Jeff Wivholm isn’t partial to mountains. He likes to be able to see the weather rolling in, which is remarkably possible in the northeastern corner of Montana.

On a cold January morning, Wivholm drives the dirt roads between farms in Sheridan County, where he’s lived for all his 63 years, with practiced ease, pointing out different plots of land by naming their owners. And if he doesn’t know the family name, Amy Yoder with the Sheridan County Conservation District or Brooke Johns with the Medicine Lake National Wildlife Refuge — both sitting in the backseat of his truck — can supply it.

If you look to the right there, Wivholm says, you can see the valley created by the aquifer. Maybe he can, his eyes accustomed to seeing dips and crevasses in what looks to an unfamiliar eye like a starkly flat landscape. He laughs and says it takes some getting used to.

That aquifer isn’t unique in Montana. There are 12 principal aquifers running like underground rivers throughout the state. But the way Sheridan County uses the water is.

Montana is in relatively good shape as far as its groundwater supply goes, unlike much of the country, geologist John LaFave with the Montana Bureau of Mines and Geology says. State officials initiated a groundwater study more than 30 years ago to address a lack of data after years of intense drought and fires. 

But Sheridan County was even further ahead of the game. The county’s conservation district started studying its groundwater in 1978, before state monitoring began.

In 1996, the state granted the district a water reservation, or a water allocation for future uses, which meant the district could take a certain share of water from the Clear Lake Aquifer beneath Sheridan County. And based on the data it had gathered through studying its groundwater, the district developed a unique way of using and distributing that resource.  

What’s uncommon is how intentional the collaboration was, and how extensive the groundwater monitoring was and continues to be. The district works with farmers, tribes and the U.S. Fish and Wildlife Service (USFWS) to ensure that water is available to those who need it — and those who would be most affected by any degradation of the resource — without negatively impacting the environment.

And stakeholders say it’s worked. The conservation district has been using its aquifer — a gift granted by the last Ice Age — to irrigate crops, provide jobs for the region and keep agriculture dollars in the community for almost 30 years with remarkably few complaints.

“To me, this represents the way groundwater development should occur,” LaFave says.

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Sheridan County is extremely rural, home to about 3,500 people across its 1,706 square miles. Agriculture is a big economic driver. Bird hunting attracts locals and visitors. The Medicine Lake National Wildlife Refuge, spanning Sheridan and Roosevelt Counties and managed by the USFWS, is home to dozens of migratory bird species. It’s the largest pelican breeding ground in Montana, and the third-largest in the country. 

On this early January morning, it’s about 5 degrees outside, but there isn’t much snow on the ground. Over coffee and breakfast in Plentywood — the county seat — Yoder and Wivholm say this winter has been warmer and drier than usual.

Dry weather is not uncommon here. Droughts in the 1930s and ’80s were particularly rough. Also in the ’80s, irrigation technology was becoming more common and efficient, Wivholm says, and people began to pay more attention to the aquifer as a potential source of irrigation water. 

“There are several nicknames for much of this property, but it was basically ‘poverty flats,’” says Jon Reiten, a hydrogeologist with the Montana Bureau of Mines and Geology. The soil is sandy and gravelly and the local climate is drought-prone. It’s not great for dryland farming.

In 1976, Marlowe Onstead became the first farmer in Sheridan County to use the aquifer for pivot irrigation. 

“Couldn’t raise the crop on it before,” Onstead says. With irrigation, he was able to grow alfalfa. 

According to Reiten, the aquifer ranges from one to six miles wide and from 200 to 300 feet deep. The ancestral Missouri River channel, discovered in Sheridan County in 1983 as monitoring began, flowed north into Canada and then east into Hudson Bay. That channel was dammed by glaciers in the last Ice Age and left behind a reservoir that was buried as glaciers melted, creating the Clear Lake Aquifer. Since the glacial debris that was left behind was coarse and varied in size, water could move through it easily and be stored at great depths. A downside is that such glacial aquifers can take a long time to refill. 

As drought dragged on in the ’80s, local residents and county and state authorities set about determining the best way to distribute the aquifer’s water. Medicine Lake lies on top of part of the aquifer, and Big Muddy Creek — where the Fort Peck Tribes require a minimum instream flow to promote ecosystem health — is at its southwestern border.

The Fort Peck Tribes and USFWS were concerned about their respective resources’ water levels and how they’d be impacted by irrigation. Reiten says USFWS objected to just about every water rights case that went to the state at the time, and all that litigation ended up in water court. 

“That’s a lot to put on [an agricultural] producer, to have to go up against the federal government,” Reiten says.

Negotiations with the USFWS and the Fort Peck Tribes led to the formation of an advisory committee and the transfer of the water reservation on the aquifer from the state to the conservation district. (Per Montana water law, all water within the state belongs to the state and individuals are required to acquire a water right, or reservation, to use it in a particular way — in this case, for irrigation.) Since then, the Sheridan County Conservation District has had the authority to distribute water allocations from the Clear Lake Aquifer to ag producers without the producers having to seek a claim with the state directly. 

The maximum amount of water that can be pulled from the aquifer by all rights holders is just over 15,000 acre feet annually, a number set by the state’s Department of Natural Resources and Conservation. Currently, the district is using about 10,000 acre feet per year. Increases are allowed as long as monitoring shows the aquifer isn’t being overly impacted by the withdrawals.

“We were basically forced to monitor it, but it only makes good sense,” says Wivholm, who has been on the conservation district board since 1994. The district wouldn’t want to grant a right only to find out in five years that there’s not enough water to fulfill it.

Once a year, the advisory committee meets to assess new water rights. The committee includes the Montana Bureau of Mines and Geology, the state Department of Natural Resources and Conservation, representatives from Medicine Lake National Wildlife Refuge, county commissioners, a county planner, the Fort Peck Tribes and a representative from the United States Geological Survey. 

If a farmer wants an irrigation pivot, they have to “pump it hard for 72 hours,” Wivholm says, to make sure there is enough water to fill their request, and to demonstrate how that pumping affects other wells nearby. 

From April through October, Yoder collects readings from data sensors placed in the ground throughout the county. For each of the first and last collections, she visits 201 wells, and it takes her three 12-hour days to get to them all. Driving around in Wivholm’s truck, she points out some of her sensors sticking up from the ground every few minutes.

Through monitoring, the Sheridan County Conservation District and the Montana Bureau of Mines and Geology have been able to map the entire aquifer. They take note of water levels, monitor irrigation pivots, and record seasonal fluctuations. 

“It’s kind of a hidden resource, but the amount of crops that we can get off of the poor ground that is above the aquifer is amazing,” Yoder says. She lists corn, wheat, chickpeas, lentils, canola, mustard and alfalfa. 

Another farmer in the area, Rodney Smith, has been irrigating from the Clear Lake Aquifer for over 35 years, and has the biggest pivot connected to the aquifer.

Smith says irrigating has been economically beneficial: His farm isn’t as dependent on the weather as it used to be, and the aquifer has taken some of the risk out of production. Smith Farms Incorporated produces hay for livestock and sells it to other ranchers in the area. Smith also leases land to other farmers who grow potatoes and sugar beets. 

“It’s kind of a hidden resource, but the amount of crops that we can get off of the poor ground that is above the aquifer is amazing.”

Amy Yoder, Sheridan County Conservation District 

An aerial view of his circular pivot plots shows different shades of green and brown, indicating the variety of crops grown on his property.

Smith was part of an early contested pivot case with the state of Montana, before the water reservation was transferred to the conservation district, which went to the state water court. 

The gist of the case was that Smith Farms wanted to change its method of irrigation, and USFWS was concerned the change might impact Medicine Lake National Wildlife Refuge. Data and monitoring done by the conservation district supported Smith’s case.

“When you start irrigating, you wonder what is the capacity, or how much can you irrigate,” Smith says. “It’s always interesting to know what it’s doing.”

Johns, with the wildlife refuge, says the refuge has a water reservation on Medicine Lake and is allowed to keep the lake filled for the protection of migratory birds. The refuge operates dams and diversions to manage the resource for that purpose. Making sure that irrigation doesn’t draw down Medicine Lake has been a goal from the beginning, Johns says, and so far, it hasn’t been an issue.

“Water rights are such a contentious thing. And without the data, had they not started this years ago, it would be hard to start it today and get the same momentum they did.”

Brooke Johns, Medicine Lake National Wildlife Refuge

There haven’t been any other contested cases regarding aquifer irrigation, and many area residents, including Smith, see that as a success attributable to local control over a local resource.

“Water rights are such a contentious thing,” Johns notes. “And without the data, had they not started this years ago, it would be hard to start it today and get the same momentum they did.”

Arnold Bighorn, water rights administrator for the Fort Peck Tribes, says the collaboration between all the parties that rely on and are affected by the aquifer — counties, tribes and the wildlife refuge — has worked well. 

“Everybody’s on the same page, which is good,” Bighorn says.

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Groundwater monitoring of the sort the Sheridan County Conservation District employs to inform irrigation is unique in Montana, according to Reiten, but there are successful examples in other states. 

Before he came to Montana, Reiten worked for the North Dakota State Water Commission, where the same type of monitoring was happening that he helped start in Plentywood. He is working to develop a similar system on another aquifer in Sidney, about 85 miles south of Plentywood.

“We’re applying the same methods there to try to develop that aquifer without affecting anything else,” Reiten says.

Many conservation districts across Montana have water reservations on surface water, Yoder says, but the Sheridan County Conservation District is one of only two districts in the state that manage a groundwater reservation.

“I haven’t heard of any other places that have quite the extensive monitoring that we have, and the time range that we have,” Yoder says.

There continues to be more water accessible via the district’s reservation, and room for improvement in how it’s used.

Wilvhom would like to see soil monitoring, so producers can have a more precise idea of when to water and when they’re using too much. Devices are available that farmers could bury in the ground to monitor soil moisture and temperature, but the cost makes soil monitoring impractical at present.

Managing the aquifer has been “a collaboration to help the whole community do good,” Wivholm reflects later in the week, when Plentywood has reached -58 degrees, accounting for windchill. “It helps the whole health of the whole ecosystem.”

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