Groundwater Recharge Studies
Recharge is the process of adding water to the saturated zone. Because it is almost impossible to measure directly, recharge is usually estimated by indirect means. Recent studies conducted by the U.S. Geological Survey provide (1) estimates of groundwater recharge in Pennsylvania and (2) methods for estimating recharge.
Recharge Estimates for Pennsylvania
- Summary of groundwater-recharge estimates for Pennsylvania: Pennsylvania Geological Survey, Water Resource Report 70.
- Regression method for estimating long-term mean annual ground-water recharge rates from base flow in Pennsylvania: USGS Scientific Investigations Report 2008-5185.
- Estimates of groundwater recharge based on streamflow-hydrograph methods:
- Spatial distribution of ground-water recharge estimated with a water-budget method for the Jordan Creek watershed, Lehigh County, Pennsylvania: USGS Scientific Investigations Report 2008-5041.
- Estimated mean annual natural ground-water recharge in the conterminous United States: USGS Open-File Report 03–311 (digital spatial data).
- Estimated hydrologic characteristics of shallow aquifer systems in the Valley and Ridge, the Blue Ridge, and the Piedmont Physiographic Provinces based on analysis of streamflow recession and base flow: USGS Professional Paper 1422B.
Methods for Estimating Recharge
- Methods for estimating groundwater recharge In humid regions: Resource guide for selecting appropriate methods for estimating recharge in humid areas.
- Comparison of recharge estimates at a small watershed in east-central Pennsylvania, USA : Hydrogeology Journal, 2009, vol. 17, p. 287-298.
- Ground-water recharge in humid areas of the United States--A summary of ground-water resources program studies, 2003-2006: USGS Fact Sheet 2007-3007.
- Multiple-methods investigation of recharge at a humid-region fractured rock site, Pennsylvania, USA: Hydrogeology Journal, 2007, vol. 15, p. 915-927.
- A computer program for predicting recharge with a master recession curve: USGS Scientific Investigations Report 2005-5172.
- Comparison of methods for estimating ground-water recharge and base flow at a small watershed underlain by fractured bedrock in the Eastern United States: USGS Scientific Investigations Report 2005-5038.

