Above average snowpack helps Prineville Reservoir fill for second year running

April 11, 2024
Above average snowpack helps Prineville Reservoir fill for second year running

By MICHAEL KOHN The Bulletin

After several years of low water levels caused by a historic drought, Prineville Reservoir has filled for the second time in two years.

As of Wednesday morning Prineville Reservoir was 98% full, about 3,000 acre-feet below maximum capacity, according to data compiled by the U.S. Bureau of Reclamation. Above-average snowpack in the Upper Deschutes and Crooked River Basin has helped to lift reservoir levels across the region.

Boosted snowpack and reservoir levels are a welcome sight for irrigators who have suffered through multiple years of drought. Crook County has been hit particularly hard, and local officials had to declare drought emergencies four consecutive years from 2020 to 2023. Fish will also benefit from the higher water line as low levels increase water temperatures, causing stress that can lead to poor health and low reproduction rates.“It’s good for agriculture and recreation. And it’s great for fish and wildlife,” Bill Nashem, the watermaster for the Crooked River Basin, said about the high water levels.

“So there’s enough water for everybody this year.”

Managing water levels

Two years ago, dam managers slowed the Crooked River to a trickle because of a lack of water, putting large numbers of fish in peril. The low levels persisted into early 2023, but the region then experienced a succession of late-season snowstorms. The reservoir went from empty to full in just a few weeks last April. This year the increases have been more incremental, said Nashem.Snowpack is “coming off slower this year at more of a normal rate,” he said. “It’s more predictable.”

The inflow rate into the reservoir has slowed this week, so the managers of Bowman Dam have lowered the release rate into the lower Crooked River to keep more water in the reservoir.

The inflow peaked at 1,490 cubic feet per second on Friday but has since slowed to around 770 cfs, according to Bureau of Reclamation data. Cooler temperatures in Crook County and the Ochocos slowed the flow of water in the reservoir, said Nashem.

Multiple data sources are used to determine the outflow rates of water from the dam, including the current reservoir contents, snowpack in the Ochoco and Maury mountains and various weather forecasts.

If precipitation or warm temperatures are in the forecast while the reservoir is full, dam managers will lower Prineville Reservoir to make room for water headed its way.

“The main goal is to fill the thing plum full and have it full when the growing season starts,” said Nashem. “A lot of factors go into managing its contents. We have to be prepared for unforeseen inflow.”

Other reservoirs also filling up

Other reservoirs in Central Oregon are also performing better than in previous years. Ochoco Reservoir is 90% full, and Wickiup Reservoir is 78% full.

“We are very fortunate to have a full Prineville Reservoir and even more encouraging is the contents of Ochoco Reservoir,” said Bruce Scanlon, the general manager for Ochoco Irrigation District. “The storage we have does provide some assurances to our patrons for this year and next.”

Scanlon said reservoir levels provide a good hedge against the ever-present possibility of dry weather returning.

“With the volatility of the Crooked River from year to year, we will continue to do all we can to manage the resource wisely with drought potential always present,” he said.

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