation and relationships between groundwater levels and environmental processes in saline pans are not well understood. The results presented here, which improve characterizations of saline pan water balances and movement, enable predictions of salt growth or dissolution associated with geoengineering to mitigate the impacts of mining saline pans. Three months of eddy-covariance evaporation measurements were collected, spanning a flooded to desiccated surface transition. Two techniques, an artificial neural network and an albedo-based calibration of the Penman equation, were evaluated and used to estimate evaporation with over four years of inexpensive micrometeorological measurements. Albedo, a water availability proxy, inversely correlated with evaporation. Shallow groundwater levels varied seasonally by >50 cm and daily by >6 cm in response to temperature fluctuations. Groundwater level fluctuations should be carefully interpreted as they may not reflect recharge or discharge. Evaporation had a minor, <10 cm y-1, effect on groundwater levels. Surface moisture, primarily from rain, controlled evaporation. Summer desiccated surface evaporation was ~0.1 mm d-1. The net annual water balance was < +/-1.5 cm y-1, indicating the saline pan stabilizes the water table. Surface dynamics of these environmentally-sensitive and variable landscapes are increasingly important to understand as water scarcity in arid environments rises.

The Jordan River Basin, and its seven sub-catchments of the Central Wasatch Mountains immediately east of Salt Lake City, UT, are home to an array of research infrastructrure that collectively form the Wasatch Environmental Observatory (WEO). Each sub-catchment is comprised of a wildland to urban land use gradient that spans an elevation range of over 2000 m in a linear distance of ~25km. Geology varies across the sub-catchments, ranging from granitic, intrusive to mixed sedimentary rocks in uplands that drain to the alluvial or colluvial sediments of the former Lake Bonneville. Vegetation varies by elevation, aspect, distance to stream channels, and land use.  The sharp elevation gradient results in a range of precipitation from 700 to 1200 mm/yr (roughly 2/3 as snow) and mean annual temperature from 3.5 o to 6.8o C. Spring snowmelt dominates annual discharge. Although climate is relatively similar across the catchments, annual water yield varies spatially by more than a factor of 3, ranging from 0.18 to 0.63. With historical strengths in ecohydrology, water supply, and social-ecological research, current infrastructure supports both basic and applied research in meteorology, climate, atmospheric chemistry, hydrology, ecology, biogeochemistry, resource management, sustainable systems, and urban redesign. Climate and discharge data span over a century for the seven sub-catchments of the larger basin. These data sets, combined with multiple decades of hydrochemistry, isotopes, ecological data sets, social survey data sets, and high-resolution LiDAR topography and vegetation structure, provide a baseline for long-term data collected by NEON, public agencies, and individual research projects. The combination of long-term data with active state of the art observing facilities allows WEO to serve as a unique natural laboratory for addressing research questions facing rapidly growing, seasonally snow-covered, semi-arid regions worldwide and an excellent facility for providing student education and research training.