SPRINGS OF THE APPALACHIAN VALLEY & RIDGE: THERE’S MORE THAN JUST KARST OUT THERE

The springs in the Appalachian Valley and Ridge (V&R) Province are critical public and private water supplies throughout the eastern US. The V&R covers <3% of the contiguous U.S but extends over 9 states from Vermont to Alabama. The region is structurally and stratigraphically complex; differential erosion of the folded Paleozoic strata has commonly resulted in ridges defined by resistant clastic rocks and valleys underlain by soluble carbonate limestones and dolomites. The higher-elevation clastic rocks include fractured sandstones on the ridge tops and mixed-shale units often found on the ridge flanks or in high-elevation valleys. Much of the hydrogeologic research in the V&R has focused on case studies or wells and springs in the carbonate units. However, clastic rock units play an essential role in creating headwater streams, recharging the carbonate aquifers, sustaining base flow, supporting ecosystems, and providing water supplies for private landowners and small towns. In some areas, deeper flow along thrust faults contributes to valley warm springs which played an economic role in the pre-Civil War development of spas. Interpreting the hydrogeology of the V&R requires a conceptual model that incorporates stratigraphy, structure and elevation alongside with flow and water chemistry variability. In this talk we present our current conceptual model for V&R clastic and carbonate springs with supporting data from sites in Pennsylvania and West Virginia.