Dennis William Risser (Former Employee)

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.

USGS and Pennsylvania Geological Survey analyzed rock cuttings, geophysical logs, water quality, water-bearing zones, gas-isotope, and other data from deep test holes drilled in fractured bedrock in north-central Pennsylvania. The results of this study helped to quantify the depth and character of fresh and saline groundwater in areas of shale-gas exploration and development.

The Pennsylvania Department of Environmental Protection relies upon a number of parameters to monitor water-supply-drought conditions, including precipitation, streamflow, groundwater levels, and Palmer Drought Index, an indicator of soil dryness.

Within hours after the Pymatuning earthquake of September 25, 1998, in northwestern Pennsylvania, local residents reported wells becoming dry, wells beginning to flow, and the formation of new springs. About 120 household-supply wells reportedly went dry within 3 months after the earthquake. About 80 of these wells were on a ridge between Jamestown and Greenville, where water-level declines of as...

Pennsylvanian- and Mississippian-age aquifers occupy approximately 86,000 square-miles in the Appalachian Plateaus Physiographic Province of Pennsylvania, Ohio, Maryland, Virginia, West Virginia, Kentucky, Tennessee, and Alabama. As one of several USGS Regional Groundwater Studies, the primary goal of this study is to provide a regional understanding of groundwater flow and availability in the...

In fractured bedrock aquifers used for domestic supply conditions can exist where contaminants such as bacteria are not filtered out by the soil. Once in the fracture system, little additional filtration takes place. The results of a synotic sampling of domestic wells in the Lower Susquehanna River basin, Pennsylvania and Maryland, showed that bacteria concentrations were higher in areas with high...