The Gallatin River flows between the future site of the Riverbend Glamping Getaway and multiple homes in Gallatin Gateway.

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The Gallatin County Planning Department has approved a floodplain permit for NorthWestern Energy to place a natural gas pipeline under the Gallatin River as part of a larger project to construct a vacation rental destination on an island in Gallatin Gateway.

NorthWestern Energy plans to place a two-inch pipeline 10 to 15 feet below the riverbed about 225 feet downstream of the Mill Street bridge, according to the permit, which was issued on Friday.

The vacation rental project, called the Riverbend Glamping Resort, would use about half the natural gas capacity of the pipeline, according to documents NorthWestern sent to the county. The remaining capacity will be available to other NorthWestern customers.

In its permit application, NorthWestern outlined measures it will take to minimize the environmental impact of the project, including boring the pipeline deep enough to prevent flotation, collapse or lateral movement and completing construction in the winter and early spring to limit impacts on flooding.

NorthWestern also said there is little likelihood of natural gas entering the river because natural gas has low solubility, so if it leaked, it would escape into the atmosphere.

“The main concern with natural gas is explosion potential,” the company wrote in its application. “In elevated concentrations it can escape quickly from water, causing an explosive hazard in poorly ventilated or confined areas, none of which are present at the proposed bore site, and is why the pipeline is not encased in conduit and odorant is added.”

NorthWestern explored alternatives to placing the pipeline under the river, including attaching it beneath the Mill Street bridge and installing it in an excavated trench, but determined that boring beneath the river was the best option.

Gallatin County Floodplain Administrator Sean O’Callaghan said he approved the application because it complied with local regulations.

“The project will be located below ground and is being installed in such a way that there will be no disturbance to the bed or banks of the River, and minimal disturbance to upland locations, meaning that increased risk of flooding due to the project is expected to be negligible,” O’Callaghan wrote in a document associated with the permit.

Hundreds of people voiced opposition to the pipeline last year when NorthWestern applied for the floodplain permit, which is required because the entry and exit locations for boring are within the floodplain.

Peggy Lehmann, a landowner near the proposed Riverbend Glamping Resort, rallied her neighbors against the pipeline and eventually began collaborating with a large group of local landowners and environmental groups, called Protect the Gallatin River, in opposing the myriad permits required for the development.

“The risk of damage to the river and ecosystem caused by boring and/or pipeline construction is being put ahead of community concerns at the expense of serving one person’s desire to put a business in the floodplain,” Lehmann said.

She said the pipeline shouldn’t have been approved because it could adversely impact the aquatic ecosystem, the river, riparian habitat and public recreation. She also said there could be significant environmental consequences if the pipeline broke or leaked.

“The floodway or floodplain should be protected from this kind of damaging development,” she said.

O’Callaghan’s decision to issue the floodplain permit to NorthWestern can be appealed to the Gallatin County Commission until April 4.

Lehmann said Protect the Gallatin River doesn’t have plans to appeal.

No additional permits are needed to install the pipeline, said spokesperson Jo Dee Black. NorthWestern has acquired the necessary permits or been notified that it does not need a permit from the Gallatin County Conservation District, U.S. Army Corps of Engineers and the Montana Department of Natural Resources and Conservation.

Installation of the pipeline is contingent upon O’Callaghan’s approval of a floodplain permit for the Riverbend Glamping Resort, which is under review.

O’Callaghan previously approved a floodplain permit for the placement of a sewer force main and fiber optic cables beneath the Gallatin River for the development. Lehmann initially planned to appeal that decision but later rescinded her request.

That floodplain permit is also contingent upon approval of the floodplain permit for the resort, which is being built by Bozeman developer Jeff Pfeil and will have Airstream trailers, tiny homes and Conestoga wagons for guests. The camping units will have access to water from a well on the property, electricity from lines along Gateway South Road and wastewater services and natural gas from the pipelines under the Gallatin River.

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Perrin Stein can be reached at or at 582-2648.

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