Point Locations of 849 Continuous Record Streamflow Gages Used to Estmate Annual and Average Values of Water-Budget Components Based on Hydrograph Separation and PRISM Precipitation in the Appalachian Plateaus Region, 1900-2011
Description
As part of the U.S. Geological Survey’s Groundwater Resources Program study
of the Appalachian Plateaus aquifers, estimates of annual water-budget components
were determined at 849 continuous-record streamflow gaging stations from Mississippi
to New York. Base flow, which can serve as a proxy for annual recharge, streamflow,
and runoff were estimated from computer programs—PART (Rutledge, 1993), HYSEP
(Sloto and Crouse, 1996), and BFI (Wahl and Wahl, 1988)—that are included in the
hydrograph analysis component provided with version 1.0 of the U.S. Geological
Survey Groundwater Toolbox. Only complete years (January to December) of record
at each gage were used to determine annual estimates. Estimates of base-flow index,
which is the percentage of streamflow from base flow, are included in the annual and
average tables. Precipitation was estimated by calculating the average of cell values
in the PRISM dataset intercepted by basin boundaries where previously defined in the
GAGES-II dataset (Falcone, 2011). Estimates of evapotranspiration were then
calculated from the difference between precipitation and streamflow.