A major concern of BSWA is the commercial development of warehouse/truck terminals within contributing areas of Big Spring. Housing development pressures are also increasing in the area. At the time of this writing, West Pennsboro has granted preliminary plan approval to a development on SR223 south of the town of Newville and in the surface watershed. Farming pressures include a large facility, such as a recently proposed hog farm near SR233. Areas to the south and east are zoned and being developed industrially, and these are likely contributing areas to Big Spring or Newville Municipal Spring (Cool Spring). Like any area with karst (limestone) geology, groundwater flow patterns are unpredictable based on surface topography. Springs such as Big Spring are derived from source water areas (recharge zones) far outside their surface watersheds. This characteristic is of paramount importance in protecting Big Spring Creek and its associated springs. Hydrological traces associated with the project have recently demonstrated that rapid infiltration of runoff into sinkholes will pour into the aquifer and be carried directly in limestone conduits to Big Spring. One of the PAFBC hatchery culverts acts as a conduit for roadside runoff to the stream’s headwaters. In one rain event in 2005, this resulted in substantial sediment loading to the stream. BSWA would like to work with PAFBC to mitigate this problem. Raceways exist at the old Thomas hatchery site further downstream, on the west side of the stream. These are in ruins and covered with successional forest. They should be examined further to determine if they contribute siltation to Big Spring through outlet pipes, or serve as habitat to wetland organisms.
The west spring of Big Spring is susceptible to sedimentation during strong rain events. This spring is connected to at least one large sinkhole to the west near Shippensburg that occurs, ironically, in a failing detention basin engineered to slow runoff from an impervious surface. A second failing detention basin exists at the Pennsy Quarry site within the surface watershed. The basin contains a sinkhole-drainage of turbid water observed to enter directly into the aquifer rather than percolate through the system of drainage pipes and rock-fill. While this situation was mitigated by PA DEP Mining and Pennsy Supply, it is likely that the drainage will open further with additional runoff and pumping. While this quarry is permitted to blast to sea-level (a depth of about 600 feet), the permit conditions require approval from PA-DEP to continue with each 50’ increase in depth beyond the water table. Given the position of this quarry on the down-gradient side of the regional flow pattern (east surface watershed), any likely influence to Big Spring would likely occur on the smaller east contributing source spring or to Cool Spring, another east-contributing source spring that is utilized for public water supply by the Borough of Newville.
