Crack in Wanapum Dam creates irrigation challenges as frost season approaches
Cracked dam in WA causes scramble for water
Geraldine Warner // Mar 14, 2014
This photo of the Columbia River at Vantage shows the effects of the drawdown of the Wanapum Dam. (Courtesy Grant County Public Utilities District)
With the frost protection season looming, Washington fruit growers who have been left high and dry because of draw downs in sections of the Columbia River, need to assess what they need to do reach the water, says Bruce Grim, president of the Washington State Horticultural Association. It’s not known how long it will be before the water levels in the river can be raised again.
Spring is a time when orchardists might need to apply copious amounts of water to their trees to protect them from frost damage. As the water freezes, it generates heat that protects the fruit buds.
The level of Wanapum Dam, six miles south of Vantage, had to be lowered by about 25 feet after a spillway pier was discovered to have a large crack on February 27. Lowering the water level took pressure off the spillway but left 11 large orchard irrigators without water. One of them is Zirkle Fruit Company, which draws water for its CRO ranch between East Wenatchee and Quincy.
Thousands of acres in three counties are affected by the drawdown, according to Chelan County PUD.
The level behind the next dam upstream, Rock Island, also had to be lowered by several feet, affecting 150 water withdrawal sites, including three irrigation districts. The Rock Island reservoir level is normally maintained at about 612 to 613 feet, though it fluctuates, partly based on weather and snowmelt. Irrigation districts serving Wenatchee Heights and Stemilt Hill draw water from a pond that’s normally filled by seepage from that section of the river but is no longer being filled.
Many state and federal agencies have become involved in the dam crisis because of the implications for fish passage and power generation as well as irrigation. Governor Jay Inslee has held several conference calls in recent days with interested parties to help figure out how users can regain their access to water.
Grim, who is representing the tree fruit industry in the discussions, said it is not yet known how long it will take to repair the dam so irrigators need to figure out what they need to do in the meantime.
For those whose water intake is on a steep bank, it might just be a case of removing the fish screen, extending the pipe a few feet, and putting the screen back on. But where the intake is on a shallow slope, the pipe might need a long extension involving use of heavy equipment on the riverbank.
The Chelan County PUD, which operates Rock Island Dam, plans to maintain the Rock Island reservoir at 609 to 610 feet, but Grim said users would be wise to extend their pipes enough for a level of 607 feet, to account for fluctuations and avoid damage to their pumps if the level drops further.
“I’m afraid if we’re aiming for a 609-foot level and it just falls below that at 2 a.m. some frosty night, it’s a little late to do anything about it,” he said.
The low water level might also affect some wells along the river, he said. “Those people might not think they have a problem at this point, but when they start pumping in volume they might not have the water they think they have,” he warned.
Grim said Tom Tebb, central regional director at the Washington State Department of Ecology, is aware that growers don’t have time to go through all the notices and time-consuming permitting that would normally be required.
“I think that came through loud at clear,” Grim said, following a stakeholder meeting in Wenatchee on March 13. “Everybody realizes the magnitude of the problem and we don’t have months to fix it. We have a few short weeks.”
Geraldine Warner was the editor of Good Fruit Grower from 1992-2015. During her tenure, she planned and prepared editorial content, wrote for the magazine, and managed the editorial team.
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