To better understand irrigation water consumptive use (CU) as driven by crop evapotranspiration (ET) in the South Platte Basin in northeastern Colorado, results from a satellite-based surface energy balance method of estimating ET were compared with traditional CU estimates as calculated in an existing water management decision support system (DSS). Using available historical satellite and meteorological data, the METRIC (Mapping ET at high Resolution with Internalized Calibration) method was applied to a region in the South Platte River Basin for a full irrigation and cropping season. The METRIC-derived ET estimates were compared to CU estimates generated from the Colorado Water Conservation Board's South Platte DSS StateCU model. Inputs to the StateCU model were modified to produce detailed results for assessing CU by crop type, irrigation method, water source, and water availability. Over 400,000 acres of irrigated lands were analyzed. Funded by a NASA Research Opportunities in Space and Earth Sciences (ROSES) grant, the objectives of this research are to better understand the currently-applied CU estimation methods in the South Platte Basin and to assess remote sensing techniques as an alternative to or enhancement of conventional methods for improved water management in the basin.