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River drawdowns threaten orchards

Dan Wheat
A crack in Wanapum Dam, causing drawdowns of reservoirs upriver, is threatening numerous orchards within weeks of when irrigation water is critical. It is unknown how long the drawdowns will last.

WENATCHEE, Wash. — Thousands of acres of tree fruit orchards are in jeopardy of having no water because of a crack in Wanapum Dam causing drawdowns of the Columbia River behind Wanapum and Rock Island dams.

The situation is urgent with growers needing water within in the next few weeks for late dormant sprays, frost protection and soon thereafter for watering trees, said Bruce Grim, executive director of the Washington State Horticultural Association in Wenatchee.

“We have 150 growers or so and three irrigation districts pumping out of the Rock Island reservoir and some of their intakes are out of the water,” Grim said.

Without fast action there could be crop loss and in some cases loss of orchards, said Norm Gutzwiler, a Wenatchee cherry grower and Chelan County Public Utility District commissioner. The PUD operates Rock Island, Rocky Reach and Chelan dams.

It is not known how long the drawdowns will last but it could be months. Grant PUD is meeting power customer needs but is generating only half the electricity it normally does from Wanapum Dam. Rock Island power generation was suspended for a week.

At a March 13 meeting with growers in Wenatchee, Grim and state officials likened circumstances to the May 23, 2013, collapse of the Interstate 5 Skagit River Bridge in terms of potential economic threat. Jesus Sanchez, director of regulatory innovation and assistance for the governor, and Tom Tebb, central regional director of the Department of Ecology, pledged to expedite permit processes to help growers get water. Bud Hover, director of the Department of Agriculture, said it’s critical to begin irrigation.

But the officials said they need help determining the scope of the problem — finding out how many irrigation systems no longer reach the water, particularly in the Rock Island reservoir which serves more orchards than the Wanapum reservoir. They asked growers to fill out information sheets to let them know.

While the number of systems was believed to be about 150, it probably is closer to 70, said Suzanne Hartman, Chelan County PUD spokeswoman.

Rock Island, the oldest dam on the river, was built in 1930 to 1933 as a stand alone dam but was modified to have a larger reservoir in the late 1970s with dependence on back pressure on its downriver side from the water in the Wanapum reservoir, said Steve Wright, Chelan County PUD general manager.

With Wanapum reservoir drawn down 26 feet its back pressure to Rock Island is gone and Rock Island had to be lowered to prevent catastrophic damage to its turbines and penstocks, Wright said.

Normally, Rock Island reservoir is at 612 to 613 feet above sea level but it was lowered to 607 feet and now is being kept at 609, Wright said.

The Wanapum reservoir usually it at 571 feet but now is 26 to 30 feet lower.

Michael Miller, manager of the Greater Wenatchee Irrigation District, said the district’s pumps should be able to keep their scheduled March 24 start but will use more power and provide a little less flow to customers at the 609 foot level. He said he was concerned about pump cavitation at lower levels. The district serves 2,700 residential and 500 agricultural customers on 4,500 acres in and around East Wenatchee.

There are thousands more acres of mostly cherry orchards on the Wenatchee side of the river and extending up to Wenatchee Heights and Stemilt Hill. Three irrigation districts serving the heights and hill get water, in part, from a pond close to the river, fed by seepage from the river, Gutzwiler said. The pond is lower than normal and not rising, he said.

Gutzwiler said he will be able to extend the irrigation intake of his Malaga orchard without permits because he won’t need to install piling or relocate his pump. He said growers who need piling or to move pumps will need permits.

Extension of pipes without use of heavy equipment can basically be done without Department of Ecology permits, Tebb said.

Jim Brown, North Central regional director of the state Department of Fish and Wildlife, said standard guidelines will be available of what that department allows in pipe extensions.

In a news release, Ecology said it wants to help growers get water while ensuring safe and legal water use with continued fish screens at irrigation intakes. Irrigators and well users along the 58 miles of the river from Wanapum to Rocky Reach Dam who may be unable to get water should report it. Grant County residents should call (509) 329-3400. Chelan, Douglas and Kittitas County residents should call (509) 575-2490.

In the Wanapum reservoir, there are 10, possibly 11, affected intakes that irrigate 1,351 acres of orchard, said Chuck Allen, Grant County PUD spokesman. They are upriver from Crescent Bar, he said.

A Wanapum Dam worker noticed part of the dam’s mile-long deck out of alignment on Feb. 24. On Feb. 27, a dive team discovered a 65-foot-long crack, two inches wide at its widest point, along the bottom of one of the dam’s piers, Allen said. The pier had rotated two inches downriver, he said.

The PUD began the drawdown and when it was completed the pier, under less water pressure, pivoted back upriver by one-and-three-fourths inches and the crack, still under water, mostly closed, Allen said.

Engineers are drilling into the 50-year-old dam and using ground-penetrating radar and echo-imaging technology to determine the extent of damage, how it can be repaired and if the reservoir can be raised any during restoration, Allen said.

Plans are being developed to modify fish ladders so spring Chinook salmon can return upriver in mid-April, he said. Wanapum reservoir shoreline and boat launches are closed and the PUD is assessing affects on recreation.

A woman sank up to her chest in what she thought was stable riverbed in the Crescent Bar area a week ago and had to be rescued, he said.



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