Using a Surface Energy Balance Model (ReSET-Raster) to Estimate Seasonal Crop Water Use for Large Agricultural Areas: Case Study of the Palo Verde Irrigation District

Abstract

Water accounting for agricultural areas is crucial for irrigation water management. Actual crop evapotranspiration (ET) is needed as an important input for agricultural water accounting, yet obtaining accurate measurements of actual ET for all crops in an area that reflects the spatial variability in crop condition is not possible with the traditional ET estimation methods. The traditional ET estimation methods are based on using weather-based reference ET and crop coefficients (Kc). This traditional approach usually overestimates crop water use because most users assume that crops are in close to optimal growing conditions (i.e., potential ET) which is not always the case. The objective of this paper is to assess the use of actual evapotranspiration estimated by a surface energy balance model called