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Preliminary Estimates Of Potential Costs For Repairs At Wanupum Dam Pegged At $61 Million
Posted on Friday, April 25, 2014 (PST)

The Grant County Public Utility District’s Board of Commissioners was presented this week with a preliminary estimate of potential costs associated with repairs to the structural fracture discovered at Wanapum Dam’s spillway – approximately $61 million including power sale impacts, repairs to the structure and the remodeling of fish ladders and related expenditures.


Those costs include an estimated $15 million to assure passage for migrating salmon and other fish, protect cultural and other resources bared by a drawdown of the dam’s reservoir and to investigate causes and cures for a 65-foot-long fracture discovered in a supporting pier between two of the facility’s spillbays.


The cost estimates include $38 million for the repair of the fracture, and an $8 million negative impact on the PUD’s power sales resulting from forces changes in operations because of a drawdown of as much as 26 feet from normal reservoir elevations to reduce pressure on the damaged concrete structure.


Grant PUD spokesman Chuck Allen stressed that the cost estimates presented Tuesday to the Grant PUD Commission are “conservative.”


Work is still ongoing to evaluate the damage, and develop a plan for repairing the project, located in central Washington on the mid-Columbia River. The estimate is based on information presently available and may vary depending on results from the analysis into the cause of the fracture and the investigation of the fracture’s geometry, as well as how soon repairs can be completed.


The utility is evaluating how it will use a combination of reserve funds, debt financing and expense reductions to cover the cost of restoring the Wanapum Dam spillway. Staff continues to work with its insurers to explore potential insurance coverage as well.


Grant PUD plans to maintain the current 2 percent rate trajectory adopted by commissioners last December and will consider rate increases as a last resort. Maintaining a strong financial position to ensure long-term low rates for customers continues to be a priority.


Investigative drilling into the spillway has resumed. Grant PUD’s engineering team and the independent board of consultants assembled for the project determined that construction of a platform was no longer required to finish the necessary drilling, which will help determine the geometry of the fracture and will also aid in the repair process.


Drilling will now resume from a corridor under the dam’s spillway known as the grout gallery. Once the drilling and the root-cause analysis are finished, Grant PUD will begin making repairs to the spillway. The reservoir level will not be raised to its normal minimum of 562 feet above sea level until the repairs are complete.


Until the reservoir is raised, Grant PUD will continue to rely on modifications to the Wanapum Dam fish ladders for adult fish passage. As of April 21, 188 adult steelhead and 16 spring chinook salmon have been counted safely passing the left bank fish ladder.


Tagged adult chinook salmon and steelhead have also been observed traveling from Priest Rapids Dam, then navigating Wanapum Dam’s modified fish ladder, and eventually reaching Rock Island Dam in less than five days. Rock Island, owned by Chelan PUD, is about 36 river miles upstream of Wanapum.


Modifications to the dam’s right bank ladder are expected to be finished at the end of April. The utility is also working with the Washington Department of Fish and Wildlife to trap adult spring chinook salmon and steelhead at Priest Rapids Dam and truck them past Wanapum Dam until the fish ladder modifications are proven under working conditions.


The Wanapum reservoir shoreline is closed to the public and will stay closed until the reservoir is raised to minimum normal operating levels, likely beyond July 4. All Grant PUD and WDFW shoreline access points are closed, including boat launches and recreation areas. The closure is necessary to protect sensitive cultural areas and for public safety.


The utility has reopened the Wanapum Lower Boat Launch and day-use park near Wanapum Dam. The Wanapum Heritage Center remains closed, however.


During the low-reservoir condition, Grant PUD is accelerating scheduled work on Wanapum reservoir boat launches to reduce environmental impacts and expenses. Work began on the Kittitas County Boat Launch on April 21 and work is scheduled for the Frenchman Coulee Boat Launch.


Wanapum Dam continues to generate electricity at about 50 to 60 percent of its current capacity and is passing spring runoff flows in coordination with other dam operators on the river.

For additional information, visit:


According to a press release provided this week by Chelan PUD, fish counts at its Rock Island Dam so far are “normal” for this time of year.


Juvenile salmon and steelhead on their way to the ocean will have safe passage as in previous years through the use of dedicated spill for the duration of the outmigration, Chelan PUD says.


Through collaboration and cooperation from the Bonneville Power Administration, Bureau of Reclamation, Corps of Engineers, and other Mid-Columbia utilities, the Columbia River will be managed to ensure a consistent river flow of 45,000 cubic feet per second. The consistent river flow and river level is intended to provide for fish, irrigators, recreation and power operations.


BPA markets power generated at federal dams on the Columbia and Snake. The Bureau and Corps own and operate most of those dams. Much of the water storage needed to maintain those flows is provided by the Bureau’s Grand Coulee Dam, located about 140 river miles upstream from Rock Island,


“Because of the uncertainty around what response will be needed to address the situation at Wanapum Dam, we can't guarantee river levels,” the Chelan PUD press release says.


For background, see:


-- CBB, April 18, 2014, “Extended Fish Ladders, Trap/Haul: ESA-Listed Spring Chinook Moving Upstream Of Cracked Wanapum Dam”


-- CBB, April 11, 2014, “Wanapum Dam: Tribes Urge Feds To Be ‘Proactive’ In Requiring Monitoring, Evaluation Of Fish Passage”


-- CBB, April 4, 2014, “Fish Passage Fixes At Wanapum Dam To Be Completed April 15; Trap/Truck First Weeks Of Spring Run”


-- CBB, March 14, 2014, “Wanapum Dam Crack: With Spring Chinook On the Way Upstream Fish Passage High Priority”


-- CBB, March 7, 2014, “Crack In Wanapum Dam:Reservoir Drawn Down 26 Feet, Officials Assess Options, Fish Passage Strategies”


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