Mean-annual and mean-seasonal water-budget estimates from a Soil-Water-Balance model of the Appalachian Plateaus, 1980 through 2011

As part of the U.S. Geological Survey Groundwater Resources Program study of Appalachian Plateaus aquifers, mean-annual and mean-seasonal water-budget estimates for the period 1980 through 2011 were determined for a 162,000 square-mile area covering parts of New York, Pennsylvania, Maryland, Ohio, West Virginia, Kentucky, Virginia, Tennessee, North Carolina, Georgia, Alabama, and Mississippi. Mean-annual and mean-seasonal precipitation, recharge, and actual evapotranspiration (ET) estimates were derived from annual and monthly Soil-Water-Balance (SWB) model (McCoy and others, 2015; Westenbroek and others, 2010) output and compiled in a geodatabase. Precipitation estimates from the Appalachian Plateaus SWB model were derived from daily Daymet climate grids (Thornton and others, 2012). Estimates of recharge from the SWB model were calculated using a modified Thornthwaite-Mather soil-water accounting method (Thornthwaite and Mather, 1957; Westenbroek and others, 2010). Estimates of ET from the SWB model were derived by adjusting a spatially-variable estimate of potential ET (Hargreaves and Samani, 1985) with estimates of precipitation and soil-moisture (Westenbrok and others, 2010). The geodatabase contains polygon and point feature classes representing the model grid cells and their centers, respectively, and two tables containing mean-annual and mean-seasonal estimates for each cell. Mean-annual estimates were computed for full calendar years (January through December) and are presented in inches per year (in/yr) for the 1980 through 2011 period. Mean-seasonal estimates for spring (March through May), summer (June through August) and fall (September through November) are presented in inches for the 1980 through 2011 period. Mean-seasonal estimates for winter (December through February), also presented in inches, were calculated for December 1980 through February 2011.