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Estimates of ground-water recharge based on streamflow-hydrograph methods: Pennsylvania

September 22, 2005

This study, completed by the U.S. Geological Survey (USGS) in cooperation with the Pennsylvania Department of Conservation and Natural Resources, Bureau of Topographic and Geologic Survey (T&GS), provides estimates of ground-water recharge for watersheds throughout Pennsylvania computed by use of two automated streamflow-hydrograph-analysis methods--PART and RORA. The PART computer program uses a hydrograph-separation technique to divide the streamflow hydrograph into components of direct runoff and base flow. Base flow can be a useful approximation of recharge if losses and interbasin transfers of ground water are minimal. The RORA computer program uses a recession-curve displacement technique to estimate ground-water recharge from each storm period indicated on the streamflow hydrograph.

Recharge estimates were made using streamflow records collected during 1885-2001 from 197 active and inactive streamflow-gaging stations in Pennsylvania where streamflow is relatively unaffected by regulation. Estimates of mean-annual recharge in Pennsylvania computed by the use of PART ranged from 5.8 to 26.6 inches; estimates from RORA ranged from 7.7 to 29.3 inches. Estimates from the RORA program were about 2 inches greater than those derived from the PART program.

Mean-monthly recharge was computed from the RORA program and was reported as a percentage of mean-annual recharge. On the basis of this analysis, the major ground-water recharge period in Pennsylvania typically is November through May; the greatest monthly recharge typically occurs in March.

Publication Year 2005
Title Estimates of ground-water recharge based on streamflow-hydrograph methods: Pennsylvania
DOI 10.3133/ofr20051333
Authors Dennis W. Risser, Randall W. Conger, James E. Ulrich, Michael P. Asmussen
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Open-File Report
Series Number 2005-1333
Index ID ofr20051333
Record Source USGS Publications Warehouse
USGS Organization Pennsylvania Water Science Center