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Colorado Dam Project: Creating a Safe Passageway

Thu December 11, 2014 - West Edition
Lori Tobias


The existing bridge is an old road bridge that had been repurposed for pedestrian and cyclist use. It’s low to the water and presents a safety issue for paddlers. The new bridge will be raised and placed in a different location.
The existing bridge is an old road bridge that had been repurposed for pedestrian and cyclist use. It’s low to the water and presents a safety issue for paddlers. The new bridge will be raised and placed in a different location.
The existing bridge is an old road bridge that had been repurposed for pedestrian and cyclist use. It’s low to the water and presents a safety issue for paddlers. The new bridge will be raised and placed in a different location. Work is underway on a $9.7 million project that will include restoration of a dam, construction of a pedestrian/cyclist bridge and for the first time in Oregon, the manmade sculpting of a white water course. Hamilton Construction Company began work as the CM/GC on the Bend Park and Recreation Colorado Dam Safe Passage Project in October, working with OTAK Engineering on the design for the past 18 months. There are four other dams on the Deschutes, but the Colorado Dam is the most dangerous and so it became the top priority. The project includes dividing the river into three channels. On the right will be the habitat channel at 80-ft. (24.4 m) wide. The center channel will be the white water channel, and also 80-ft. wide, and on the left, at 20-ft. (6 m) wide, will be the saf

Work is underway on a $9.7 million project that will include restoration of a dam, construction of a pedestrian/cyclist bridge and for the first time in Oregon, the manmade sculpting of a white water course.

Hamilton Construction Company began work as the CM/GC on the Bend Park and Recreation Colorado Dam Safe Passage Project in October, working with OTAK Engineering on the design for the past 18 months.

The project has been under discussion for about a decade, said Chelsea Schneider, project manager of the Bend Park and Recreation District. That was about the time the Deschutes River was opened to boaters.

“Previously this was mill property,” Schneider said. “No was getting into the area. Then the mill closed down, and people started to float the river. They were to float to the Colorado Dam and take out. Unfortunately, some people have failed to take out. There were rescue events every summer. Just downstream of the spillway, there is a complete jumble of rip rap. That’s what people can get caught in. They get trapped, even trapped upside down. There was one fatality on the site.”

There are four other dams on the Deschutes, but the Colorado Dam is the most dangerous and so it became the top priority, Schneider said.

While the dam is not being removed, workers will “punch some holes in it,” said Evan Stuart, Hamilton Project Manager.

“The dam remains functional and will preserve water levels for multiple users,” he said. “It eliminates a navigation and fish passage obstruction while maintaining water rights of upstream users.”

The project includes dividing the river into three channels. On the right will be the habitat channel at 80-ft. (24.4 m) wide. The center channel will be the white water channel, and also 80-ft. wide, and on the left, at 20-ft. (6 m) wide, will be the safe passage channel and also for fish passage.

“Also in the safe passage channel, we will use inflatable panels — raised and lowered by pneumatics — that will control the flow,” Schnieder said. “The panels — or bladders — are inflated with air and you use them to sculpt the way the water flows downstream. They will help us change how the water functions. It can be novice level one day, and then changed the next day to be a black diamond level.”

The white water features are also adjustable, said Stuart. “In the case of an emergency, water can be mostly diverted from one channel to another by means of remotely adjustable gates.” In addition to the roughly 20 large bladders, there will be three fixed wave features. It’s a first in Oregon, though Stuart noted that River Restoration, the company building the white water course, has built a number of them in Colorado.

“But it’s quite a different exercise here in Oregon where the environmental regulations are more stringent,” he said.

The river work will begin with the white water and safe passage channel. Water from those channels will be redirected to what will eventually become the habitat channel. Once the first two channels are complete, the work on the habitat channel will begin.

The habitat channel will also include multiple water cascades and shallow bedding areas and back water areas for fish and other aquatic animals.

“It is actually an expansion of habitat,” Stuart said. “This will make the passage possible for fish and other aquatic animals — it includes the creation of some quiet pools that are at the bases of small waterfalls that will improve the aeration of the water.”

Crews also will replace the pedestrian/bike bridge. The existing bridge is an old road bridge that had been repurposed for pedestrian and cyclist use. It’s low to the water and presents a safety issue for paddlers. The new bridge will be raised and placed in a different location. It will feature a small bump out to allow people to hang out and watch the white water activity. There also will be booms — or floating fences — directing white water paddlers one way and floaters the other.

The project is scheduled to be completed in June 2015.

The most challenging part of the construction will be controlling the water flow, Stuart said. “The time frame for in-water work is designed to coincide with the Deschutes lowest flow period. The water level is somewhat controlled by how much water is released from Wickiup Reservoir and is impacted in part by the needs of irrigation users. In addition to use of water for crops there is a period of time in the fall when stock ponds are being filled so more water is put down the Deschutes.”

River work can be a challenge, said Linda Scronce-Johnson, Hamilton spokeswoman. “But Hamilton is a heavy civil contractor specializing in bridge work, so we’re very familiar with all the river work. It is unique. It is a niche, but it is our niche. It’s a fun project. We’re all excited to be involved.”