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Karst landscapes bring challenges, concerns for pipeline projects

Karst landscapes bring challenges, concerns for pipeline projects

Areas with sinkholes, springs and caves may be vulnerable to problems.

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NEWPORT — Worry sometimes wakes widower George Lee Jones, 85, long before daybreak.

Jones’ pre-dawn fretting began in early August, when he learned that his family’s Giles County farm might be in the path of the proposed Mountain Valley Pipeline. Jones said he has awakened at 2 and 3 a.m. at his Salem home, wracking his brain for a strategy to defeat the pipeline.

During a visit by Jones earlier this month to the farm where he grew up, the Korean War veteran expressed a mix of anger, helplessness and disbelief that a private company could route a natural gas transmission pipeline through his property whether he likes it or not.

His incredulity focused in part on Mountain Valley’s plans to bury the pipeline across a landscape dotted with sinkholes, caves and springs.

“It’s being built on a powder keg,” Jones said.

Giles County’s topography is rife with a landscape type known as karst, named after a province in Slovenia dominated by sinkholes, caves, large springs and other features often found in soluble rocks such as limestone.

Karst features also are prevalent in Craig and Montgomery counties, and Monroe County, West Virginia. Each county would be impacted by the route of the 300-mile Mountain Valley Pipeline.

Are karst landscapes and buried natural gas pipelines incompatible? Not necessarily.

But experts say that human activity in such topography, including pipeline construction, can induce sinkhole formation, pollute or divert groundwater flows and create other hazards.

The Virginia Cave Board suggested that “pipelines within karst terrain can be structurally stable, if properly designed, constructed and maintained.”

The key word in that sentence would seem to be “if.”

Estimates suggest that a third of the U.S. east of the Mississippi River and about 18 percent of Virginia contains karst. Thus, many natural gas pipelines are operating in karst without major incidents specifically linked to the relative instability of this landscape.

But the Mountain Valley Pipeline and the separate Atlantic Coast Pipeline project would feature 42-inch diameter pipelines. Burying pipelines of this size would require clearing wide swaths of brush, digging trenches both deep and wide, as well as boring, drilling, blasting and use of fuels and lubricants for heavy equipment — all activities that can affect karst landscapes.

“Ground disturbance of any kind in karst terrain can lead to complications, and trenching involves a lot of ground disturbance,” the Virginia Cave Board observed.

Atlantic Coast Pipeline project officials have estimated trench depths likely would range from 6 feet to more than 13 feet. Mountain Valley has said most trenches would be 7 feet to 8 feet deep.

Groundwater associated with karst terrain can be especially vulnerable to pollution because contaminants can travel quickly through conduits dissolved by mildly acidic rainwater in the soluble bedrock.

On Friday, Mountain Valley submitted an application to the Federal Energy Regulatory Commission, seeking the commission’s approval of the $3.2 billion project.

The application included references to karst aquifers, noting, “Karst terrain often has unique hydrology and highly productive aquifers, which can be highly susceptible to contamination.”

And blasting can alter or disrupt water flow.

The Virginia Cave Board said that if changes in water quality or quantity occurs in karst landscapes, “it is highly improbable that the previous groundwater conditions can be restored.”

Opponents of the two pipeline projects have cited potential impacts to groundwater as a key concern, especially for rural counties where residents rely on wells or springs for drinking water and watering livestock.

Jean Porterfield said the farm she calls home in Giles County has been in the Porterfield family since 1810. The property includes the Pig Hole Cave.

The original pipeline route identified by Mountain Valley would have come within about 300 feet of the cave entrance, she said. The route proposed by Mountain Valley, according to its FERC application, would be about 400 feet south of the cave’s main entrance.

“My greatest concern is for our water supply,” Porterfield said. “Most of us along this route get our water from springs or wells. What will happen to our water when 8- to 10-foot trenches are dug or blasted through the limestone karst and our water aquifers are disturbed or destroyed?”

A fragile landscape

The question isn’t whether karst would be affected by a pipeline project but to what extent, according to Wil Orndorff, karst protection coordinator for the Virginia Department of Conservation and Recreation.

He is based in Christiansburg, near much of the state’s most intensive karst topography, including caves that have biological significance for rare species and bats and are popular with cavers.

Orndorff has submitted comments to FERC about regional karst landscapes and the Mountain Valley Pipeline. FERC ultimately will decide whether the pipeline project moves forward.

“The intensity of karst features in some areas proposed for the pipeline is not necessarily an insurmountable obstacle, but careful planning and design will be essential to minimize the footprint of the pipeline on this fragile and hazardous landscape,” Orndorff observed.

Atlantic Coast officials estimates that about 32.5 miles of that pipeline would pass through karst landscapes in Randolph and Pocahontas counties in West Virginia and Highland and Augusta counties in Virginia.

Mountain Valley officials estimate that line would pass through about 22 miles of karst.

Orndorff said the karst that would be crossed by the Atlantic Coast Pipeline tends to be less intense than in the New River Valley, where karst features tend to be larger and more common.

The challenge with the Mountain Valley Pipeline will be working to minimize the damage and risks for karst landscapes, he said.

Erosion and sediment control measures, as well as spill containment plans, should be “followed to the letter and monitored,” Ordorff said.

“In addition, construction engineers may be faced with challenges related to ensuring the structural stability of the line in some areas, depending on what is encountered during construction,” he said.

Mountain Valley’s application reports, “Provided that a buried pipeline can span a sinkhole while loaded with soil overburden, the sinkhole will not pose a threat to the integrity of the pipeline.”

The application says that the minimum pipe wall thickness in karst areas will be 0.74 inches and suggests the pipeline company “will have adequate response time to mitigate sinkhole formations in the event they should occur.”

But Ralph Ewers, a professor emeritus of geology at Eastern Kentucky University and an expert in karst hydrogeology, said pipelines buried in karst landscapes can end up perched on rock pinnacles spanning an undetected void, an outcome that can stress the pipe and make it vulnerable to stress-induced corrosion.

Developers often try to avoid building in landscapes where sinkholes are common.

Fears about unstable ground were among the reasons Microsoft opted to bypass Montgomery County in 2010 for construction of a multi-million dollar data center, according to officials.

When the Roanoke Regional Partnership recently hired a consultant to identify potential 100 acre-plus developable sites in the region, parcels exhibiting karst features were eliminated early on “due to the detrimental nature of karst features to development,” according to a report summary.

Orndorff said the original route proposed for the Mountain Valley project would have passed directly over passages in two Giles County caves that the Virginia Natural Heritage Program considers significant: Tawneys and Smokehole.

The route proposed in Mountain Valley’s application skirts the Smokehole Cave.

Potential impacts to Tawneys Cave, the Mount Tabor sinkhole plain north of Blacksburg and associated caves and conservation zones was not entirely clear Friday.

But Mountain Valley’s application warns that there could be impacts during construction for Canoe Cave in Giles County and a nearby spring. The company acknowledges the potential for pipeline instability, as well as construction runoff and discharge into groundwater.

“MVP will adjust construction activities as needed [at Canoe Cave], based on field observation,” the application reports.

It also appears that the route identified Friday would pass through the farm where George Jones grew up, a landscape that includes several large sinkholes and mountain springs that surface and then disappear.

Limiting negative impacts

Both the Atlantic Coast Pipeline and the Mountain Valley Pipeline hope to transport natural gas at high pressure from West Virginia to Virginia and beyond to meet demand tied to generation of electricity and other uses.

Both projects have received support in some quarters but also have stirred fierce opposition. The latter has intensified as landowners like Jones have realized that the pipeline companies will be able to acquire a right-of-way across their property through the use of eminent domain if FERC green-lights the projects.

Atlantic Coast project officials filed a formal application Sept. 18 with FERC for the company’s proposed 564-mile, $5 billion pipeline. The application included a 32-page “Karst Terrain Assessment, Construction, Monitoring and Mitigation Plan” prepared by GeoConcepts Engineering.

Mountain Valley’s application includes a karst hazard assessment and karst mitigation plan that the company said reflects the work of consulting contractor Draper Aden Associates.

“I can tell you that we will commit to having a karst specialist onsite daily during construction in karst areas,” spokeswoman Natalie Cox said. “MVP has made, and continues to make alignment adjustments to avoid sensitive karst areas.”

She said a karst team will “assist in limiting potential negative impacts to karst features and water resources” and will alert relevant state agencies in West Virginia or Virginia “if a karst feature forms during construction.”

Cox said a spill prevention, control and countermeasures plan will focus on keeping soils or pollutants from flowing into karst features such as sinkholes. For example: “Hazardous materials, chemicals, fuels, lubricating oils and petroleum products will not be stored within 100 feet of any karst feature.”

On Jan. 27, 2000, a crude oil pipeline operated by Marathon Ashland ruptured in the vicinity of Winchester, Kentucky, spilling about 489,000 gallons. The rupture occurred in karst topography, which is common in Kentucky, but was not attributed to karst.

“A couple of families there depended on a spring for their livestock and it was badly contaminated,” recalled Jim Currens, a geologist and karst hydrogeologist with the Kentucky Geological Survey.

Ewers said graduate students he supervised labeled one contaminated spring the “Jed Clampett spring,” a reference to a character in “The Beverly Hillbillies” TV show who got rich after oil “came a-bubblin’” up on his property.

Unlike crude oil, natural gas is lighter than air and tends to dissipate if a leak occurs. There could be rare circumstances that would allow leaking natural gas to enter a cave system, creating the possibility of an explosion.

The natural gas transported through the Atlantic Coast or Mountain Valley pipelines would not be odorized with mercaptan, the chemical that adds the rotten-egg smell to natural gas distribution lines. Leaks might go undetected for some period.

Catastrophic leaks are obvious, Ewers said.

“It’s the smaller leaks that really concern me most because we don’t know they’re happening,” he said.

Karst landscapes are common in Florida. A 37-year-old man died in February 2013 when a sinkhole opened beneath his bedroom in a house in Hillsborough County. The sinkhole was filled but reopened this summer.

Hillsborough County was the setting for another sinkhole, one induced by horizontal directional drilling used in late 2010 and early 2011 to install a 36-inch diameter natural gas pipeline. This type of drilling is sometimes used to install pipe beneath rivers, roads and other surface features.

Mountain Valley’s application said the company does not intend to use horizontal directional drilling, a practice it had previously touted as a way to reduce impacts at stream crossings.

A sinking heart

In 2009, FERC’s final draft environmental statement for a Florida Gas Transmission interstate pipeline project warned against discharging large volumes of water in concentrated areas during construction, “especially in areas prone to sinkhole formation.”

That warning came about seven years too late for Edd Jennings.

Jennings, 62, tried to monitor contractors in 2002 when they buried the 24-inch diameter Patriot Pipeline through a portion of his family’s farm in Wythe County. But lasting damage occurred anyway, he said.

“Duke Energy put a gas line through my farm on the New River 13 years ago, and I will live with the devastation for the rest of my life,” Jennings said.

A former alfalfa field hosts two separate sinkholes that developed after Duke Energy’s pipeline contractor dumped more than a million gallons of water onto the ground after using the water for hydrostatic pressure-testing of the pipeline, Jennings said. He said drill rigs that plumbed the sinkholes never found their bottoms.

Today, instead of alfalfa, the sinkholes’ slopes host a tangle of brush — stickweed, horsenettle, tree-of-heaven, goldenrod and blackberry. A pipeline subcontractor fenced off the sinkholes but the fencing is in sad shape.

Jennings sued Duke Energy in 2003 and the parties reached an undisclosed settlement in 2004.

In 2007, Duke Energy spun off Spectra Energy, which now owns and operates the Patriot Pipeline. It’s part of the East Tennessee Natural Gas Pipeline system, which also operates a natural gas pipeline through Montgomery and Roanoke counties.

Duke Energy is a partner with Dominion and others in the proposed Atlantic Coast Pipeline.

Jennings said his heart sank for landowners along pipeline routes when he heard about the Mountain Valley and Atlantic Coast projects. Pipeline companies and their contractors seem to do what they please, he said.

Meanwhile, if nothing else, the pipeline controversies have educated many more people about karst landscapes and their unique vulnerabilities, Orndorff said.

He said the potential environmental impacts of a similar infrastructure project proposed 20 years ago would have received much less scrutiny.

“I feel like it’s a tough issue for everybody involved. But it’s encouraging that people are so concerned about karst,” he said.

The pipeline companies’ strategies to protect karst features and groundwater sound good on paper, Orndorff said.

“If the plans are followed, I think the potential for contamination is pretty low,” he said. “But the rubber will hit the road when the pipelines are being built.”

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