Groundwater Recharge - Pennsylvania Active
New Recharge Estimates published in 2023
Estimates of Baseflow, Runoff, and Groundwater Recharge Based on Streamflow-Hydrograph Methods
New baseflow and recharge estimates were published in a USGS data release in 2023 (see 'Data' tab).
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.
Completed USGS studies provide estimates of groundwater recharge in Pennsylvania and methods for estimating recharge in humid regions.
New estimates of groundwater recharge in Pennsylvania were published in 2023: (Donmoyer, S.J., Killian, C.D., Conlon, M.D., and Fleming, B.J., 2023, Estimates of Baseflow, Runoff, and Groundwater Recharge Based on Streamflow-Hydrograph Methods: Pennsylvania: U.S. Geological Survey data release, https://doi.org/10.5066/P9OGVKKQ).
Content below refers to previous recharge estimates published in 2010.
Reese, S. O., and Risser, D. W., 2010, Summary of groundwater-recharge estimates for Pennsylvania: Pennsylvania Geological Survey, 4th ser., Water Resource Report 70, 18 p.
Groundwater recharge rates were estimated for 197 watersheds throughout Pennsylvania in a USGS study in cooperation with the Pennsylvania Geological Survey. Recharge estimates were based on two automated streamflow-hydrograph methods -- PART and RORA (available from the Water Mission Area Legacy Software archive). The PART program uses a hydrograph-separation technique to estimate base flow. Although base flow is not recharge, it commonly has been used as an approximation of recharge when underflow, evapotranspiration from riparian vegetation, and other transfers of groundwater to or from the watershed are thought to be minimal. The RORA program uses streamflow data to estimate groundwater recharge, but it is not a "hydrograph-separation" method. RORA uses the recession-curve displacement method to estimate groundwater recharge, based on a theoretical equation of one-dimensional groundwater flow to a fully penetrating stream in an idealized, homogeneous aquifer.
Recharge estimates based on the PART and RORA streamflow-hydrograph methods can be accessed from
- Web Tool (archived)
- Data Table (archived)
- All mean-monthly values (archived)
- All annual values (archived)
The methods and results are from the report Estimates of Ground-Water Recharge Based on Streamflow-Hydrograph Methods: Pennsylvania.
The USGS Water Science School describes base flow to streams and groundwater budgets, and their relation to groundwater recharge.
Base Flow in Rivers
Groundwater Budgets
- Overview
New baseflow and recharge estimates were published in a USGS data release in 2023 (see 'Data' tab).
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.
Completed USGS studies provide estimates of groundwater recharge in Pennsylvania and methods for estimating recharge in humid regions.
New estimates of groundwater recharge in Pennsylvania were published in 2023: (Donmoyer, S.J., Killian, C.D., Conlon, M.D., and Fleming, B.J., 2023, Estimates of Baseflow, Runoff, and Groundwater Recharge Based on Streamflow-Hydrograph Methods: Pennsylvania: U.S. Geological Survey data release, https://doi.org/10.5066/P9OGVKKQ).
Content below refers to previous recharge estimates published in 2010.
Reese, S. O., and Risser, D. W., 2010, Summary of groundwater-recharge estimates for Pennsylvania: Pennsylvania Geological Survey, 4th ser., Water Resource Report 70, 18 p.Groundwater recharge rates were estimated for 197 watersheds throughout Pennsylvania in a USGS study in cooperation with the Pennsylvania Geological Survey. Recharge estimates were based on two automated streamflow-hydrograph methods -- PART and RORA (available from the Water Mission Area Legacy Software archive). The PART program uses a hydrograph-separation technique to estimate base flow. Although base flow is not recharge, it commonly has been used as an approximation of recharge when underflow, evapotranspiration from riparian vegetation, and other transfers of groundwater to or from the watershed are thought to be minimal. The RORA program uses streamflow data to estimate groundwater recharge, but it is not a "hydrograph-separation" method. RORA uses the recession-curve displacement method to estimate groundwater recharge, based on a theoretical equation of one-dimensional groundwater flow to a fully penetrating stream in an idealized, homogeneous aquifer.
Recharge estimates based on the PART and RORA streamflow-hydrograph methods can be accessed from
- Web Tool (archived)
- Data Table (archived)
- All mean-monthly values (archived)
- All annual values (archived)
The methods and results are from the report Estimates of Ground-Water Recharge Based on Streamflow-Hydrograph Methods: Pennsylvania.
- Science
The USGS Water Science School describes base flow to streams and groundwater budgets, and their relation to groundwater recharge.
Base Flow in Rivers
When a drought hits and little or no rain has fallen in a long time, you might expect small streams and even larger rivers to just dry up, right? In many cases, they don't. Streamflow might lessen to a trickle or so, but water continues to flow. How is that possible? Read on to find out how "base flow", which is water seeping into the stream from groundwater, helps keep water in streams during...Groundwater Budgets
Groundwater budgets are commonly used in water-resource studies to gain a better understanding of the groundwater-flow system. The hydrologic cycle in the basin can be represented by a long-term water budget in which inflows are balances by outflows and, thus, no long-term change in storage occurs. The water budget can be evaluated through use of two internal budgets and their corresponding... - Data
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