By Jack Reaney SENIOR EDITOR
On Nov. 25, the Montana Department of Environmental Quality released a draft of an environmental assessment of the Quarry, a planned unit development in the Gallatin Canyon portion of Big Sky.
Plans for the Quarry are outlined in phases, amounting to 135 single-family homes, 130 apartments and commercial spaces at full build. The first phase—90 single-family homes—is already approved and permitted by DEQ. The current environmental assessment is focused on the second phase, containing the remaining 45 homes.
Public comment on phase two remains open until Jan. 10 through DEQ’s Water Quality Division. Originally scheduled to close Dec. 27 as part of a 30-day window, DEQ granted a two-week extension on Dec. 9 to allow the public to participate without conflicting with busy holiday schedules, according to an email from DEQ Public Information Officer Madison McGeffers.
Activists and environmental groups have expressed concerns about the Quarry project—including a 2023 lawsuit against DEQ and a 2024 letter to DEQ Director Chris Dorrington urging the importance of public comment—due to potential wastewater impacts from the large-scale subdivision on the nearby and impaired Gallatin River.
Plans regarding the Quarry’s wastewater treatment are complicated. Developers plan to begin construction using decentralized SepticNET systems, with the goal of eventually transitioning all properties to a centralized sewer pumping water up to Big Sky’s new high-tech Water Resource Recovery Facility. Developers say all homes and buildings will be constructed with sewer-friendly infrastructure to allow a swift transition.
Developers and activists disagree on the quality of treatment those septic systems will provide. Quarry developer Scott Altman told EBS in March that developers are going “above and beyond” environmental requirements and reiterated in a Dec. 10 phone call that “the temporary solution is still damn good.” In contrast, Guy Alsentzer, executive director of Upper Missouri Waterkeeper, stated in a Dec. 5 press release that phase two’s potential approval would be “a raw deal” for the Gallatin River, roughly 1,200 feet downhill to the east.
Developers argue, however, that if the new Gallatin Canyon County Water and Sewer District is successful in building the sewer, disputes over the quality of SepticNET treatment will be moot—those systems would be decommissioned, and their drain fields repurposed for groundwater discharge with highly treated water as a release valve for Big Sky’s excess effluent.
Furthermore, developers believe the Quarry will provide a crucial customer base to support the sewer’s economic feasibility, enabling a net benefit to the Gallatin.
Despite praise from local districts including water and sewer and Resort Tax, the potential canyon sewer is no sure thing: it faces rising construction costs with a price tag estimated near $55 million, and local leaders continue to explore funding mechanisms.
If permitted in the meantime, the Quarry project’s second phase would add 45 single-family homes with an uncertain future for wastewater treatment.
Phase two was approved by Gallatin County commissioners on March 5, 2024, but construction on the additional 45 homes cannot begin until developers are granted a DEQ permit.
