Idaho loosens east Snake River Plain groundwater curtailment

Above-average precipitation events during April and May improved the dire state of the drought for farmers from abysmal to merely dreadful. As a result, on July 20, the Idaho Department of Water Resources (IDWR) amended the curtailment it issued on May 5 for ground water users in seven south central counties. The amendment applies to seven water districts and canal companies that deliver water in counties stretching from Cassia County in the east to Elmore County in the west.

The curtailment

The May 5 curtailment applied to holders of ground water users “holding water rights bearing priority dates junior to December 25, 1979, within the Eastern Snake Plain Aquifer.” The curtailment affected the A&B Irrigation District, the American Falls Reservoir District #2, the Burley Irrigation District, the Milner Irrigation District, the Minidoka Irrigation District, the North Side Canal Company and the Twin Falls Canal Company. Collectively, these seven are known as the Surface Water Coalition (SWC).

While much of the water allocated is for crops, the order and amendment also covered commercial, domestic and municipal uses. The variety of ground water users on the original curtailment list included the Bureau of Land Management, the Idaho Transportation Department, the Jefferson and Valley school districts, the cities of Pocatello and Idaho Falls, the Knife River Corporation, the Mud Lake Water Users Inc., the Woodville Water and Sewer District and several home owners associations.

Technically, the IDWR label for the curtailment and its amendment are categorized as “delivery call actions.” All such actions are listed on the IDWR website.

The amendment

The amendment widens the number of users by lifting curtailment for rights senior to March 12, 1989. However, “all ground water users holding water rights listed in…the May 5, 2022 Curtailment Order bearing priority dates junior to March 12, 1989, shall continue to be curtailed from diversion and use of ground water.”

Challenging curtailment orders

Water right users have means to file mitigation plans that might allow for more water use subject to IDWR approval. They also have means to appeal the terms of a curtailment under Idaho’s water laws. Both the May curtailment and the July amendment were challenged.

The cities of Pocatello and Idaho Falls and a 27-city coalition of many eastern Idaho cities submitted their intent to follow a mitigation plan they collectively submitted in 2019. Their purpose was to state their “intent to mitigate to avoid curtailment,” which is allowed by Idaho law and IDWR regulations.

Another action was the July 21 “request for status conference” by the SWC to discuss and potentially revise some of the terms of the July 20 amendment of the original May curtailment order. Since water users have 14 days after an order is issued to request such a hearing, the speed at which the request was filed is not uncommon in the Idaho water rights arena.

Given the complexity of water calculations required by Idaho’s water laws, some of the grounds for this request for conference are numbers that IDWR used to calculate the revised shortfall for this water year. For example: “IDWR’s reduction calculations were significantly different than (the) Idaho Ground Water Appropriators’ (IGWA) resulting in IDWR using a diversion reduction value of 66,586 acre-feet compared to IGWA’s number of 56,952 acre-feet. The Coalition requests further review of this issue given the large disparity. IDWR also used a smaller recharge value which was 1,514 acre-feet less than IGWA’s.” Such detailed challenges are not at all uncommon in the almost-yearly tussles over Idaho’s water.

The IGWA is a group of water users and distributors who were parties to a far-reaching 2015 settlement agreement with the SWC over water use in the Blackfoot to Milner region of the east Snake River Plain. It includes the Aberdeen-American Falls Ground Water District, Bingham Ground Water District, Bonneville-Jefferson Ground Water District, Carey Valley Ground Water District, Jefferson Clark Ground Water District, Madison Ground Water District, Magic Valley Ground Water District, North Snake Ground Water District, Southwest Irrigation District and Fremont-Madison Irrigation District, Anheuser-Busch, United Water, Glambia Cheese, City of Blackfoot, City of American Falls, City of Jerome, City of Rupert, City of Heyburn, City of Paul, City of Chubbuck and City of Hazelton.