Project tackles Trapper Point flooding

Most every year, during periods of high rainfall and snowmelt, a portion of Camp Polk Road north of Sisters and just beyond the Sisters Airport has been prone to flooding.

"That's actually called Trout Creek," said Tom Shamberger, operations manager for the Deschutes County Road Department. "Every year since I've been here it's flooded; and, ever since the Pole Creek area burned, the forest no longer has the capacity to absorb all that water."

The result has been recurring standing water across Camp Polk Road at its junction with Trapper Point Road.

Lead workman at the site, Aaron Garner, said, "Every spring when the snow melts, everything starts flowing. It's a trouble spot for only about two weeks out of the year; but, when it is, it's a real pain."

Southwest of Sisters, where Trout Creek has its origins, topographical maps show the creek as seasonal until it "disappears" in the vicinity of the McKenzie Highway. In reality, it sometimes flows beyond there, north of Sisters High School, under Highway 20, and all the way to Indian Ford Creek.

"When it hits Camp Polk Road," said Shamberger, "it just couldn't handle it; and it gets pretty dangerous."

The standing water posed serious hazards, including the possibility of car tires hydroplaning on the water. During each flood event, the highway department deployed temporary warning signs and tried to find ways to alleviate the backed-up water.

In the end, though, road officials decided to seek a more permanent solution.

"You can't put a price on public safety," said Shamberger. "We take that pretty seriously. As far as we were concerned, it was a road hazard."

He estimated the final project cost of the fix to be about $45,000.

"A lot of that was concrete and pipe," he said.

Supervisor at the site, Chuck Schutte, said that the new improvement to the creek crossing will double the previous water-volume capacity. The crossing already had one 22-inch-by-32-inch "squash pipe" running under the road. The project, which slowed and sometimes stopped traffic over a period of several weeks, added a second squash pipe of equal size under the road.

The oblong cross section of a squash pipe carries considerably more water than a round culvert of the same vertical height, yet it can be buried at the same depth.

After installation of the second culvert, it was determined that it would be necessary to pipe the water flow along the highway to prevent erosion and protect fiber-optic cables in the area.

"We were going to leave it open," said Shamberger, "but then we had to order the pipe, and that's why the project took more time to complete. We also put in concrete headwalls to stabilize the road. You can't just throw a culvert in there."

Water will flow first through the new culvert, and the Trapper Point culvert will become a secondary route to handle the overflow, which is directed farther along toward the original squash pipe under Camp Polk Road.

The new fix is expected to eliminate the hazardous flooding that has plagued the area in the past.

"Unless it's a bigger flood than we anticipate, we should be able to keep the water off the road now," Shamberger said.