Farmers and ranchers in the Mission Valley will have to pray for rain because water for irrigation is being rationed and in some cases shut off.

The Bureau of Indian Affairs on Thursday announced that it was temporarily shutting off water from Pablo Reservoir.

The bureau manages the Flathead Indian Irrigation Project, a system of irrigation in the Mission Valley that supplies water to about 130,000 acres.

Pablo Reservoir is one of the main reservoirs that supplies water to the west side of the Mission Valley. It is fed from the Flathead River pump system that draws water from the Flathead River near Kerr Dam.

“Although all reservoirs are well below average for this time, Pablo Reservoir is well below capacity and is near critical low levels,” said Pete Plant, Bureau of Indian Affairs manager for the Flathead Indian Irrigation Project.

Plant said that the temporary shutdown of water delivery from Mission Reservoir will be for five to 10 days. During the shutoff period, the irrigation project will continue to operate the Flathead River pumps and transfer as much as possible of the available upstream water to the reservoir, Plant said.

Once releases are resumed, deliveries from Pablo Reservoir will be under a strict rationing and rotation schedule that will be based solely on what the Flathead River pumps can provide, he said.

“We expect water users to work cooperatively with the irrigation system operators during this shortage,” he said. “Additional shutdown periods and lengths will be dependent upon storage and the operation of the Flathead River pumps.”

Pablo Reservoir — and the irrigators that it feeds — aren’t the only water storage facility that’s hurting.

The Flathead Indian Irrigation Project has about 1,100 miles of ditches and canals that convey water to Mission Valley irrigators. Built in 1904, the system is archaic and needs replacement, which would happen under the negotiated water compact between the state and Confederated Salish and Kootenai Tribes.

Because of poor conveyance of water in the ditch and canal network, much of the available water is being lost, Plant said.

He said he expects the lack of precipitation, extreme heat and high irrigation demands to continue throughout the remaining irrigation season.  

“Consequently, certain water management actions must be taken to ensure that all water users share in the shortage,” he said.

Following is a summary of water availability and outlook for irrigation districts in the Flathead Indian Irrigation Project:

Camas

A quota of 0.70 acre feet was set for the Camas division at the beginning of the irrigation season. Although Camas is experiencing the same lack of precipitation and extreme heat, current storage is 77 percent of capacity and 127 percent of average. Project management expects to meet the delivery quota, Plant said.

Jocko Valley

Storage in the Jocko Valley is 43 percent of capacity and 78 percent of average. Current usable water is 5,015 acre feet.

However, spring runoff was significantly less than average. The runoff peaked early in June and has now subsided well below delivery needs, Plant said.

This has forced the irrigation project to begin releasing water from storage on June 25 — much earlier than normal. This reliance on stored water started about a month earlier than normal. To deliver water in an equitable manner, a quota of 0.50 acre-feet per acre has been implemented in the Jocko Valley.

Mission Valley

Recorded precipitation for April through June is 2.15 inches at St. Ignatius and 1.47 inches at Round Butte.

The April-to-June average for these sites is 6.31 inches and 5.18 inches. This is approximately 30 percent of normal, according to Plant. Temperatures in the valley and in the mountains have been well above average for an extended period, Plant said.

“Demand for irrigation deliveries began early and has remained high throughout the season,” he said. This demand, combined with less than average runoff, has resulted in lower than average water storage. Current storage across the valley is 48 percent of capacity and 49 percent of average.

The low storage and high demand will likely result in the Flathead Indian Irrigation Project implementing a ration or rotation schedule for the entire Mission Valley for the remainder of the irrigation season, Plant said.

He encouraged irrigators to work together. “Water users must work cooperatively with their irrigation system operators to complete the proposed action,” he said.