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
New baseflow and recharge estimates were published in a USGS data release in 2023.
National and Chesapeake Bay watershed datasets are also available below.
Archived data is available for 197 watersheds, from the 2005 report, in cooperation with the Pennsylvania Geological Survey.
Estimates of Baseflow, Runoff, and Groundwater Recharge Based on Streamflow-Hydrograph Methods: Pennsylvania
Hydrograph-separation results for 225 streams in the Chesapeake Bay watershed derived by using PART, HYSEP (Fixed, Local minimum, Slide), BFI, and a Recursive Digital Filter with streamflow data ranging from 1913 through 2016
Publications below contain methods for estimating and (or) estimates of groundwater recharge in Pennsylvania.
The highlighted publication is available for download from the Pennsylvania Geological Survey at:
Summary of groundwater-recharge estimates for Pennsylvania
User manuals for the Delaware River Basin Water Availability Tool for Environmental Resources (DRB–WATER) and associated WATER application utilities
Comparison of recharge estimates at a small watershed in east-central Pennsylvania, USA
Regression method for estimating long-term mean annual ground-water recharge rates from base flow in Pennsylvania
Spatial Distribution of Ground-Water Recharge Estimated with a Water-Budget Method for the Jordan Creek Watershed, Lehigh County, Pennsylvania
Ground-water recharge in humid areas of the United States: A summary of Ground-Water Resources Program studies, 2003-2006
Multiple-methods investigation of recharge at a humid-region fractured rock site, Pennsylvania, USA
A computer program for predicting recharge with a master recession curve
Estimates of ground-water recharge based on streamflow-hydrograph methods: Pennsylvania
Comparison of methods for estimating ground-water recharge and base flow at a small watershed underlain by fractured bedrock in the Eastern United States
Estimated mean annual natural ground-water recharge in the conterminous United States
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
HYSEP: A Computer Program for Streamflow Hydrograph Separation and Analysis
Groundwater Recharge in Pennsylvania
A map app to get recharge values from streamgage locations in Pennsylvania. Development of this app is described at the Related Science page.
Methods for Estimating Groundwater Recharge In Humid Regions - Archived Resource Guide
Application, data needs, strengths, and weaknesses of widely-used methods for estimating groundwater recharge in humid regions (USGS Groundwater Resources Program, 2017):
* Software and Models
* Methods
* Comparisons of Methods
* References
Soil-Water-Balance (SWB) for estimating groundwater recharge
The Soil-Water-Balance (SWB) model has been developed to allow estimates of potential recharge to be made quickly and easily. The code calculates components of the water balance at a daily time-step by means of a modified version of the Thornthwaite-Mather soil-moisture-balance approach.
This compilation is based in part on studies in cooperation with the Pennsylvania Geological Survey.
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
New baseflow and recharge estimates were published in a USGS data release in 2023.
National and Chesapeake Bay watershed datasets are also available below.
Archived data is available for 197 watersheds, from the 2005 report, in cooperation with the Pennsylvania Geological Survey.
Estimates of Baseflow, Runoff, and Groundwater Recharge Based on Streamflow-Hydrograph Methods: Pennsylvania
Hydrograph-separation results for 225 streams in the Chesapeake Bay watershed derived by using PART, HYSEP (Fixed, Local minimum, Slide), BFI, and a Recursive Digital Filter with streamflow data ranging from 1913 through 2016
Publications below contain methods for estimating and (or) estimates of groundwater recharge in Pennsylvania.
The highlighted publication is available for download from the Pennsylvania Geological Survey at:
Summary of groundwater-recharge estimates for Pennsylvania
User manuals for the Delaware River Basin Water Availability Tool for Environmental Resources (DRB–WATER) and associated WATER application utilities
Comparison of recharge estimates at a small watershed in east-central Pennsylvania, USA
Regression method for estimating long-term mean annual ground-water recharge rates from base flow in Pennsylvania
Spatial Distribution of Ground-Water Recharge Estimated with a Water-Budget Method for the Jordan Creek Watershed, Lehigh County, Pennsylvania
Ground-water recharge in humid areas of the United States: A summary of Ground-Water Resources Program studies, 2003-2006
Multiple-methods investigation of recharge at a humid-region fractured rock site, Pennsylvania, USA
A computer program for predicting recharge with a master recession curve
Estimates of ground-water recharge based on streamflow-hydrograph methods: Pennsylvania
Comparison of methods for estimating ground-water recharge and base flow at a small watershed underlain by fractured bedrock in the Eastern United States
Estimated mean annual natural ground-water recharge in the conterminous United States
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
HYSEP: A Computer Program for Streamflow Hydrograph Separation and Analysis
Groundwater Recharge in Pennsylvania
A map app to get recharge values from streamgage locations in Pennsylvania. Development of this app is described at the Related Science page.
Methods for Estimating Groundwater Recharge In Humid Regions - Archived Resource Guide
Application, data needs, strengths, and weaknesses of widely-used methods for estimating groundwater recharge in humid regions (USGS Groundwater Resources Program, 2017):
* Software and Models
* Methods
* Comparisons of Methods
* References
Soil-Water-Balance (SWB) for estimating groundwater recharge
The Soil-Water-Balance (SWB) model has been developed to allow estimates of potential recharge to be made quickly and easily. The code calculates components of the water balance at a daily time-step by means of a modified version of the Thornthwaite-Mather soil-moisture-balance approach.
This compilation is based in part on studies in cooperation with the Pennsylvania Geological Survey.