Estimating the value of satellite-derived measurements of evapotranspiration to inform irrigation scheduling in California almond orchards

Abstract

Advances in satellite remote sensing have led to the development of improved methods and tools for calculating evapotranspiration (ET), allowing for improved irrigation scheduling. Researchers have been working closely with industry groups for the last decade on developing an "ET Toolkit" that could be used operationally to improve irrigation scheduling for specialty crops in California's increasingly drought-prone Central Valley. A unique collaboration between government and academic researchers and the Almond Board of California aimed to develop and refine the ET Toolkit to improve water use efficiency through irrigation scheduling for almond growers. In this study, the monetary value of applying the ET Toolkit to improve water use efficiency through irrigation scheduling for almonds is estimated. Benefits are valued by comparing existing irrigation scheduling methods, which rely on calculating crop ET in grower fields based on nearby weather station measurements, to future adoption of a field-scale satellite-based actual ET tool. As publicly available field-scale information has only recently come on-line through OpenET, the benefits estimated are prospective. Two valuations are conducted: one that captures private benefits to farmers, and another that captures the economic value for all water users based on the price that buyers are paying in active California water markets. Given assumptions on scaling pathways and drought's impact on values of water, the average annual water savings are estimated to be 241,000 acre-feet, and value to farmers is estimated to be $45.5 M, while economic benefits reach $127.6 M over the period 2028-2033.