The letter was released in response to a Freedom of Information Act request by environmental law firm Appalachian Mountain Advocates.

The project previously held a Corps Nationwide-12 permit that allowed project-wide water crossings without individual impact review, but it was withdrawn last year after a federal court struck down the blanket permits.

Mountain Valley developers are instead pursuing an “individual permit" that incorporates review of hundreds of water body crossings.

The project would permanently impact 1,198 linear ft of streams and temporarily affect 38,312 linear ft, said EPA. It would permanently affect 0.5 acres of wetlands, temporarily affect 13.92 acres, and convert 3.7 acres of forested and scrub-shrub wetlands to emergent wetlands, the agency said.

“While EPA recognizes the proposed project’s purpose and need for providing transmission of natural gas, the extent of anticipated impacts, notably the large amount of temporary discharges from the proposal to the aquatic resources, warrants careful review,” Lapp said. The proposed discharges have implications to downstream waters, he said.

Mountain Valley is currently reviewing EPA’s comments and plans to provide responses to the Corps that will address agency recommendations. “We are confident that the current application with our additional responses will satisfy EPA’s recommendations,” Todd Normane, deputy general counsel for the project and its operator EMQ Gathering Opco, said in a July 12 letter to the Corps district office in Huntington, W. Va.

Normane said EPA’s comment was in response to the Corps process for reviewing permit applications, which Mountain Valley submitted in February.

The pipeline also has other permits to acquire, including an approval by the Federal Energy Regulatory Commission to tunnel under certain streams.

Overland crossings were approved in 2017, but EMQ Gathering Opco's decision to bore under certain streams required a new authorization. FERC’s public comment period is open until early August.

Virginia and West Virginia have until later this year to certify the project under Clean Water Act Section 401. West Virginia has until Nov. 29 and Virginia has until Dec. 31 to either grant or waive certification. If either state denies certification, the Corps will deny the applications.

If certification is waived, the Corps will issue the permit, Melanie Davenport, a Corps official in Norfolk district said in a June 28 letter to Virginia regulators.

Mountain Velley originally was scheduled for completion by the end of 2018 at a cost of just $3.5 billion. The project’s targeted summer 2022 in-service date is based on receiving all water crossing approvals and the lifting of a remaining exclusion zone around the Jefferson National Forest by the end of 2021.

Mountain Valley released on July 12 its plan to acquire an estimated $150 million in carbon offsets for greenhouse gas emissions for 10 years of the project’s operation. Emissions include carbon dioxide from engines used to drive compressor stations, methane released during operation and maintenance and carbon dioxide resulting from generation of power it purchases for O&M.

The cornerstone of the plan is a coal mine methane abatement project in Virginia that would capture methane from the mine and convert it to carbon dioxide and water vapor, the pipeline operators said. Critics wondered, however, how it is “greener” to convert methane to CO2, another greenhouse gas.

Mountain Valley also is pursuing greenhouse gas abatement projects in West Virginia including addressing abandoned and orphaned gas wells, the company said.

Owners expect Mountain Valley to be one of the first large scale natural gas pipelines to be carbon neutral for its operation emissions.

Environmentalists are concerned that the plan does not address greenhouse gas emissions from the natural gas as fuel that the pipeline transports.