Research about Chester County, Pennslyvania

USGS2006

Altitude and configuration of the potentiometric surface in East Nottingham and West Nottingham Townships, Chester County, Pennsylvania, April through June 2004

Since 1984, the U.S. Geological Survey (USGS) has been mapping the altitude and configuration of the potentiometric surface in Chester County as part of an ongoing cooperative program to measure and describe the water resources of the county. Areas where the potentiometric surface has been mapped are shown on figure 1. These maps can be used to determine the general direction of ground-water flow and are frequently referenced by municipalities and developers to evaluate ground-water conditions for water supply and resource-protection requirements (Wood, 1998). The maps shows the potentiometric surface for an area along the western boundary of Chester County that includes parts of East Nottingham and West Nottingham Townships. The study area is mostly uderlain by metamorphic rocks of the Peters Creek Schist and Wissahickon Formation(Sloto, 1994). Ground water is obtained from these bedrock formations by wells that intercept fractures.

Pennslyvania↗

USGS1980

Development of a digital model of ground-water flow in deeply weathered crystalline rock, Chester County, Pennsylvania

The model developed in this study simulates .recharge to, flow through, and discharge from the water-table aquifer in the upper Pickering Creek basin, a 5.98-square-mile basin representative of most of Chester County, Pennsylvania. The two-dimensional finite-difference model of Trescott, Pinder, and Larson was used with slight modification. The way ground-water evapotranspiration varies with depth was modified, and a minimum transmissivity was used to prevent the model from "going dry" during water-table simulations. Tests of the model showed good correlation with field data, but also showed that certain additional types of information would be useful to make the model more reliable. Particularly helpful would be more water-level and evapotranspiration data, synoptic base-flow measurements in the subbasins, and better information on the variation of permeability and specific yield with depth. Predictive simulations made by the model show the effects of imposing various changes on the hydrologic system. Residential development was simulated in 1 square mile of the basin by combinations of the following conditions: 1-acre, 1/2-acre, and 1/4-acre lot size; wastewater disposal by septic systems or by public sewers; domestic wells or public-supply wells for water supply; and 0, 1, and 5 percent reduction in recharge in the developed area. Where water is supplied locally by wells, decreased lot size and reduced recharge result in increased drawdowns and reduced base flow. When wastewater is exported by sewers, these effects are magnified. The simulations by the model show the relative severity of the effects of various development schemes.

Pennslyvania↗