Orange traffic cones encircling a low spot in the center turn lane of the Kenai Spur Highway at Mile 11.8, before the Forest Drive stoplight, should be gone by late fall.
According to Carl High, the Department of Transportation Peninsula District Superintendent, a 48-inch drainage cross pipe under the highway is corroding and the bottom of the pipe is starting to show wear, causing the portion of the road to sink.
“We are just leaving it coned up for safety,” High said. “We have done some repairs inside the pipe and above the pipe since then, so we are just leaving it coned off incase there is some subsidence again,” he said.
High said DOT has looked at trying to retrofit the pipe by either lining it or using some other method of reinforcing it. He said crews cannot get the right gradient for fish passage there, so the plan is to replace it with a new pipe.
High said DOT has to install a new pipe that will accommodate fish passage.
“One of problems has been that it is catalogued as anadromous, meaning that it is a fish pipe, that fish migrate through it.”
This is not the first time issues with the pipe has plagued DOT. In 2011 beavers plugged up pipe and High said the animals had to be trapped.
“They plugged it up and it backed all the water in there, we had quite a time getting it opened back up,” he said.
High said the project that is in design actually entails replacing two pipes, the one at Mile 11.8 and another which is a 36 inch pipe at Mile 11.5, in front of Swanson Square strip mall. Both pipes will be replaced under this project.
“Right now our best guess is that (construction) will be in 2014. That’s if everything goes to plan, if we have any hiccups with environmental permitting or anything like that, it could delay it,” he said.
The project is assigned to an Anchorage design engineer.
“The project will involve replacing both pipes, and we are probably looking at boring the pipe right now,”
Boring is the process of pushing the pipe under the road to avoid digging the road up. High said boring is the preferred method as to not disrupt traffic. The cost for the 2014 project has yet to be determined.
“That will be determined once they define the methodology that they going to use, whether it is going to be bored or use some other technologies to put (the pipe) under the road. They will determine the methodology and then they will do an estimate based on that,” he said.
The other option would be to take the road up and deal with the replacement of the pipes, which DOT wants to avoid.
High said the cones will be removed from the site when DOT applies a more permanent patch on the highway’s surface before the snow flies. High said patching will probably occur in late September with an estimated cost of less than $2,000.
“Right now we are leaving (the cones) there so we can monitor it, keep traffic off of it, that way if there is subsidence, we don’t have someone drive on it,” High said. High said the Kenai police and city electricians help make sure the cones are standing several times each day.
High said DOT has other repairs going on across the peninsula, mostly in the Homer area.
Work includes surface maintenance projects, ditch cleaning, paint striping and chip seal, a newer process used in northern regions where existing roads are ground up, and used for new road.
High said DOT recently finished roadwork on the north end of Cohoe Loop and the Mackey Lake Road project will start soon.
“We will be working right until the snowballs hit us,” he said.
Reach Sara Hardan at firstname.lastname@example.org.