It may not be widely known that for large portions of the PennEast route mere “digging” isn’t going to cut it. The route is going through very mountainous terrain with rock formations exposed right at the surface. Drive around West Amwell, Lambertville, and Hopewell township and you’ll see what I mean. Exposed rock everywhere! Driving along route 29, or route 518, or even on 202 near the Delaware river bridge and you’ll see the stone formations. They’re actually quite beautiful in the winter as small water falls freeze in place on the walls. If you’re not from the area think of the NJ palisades, those are made of the same stuff.
What you’re seeing is diabase, which is what makes up the bulk of the Sourland mountains. Goat Hill, Belle Mountain, and Baldpate are all made of diabase.
As I said, digging isn’t going to cut it for installing a pipeline. So they’re going to have to blast out the rock.
William and Dorothy of Hopewell, NJ tell the FERC why it’s a very, very bad idea to do this.
We are writing to voice our concerns regarding the proposed PennEast pipeline. The PennEast pipeline is one of more than ten pipelines being proposed to supply gas to New Jersey, a state already well supplied with natural gas. The two routes proposed by PennEast are particularly detrimental for Hopewell Township and neighboring townships to its north. The original route sought to minimize disturbance of private landowners by traversing public lands where possible. This route disregarded the fact that many of these environmentally sensitive lands had been specifically purchased to protect forests and the wildlife therein. The second route would traverse sensitive lands north of Hopewell Township but within the township. It would co-locate with an existing JCP&L high tension right of way to minimize environmental disturbance. However, that route would necessitate passing near Belle Mountain and then crossing Baldpate Mountain. Both formations are comprised of diabase extending more than 1000 feet below the surface. This particularly hard rock will require significant blasting to excavate an 8-10 foot deep trench that would be required to safely bury a 36 inch pipe.
Our concern is the potential consequences of the blasting. Vibrations are transmitted very efficiently through this diabase over unexpectedly long distances. As an example, at present we feel the vibrations from the blasting at the Trap Rock mine which is more than two miles away on Route 29.
Based on this ongoing experience, we anticipate even stronger vibrations arising from construction of a pipeline trench within 0.25-0.5 miles of the houses along Pleasant Valley Road even if well designed explosive charges are employed. Depending on the structural integrity of the diabase, the vibrations of the blast can be very efficiently transmitted to neighboring houses causing structural damage. Such damage could be manifested by cracking of foundations, tiled surfaces, plaster walls or swimming pools.
Even more troubling is the potential for the blasting vibrations to adversely impact the wells of the homes along Pleasant Valley Road and Valley Road. In this area all homes and farms depend on well water. Unlike wells which draw from alluvial aquifers, these wells are low yielding because they depend on ground water recharge which is delivered through existing sporadic fractures in the diabase. Depending on how the fractures respond to the blast vibrations, the water output of these wells could be increased, decreased or stopped entirely. Failure of a well would be devastating for a homeowner.
Drilling a replacement would be expensive since these wells typically are several hundred feet deep. In addition the new bore may not be successful since the source is not an aquifer but rather a chance pocket of water.
The potential economic benefits for construction of a new single-sited pipeline do not compensate for the impact on the New Jersey communities through which it passes. Here we alert FERC to the issue of blasting vibrations and well viability that is directly related to the underlying geology of the area through which the pipeline passes. After consideration of these environmental and geological concerns, we hope that you will reject the PennEast pipe line proposal.
Their submission is below: