Remote Sensing and GIS Techniques for Assessing Irrigation Performance: Case Study in Southern California

This paper presents the potential of remotely sensed data in addressing spatially distributed irrigation equity, adequacy, and sustainability. The surface energy balance algorithm for land (SEBAL) was implemented to map actual evapotranspiration (ET) over an irrigation district in southern California. Potential ET was also mapped based on the Priestley–Taylor method, modified to account for the effect of horizontally transported energy on enhancing/suppressing ET. Remotely sensed products were integrated with ground-based data in a Geographical Information System (GIS) environment to quantify several irrigation and drainage performance indicators. The among- and within-field coefficients of variation of actual ET were comparable to previous studies, suggesting that water consumption was uniform across the irrigation district. The relative ET was high, indicating that irrigation supply was adequate. The extensive network of open drains was also found to be functioning at an optimal level according to the results of two performance indicators based on the magnitude and uniformity of groundwater depth.