The Installation, Operation and Analysis of Eddy Covariance for Quantifying Evapotranspiration

During the contract period from January 2021 through December 31, 2023, the University of Texas at Austin, Bureau of Economic Geology (UT-BEG) installed and maintained two eddy covariance stations across the Edwards Aquifer recharge region. The Cibolo station was installed on February 25, 2021, in the more humid eastern portion of the region within an oak-ashe juniper ecosystem adjacent to Cibolo Creek at the Field Research Park (FRP) operated by the Edwards Aquifer Authority (EAA). The Uvalde station was installed on April 8, 2021, in the more arid western portion of the region within a mesquite woody savanna northwest of Uvalde, TX, near the Nueces River. The Uvalde station was demobilized on March 1, 2023, and relocated to a permanent location approximately 30 miles north, within an oak-ashe juniper woody savanna on the Shield Ranch east of Camp Wood, TX, and renamed the Nueces station. Installation of the Nueces station was completed on July 19, 2023. Site visits were performed throughout the contract period for regular maintenance, such as calibrating (i.e., zero-spanning) the infrared gas analyzer, and as-needed maintenance such as troubleshooting issues with power, communication or individual sensors. The Cibolo, Uvalde, and Nueces sites have been registered with AmeriFlux (a collaborative network of flux site across North, Central, and South America with standardized processes and procedures) with site designations of US-EA4, US-EA5, and US-EA6, respectively. Data submission to AmeriFlux for the eddy covariance sites is ongoing.