State drilling to test Big Sky’s water supply

By Joseph T. O’Connor Explore Big Sky Managing Editor

BIG SKY – Scores of dump trucks and work vehicles leaving Big Sky each evening bear witness to the spike in area development over the past year. Just how much development will occur in Big Sky’s Meadow Village depends on the amount of available water there.

It’s a question the state aims to answer in the next two years, which explains the drilling rig moving around Big Sky.

At the behest of the Montana Department of Natural Resources and Conservation’s Water Resource Division, the Montana Bureau of Mines and Geology is leading a Big Sky study to determine the amount of groundwater available in the Meadow Village area by drilling and mapping out the complex bedrock geology that determines the groundwater flow system.

Part of MBMG, the Ground Water Investigation Program is overseeing 17 wells being drilled to monitor both water levels and water quality in the meadow’s alluvial aquifer, an underground natural water source that stores groundwater adjacent to the west fork of the Gallatin River.

Understanding this aquifer’s characteristics and capacity to hold water is imperative since it’s the primary water supply for residents and businesses in the Meadow Village and Town Center, according to Kirk Waren, Senior Hydrogeologist with MBMG.

“The geology here has limitations to the good, fresh water you can get out of the system,” Waren said. “That’s a fact.”

But individuals close to the project say it won’t impact development or water availability in the immediate future. “We’re not stopping new hookups or anything,” said Ron Edwards, General Manager of the Big Sky Water and Sewer District. “[But] you can’t just go drill a well on your lot here in Big Sky. People need to understand that this is a part of an investigative study that the Bureau is doing.”

Edwards says he’s been fielding calls of late about drilling rigs in the area. One prominent rig was posted up on the building site for the Big Sky Medical Center, just off Lone Mountain Drive. Workers were drilling to utilize the earth’s heat for a geothermal system, Edwards said, which is a closed-looped design that will heat the structure in winter and cool it during the summer.

The BSWSD operates and maintains a total of 14 wells that provide water to the area, with the exceptionsof the Yellowstone Club, the Spanish Peaks Mountain Club, Moonlight Basin and Gallatin Canyon locations. There are currently three operating wells in the meadow, and they’re working to bring two more online by summer 2015, Edwards said.

Last summer the Big Sky Water and Sewer District imposed Level 2 Irrigation Restrictions in the area, limiting residents to watering their lawns every other day with sprinklers, and only during morning and evenings.

Edwards says he wants to inform people that Big Sky’s water supply is ultimately finite – this study will determine the aquifer’s productivity – and that the water table rises in spring with snow runoff and drops again later in the summer. With summer comes tourism, as well as second homeowners, bringing with them a higher demand on the water resources.

“We have a lot of people that come from other places where they get enough rainfall,” Edwards said. “We’re a semi-arid climate here in Big Sky. We need to protect the well points we have by not over-depleting [those] water sources.”

Drilling began on Oct. 24, and is expected to last through mid-November. The state-funded project is expected to top out at approximately $400,000, Waren said, with the 17 test wells accounting for $51,000 of that total. MBMG undertook Big Sky’s water-monitoring project in June 2013 and should wrap up in 2016 with the end result being a 3-dimensional groundwater flow model of the meadow’s aquifer, Waren said, as well as an interpretive report for the hydrogeology of the greater Big Sky area.

Waren doesn’t expect any of the monitoring wells to exceed 65 feet, and said each site will be fully reclaimed as soon as drilling is complete. Waren or his colleague, MBMG Associate Hydrogeologist James Rose, is on site at each of the drilling locations, overseeing the project.

Agencies and individuals cooperating with this study include the Montana Department of Natural Resources and Conservation; Big Sky Water and Sewer District; Blue Water Task Force; Gallatin Local Water Quality District; and retired Montana State University geology professor Dr. Steve Custer.