Erin Whorton

NRCS Idaho Water Supply Specialist Erin Whorton.

Idaho water-supply specialists say irrigators in many locations will have less water to work with as the season continues.

“Based on dry soil conditions and lack of spring precipitation, we expect continued water supply shortages in the Big Wood, Little Wood, Big Lost and Little Lost basins,” Erin Whorton, a hydrologist with the USDA Natural Resources Conservation Service Snow Survey in Idaho, said in a news release. “Diminished agricultural irrigation water supply is also predicted for the Snake River above Heise, and Oakley, Salmon Falls and Owyhee basins. Dry conditions across Idaho will continue to impact ranchers who utilize non-irrigated pastures.”

NRCS said snowpack is melting earlier and faster than normal despite a few April storms bringing minimal gains to the highest-elevation sites. Peak snowpack occurred up to 26 days earlier than normal at some sites.

“Based on what we are seeing, we are anticipating a potentially very difficult year,” Pat Purdy of Picabo Livestock Co., in the Big Wood River Basin, told Capital Press.

He said the farm and ranch this year installed additional soil-moisture sensors. It will work with neighbors to cooperate on water usage, and keep some feeder hay it would have sold in a normal water year.

Purdy said he fallowed just over 200 acres, mostly barley.

University of Idaho cereal agronomist and pathology specialist Juliet Marshall, based in Idaho Falls, said that barley planting was nearly completed in the state and focused on higher-elevation areas.

In non-irrigated farming areas, “we’ve got some soil, especially topsoils that have recently been worked, with a little dryness on the surface depending on location,” she said. Despite some recent rains, “we are concerned about soil moisture levels being low.”

Marshall said top-layer moisture appears sufficient for barley germination. But without additional soil moisture, the soil can dry faster than the roots can grow downward. Drought early in the crop season can reduce the number of tillers or stems per plant.

NRCS Idaho said dry weather in April reduced expected streamflow volumes compared to previous forecasts.

Streamflow is expected to be nearly normal in Clearwater and Panhandle basins in the north.

Basins with 50-70% of normal streamflow are Salmon in the central region; Weiser, Payette and Boise in the southwest; Little Lost in the east central mountains; and Henrys Fork-Teton, Willow-Blackfoot-Portneuf, and the Snake River Basin above Palisades in the east.

Basins with forecast streamflow well below normal include Big Wood, Little Wood, Big Lost, Birch-Medicine Lodge-Bear-Camas, Bear River, Goose Creek, Salmon Falls, Bruneau and Owyhee.

NRCS Idaho said water carried over in reservoirs is above normal in the Upper Snake, nearly normal in west-central basins and below normal in most southern Snake basins. Carryover as of May 1 in the east-central mountains included 33% of normal in Magic Reservoir, 82% in Little Wood and 99% in Mackay.

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