Published Jan. 30, 2004 by Dylan Darling Drip, drip, drip. Water taps incessantly on the hard hats of workers in the A Canal tunnel. In the dank shaft that runs from Conger Field under a hill to Oregon Avenue, construction crews are prepping the century-old floor for a new layer of concrete. The only water in the tunnel during the winter months is found in puddles on the floor and dripping from cracks in the walls and ceiling. But during the irrigation season, from April 1 to Oct. 15, water flows through the tunnel at a velocity of 8 feet per second.

The continual rush of water has worn dips and divots in the floor all along the 3,200-foot tunnel. To keep water flowing smoothly to the Klamath Reclamation Project, the Klamath Irrigation District is paying contractors nearly $1 million to fill the holes and lay a new floor.

"This is our water supply here. If this baby doesn't flow, we are done," said Ross Flemming, a district director.

Much of the water Klamath project irrigators spread on about 180,000 acres passes through the tunnel, which is just below the project's starting blocks, the A Canal headgates. If the tunnel should have a problem during the irrigation season, much of the project would have to be shut down until repairs were done.

To avoid that scenario, Dave Solem, KID manager, said the district put a priority on the resurfacing of the floor. The project is expected to be done by March 1.

The straight-shot tunnel was first used in 1906, replacing a canal that ran parallel to the Link River and then took a left turn, cutting through town before feeding the project.

Though it is long and dark, there is light at the end of the tunnel, with one end visible from the other during the day. With 8-inch-thick concrete walls and a 6-inch-thick concrete floor, the tunnel was built to last.

Solem said the walls and ceiling are in "real good shape," but district officials keep an eye on them and patch any major cracks.

In getting the tunnel ready for work, workers first had to clean it out. Solem said there was algae and dirt built up in the tunnel, along with other debris - including a dead deer in a trash sack and a bicycle.

Now the workers are filling in the holes, pits and cracks. These defects in the floor vary in size, from a couple of inches to several feet.

Next, the workers will put in a new concrete floor that will be at least 5 inches thick, have steel reinforcement, and a coating of epoxy binding it to the old floor.

Using motorized wheelbarrows, workers will haul in the concrete half a cubic yard at a time. In all, 16 workers contracted by Donald W. Thompson Inc. of North Bend will put down 1,100 cubic yards of concrete.

The construction workers aren't afraid of the dark. And they are used to working in tight spots.

Don Thompson, company president, said his firm often works in Oregon highway tunnels and under bridges.

Time is the hardest part of this concrete job.

He said the crew has a short calendar before it wants to get the concrete down and cured in time to be ready for irrigation season.

"Everything is time-critical," Thompson said.

Though the weather is a bit cold, it's good enough for concrete pouring, he said. But to make sure nature doesn't foul up the mix of concrete, workers make it with warm water and then keep blankets over it.

After putting down 900 feet of concrete from the Conger Side, the workers will then start bringing it in from the Oregon Avenue side and work in the other direction.

The tunnel's new floor will be just the start of concrete work to spruce up the Klamath project over the next several years, Solem said.

"The project is full of 100-year-old concrete structures," he said.

Next on the priority list will be fixing up the C Canal flume. Other structures on the list include the Lost River Diversion Dam, Gerber Dam and pump houses around the project.

Reporter Dylan Darling covers natural resources. He can be reached at 885-4471, (800) 275-0982, or by e-mail at ddarling@heraldandnews.com.

Tunnel facts

Dimensions: 13 feet wide, 11 feet tall on the sides, 14 feet tall at the top of the arch.

Water flow: Volume: about 1,100 cubic feet a second. Velocity: 8 feet a second.

Water depth: About 10 feet during irrigation season.

Cost of Project: About $993,000.

Expected completion: March 1.


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