The purpose of this task is to identify a consumptive use methodology suitable for estimates of crop evapotranspiration in southwest Colorado. It includes a review and discussion of the more common predictive equations and sample calculations using measured and derived climatic data at a weather station in the project area. Mean data are used for all calculations except precipitation in which a 60 percent recurrence interval is used in effective precipitation calculations. Discussions of crop coefficients yield and ET correction factors and other parameters affecting irrigation requirements are included It does not include the determination of consumptive use for all crops at all locations for all methods