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.