This article was published on: 04/24/24 12:45 PM
When April comes around, the Deschutes becomes a tale of two rivers.
The Upper Deschutes from Wickiup Dam to Bend is filling fast, benefiting farmers and wildlife. Meanwhile, the Middle Deschutes, River, from the North Canal Dam in Bend to Lake Billy Chinook, has dropped like a rock.
That’s because irrigation districts have ramped up their efforts to deliver water to farms and ranches, which requires higher releases from Wickiup Dam. But once all that water gets to Bend, it’s diverted away, leaving little for the next section of the river. Water in the Upper Deschutes is also managed by biologists to protect the threatened Oregon spotted frog, which is prevalent upstream from Bend but does not have habitat in the middle or lower sections of the Deschutes River.
“Because so much of the restoration focus is on restoring flows to the Upper Deschutes in the winter to support endangered species, it has become more difficult to see consistent gains in the Middle Deschutes,” said Kate Fitzpatrick, executive director of the Deschutes River Conservancy, an environmental nonprofit.
Agriculture season underway
Releases from Wickiup Reservoir are rising and expected to increase in the coming days as agricultural season gets underway across Central Oregon.
As of Tuesday, the water in Wickiup Reservoir was being released at 600 cubic feet per second into the Upper Deschutes, according to data compiled by the Bureau of Reclamation.
Water diversions into most canals have started. The North Unit main canal is siphoning off 347 cfs, while flows into the Central Oregon canal — operated by the Central Oregon Irrigation District, also in Bend — are 233 cfs.
“It is a normal start to the water season. All systems are a go,” said Craig Horrell, general manager for Central Oregon Irrigation District.
Water for frogs
Water releases to benefit spotted frog habitat — listed as a threatened species under the Endangered Species Act — began in early April to meet the needs of its reproductive cycle. The U.S. Fish and Wildlife Service is one of several agencies monitoring the early season water flows to ensure the frog’s habitat is not degraded.
Oregon spotted frogs lay their eggs masses in early spring in seasonally flooded areas and shallow waters.
As releases from Wickiup Reservoir rise, biologists are monitoring known spotted frog breeding sites. Erratic flows can damage their habitat and sweep away their egg masses.
The information they collect is used by water managers to determine the timing and amount of flow releases from reservoirs, said Jodie Delavan, a spokesperson for U.S. Fish and Wildlife.
“Ramping up the flows gradually during this period helps inundate the wetlands along the Deschutes to support successful spotted frog breeding,” she said.
Delavan advises the public to be cautious in areas of sensitive frog habitat. The public should not get close to threatened frog species or their egg masses, she said.
“All biologists involved in spotted frog monitoring efforts are trained specifically for that task and are permitted by the U.S. Fish and Wildlife Service,” she said.
But low water in the Middle Deschutes
While the spring water releases bring the Upper Deschutes closer to its historical flows before the construction of Wickiup Dam, other sections of the river have gone in the opposite direction. This includes the Middle Deschutes — which begins at the North Canal Dam in Bend, just past the irrigation diversions.
Water flows past the diversions in winter but in spring, when irrigation season starts, around 90% of the water is diverted away from this section. Water that is allowed to remain in the Middle Deschutes comes largely from conserved water projects, in-stream leases or in-stream transfers.
North of Bend, flows in the Middle Deschutes are currently 109 cfs. The Oregon Department of Fish and Wildlife has a goal of increasing Middle Deschutes flows in summer to 250 cfs.
Fitzpatrick said a critical issue is increasing short periods of low flows in fall and spring when the Middle Deschutes can drop to as low as 60 cfs.
“Those shorter periods or lower flows are the priority right now, getting those sorted out,” she said.
The long-term goal of getting to at least 250 cfs could take 10 to 20 years, she said.
Jerry George, a fish biologist with Oregon Department of Fish and Wildlife, said the diversions and low flows negatively impact fish in the Middle Deschutes, contributing to high water temperatures that can stress trout or cause them to migrate to tributaries to seek cooler water.
“This results in challenging conditions in one of the key reaches in the watershed for redband trout,” said George. “Improving conditions for fish and a healthy river system downstream from Bend requires continuing efforts to restore more summer streamflow.”