Central Oregon reservoirs ready for refill

As irrigation season nears a close in Central Oregon, water managers say reservoirs have enough water left in them to be refilled by rain and snowmelt in the fall, winter and early spring.

“Depending on the type of water year we get, I do expect the reservoirs to fill this year,” said Jeremy Giffin, watermaster for the Oregon Water Resources Department in Bend. A water year runs from Oct. 1 to the end of the following September. Water managers such as Griffin use water years to judge how much water might be available for irrigation.

The last water year was dry, Giffin said. Despite the dry conditions, the water supply for growers this year relying on the Deschutes River system was good thanks to higher-than-expected stream flows in and around Wickiup and Crane Prairie reservoirs.

As of Thursday, Wickiup Reservoir was 25 percent full and Crane Prairie Reservoir was 54 percent full.

“We didn’t run the reservoirs down as low as we thought they would,” he said.

In response to irrigation districts soon ending their diversions for the year, the department will start filling Wickiup and Crane Prairie reservoirs in earnest next week. Doing so will reduce flows along the Deschutes River.

But Giffin said the annual cut in river flows, which can drop the water level in some stretches by as much as 2½ feet, will be different this year. Typically, the change in flows has been done over three or four days. This year it will take closer to two weeks.

This change is because of a fish kill last October in a side channel to the Deschutes River near Lava Island Falls. Hundreds of fish died after becoming trapped when the river’s water level dropped. By slowly changing the flow in the river, Griffin said, the department intends to give U.S. Forest Service scientists a chance to study the river at different levels.

In hopes of not losing fish as it did last year, the Oregon Department of Fish and Wildlife and a team of volunteers are bracing for a fish rescue and relocation program the week of Oct. 20. Volunteers plan to haul fish pulled from dwindling pools of water in buckets equipped with aerators. They’ll carry buckets full of fish from the side channel up a trail along the Deschutes River and then dump them into the river.

“We are planning on being out there when the side channel gets cut off from the main river,” said Erik Moberly, Fish and Wildlife assistant district biologist in Bend.

The Bend Casting Club is gathering volunteers for the fish rescue, but Moberly said the department will be leading the effort.

About 80 people have volunteered to help with the fish, said Kim Brannock, a board member of the Bend Casting Club. She found last October’s fish kill while on a run along the Deschutes River trail and then led a small-scale fish rescue.

This fall, Brannock has been checking along the river for other spots where fish may become stranded once the water drops. “I just have to watch the river to see,” she said.

Water Resources’ slower ramping down of flows on the Deschutes isn’t the only difference in how this year’s irrigation season is ending. For the second year in a row, the Tumalo Irrigation District plans to end water deliveries on Oct. 15 — two weeks later than had long been the norm for the district. Improvements to the efficiency of the district’s system brought by piping canals has led to the later end date, said Ken Rieck, assistant manager for the Bend-based district.

“With the less we use, the longer we can run,” he said.

Over the past 15 years, the district has piped about 6½ miles of the 12-mile main canal system. Rieck said the goal is to someday pipe the entire district, including the main canals and ditches leading to individual farms, but it could be a couple of decades away.

For now it’s time for Giffin, Rieck and others involved with irrigation in Central Oregon to wait on the weather. In the near forecast there could be rain, but the long-term outlook could be worrisome.

The National Weather Service is calling for a slight chance of rain Sunday, and the possibility of rain increases until Wednesday, said Mike Murphy, a National Weather Service meteorologist in Pendleton.

“It looks like we certainly could see some rain,” he said.

But the agency’s three-month forecast is for above-average temperatures and below-average precipitation.

— Reporter: 541-617-7812, ddarling@bendbulletin.com