The Wasatch Environmental Observatory: A mountain to urban research network in the semi-arid Western US

Abstract

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 6.8 o 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.

Groundwater‐Mediated Memory of Past Climate Controls Water Yield in Snowmelt‐Dominated Catchments

“…Interannual variability in subsurface water storage is quantified using mean daily streamflow in January when catchments are snow covered and isotopic and geochemical analyses indicate that streamflow from these and other regional watersheds is derived from groundwater (Follstad Shah et al, 2019;Gabor et al, 2017;Hall et al, 2016;Follstad Shah et al, 2021). The annual cycle of streamflow in these catchments is typical for montane snowmelt systems with peak discharge in spring and early summer during melt, annual minimum in late summer when ET is high, and a slow rebound in fall as plants senesce followed by stabilization in mid-winter.…”

“…Trend analysis using PRISM data, especially when it includes SNOTEL stations, is subject to artifacts associated with changes in number, type, and location of instruments. Fortunately, northeast Utah has a large number of long-term climate observations (Horel et al, 2002;Follstad Shah et al, 2021) and a hydroclimatic reanalysis has indicated minimal bias in the region (Maurer et al, 2002). Additionally, changepoint analysis was used to identify when any periods of increase or decrease began and no changes were associated with the instrument changes at local SNOTEL sites.…”