Residential Developments

Location: Tinicum Township, Pennsylvania

Regulatory Program: Local municipal ordinance

Duration: 2000 and 2001

Summary: Hydrogeologic Assessment for Residential Water Supply

Princeton Geoscience provided technical support to another consulting firm in the performance of aquifer tests at three prospective residential development sites.  The purposes of the tests were to evaluate groundwater supply systems installed on the sites to determine whether sufficient yield could be obtained and whether operation of the systems might cause unacceptable drawdown of water levels and interfere with the performance of wells on adjacent developed properties.   The tests were required by a local ordinance applicable to new residential development in Tinicum Township, PA.  Development of groundwater supplies within the Township is complicated by the presence of dense, hard rock with limited water storage capacity (Lockatong Formation) at many locations, and the ordinance was established to ensure that new residential development takes place in a manner consistent with available water resources.

The aquifer tests consisted of constant-rate pumping tests 24 to 48 hours in duration.  During the tests, the water supply well at each prospective development site was pumped at a constant discharge rate while water levels were monitored at the pumping well and at wells on adjacent properties.  Water level monitoring was accomplished manually using an electronic water level indicator and continuously through use of pressure transducers attached to an electronic datalogger.  Adjacent property owners agreed to suspend or limit withdrawals from their wells during the test period, so that the effects of the new well could be independently evaluated.  As the test progressed, water level measurements were periodically downloaded from the datalogger and plots of time vs. drawdown were inspected to evaluate effects of the pumping.  The plots also showed short-term effects of periodic operation of several of the offsite wells.

Upon completion of each of the tests, plots of distance vs. drawdown and time vs. drawdown were inspected to assess the effects of pumping at the proposed new development property.  Based on the test results, Princeton Geoscience concluded that sufficient well yield was available at each of the prospective residential properties and that operation of wells on the properties would not interfere with operation of existing wells on adjacent properties.