Laurel Lake in Pine Grove Furnace State Park, PA (Photo By Pierre MaCoy)

Home ** Our Work **Programs** Planning & Operations ** Identifying Optimal Groundwater Recharge Locations

# Identifying Optimal Groundwater Recharge Locations

#### Purpose

The Commission’s Comprehensive Plandirects staff to identify and promote the protection of open space andother land uses that provide for increased groundwater recharge. Recharge isinfiltration of water from the land surface to underground water-bearing zones andis the primary means of ensuring water is available in aquifers for water supplyand as baseflow to streams. Differentgeologic materials,structures, and landuses all influence the rate in which water can recharge underlying aquifers.The Susquehanna River Basin’s (27,500 square miles of) diversity in these factorsleads to considerable variations in local recharge rates.

#### The Study

The authors of thestudyincorporated multiple factors influencing recharge through standardization andweighting assignments using theGeographic Information Systems – Multi-Criteria Decision Analysis frameworkto identify land-surface areas with the best/highest capacity for sustained orenhanced recharge. The following datasets were used to describe recharge potentialwithin theSusquehanna Basin:- percent impervious cover
- land surface slope
- percent sand and clay
- depth to bedrock
- drainage density
- karst density
- fault density

The GIS tool developed for this study can be applied at abasinwide scale, and local scale for subwatershed, county,or regional assessments, based on the needs of the user.The basinwide output can aid in developing and/or prioritizing preservation,restoration, or enhancement projects throughout the basin. The tool also enablesthe user to identify high recharge potential areas that may otherwise havelimited recharge potential, increasing development, and/or water supplylimitations. With these considerations, Commission staff identified**Critical Aquifer Recharge Areas (CARAs)** in select locationswhere water withdrawals from aquifers have approached or are exceeding thesustainable limit. Protecting and enhancing CARAs will assist withdroughtresiliency, improving or maintaining water quality, and preserving water supplyfor future use.

#### Groundwater Recharge

Groundwater recharge, the process of adding water to the saturated zonebeneath the Earth's surface, is crucial in the Susquehanna River Basin.The Commission defines groundwater as

*“water beneath the surface ofthe ground within a zone of saturation, whether or not flowing throughknown and definite channels or percolating through underground geologicformations, and regardless of whether the result of natural or artificialrecharge”*

##### Report

Identifying Optimal Groundwater Recharge Locations and CriticalAquifer Recharge Areas Within the Susquehanna River Basin

##### Fact Sheet

Optimal Groundwater Recharge Locations & Critical Aquifer Recharge Areas

##### Map

View the layers in the Susquehanna Atlas:** Groundwater Recharge Potential** Highest Groundwater Recharge Potential

Access the GIS datasets at the Pennsylvania Spatial Data Access website:** Groundwater Recharge Potential** Highest Groundwater Recharge Potential Areas

*Credit: Multi-Criteria Decision Analysis and GIS, Siobhan Ryan and Ellis Nimick*

----

*Recharge Potential in the Susquehanna River Basin*

#### Critical Aquifer Recharge Areas (CARAs)

CARAs are areas of increased or optimal recharge located in aquifers that havelimited recharge,water availabilityor demand limitations and development pressureswhich impact groundwater quality or quantity. These land surface areas areresponsible for a larger fraction of recharge by virtue of high aquiferpermeability,soil characteristics,vegetative cover and locations with respect to discharge rates and/orwithdrawals topographic setting or combination of these(SRBC GWMP, 2005).

*Highest Recharge Potential in the Susquehanna River Basin*

#### Compare All Recharge Potential Areas with Highest Recharge Areas