Grant PUD’s Board of Commissioners were presented with a preliminary estimate of potential costs associated with repairs to the fracture at Wanapum Dam’s spillway.
The estimate of $61 million, given during the commission meeting today, (April 22) includes all costs associated with: fracture investigation, spillway repairs, fish passage modifications, shoreline protection and power supply costs. 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 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 (See spillway X-sect .pdf attached). 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.
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 4th. 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: http://www.grantpud.org/your-pud/media-room/wanapum-dam-spillway-response.