Plentiful storms have helped Idaho’s water outlook

By Sean Ellis

Idaho Farm Bureau Federation

POCATELLO – The constant stream of rain and snowstorms that have hit Idaho since the first part of April have improved the state’s water supply outlook for 2022.

But they haven’t solved the state’s drought and farmers and other irrigators still face some tight water supplies this year.

According to water managers, there will almost certainly be some curtailment of water supplies this year.

The storms “have helped a little bit but it’s certainly not going to prevent some water rights from being curtailed later this year,” said Tony Olenichak, watermaster for Water District 1, which encompasses the upper Snake River system.

Water District 1 is the state’s largest and most important in terms of providing water to farmers. It typically provides enough water to irrigate well over 1 million acres of farmland in southern Idaho.

Idaho started its water year Oct. 1 with reservoir levels that were well below normal for that time of year and while the late-season storms have helped, they haven’t come close to solving the drought issues, Olenichak said.

“We’re still below average and we still have a deficit from last year,” he said.

Mountain snowpack levels around Idaho were well below average on April 1, which is typically the time of year that peak snowpack occurs in Idaho.

Snowpack is important because it’s snowmelt that fills the state’s reservoir systems and those reservoirs provide water to farmers and other irrigators during the hot, dry summer months.

The late-season storms brought some much-needed extra precipitation to the state but it wasn’t enough to end the drought conditions that have plagued Idaho since last year, said Corey Loveland, a supervisory hydrologist with the Natural Resources Conservation Service’s Idaho snow survey program.

“They have helped a little, but we’re not out of the drought,” he said.

Farmers and ranchers in arid southern Idaho depend on the water from the state’s reservoir systems to get them through the hot, dry summer months.

Heading into 2022, most reservoir systems in the state were well below average and irrigators were hoping for good snowpack levels through the winter to fill those reservoirs to levels that could ensure irrigators had an adequate amount of water this year.

That didn’t happen.

The recent storms that have hit the state since early April have helped the water situation in Idaho but they haven’t been enough to get the state out of its drought, according to water managers around the state.

The upper Snake River and Boise basins received the most late-season snow, said David Hoekema, a hydrologist with the Idaho Department of Water Resources.

That made somewhat of a difference in the water supply outlook for irrigators that depend on the reservoirs that are filled with snowmelt from those basins.

For example, on April 1, water supply forecasters gave the Boise valley about a 70 percent chance of experiencing water shortages in 2022, Hoekema said. On May 1, there was a 50 percent probability of the valley having an adequate water supply this year.

While the precipitation in the Boise valley didn’t solve the drought issues, “It’s definitely put us in a better position than we were,” said Mark Zirschky, manager of Pioneer Irrigation District, which provides water to 34,000 acres in the Treasure Valley of southwestern Idaho.  

Based on river flow forecasts, the late-season snowfall in the upper Snake River basin added about 350,000 acre-feet of water in that basin.     

“That’s nowhere near enough to prevent shortages in the Snake River system, but it certainly helps,” Hoekema said.

Even with the added precipitation, “I think there’s very little chance that we’ll fill any of the major reservoir systems this year,” he added.

On its Facebook page, the Idaho Water Users Association noted on May 4 that, “Although this precipitation has improved the immediate water outlook, much of Idaho remains in drought conditions. This recent precipitation has not been enough to overcome the lack of precipitation in January through March.”

“River flows are low, water in reservoirs remain low,” the IWUA post added. “Irrigation districts and canal companies throughout southern Idaho are limiting water allocations and remain skeptical that supply will get them through the ‘normal’ season.”

The plentiful spring storms took some of the rough edges off of the year from a water supply perspective, but the lack of snow from January through April left a pretty big water hole to fill, IWUA Executive Director Paul Arrington told Idaho Farm Bureau Federation.

“While the extra moisture we received … has been very welcome and has maybe allowed the season to maybe stretch a few days longer, ultimately it sill is a drought year and we still need to be mindful of water usage throughout the state,” he said.