‘Thousands of tons of flowing water’

KSEN Radio announcer Bob Norris recalled how the 157-foot-high dam on Birch Creek disintegrated “with a great cracking sound like a giant thunder and lightning bolt,” and “thousands of tons of cascading water roared down into the valley, snuffing out homes and lives in a matter of seconds.” Ten miles below the dam, Ramona Tatsey was gathering her family to leave for safety in Browning when she saw mature trees along the creek start to topple: “They were falling like they were being chopped down,” she recalled. The family barely managed to scramble up a hillside before their home was obliterated in the flood.

What’s widely considered the greatest natural disaster in Montana history killed at least 30 people on the Blackfeet Indian Reservation that June 8, 1964. The Two Medicine Dam also collapsed that day, contributing to several of the deaths.

Farther east, floodwaters deluged Great Falls. On the west side of the Continental Divide, the Flathead River watershed inundated Columbia Falls and Kalispell. Hungry Horse News publisher Mel Ruder earned a Pulitzer Prize for his coverage of the catastrophe. All told, the flood of 1964 touched almost 30,000 square miles, or 20% of Montana. A 2020 dam safety analysis estimated the damage at $500 million.

The 60th annual Blackfeet Flood Memorial takes place Saturday at Browning’s Museum of the Plains Indian, with honor songs, re-telling of the events of the disaster, and a community meal. But 177 miles south in Helena, officials contemplate an opposite problem: Montana can’t find enough water to fill its reservoirs.

Persistent drought, changing snow patterns and population growth have left water storage facilities underfilled. And while many need extensive maintenance, an effort is underway to help them hold more water than they used to.

Supply and demand have switched

Montana has 3,007 dams. At least 200 of them have “high” hazard potential, according to the National Inventory of Dams. Their average age is 72 years. About 300 are federally managed. The state of Montana owns 22. The remainder belong to private or independent water use groups such as irrigation districts or farming cooperatives.

“We’re trying to put our finger in cracks of a lot of dams,” said Clayton Elliot, Montana Trout Unlimited’s government affairs director and member of the state Department of Natural Resources and Conservation’s Comprehensive Water Review stakeholder working group. “We’re doing a good job keeping safety and integrity of the dams we have. But we’re way behind other states in investing large sums to maximize existing infrastructure and think about new infrastructure.”

An economist by background, Elliot said both the supply and demand curves of Montana’s water supply have not kept pace with the times.

“It’s not like the old days, when mining and cities and agriculture had the priority,” Elliot said. “Now there are new demands from fisheries and recreation and increasing populations all making demands, and trying to make the water supply go further.”

At the same time, the market value of water has risen like steam. Most of Montana’s fastest-growing regions are water-constrained, meaning all the available water has already been legally appropriated to existing users. That’s resulted in serious discussions about, for example, piping water from Canyon Ferry 64 miles to the fast-growing suburbs of Bozeman.

Meanwhile, the Big Hole Valley doesn’t have enough water for all the property owners who possess water rights — which has threatened the blue-ribbon fishing quality of the Big Hole River. That’s spurred conversations about how to enhance local reservoirs to capture more rainfall, essentially creating new unappropriated water. It would copy what Montana Fish, Wildlife & Parks did in funding improvements to Painted Rocks Reservoir, which now keeps the Bitterroot River (and its trout fishing fans) from running dry.

But both the amount and timing of western precipitation has changed too. A recent analysis by the Montana Climate Office found that western Montana snowpack levels have shrunk between 20% and 80% since 1950. But the total moisture hasn’t changed much — it’s just falling as rain instead of snow.

That can have a huge effect on facilities like Swift Dam, which was rebuilt in 1967, or on Hungry Horse Dam and Seliš Ksanka Q ispe Dam on the Flathead side. Those reservoirs were engineered to catch and hold snowmelt that would slowly release through spring and summer. New climate models forecast that snow levels which used to extend down to 5,000 feet elevation will retreat to 10,000 feet. That means peaks as high as the Mission Mountains or Rocky Mountain Front could go snow-free most of the winter. The annual precipitation would instead fall as rain.

It was a rain-on-snow event that unleashed the 1964 flood. Unlike the recent atmospheric rivers shuttling moisture from the Pacific Ocean, the 1964 storm that reached Montana on June 7 had originated in the Gulf of Mexico. It hit a Rocky Mountain Range that had an average snowpack for most of the winter followed by a freak snow dump in April and May. Below-normal temperatures delayed the spring runoff, leaving the high country bulging with snow.

The 36-hour storm poured between 12 and 16 inches of rain into the basins above Swift and Two Medicine dams. Lake McDonald on the west side of Glacier National Park got 10 inches. Weather analysts calculated it was a 1:5,000-, maybe 1:10,000-year event.

By comparison, the 2022 storm that destroyed homes and tore out roads from Gardiner to Red Lodge was considered a 1:500-year event. But the bigger issue for dam managers and disaster planners is what scientists call the “breakdown of stationarity.” In other words, past weather patterns no longer reliably predict future conditions.

“We’re seeing earlier runoffs and these flashy precip events,” Elliot said. “We’ll go months or weeks without precip and all of a sudden you get an inch or two inches.”

Stakeholders seek investment </p>

Water storage could mitigate a lot of that, if the dams and reservoirs were enhanced to take advantage of the different tempo. But that takes lots of money, and the water users who built the old dams no longer have the economic clout to replace them.

“They can only sell so many bales of hay,” Elliot said of the farmers and ranchers who benefit from the dam-supplied irrigation, but lack the cash for upgrades. Most are only able to contribute between 10% and 15% of ongoing maintenance needs, according to state records.

The Legislature has also been reluctant to wade in, given the estimated $50 million backlog in maintenance needs. On Thursday, the federal Bureau of Reclamation announced plans to replace the St. Mary River diversion dam. That specific irrigation and drinking water project is budgeted at $88.2 million.

DNRC maintains its 22 dams with revenue from the sale of hydropower at Tosten Dam, between Townsend and Three Forks. But that dam’s power contract expires this summer, and state officials expect a new one will pay 50% less due to changes in the price of electricity.

“We’re trying to figure out how do we meet growing water needs while protecting existing water users and water right holders,” said Anna Pakenham Stevenson, the water resources administrator for DNRC. “We’re looking for holistic solutions.”

The water stakeholder group that Elliot serves on and Pakenham Stevenson guides has four focus areas. One is mitigation: finding market tools to allocate water supplies between water rights holders and new water customers. The second is improving access to public water and sewer services, which is more cost-effective and environmentally beneficial than independent water developments.

The remaining two are more challenging. Exempt wells allow one property owner to provide water to multiple subdivisions, even though the owner’s initial water right might not be big enough to supply all those additional users. That can reduce the supply of all the other users in a water basin. It’s like if a table of diners share a milk shake, but one person sucks from five straws instead of just one.

Then there’s water storage. This July, the DNRC Comprehensive Water Review stakeholders hope to frame some proposals for the Legislature and governor’s office to consider.

In addition to raising dams so the reservoirs behind them can hold more water, lots of other methods can capture rain and snow for growing needs. For example, improving wetlands and floodplains can allow underground aquifers to recharge more effectively, which can increase the flows coming out of area wells.

More storage means more than just more hay crops. Having reserve water in Painted Rocks Reservoir not only keeps the Bitterroot River high enough to float boats, it keeps temperatures low enough for cold-water trout species to stay healthy.

“Other states like Wyoming and Oregon are spending big dollars on storage,” Elliot said. “We’re way behind our neighbors in investing in storage. And the real barrier to water storage is funding. It’s not $50,000, but $50 million.”

Reporter Rob Chaney can be reached at 523-5382 or at rchaney@ missoulian.com.