Oregon Irrigation Consumptive Use Project

Irrigation in Oregon is the leading use of water at 85%. Consumptive water use (CU), the primary loss from irrigation, represents water that is lost to evapotranspiration (ET) through both evaporation from surfaces and transpiration from plants into the atmosphere after being withdrawn from a stream or aquifer. Currently, the Oregon Water Resources Department does not have an operational method for estimating ET or CU from irrigated agriculture. However, satellite optical and thermal imagery can be combined with gridded climate data to estimate actual ET and CU at the field scale for large regions, providing more accurate and defensible water use estimates using widely accepted methods and best available science that can be applied consistently statewide.

The main objective of this project is to develop the necessary datasets for estimating irrigation withdrawals at the HUC-12 watershed scale. These necessary datasets include field-level ET and consumptive use (CU, ET less effective precipitation), GIS polygons of agricultural fields, and GIS field attributes of irrigation status, irrigation source type, crop type, and irrigation method.

The successful completion of this project will enable the Oregon Water Resources Department and U.S. Geological Survey to better quantify agricultural water use and irrigation withdrawals.