Friday, March 3, 2017

Getting to the root of the problem

by Ally Barrera

Our maintenance crews see a lot of unusual things while they're out on the job. But this might be one of the strangest.
WSDOT workers found this root lodged in a pipe near Auburn's Centennial Viewpoint Park by SR 181.

While clearing out a drain near Auburn's Centennial Viewpoint Park in February, one of our maintenance crews noticed a lot more water than usual rolling down the hill towards West Valley Highway. That water should have been running through one of our underground pipes.

After some investigating the workers found exactly what was causing the problem: a massive, gnarly-looking root lodged into an underground pipe, about 50 feet up the steep hill to the park.

"We pointed a flashlight in there, and you could see [the root]," maintenance superintendent Mike Golden said.

But that wasn't all. About 75 feet farther up the pipe, another massive root was clogging things up as well. How could they tell? Well, with water bursting out of the pipe because of built-up pressure from the obstruction, it was pretty obvious.
The crew recognized it was only a matter of time before this turned into a much bigger problem. The combination of heavy recent rainfall and a very steep area presented a danger of the hillside washing out and falling onto the highway.
A branch had already punctured
the corrugated aluminum pipe.
But the geography of the area presented another challenge. A steep hill covered with trees is not conducive to bringing in large machinery like excavators. So our crew went the old-fashioned route: Their own two hands.

After working most of the day to dig out the pipe by hand, it wasn't just the twisted root that was unusual. The pipe itself presented its own surprise.

Most pipes in our state these days are made of durable steel or concrete. But this pipe was likely installed at least 30 years ago, when corrugated aluminum was popular because they were light-weight and less susceptible to rust. That's the type of pipe our crew encountered, and it helped answer the mystery of what was happening.

"They're not as strong as steel or concrete," Golden said of the older pipes. "During a storm, a tree branch can fall and puncture a pipe like that. Or a root can find an opening in a joint and get in."

Once the crews knew what they were working with, the time came to get the root out. They cut the top of the pipe to make a doorway then reached in with a chisel and cut the root out. Once they removed the root, they sealed the pipe back up.

The twisted plait of thick wooden strands fit snugly in the 12" diameter pipe, and stretched nearly three feet long. How did it manage to grow that big?
The unearthed root next to one of our workers.

"The roots feed off the water running through the pipes and continue to grow," Golden said. "Even during the dry summer months, there's always water through there."

As unusual as this sight was for Golden, he said it's not the biggest root he's seen in his almost 40 years at WSDOT.

"A couple years ago, right by I-405 and State Route 181, there was a cotton wood tree growing near a 24" culvert. One root got inside, and grew about 50 feet long," he said.
How to spot a blocked pipe
Blocked pipes are serious business. Left unnoticed, they can lead to landslides, or worse. That's why we need your help to spot plugged pipes before they cause big problems.

So how do you spot a blocked pipe? Look for brush growing out of the ends of the pipes. That's a good indication that a root or branch is lodged in there, and continued to grow.

If you see something like that, contact your local maintenance office by phone, or send us your concern.