Monitoring of regional evapotranspiration allows decision makers (i) to follow where, when, and how much water has moved into the atmosphere by evapotranspiration; (ii) to monitor crop performance and the effects of droughts for famine prediction; (iii) to better evaluate the performance of irrigation systems; and (iv) to improve weather predictions. The overall goal of this proposal is to determine the value of integrating best estimates of regional evapotranspiration from NASA earth science results into two existing decision support systems: the Agricultural WAter Resources Decision Support (AWARDS)/ET Toolbox system developed by the US Bureau of Reclamation and the Gridded Surface/Subsurface Hydrologic Analysis (GSSHA) model developed by the US Army Corps of Engineers. Two different implementations of the Surface Energy Balance Algorithms for Land (SEBAL) are used in the proposed study. SEBALNM is an adaptation of SEBAL developed at New Mexico Tech by PI Hendrickx for assessment of evapotranspiration rates in the heterogeneous riparian valleys of the southwestern United States. The algorithm Mapping Evapotranspiration at High Resolution with Internal Calibration (METRICTM) has been developed at the University of Idaho by Advisor Allen for precise mapping of evapotranspiration of irrigated fields and rangelands. SEBALNM and METRICTM need as input at least one emissivity in the thermal infrared band and reflectances in the visible, near-infrared, and mid-infra bands. Therefore, the NASA sensors to be used are limited to Landsat, MODIS, NPP, and NPOESS. The performance indicator for this study is how well regional evapotranspiration and river flows are predicted.