National Weather Service says farmers are in for a hot, dry summer as water users prepare for growing season

POCATELLO – While reservoirs are nearly filled to the brim, farmers could still be in for water woes this growing season.

The National Weather Service in Pocatello forecasts higher than average temperatures and below average precipitation for the months of June, July and August. This drives up demand for water filling eastern Idaho’s reservoirs.

It remains to be seen how quickly water will be used this year, but junior groundwater users would be obligated to deliver storage water to senior users if natural flow levels run too low.

“A hot and dry summer is more likely to lead to an obligation from the groundwater users to supply some storage water to the surface water coalition,” said Craig Chandler, the Idaho Department of Water Resources water master for District 1.

In its three month outlook, NWS forecasts the temperature this summer to be “likely above” average, with the majority of eastern Idaho having a 60% to 70% chance of experiencing above normal temperatures. This percentage represents the probability that temperatures will be above average.

And for precipitation, NWS forecasts a “leaning below” probability of receiving below normal levels. Specifically, nearly all of eastern Idaho is expected to have a 40% to 50% chance of receiving below normal precipitation levels.

Carter MacKay, a meteorologist at the Pocatello office, explained that NWS has a “fairly high confidence” of the summer being hot and dry.

“Normal highs are typically pushing into those 90 and 80 degree temperatures around the peak of the summer, which is late July to August. So expect temperatures to be slightly above normal … as we head into the warmest part of the summer,” MacKay said.

Mackay added that precipitation will likely be below the summer’s normal levels, which are around one to two inches during that period.

Chandler said that warmer temperatures over the spring led to quick snow melt and high irrigation demand.

“Where that puts us now is that the remaining snow that we have is below average, and the forecasts for the remaining runoff from the snow are below average,” Chandler said.

Chandler said that an update from the Bureau of Reclamation put the snowpack of the Snake Basin above Palisades to be at 75% of normal, meaning that it’s 25% below its normal levels.

But Chandler said that the storage built up in the reservoirs are at a good level, and that farmers will have good storage allocations this year.

According to provisional data from the Bureau of Reclamation, Jackson Lake and Palisades reservoirs are respectively 97% and 98% full, while the American Falls Reservoir is 86% full.

However, Chandler pointed out that the forecasted higher than average temperatures and below average precipitation levels would increase water demand, requiring farmers to put more water on their crops.

“With the low base flows that we’ve had over the winter and last year, it may be a year where the reservoirs are drafted aggressively,” Chandler said.

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Because of last year’s long-term mitigation agreement, the 2024 Stipulated Mitigation Plan, junior water rights users have safe harbor from water curtailments, but if the natural flow of the Snake River is too low, they may have to provide storage water to senior water rights holders. This means they would have to purchase water storage and take on the cost for senior rights holders.

In order to prepare for this possibility, Chandler said that junior water rights holders should be “doing the things that they’re probably already doing, which is adhering to their settlement agreement.”

One of the core components of the agreement is reducing water usage, which farmers can do by “drying up” acres of their land. Chandler said another thing they can do is preemptively buy water storage for senior water rights holders, which counts towards their water reduction.

Chandler thinks it’s a good idea for junior water rights holders to start getting contracts in place, and looking for partners to acquire water from now.