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
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.
- 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
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
The U.S. Geological Survey (USGS) in cooperation with the Pennsylvania Department of Conservation and Natural Resources, Bureau of Geological Survey, estimated groundwater recharge by automated streamflow-hydrograph methods for watersheds throughout Pennsylvania. These data serve as an update to previous estimates of groundwater recharge described in Risser and others (2005). The current analysisHydrograph-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
This U.S. Geological Survey (USGS) data release contains daily-mean streamflow and estimated-daily base flow for 225 stream gages in the Chesapeake Bay watershed ranging from 1913 to 2016 (beginning and end dates may vary). There is a table containing hydrograph-separation results by six methods for 225 sites (Hydrograph_separation_results_for_225_streams_in_the_Chesapeake_Bay_watershed) and a sum - Publications
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
Groundwater recharge is water that infiltrates through the subsurface to the zone of saturation beneath the water table. Because recharge is a difficult parameter to quantify, it is typically estimated from measurements of other parameters like streamflow and precipitation. This report provides a general overview of processes affecting recharge in Pennsylvania and presents estimates of recharge raAuthorsStuart O. Reese, Dennis W. RisserUser manuals for the Delaware River Basin Water Availability Tool for Environmental Resources (DRB–WATER) and associated WATER application utilities
The Water Availability Tool for Environmental Resources (WATER) is a decision support system (DSS) for the nontidal part of the Delaware River Basin (DRB) that provides a consistent and objective method of simulating streamflow under historical, forecasted, and managed conditions. WATER integrates geospatial sampling of landscape characteristics, including topographic and soil properties, with a rAuthorsTanja N. Williamson, Jeremiah G. LantComparison of recharge estimates at a small watershed in east-central Pennsylvania, USA
The common recommendation that recharge should be estimated from multiple methods is sound, but the inherent differences of the methods make it difficult to assess the accuracy of differing results. In this study, four methods for estimating groundwater recharge and two methods for estimating base flow (as a proxy for recharge) are compared at two hydrologic research sites in east-central PennsylvAuthorsD. W. Risser, W.J. Gburek, G.J. FolmarRegression method for estimating long-term mean annual ground-water recharge rates from base flow in Pennsylvania
A method was developed for making estimates of long-term, mean annual ground-water recharge from streamflow data at 80 streamflow-gaging stations in Pennsylvania. The method relates mean annual base-flow yield derived from the streamflow data (as a proxy for recharge) to the climatic, geologic, hydrologic, and physiographic characteristics of the basins (basin characteristics) by use of a regressiAuthorsDennis W. Risser, Ronald E. Thompson, Marla H. StuckeySpatial Distribution of Ground-Water Recharge Estimated with a Water-Budget Method for the Jordan Creek Watershed, Lehigh County, Pennsylvania
This report presents the results of a study by the U.S. Geological Survey, in cooperation with the Pennsylvania Geological Survey, to illustrate a water-budget method for mapping the spatial distribution of ground-water recharge for a 76-square-mile part of the Jordan Creek watershed, northwest of Allentown, in Lehigh County, Pennsylvania. Recharge was estimated by using the Hydrological EvaluatioAuthorsDennis W. RisserGround-water recharge in humid areas of the United States: A summary of Ground-Water Resources Program studies, 2003-2006
Increased demands on water resources by a growing population and recent droughts have raised awareness about the adequacy of ground-water resources in humid areas of the United States. The spatial and temporal variability of ground-water recharge are key factors that need to be quantified to determine the sustainability of ground-water resources. Ground-water recharge is defined herein as the entrAuthorsGeoffrey N. Delin, Dennis W. RisserMultiple-methods investigation of recharge at a humid-region fractured rock site, Pennsylvania, USA
Lysimeter-percolate and well-hydrograph analyses were combined to evaluate recharge for the Masser Recharge Site (central Pennsylvania, USA). In humid regions, aquifer recharge through an unconfined low-porosity fractured-rock aquifer can cause large magnitude water-table fluctuations over short time scales. The unsaturated hydraulic characteristics of the subsurface porous media control the magniAuthorsC.S. Heppner, J. R. Nimmo, G.J. Folmar, W.J. Gburek, D. W. RisserA computer program for predicting recharge with a master recession curve
Water-table fluctuations occur in unconfined aquifers owing to ground-water recharge following precipitation and infiltration, and ground-water discharge to streams between storm events. Ground-water recharge can be estimated from well hydrograph data using the water-table fluctuation (WTF) principle, which states that recharge is equal to the product of the water-table rise and the specific yieldAuthorsChristopher S. Heppner, John R. NimmoEstimates of ground-water recharge based on streamflow-hydrograph methods: Pennsylvania
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 aAuthorsDennis W. Risser, Randall W. Conger, James E. Ulrich, Michael P. AsmussenComparison of methods for estimating ground-water recharge and base flow at a small watershed underlain by fractured bedrock in the Eastern United States
This study by the U.S. Geological Survey (USGS), in cooperation with the Agricultural Research Service (ARS), U.S. Department of Agriculture, compared multiple methods for estimating ground-water recharge and base flow (as a proxy for recharge) at sites in east-central Pennsylvania underlain by fractured bedrock and representative of a humid-continental climate. This study was one of several withiAuthorsDennis W. Risser, William J. Gburek, Gordon J. FolmarEstimated mean annual natural ground-water recharge in the conterminous United States
This 1-kilometer resolution raster (grid) dataset is an index of mean annual natural ground-water recharge. The dataset was created by multiplying a grid of base-flow index (BFI) values by a grid of mean annual runoff values derived from a 1951-80 mean annual runoff contour map. Mean annual runoff is long-term average streamflow expressed on a per-unit-area basis.AuthorsDavid M. WolockEstimated 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
Inferences are drawn about properties of aquifer systems from the interpretation of streamflow records in the Appalachian Valley and Ridge, Piedmont, and Blue Ridge physiographic provinces. The analysis is divided into two parts--analysis of streamflow recession and base-flow analysis. Analysis of recession yields information about aquifer diffusivity and variation in specific yield. Base-flow anaAuthorsA. T. Rutledge, T. O. MeskoHYSEP: A Computer Program for Streamflow Hydrograph Separation and Analysis
HYSEP is a computer program that can be used to separate a streamflow hydrograph into base-flow and surface-runoff components. The base-flow component has traditionally been associated with ground-water discharge and the surface-runoff component with precipitation that enters the stream as overland runoff. HYSEP includes three methods of hydrograph separation that are referred to in the literatureAuthorsRonald A. Sloto, Michele Y. Crouse - Web Tools
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.
- Software
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.
- Partners
This compilation is based in part on studies in cooperation with the Pennsylvania Geological Survey.