Gallatin County Commission Rightfully Denied Major Subdivision Application

Sandhill Subdivision Lacked Sufficient Studies of Impacts to Local Water 

On Tuesday, May 9th, the Gallatin County Commission denied the preliminary plat application for the Sandhill Major Subdivision, a proposed 34-lot subdivision south of Kagy Blvd in Bozeman reliant on exempt wells and septic systems. 

One key rationale from the Commission was the identification of existing, unnaturally high concentrations of nitrate in local groundwater, a pollutant that at high levels can contaminate drinking water supplies. Another rationale was the perspective of not having sufficient knowledge of what more groundwater withdrawals, or new contributions of septic pollution, meant for local water quantity, water quality, and for adjacent existing homeowners. 

“Today the Gallatin County Commission demonstrated the type of leadership we need in SW Montana. In the face of unrelenting growth pressure, it’s especially important that our local decision-makers ensure that how and where we develop doesn’t put our local creeks, water supplies, and private drinking water wells at risk,” said Guy Alsentzer, Executive Director of Upper Missouri Waterkeeper. “At a minimum, new development needs to prove upfront that it won’t degrade our local water resources or adversely affect existing water use.”

The Sandhill Major Subdivision proposed the use of a system of “clustered” exempt groundwater wells, which would avoid the water rights permitting process and determination of “legal water availability.” The developer’s application indicated that there was groundwater available physically and that new pumping would lower the aquifer, but didn’t provide data demonstrating whether, and how much, pumping would affect adjacent homeowners.

Similarly, the Subdivision proposed the use of septic systems for wastewater treatment, despite the reality that existing groundwater nitrate levels are already elevated exponentially higher than natural background levels. Without performing an adequate assessment of potential water quality impacts on an adjacent headwater stream, or downgradient drinking water supplies, no one – not the developer, the Commission, or adjacent homeowners – would know whether their well might run dry, or be contaminated.

The Commission also had issues with public access and transportation. Given the busy nature of the frontage road (Kagy), and high pedestrian and recreational use of the local trail system, the Commissioners had questions about public safety that went unanswered by the proposed plan and increased traffic.

In Gallatin County, where we’re already facing pollution and water availability problems, it’s especially important that all new development proposals can demonstrate that water resources will not be negatively impacted. Waterkeeper is encouraged by the Commission reaching the right decision on the Sandhill Major Subdivision today and following the cautionary approach when the impacts on water quality and quantity remain unknown and unnecessarily risk neighbors and finite water resources.

The denial of the Sandhill Preliminary Plat Application is the second time in less than a year that the Gallatin County Commission has denied new development in part of water resource issues, the first being the Hyalite Creek Major Subdivision during Fall 2022. The developer has the opportunity to resubmit a revised application addressing the Commission’s concerns.