This data set contains mean annual recharge due to infiltration of precipitation, in inches (x 1000), within the upper Umatilla River Basin, Oregon, for calendar years 1981 - 2010. Recharge due to infiltration of precipitation is estimated using a regression method developed by Bauer and Vaccaro (1990) that relates annual recharge to annual precipitation. Gridded mean annual precipitation for years 1981 - 2010 was provided by the Oregon State University PRISM Climate Group. References: Bauer, H.H., and Vaccaro, J.J., 1990, Estimates of ground-water recharge to the Columbia Plateau Regional Aquifer System, Washington, Oregon, and Idaho, for predevelopment and current land-use conditions: U.S. Geological Survey Water-Resources Investigations Report 88-4108, 37 p. PRISM Climate Group, 2016, Northwest Alliance for Computation Science and Engineering: Corvallis, Oregon State University, Northwest Alliance for Computation Science and Engineering, accessed September, 2016, at http://www.prism.oregonstate.edu/