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Cleaning Up Large Debris In Preparation For Condit Dam Breaching; Reservoir To Empty In 6 Hours
Posted on Friday, September 09, 2011 (PST)

The lower portion of the White Salmon River in southwast Washington will be closed to fishing for 12 hours Sept. 17 to allow an interagency clean-up team to remove derelict boats, camping gear and other debris before Condit Dam is breached in late October.

 

The fishing closure, announced by the Washington Department of Fish and Wildlife, will be in effect from 6 a.m. to 6 p.m. on Saturday, Sept. 17. The affected area extends 3.3 miles from the Highway 14 Bridge near the river’s confluence with the Columbia River upstream to the powerhouse at the dam.

 

The river mouth downstream of the Highway 14 Bridge will remain open.

 

Condit Dam, a 97-year-old structure owned by PacifiCorp, is scheduled to be breached Oct. 26, emptying the 92-acre reservoir behind it in six hours.

 

The dam breaching is expected to open up 14 miles of habitat for chinook salmon and 33 miles of habitat for steelhead. The free-flowing river also is expected to protect critical bull trout habitat and benefit bears and other wildlife that feed on salmon.

 

Condit has long blocked salmon's upstream passage. It was completed in 1913, equipped with a fish ladder. But the ladder washed out in 1918 flooding and was never replaced.

 

John Weinheimer, a WDFW fish biologist, said the clean-up effort is designed to prevent abandoned boats and debris from being swept into the Columbia River when the 125-foot dam is breached to allow upstream passage for steelhead, salmon and bull trout.

 

"Large debris could impair fish habitat in the lower White Salmon River and present a challenge to navigation in the Columbia," Weinheimer said. "We’re pleased to be a partner in this clean-up effort."

 

Other partners include the Underwood Conservation District, Mid-Columbia Fisheries Enhancement Group, Friends of the White Salmon River, Yakama Nation Fisheries, SOLV, the U.S. Fish and Wildlife Service, Klickitat County Solid Waste, USGS Columbia River Research Laboratory, Allied Waste, the Washington Department of Transportation, Klickitat County Sheriff’s Dept. and the Skamania County Sheriff’s Department dive team.

 

Volunteers interested in assisting with the cleanup can contact the Underwood Conservation District at 509-493-1936, or email ucd@gorge.net .

 

Adrianne Zuckerman, Watershed Resource Technician at the Conservation District, said approximately 15 boats -- some submerged or partially submerged -- have been identified for removal. All have been marked with a tag notifying owners of their options.

 

In 2009, reconnaissance visits revealed approximately 100 boats and waste sites in the lower river. The 15 tagged boats are completely sunken and numerous others are partially sunken or appear to be abandoned - evidenced by holes or rusted-out portions of the hulls.

 

Farther upstream, a handful of sites have smaller concentrations of metal debris, fishing and camping gear, and other waste. Volunteers will be needed in boats and on the ground to help retrieve and remove trash and derelict vessels.

 

"Dive teams are helping remove the derelict boats from underwater," she said. "But we also need volunteers to help move boats out of the water and onto shore and clean up debris at popular fishing areas."

 

People with a boat stored at the mouth of the White Salmon River will soon notice a tag attached to it.

 

That tag will spell out two options:

 

-- Remove your boat before Oct. 26, the scheduled breach date for Condit Dam, to prevent it from being buried in sediment, damaged or swept away by high water.

-- Recognize that your boat is non-functional and understand that it will be removed on Sept. 17.

 

Only sunken, obviously abandoned or non-functional boats will be removed.

 

WDFW is currently working with PacifiCorp, the U.S. Fish and Wildlife Service and the Yakama Tribe to collect returning salmon in large seine nets and truck them up above the dam, where they will be released into the upper river to spawn.

 

Constructed between 1911 and 1913 by Northwestern Electric Company, the facility includes a concrete gravity dam, a powerhouse, a wood-stave pipe connecting the dam, a surge tank and two penstocks leading to the powerhouse, and a 1.7-mile-long project impoundment, and Northwestern Lake.

 

The White Salmon River originates on the southwestern slope of Mount Adams. The river flows south, draining a basin of approximately 386 square miles before entering Bonneville Dam’ pool on the Columbia. Major tributaries upstream of Northwestern Lake include Rattlesnake and Trout Lake creeks. Other tributaries that enter Northwestern Lake include Buck, Mill, and Little Buck creeks. No significant tributaries enter the White Salmon River downstream of Condit dam.

 

Northwestern Lake was permanently closed to boaters and others beginning starting Aug. 15. The restricted access has been necessary to ensure safety as PacifiCorp contractors carry out the on-site work to remove Condit Dam.

 

Tunneling work at the base of the dam began at that point on the water release channel that will drain the lake. The reservoir was in mid-August drawn down a total of 10 feet as a safety measure during the tunneling work and to accommodate the dredging of sediment that has built up above the hydro project.

 

The method for dam removal involves clearing sediment and debris immediately upstream from the tunnel and then drilling and blasting a 13-foot by 18-foot drain tunnel in the base of the dam to within a few feet of the reservoir. So far plastic explosives have been used in three “blasts,” each taking a 6-8-foot chunk out of the 90-foot-thick dam base, according to PacfiCorp’s Tom Gauntt.

 

Following the final tunnel blast on Oct. 26, the drain tunnel will discharge at a rate of about 10,000 cubic feet-per-second – approximately 25 percent of the estimated peak discharge during the February 1996 flood event on the White Salmon River.

 

The rapid draining of the reservoir is expected to mobilize much of the estimated 2.4-million cubic yards of sediment that has accumulated behind the dam since its construction. Previous modeling has indicated that between 1.6 million to 2.2-million cubic yards of sediment will be discharged into the White Salmon River immediately following dam removal, according to a PacifiCorp project overview.

 

Once the reservoir is drained, activities will focus on addressing the sediment and slope stability within the former reservoir area. In the spring of 2012, the dam will be excavated and removed along with the flowline, surge tank, and penstocks. Concrete from the dam will be buried onsite; other materials will be salvaged or transported to the Klickitat County waste facility.

 

The powerhouse will be left intact. The upstream cofferdam in the White Salmon River present from original dam construction will be removed from the river as soon as practicable after the breach. PacifiCorp Energy expects to complete the dam removal process within one year, start to finish. Subsequently, restoration of the former reservoir areas may take an additional year or more.

 

The dam’s removal will fulfill a multi-party lawsuit settlement agreement signed in 1999. Dam removal was determined to be less costly to PacifiCorp customers than providing the fish passage that would be required for operation as part of the federal dam relicensing process. The cost of decommissioning Condit is currently estimated at about $32 million, including funds already spent during the planning process, according to PacifiCorp.

 

Settlement parties include: American Rivers, American Whitewater Association, Columbia Gorge Audubon Society, Columbia Gorge Coalition, Columbia River United, Federation of Fly Fishers, Friends of the Columbia Gorge, Friends of the Earth, Friends of the White Salmon, The Mountaineers, Rivers Council of Washington, The Sierra Club, Trout Unlimited, Washington Trout, Washington Wilderness Coalition, the Columbia River Inter-Tribal Fish Commission , the Yakama Nation, the U.S. Forest Service, the U.S. Department of the Interior, the National Marine Fisheries Service, the Washington Department of Ecology, the Washington Department of Fish and Wildlife and PacifiCorp.

 

Go to www.pacificorp.com/condit

for updates.

Regular updates can also be found at:

http://whitesalmontimelapse.wordpress.com/

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The Columbia Basin Bulletin, Bend, Oregon. For information or comments call 541-312-8860.
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