Presentation on theme: "Prepared by: Earth Data N.E., Inc. August 19, 2008."— Presentation transcript:
Prepared by: Earth Data N.E., Inc. August 19, 2008
Oualifications EDN has performed over one hundred groundwater investigations on Southeastern Pennsylvania. Our practice areas include groundwater resource evaluation, exploration, development, aquifer testing and analysis, computer modeling and regulatory relations.
Study Objectives Compile and organize information from multiple sources, to develop a database relative to the Township’s groundwater resources Evaluate the database to assure consistency with the Township’s land use policies Develop a site conceptual model to serve as a basis for numerical modeling Assess the potential impact to Township groundwater resources resulting from the export of wastewater via BCWSA sewer system
What has been accomplished ? Information from public sources and from consultants engaged by the Township has been compiled and evaluated to formulate a consensus opinion relative to available groundwater resources and recharge
Public Information Sources For this study, we have utilized information from public resources and databases including the United States Geological Survey (USGS), the Pennsylvania Department of Environmental Protection (PADEP), the United States Environmental Protection Agency (EPA) and the Delaware River Basin Commission (DRBC).
Examples Pennsylvania Topographic and Geologic Survey Groundwater Information System ( PaGWIS) PADEP Electronic Mapping System ( eMapPa) Unites States Census Bureau records USGS water resources reports PADEP water resources reports DRBC records
Additional Information Sources Reports prepared by various hydrogeologist’s and engineers engaged by the Township Township baseflow reports Township Act 537 Sewage Facilities Plan Township and BCWSA documents
Findings The geologic formations underlying the Township exhibit minimal primary porosity and permeability. The degree of fracturing and interconnectivity of secondary openings within the bedrock is also limited. These structural limitations must be considered in the evaluation of the Township’s available water resources. The bedrock formations that underlie the Township weather to soils with high clay content. These conditions result in low groundwater recharge rates.
Opinions We concur with the following statement from the Water Budget Report prepared by Pennoni Associates: “ the majority of the Township is underlain by bedrock with relatively low recharge and yield rates such as the Lockatong formation and diabase rock. It is clear that groundwater resources are limited and must be managed wisely to ensure continued groundwater supplies and sustain adequate natural stream flows”
Opinions Despite the low recharge rates resulting from the characteristics of the geologic conditions underlying the Township, the export of groundwater via the BCWSA sewer system at the quantities contemplated by the Stipulation and Agreement will have a minimal impact on the groundwater resources of the Township.
Recomendations The Township should continue to explore for and develop additional supply wells. New wells should be large diameter to expose and develop fractured zones. The Township should anticipate that future groundwater appropriation permit applications and monitoring data from existing supply wells will receive significant technical evaluation by regulators relative to potential well interference and recharge. The Township should initate discussions with the Doylestown Borough Authority relative to the amount of supply available through the existing interconnection The Township should increase its above-ground storage capacity
Data Organization Hard copies of various reports Data compiled into a searchable database
Groundwater Model Numerical data presented in the draft report has been evaluated in cooperation with Township staff and revisions have been made as appropriate. The data has been entered into HydroGeo Analysist (HGA). This software program has the utility to be updated as new data becomes available in the future and to view and manage data in a variety of formats.
Groundwater Model Output
Cabin Run - 3
Current Conditions Average Pumping Rate – 77 GPM Ground Water Elevation
Effect of reduced septic infiltration CR-3 Observation Well 6052 German Rd.
Effect on water level of increased pumping at DRBC maximum 77 GPM115 GPM Ground Water Elevation Pumping Rate Cabin Run - 3
Effect of pumping at DRBC maximum on observation well Observation Well 6052 German Rd. Current Conditions CR-3 Pumped at DRBC Maximum
Recomendation Going forward, groundwater resource development, conservation and management will need to be a continuing concern for the Township. The computer model developed as part of the Groundwater Study will provide a tool to document baseline conditions and to evaluate changes in response to increased pumping of existing wells, adding new supply wells or increasing the amount of water exported out of the Township via sewers.
Acknowledgement EDN thanks Plumstead Township for the opportunity to work on this interesting and important project.