ARS | Publication request: USE OF REMOTE SENSING FOR MONITORING EVAPORATION OVER MANAGED WATERSHEDS 1309

Submitted to: American Society Of Civil Engineers Watershed Management Conference
Publication Type: Proceedings
Publication Acceptance Date: June 6, 2000
Publication Date: N/A

Interpretive Summary: Monitoring water loss from river basins due to evaporation is important for determining the effect of climate and management on our natural environment. Numerous studies at the USDA ARS Walnut Gulch Experimental Watershed (WGEW) near Tucson, Arizona have shown that it is possible to determine large-area evaporation from river systems using images from orbiting satellites. In this report, satellite-based approaches for estimating river basin evaporation were reviewed, with an assessment of the accuracies and the limitations of each approach. The conclusion was that satellite-based techniques could be implemented to monitor river-scale evaporation with reasonable accuracy. The examples of state-of-the-art techniques were contrasted with an operational approach implemented by the Bureau of Reclamation for the Lower Colorado River Basin. There was a gap between the approaches under development at research institutions like WGEW Wand the needs of agencies responsible for monitoring large area evaporation. Future work should be conducted with input from the potential clients to ensure that the application of this technology suits the accuracy requirements and technological capabilities of the end users.

Technical Abstract: The USDA ARS Walnut Gulch Experimental Watershed (WGEW) has been the site for numerous interdisciplinary experiments focused on the use of remote sensing for estimating distributed evaporation (E). This report documents a selection of the remote sensing techniques that have been applied at WGEW and reports the resulting accuracies of estimates of E, along with the advantages and disadvantages of each technique. This selected techniques were contrasted with an operational remote sensing approach for monitoring E implemented by the Bureau of Reclamation for the Lower Colorado River Basin.