Will Water Wells and Fracking Cracks Intersect? –
Because the fracked cracks can extend some 2,000 feet above the well bore hole, wells that lie less than a mile (5,280 feet) below the surface pose a higher risk for water contamination. According to Stanford University scientist Robert Jackson:
“Not all shallow wells pose the same threat to groundwater. The “riskiest” fracked wells are both shallow and use high levels of water—1 million gallons or more, said Jackson. Studies have shown that when these high-pressure wells fracture the bedrock, the cracks can extend as much as 2,000 feet upward. This provides an opportunity for the chemical-laced water used in fracking to migrate to the shallower depths of the water table. And the smaller the gap between drilling and surface water, the greater the chance of interaction.”
Water in eastern Bucks is supposed to be perched atop bedrock that lies between 100 and 250 feet below the surface. Sampling a few records in the domestic well database I found wells drilled to depths of 500 feet below the ground level in Wrightstown, and 300 feet in Newtown Township, but the ups and downs of local terrain influence the depth relative to the geological data. Some of the drillers reported drilling through bedrock at less than 10 feet. Some wells are for withdrawal of potable water, others are used for geothermal heat.
Most of the aquifer is recharged by infiltration from the surface and nearby streams and the Delaware River. The shale gas layers that have fair to good gas potential begin at 3,000 feet. Simple math says that hydraulic fracturing could reach to within 500 feet of layers reached by domestic water wells. One can’t know, of course, what natural fissure and cracks may exist in the bedrock that might provide pathways for fracking chemicals pumped into the ground at 9,000 psi to find there way upward. But the notion that “miles of bedrock” lie between the fracked layer and the water layer simply is not true in the Newark Basin.
Given the poor record of the gas and oil drilling industry for predicting or preventing leaks, it would seem very risky to do shallow fracking. If it were to be allowed, there should be mandatory independent monitoring of groundwater quality utilizing test wells near the drill pad. Equally important there must be substantial financial bonding and insurance requirements to fund remediation should methane or fracking chemical contamination be found.