OLYMPIC NATIONAL PARK — High water flows caused by current storms have postponed blasting at what’s left of Glines Canyon Dam on the Elwha River, Olympic National Park officials said Thursday.

Park contractor Barnard Construction Co. Inc. needs the river to recede before continuing the removal of the final 30 feet of the concrete dam, park spokeswoman Barb Maynes said.

The bottom of the once-210-foot edifice — and the pile of rubble that surrounds it — was inundated by water Thursday.

“They need to be able to get down there to assess the dam and design the next blast,” Maynes said of Barnard Construction crews.

The Elwha River was flowing at 10,500 cubic feet per second at noon Thursday — nearly 10 times its average of 1,100 cubic feet per second for a March 6, according to the U.S. Geological Survey.

The Montana-based dam contractor estimated that flows need to return to normal for it to begin preparing for the next blast, Maynes said.

The blasting schedule has been “very fluid” this winter because of heavy rains and high winds, Maynes said.

“They don’t really lock in on a date for a blast until after they have the drilling [in concrete] completed,” she added.

Several blasts are planned before the next fish “window” begins May 1. Dam removal stops during the predetermined fish spawning periods.

A large clamshell bucket attached to a giant crane at the top of the canyon will be used to remove the concrete rubble that accumulated as the 87-year-old structure was taken down in notches.

The broken concrete will be trucked to a gravel pit and crushed for use as road material, Maynes said.

Dam removal began in September 2011 as the centerpiece of the National Park Service’s $325 million restoration of the Elwha River.

The century-old Elwha Dam near state Highway 112 west of Port Angeles was fully removed by March 2012.

Maynes said crews still hope to have the rest of Glines Canyon Dam gone before the May 1 idling for salmon.

“They’re still hoping for that, but with every day that the river is high and they can’t work, it’s just another day the schedule is tightened,” Maynes said.

The contract calls for dam removal to be finished by Sept. 30.

The Elwha Ranger Station about 1.5 miles downstream from the dam received 10.2 inches of rain in February — 180 percent of normal for the month.

The cool, wet weather has provided good conditions for plants that have been transported to the former reservoir beds to take root, Maynes said.

Crews have planted more than 90,000 of the 107,000 plants that were scheduled for transplanting this season.

Later this month, park revegetation crews will shift their focus to field-monitoring and propagating next season’s transplants at the park greenhouse, Maynes said.

With dam removal winding down, park fish biologists said they are gearing up for an active monitoring season upstream of Glines Canyon.

Field observers are eager to document the first sighting of an adult salmon to return to the upper Elwha in more than a century, Maynes said.

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Reporter Rob Ollikainen can be reached at 360-452-2345, ext. 5072, or at rollikainen@peninsuladailynews.com.