Cool temperatures and consistent rainfall in recent weeks has provided some relief to Central Oregon farmers during the first stages of the growing season. But authorities warn that recent rain may not be enough to stave off water shortages later in the year.
One or more irrigation districts could be limited this year, said Jeremy Giffin, the Deschutes Basin watermaster, due to drought conditions that have afflicted Central Oregon for several years. Limitations could result in having to curtail or shut down a district’s diversion until more natural flow becomes available, he said.
Drought has kept reservoir levels in the area at or near historic lows. Wickiup Reservoir, which supplies water to the North Unit Irrigation District, started the irrigation season at its second-lowest level, just 70% of capacity. For farmers, that means less water is available for irrigating their crops, which forces many to leave portions of their farmland fallow.
“Wickiup Reservoir is very low for this time of year and I anticipate it to be the most likely reservoir to be drained, sometime late summer or fall,” said Kyle Gorman, region manager for the Oregon Water Resources Department. “The rest of the Central Oregon reservoirs hold enough water to get through this year.”
No district has completely run out of water since 1994, when Arnold Irrigation District was forced to shut down before the end of the irrigation season. Arnold relies primarily on live flow for its water supply, but does have some storage rights at Crane Prairie Reservoir.
In recent years, irrigation districts, including North Unit, have been forced to restrict water supplies to customers. Should a district exhaust its water supplies, the headgate where the water leaves the Deschutes River and enters the canal would be shut down for the season, said Giffin.
Most of Deschutes and Crook counties are in a state of severe drought, according to the U.S. drought monitor. A portion of Jefferson County is one level up, in extreme drought.
Recent rainstorms that have swept across the High Desert won’t have the cumulative effect necessary to rebuild the depleted supplies of water, said Giffin.
“The downpours really do not help because they are generally not widespread enough,” said Giffin. “It is the wintertime snowpack that we need since it recharges the aquifer.”
The snowpack accumulated over the 2019-20 winter in Central Oregon was 58% of average as of May 1. In order to catch up with depleted water supplies, Central Oregon will need to see some big snowfalls several years running, said Giffin.
“It takes several years to deplete the springs and several years to fill them back up,” said Giffin. “I think we need to be well above average for more than two years to get us back to normal.”
As of June 10, Wickiup Reservoir was 47% full. Water was being released at 1,200 cubic feet per second.
Climate change could be behind the dry conditions, said Larry O’Neill, an associate professor at OSU’s College of Earth, Ocean and Atmospheric Sciences.
“There is a trend in the U.S. West toward longer and more frequent drought conditions. The droughts in the last 20 years or so that we’ve experienced in Oregon may be part of this long term drying trend,” said O’Neill.
In response to the dry conditions, Jefferson County earlier this month declared a state of drought. Federal and state assistance and programs could be enacted as a result of the declaration. Both Deschutes and Crook counties authorities are expected to adopt a similar state of drought .
“Some ranchers can’t utilize parts of their pasture because of the lack of water,” said Brian Barney, a Crook County commissioner. “The rains have helped but it hasn’t mitigated the long term effects of the drought.”