EPHRATA — The cost to analyze and fix the cracked spillway at Wanapum Dam is estimated at $61 million, Grant County Public Utility District (PUD) financial officials told commissioners on Tuesday.

“We don’t have the final repair plans in place, so this is preliminary, but it provides a sense of the order of magnitude we’re dealing with,” PUD spokesman Tom Stredwick said.

Kevin Nordt, the utility’s chief financial officer, told commissioners that his estimate, a figure that could change as the utility continues trying to establish the cause of the fracture, includes all incurred and anticipated costs associated with a 65-foot-long crack — the fracture investigation, spillway repairs, fish-passage modifications and shoreline protection. It also includes some $8 million in lost power generation at the dam and the cost of buying power to replace it — often at a higher price — on the regional energy market.

Utility officials are evaluating how to use a combination of reserves, new debt and possible cost cutting to pay for the repairs, Nordt told commissioners.

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Rate increases of 2 percent per year, starting this year, already had been approved by commissioners, Stredwick said. Increases on top of that 2 percent would happen only as a last resort, he said.

PUD officials don’t expect to announce what caused the fracture until tests are finished in early June.

Core samples of the spillway showed that the concrete used appears to be sound, he said. The 65-foot-long crack spans the No. 4 spillway “monolith” or base section.

Crews have moved drilling operations from outside the spillway, where work was slowed by high winds, to a tall, narrow “hallway,” called a “grout gallery,” inside the spillway base. The gallery runs the entire length of the spillway, Stredwick said.

Horizontal drilling will continue to measure the size and shape of the crack, he said. Other holes will be drilled straight down through the base of the spillway and into the bedrock to map the type of rock and its suitability for holding the high-strength steel cables and anchors that have been proposed as a possible fix. Holes also will be drilled straight up to the spillway’s deck, he said.

Days after the crack was discovered Feb. 27, the PUD drew the reservoir down 26 feet behind Wanapum to take pressure off the damaged spillway. The lowered reservoir also forced the Chelan County PUD to lower its Rock Island Dam reservoir, 36 miles upriver, by a few feet to avoid damage to that dam’s generators.

The Columbia River is expected to remain at its low level through at least July 4.

Thousands of spring chinook are already headed up the Columbia, and about 1,200 to 1,500 spring chinook per day will soon be passing the Wanapum Dam. Those numbers will climb to a peak of about 25,000 fish per day during the summer run.

The crack in the dam and reduction of water levels prompted crews to modify fish ladders. Wildlife officials also were catching and transporting some steelhead and salmon around the dam.

The fish ladders at the Rock Island Dam, upstream from Wanapum, also had to be extended 30 feet because of the lowered river level.

Until they see that the migrant fish are adjusting well to the ladder changes, public-utility-district officials planned to trap as many as 1,500 fish per day as they arrive at Priest Rapids Dam, downriver, and haul them by truck to release points above Wanapum or, possibly, above Rock Island Dam.

Information from The Associated Press was included in this report.