Culvert work progressing: Coal Creek fish passage project nears completion

Posted: Friday, June 25, 2010

Construction crews are preparing to re-route water into the newly installed Coal Creek culvert next Monday or Tuesday, according to the Department of Transportation.

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Photo By M. Scott Moon
Photo By M. Scott Moon
Construction workers labor on the bank of Coal Creek outside a new culvert that they have finished installing at Mile 2 of Kalifornsky Beach Road in Kasilof. Work on the roadbed above the culvert should be done near the end of July, according to project engineer Gary Walklin.

DOT Project Engineer Gary Walklin said that crews will start raising the section of Kalifornsky Beach Road to normal grade by the end of July. Walklin said that crews have backfilled the majority of the culvert and are currently nailing in logheaders to hold down vegetation at the new culvert's inlet and outlet. The engineer estimated that workers will pave the section of the road, currently limited by occasional lane closures, next June.

Currently the stream flows through a 48-inch temporary pipe. Walklin said that the crew planned to use the previous culvert during the installation, but water flowed through holes in the bottom, saturating the work site.

Rober Ruffner, executive director of the Kenai Watershed Forum, said that the old culvert's height, steep angle and rapidly flowing water limited salmon's ability to travel up the creek.

"The outlet of culvert had a waterfall of a foot and a half," he said. "Juveniles can only jump four to six inches."

He said that the 9-foot wide culvert funneled the stream and increased the flow speed. Walklin said that 7,000 gallons of water flowed out old culvert each minute, the equivalent of over 4,000 toilet flushings. Alaska Department of Fish and Game Fish Passage Improvement Coordinator Gillian O'Doherty said that the previous culvert had a 1.4-percent grade with a bent section that reached 2.6 percent.

The speed, combined with the sizable incline, made upstream migration difficult for salmon, according to Ruffner.

"It's like holding your finger on the end of a garden hose," he said.

He said that the new, 18-foot wide culvert, with an approximately 1.7-percent grade, will allow water to flow downward at a slower pace. He said that the new culvert cost $376,000 out of the project's total $2 million budget.

The culvert will also have J-hooks, installed rockbeds, in its bottom. O'Doherty said that the J-hooks keep the water swishing back and forth, which keeps the stream going down the central channel.

Fish and Game Biologist Ginny Lichtfield said that her department transported eight steelhead salmon and about 275 juveniles upstream when it de-watered the previous culvert's inlet pool.

Tony Cella can be reached at

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