Developers of a disputed natural gas pipeline project across Virginia cleared a major regulatory hurdle recently, as the U.S. Forest Service gave its go-ahead to plans to tunnel through the Blue Ridge Mountains to avoid popular attractions like the Appalachian Trail and Blue Ridge Parkway.

The Virginia Department of Environmental Quality, meanwhile, left Atlantic Coast Pipeline opponents perplexed by seemingly contradictory statements about the degree of scrutiny state regulators intend to give to nearly 2,000 stream crossings planned along the project’s 600-mile route.

Dominion and three other energy companies are seeking federal and state approval to build a new gas transmission conduit from West Virginia to North Carolina to serve what they say are growing energy needs in the region. The consortium hopes to begin construction later this year. Meanwhile, opponents have weighed in over the past few months with complaints that the Federal Energy Regulatory Commission staff did a poor job of evaluating the potential environmental harm the project could do.

In early April, the Forest Service ended months of deliberation and approved pipeline developers’ plans to bore a tunnel through the Blue Ridge Mountains beneath the scenic parkway and hiking trail. Though more costly than laying pipe near the surface, tunneling averts significant regulatory and public relations issues that would have to be dealt with in trying to clear land to cross those scenic and very popular routes.

On April 6 — the same day public comment closed on FERC’s draft environmental impact statement —  Virginia’s DEQ raised the hopes of pipeline opponents by announcing it would scrutinize water quality impacts on every stream crossing proposed for the Atlantic project as well as another major gas transmission line, the Mountain Valley Pipeline (MVP). There are 1,787 water body crossings along the Atlantic Coast Pipeline route, according to the FERC staff’s draft environmental impact statement.

The very next day, though, the state agency announced its intention to issue a blanket water quality certification for pipelines that are covered by a nationwide permit issued by the U.S. Army Corps of Engineers, which regulates disturbance of wetlands and navigable waterways.

When asked about the seeming contradiction, DEQ spokesman William Hayden said the state agency “does not have the resources to survey hundreds of stream crossings.” The DEQ would conduct its review under the less-stringent requirements of the Corps, Hayden added, and issue a single water quality certification for each of the two pipelines projects.

It wasn’t clear how the latter announcement would affect the DEQ’s approach to the Atlantic Coast Pipeline. Agency spokesman Hayden said the DEQ’s acceptance of Corps monitoring guidelines would affect a “wide variety of projects, such as dredging, habitat restoration and utility projects. This is not directly related to the ACP and MVP projects.”

Environmental groups concerned about the proposed pipeline’s impacts found the two announcements confusing.

“We think DEQ still intends to conduct individual reviews of the ACP and MVP, but clarity is not one of DEQ’s strong points,” said Rick Webb, program coordinator with the Dominion Pipeline Monitoring Coalition. “In any case, DEQ has muddied the waters and blanket certification of future projects is bad policy and a forfeiture of responsibility.”

Webb also said the draft environmental impact statement released in December by FERC’s staff “provides inaccurate, incomplete, and incorrect information about impacts on our core forested areas, streams, wildlife, and recreation as it cuts a 21-mile permanent swath over rugged mountains and valleys in our National Forests.”

The groups filed Freedom of Information Act requests demanding to see all of the plans that the DEQ staff had relied on to determine that the project met requirements for erosion and sediment control, stormwater management and stabilization of steep slopes. When immediate access to those documents was initially denied, they went to court, prompting the state to relent and promise to provide the requested documents more promptly.

Environmental groups are concerned that the pipeline will fragment the national forests, especially their remaining patches of old growth. About 1,754 acres of woodlands are projected to be broken up by construction corridors, roadways and the pipeline itself. Cutting up intact forest creates openings for nonnative, invasive species, which can harm native plants and wildlife.

FERC’s draft environmental impact statement says five species listed under the federal Endangered Species Act would be adversely impacted by the pipeline’s construction and operation. They are the Indiana and Northern long-eared bats, the Roanoke logperch, running buffalo clover and the Madison Cave isopod. But another 13 species, either listed or candidates for listing, would also be negatively impacted. Since the impact study came out, another local species at risk, the rusty-patched bumblebee, has been listed as endangered.

Dominion spokesman Aaron F. Ruby said that the company has “coordinated very closely” with the U.S. Fish and Wildlife Service to develop appropriate conservation measures for these species.

Ruby added that the pipeline has been routed along existing utility corridors “where possible” to minimize forest fragmentation, and precautions are being taken to prevent the spread of invasive species, including requirements that construction equipment used in forested areas be cleaned to remove any non-native shoots or seeds that might be picked up.

“If we identify invasive species along the right of way during construction or operation,” Ruby added, “we’ll treat the plants with approved herbicides or mechanical methods to prevent them from spreading.”

Another major concern of environmentalists is the geology of the region. The terrain is underlain by karst, a porous limestone foundation known for its fissures and uncharted channels that can carry water or air. Karst is the cause of the region’s abundance of caves and sinkholes — sudden collapses of ground that can occur almost anywhere and at any time along portions of the pipeline’s proposed route through Virginia. Deep sinkholes actually closed down Interstate 81 in both 2011 and 2015.

Surveying karst requires precise measurements and costly, complicated instruments to detect even the largest of caverns, with deeper or smaller voids or fractures being practically unknowable. Localized surveys cannot be extrapolated because of karst’s highly irregular structure, and its disjointed, porous nature means that any contaminating spill could be disastrous. 

In the highlands of the George Washington National Forest, the environmental impact study also has identified more than 100 possible locations along the proposed route where slope instability might lead to damage to the pipeline, with 46 of those spots recommended for further evaluation because they’re classified as potentially catastrophic geohazards.

Such is the nature of central Appalachian topography and weather patterns that landslides, flash floods and stream overflows are common occurrences under the right conditions, such as heavy seasonal rains. The Forest Service has expressed concern about these landscape issues, stating that, “(s)imilar hazards on other smaller pipeline projects in the central Appalachians have led to slope failures, erosion and sedimentation incidents, and damage to aquatic resources.” The service said it was concerned that crossing such challenging terrain with a much larger pipeline, “could present a high risk of failures that lead to resource damage.”

Dominion’s spokesman said that the company and its lead construction contractor have more than 200 years’ experience safely building pipelines in steep mountainous areas nationwide, including in karst terrain.

But others contend that Dominion’s precautions are inadequate. Richard A. Lambert, president of the Virginia Speleological Survey and a member of the Virginia Cave Board, warned in a report last year that the magnitude of the pipeline project and the seeming rush to build it were a “prescription for disaster” for the karst in and around the national forest, which he called the state’s most significant formation.

“No amount of mitigation or compensation by setting aside karst lands for protection elsewhere will make this route acceptable to the Highland County Cave Survey,” Lambert wrote, asking FERC to disapprove the route through the area.

Now that the April 6 comment period has passed, FERC staff will review all pf the feedback received before issuing a final environmental impact statement. A decision on whether to approve the pipeline project will be made by the five-member energy regulatory commission, whose members are appointed by the president subject to Senate confirmation. Three of the commission seats are now vacant. 

Opponents of the pipeline face an overwhelmingly uphill battle, given FERC’s history of approving such projects over environmental objections. That tilt only got steeper early this year, when the Trump administration released a list of 50 infrastructure projects it wanted to expedite nationwide. The Atlantic Coast Pipeline was one of just one of two nationwide oil and gas projects explicitly named on the list.