EVAPOTRANSPIRATION IN UTAH: INSIGHTS FROM THE UTAH FLUX NETWORK

The Utah Flux Network, operated by the Utah Geological Survey, comprises 11 micrometeorological stations strategically located across the state to monitor energy and water exchanges within the critical zone, with a primary focus on evapotranspiration (ET). ET is a pivotal variable for water management but remains one of the least constrained components in hydrology, which is why this network is supported by water management agencies including the Colorado River Authority of Utah, the Utah Division of Water Rights, the Upper Colorado River Commission, and the Utah Division of Water Resources. Recent advances in remote sensing and measurement technologies have improved our ability to quantify and understand ET dynamics.

This presentation highlights station placement and methods used to measure and estimate ET through ground-based and remote sensing approaches. Case studies illustrate how ET data inform water management across Utah. For instance, measurements from the Bonneville Salt Flats station have refined the area's water budget, altering our understanding of salt precipitation timing and processes. At the Phragmites site near Great Salt Lake, we evaluate ET fluxes linked to invasive species treatment and demonstrate the use of remote sensing to track vegetation changes. In piñon-juniper ecosystems, our Cedar Mesa station has contributed to understanding ET in response to climate change, with recent applications incorporating camera systems to study ecological responses. We also examine water use in agricultural settings, showcasing how our stations have enhanced understanding of alfalfa, a key forage crop, and revealed multi-decade changes in water use through remote sensing. By integrating ground-based measurements with remote sensing, the Utah Flux Network provides critical insights into ET dynamics, advancing water resource management across diverse landscapes in Utah.