Home > Uncategorized > Tennessee Gas Pipeline Drilling Causes Sinkhole Road Collapse

Tennessee Gas Pipeline Drilling Causes Sinkhole Road Collapse

Pipeline Route and Drilling Hit Known Vulnerable Limestone Geology

How Many Other Places Along Pipeline Are Prone to Collapse?

Same Project Plans to Put Gas Pipeline Under Monksville Reservoir

sinkhole collapse on River Road, Montague, NJ (7/9/13) – apologies for the blur, it was raining and my lens got wet

On Monday, drilling for the Tennessee Gas Pipeline created a sinkhole that caused the collapse of a portion of River Road in Montague, NJ (for local news coverage, see:  River Road closed following roadway collapse).

Luckily, especially for nearby homeowners, the collapse occurred BEFORE the pipeline was installed and carrying gas. A collapse of an operating gas pipeline likely would cause a major explosion and fire.

The accident is not the first major fuckup by Tennessee.

And it’s not the first evidence of lax government oversight.

The sinkhole collapse is part of a pattern of seriously negligent, reckless, and illegal pipeline construction practices that have caused tremendous environmental damage in NJ (for warnings and photos of pipeline violations we’ve previously published, see this and this and this).

The latest sinkhole collapse raises important questions of how this could have been allowed to happen and whether there are other places along the pipeline route where sinkholes could cause the catastrophic collapse and rupture of the gas pipeline – there could be numerous literally ticking time bombs.

The collapse also raises questions about the adequacy of the environmental review,  permitting, and construction compliance monitoring of the project by federal and state regulators, and whether the proposal to route the pipeline under the *Monksville Reservoir should be abandoned.

The limestone and karst geology in the northwestern portion of NJ and the risks of sinkholes have long been known to federal, state and local officials – and in exactly the location site where the sinkhole emerged.

How did Tennessee engineers and government regulators apparently miss that?

We urge the following immediate actions:

  • We urge federal and state officials to issue an immediate stop work order and conduct an investigation along the entire pipeline route where there are risks from sinkhole collapse.
  • We urge federal and state regulators to take aggressive enforcement action against Tennessee Gas Pipeline for this negligence and major violation of drilling permits, including penalties to assure that all damage is restored.
  • In light of these kind of risks – created by known and unknown geological conditions – to reconsider and reject pipeline routing under the *Monksville Reservoir.
  • We urge state and federal regulations to beef up inspection and enforcement oversight of this pipeline construction to prevent any more accidents and damage.
 In case they missed it, here are reports and maps of limestone, karst and sinkholes in the vicinity of the pipeline, by USGS, NJGS and DEP and state planners – photos and maps below.

From the NJ State Geologist:



Recent mapping in northwestern New Jersey detected a large number of karst features found along Wallpack Ridge in the Delaware Water Gap National Recreation Area (fig. 1). Dozens of small sinkholes, sinking streams, springs and small caves were identified. 

Karst areas are also susceptible to the impact of human activity and can be used to monitor environmental health. In addition to its value as a natural resource, karst areas are prone to ground subsidence due to the formation of sinkholes. 


Most of the karst features in DEWA lie in the middle section of Wallpack Ridge between Dingmans Ferry and U.S. Route 206. Many factors contribute to the formation of karst in this area. Most importantly is that the Onondaga Limestone is susceptible to dissolution by water. Because rock formations that topographically lie above the Onondaga consist largely of siliclastic rocks, water that drains through

… Rain water seeping through organic-rich soil in the area also becomes slightly acidic. Over time these waters dissolve the calcium carbonate that makes up the Onondaga Limestone. Where water flow is concentrated along joints and fractures, larger conduits are formed and eventually a cave may develop. The shallow dip of the limestone beds also promotes dissolution by creating a larger surface area of limestone. In this section of the Wallpack Ridge the thin to medium-thick beds of the Onondaga dip about 10 degrees or less. Elsewhere, the limestone dips as much as 85 degrees, most notably in the southern and northern sections (fig. 3). Because of this slope difference, the width of the exposed Onondaga here is up to twice as great as elsewhere. Although the primary conduits of subsurface flow are joints, some beds of the Onondaga are more prone to dissolution due to a higher calcium carbonate content. These beds will dissolve preferentially and increase the size of the subterranean passageways.

Finally, the lack of pronounced cleavage (the tendency  for rock to split along closely-spaced parallel planes) in the middle section of Wallpack Ridge may have encouraged the flow of water through the joint system. In the Onondaga this could have accelerated the rate at which the formation dissolved.

(source NJGS)

From the US Geological Survey:

Structural and lithologic control of karst features in northwestern New Jersey 


Development is rapidly replacing farmland in western New Jersey with new housing tracts. Much of this new suburbia is underlain by carbonate bedrock so the understanding of karst formation and control is important in pre-development planning. We have initiated an ongoing study of karst, including sinkholes, caves and springs in an attempt to characterize the karst potential for these carbonate rocks.

These rocks experienced two strong deformation events in the Taconic and Alleghanian Orogenies and form a classic fold and thrust belt. Middle Paleozoic carbonates lie along the northwest boundary of New Jersey within parts of the Delaware River National Recreation Area.

From DEP and State planners

Limestone Forests

Although forested areas in general provide wildlife habitat and water quality protection, limestone forests have unique characteristics that make them especially important. Limestone forests occur in karst landscapes, which are underlain by limestone bedrock and contain sinkholes, sinkhole ponds, caves and springs. These communities support rare plant and animal species adapted to the soils and water cycle of the hydrogeologically dynamic region. Limestone outcroppings within the forests provide habitat for ferns, worts and other rare native plants as well as migratory birds and raptors.

Data for Map 12: Potential Locations of Limestone Forest in Sussex County, is sourced from NJGS’s geologic data and the NJDEP’s 1995/97 Landuse/Landcover data. It represents all forested lands that overlie limestone bedrock and thin glacial till. This map has not been field verified and provides an indication of potential areas where limestone forest is located.

According to Map 12, limestone forests occur in three distinct regions in Sussex County. The first is located adjacent to the Delaware River, on the western slope of the Kittatinny Ridge. This area extends from the Walpack Bend north into Montague.

pipeline construction in Montague, just above sinkhole collapse

note steep slopes and erosion controls along right – modest rainfall likely to wash out

pipeline bored under road – another potential sinkhole collapse? (homes and church about 200 feet away)

note steep slopes and inadequate erosion controls on right

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