The Chenoweth Creek Bridge on U.S. Highway 30 in The Dalles needs to be replaced, and the Oregon Department of Transportation (ODOT) is planning to close the roadway entirely to speed the work.
Brad DeHart, ODOT project leader in The Dalles, acknowledged the impacts of closing the highway, but pointed out there is never a good time to do a major fix on a busy road. However, taking all the factors into consideration, ODOT officials are convinced a full closure is the most efficient way to procced.
“It’ll be a three-week closure,” DeHart said. “The bridge will be closed from mid-July to early August. We’re trying to figure out a way to accommodate emergency vehicles.”
The existing 66-foot long bridge was built in 1920 and is deteriorating visibly. According to ODOT engineers, there is cracking throughout the concrete and scouring of the stream channel below the bridge to the point that it could cause the structure to become unstable.
“Significant concrete patching of the girders and crossbeams has occurred over the years,” reads an excerpt of an ODOT report describing the condition of the nearly 100-year-old bridge.
The bridge is at milepost 72.1 on Highway 30, just off the Columbia Gorge Discovery Center interchange on Interstate 84. That part of the highway, also referred to as the Historic Columbia River Highway, is designated as a scenic byway.
The project, which has a $3.8 million price tag, will complicate access to the Discovery Center, Pinewood Mobile Manor and The Dalles Country Club, among other sites, prompting The Dalles City Councilor Dan Spatz to ask if there might be a better time to do the project.
“Does it have to be at the height of the tourist season? It can’t be spring or fall?” Spatz asked DeHart during last week’s council meeting.
DeHart responded that if the project is pushed back, the bridge could be closed when school starts, and Highway 30 is a key school bus route. And in most other times of the year, working in the creek below the bridge is not allowed due to environmental considerations.
“There is a six-week window we can work in,” DeHart said. “We plan to allow our contractor to close the Historic Columbia River Highway at Chenoweth Creek Bridge for a maximum of three weeks within the six-week window of July 15 to Aug. 27, 2017.”
“They explained to us that they had two options; a total closure, or a partial closure with flaggers which would extend the construction phase and result in long waits for traffic,” said Susan Buce, marketing manager with the Columbia Gorge Discovery Center & Museum. “They opted for the swiftest resolution to the construction, to just get in and get it done.”
The new bridge will be a single span structure. It will 38 be feet wide, which will allow for wider travel lanes as well as 8-foot shoulders for safer passage by pedestrians and bicyclists. The bridge will also provide a wider and more natural stream flow to aid fish passage.
DeHart explained that the summertime construction window to replace the bridge was established based upon several constraints.
“The earliest start date for construction activities that could impact the stream channel, such as bridge demolition, is July 15,” DeHart said. “These are called ‘in-water work windows,’ and are established by the Oregon Department of Fish & Wildlife. The end of the ODFW in-water work window for Chenoweth Creek is 11 weeks later, on Sept. 30.”
The ODFW guidelines for in-water work are designed to minimize “potential impacts to important fish, wildlife and habitat resources.” The restricted time periods were established by fish biologists to avoid the most vulnerable life stages of fish.
In addition to the in-water work windows, ODOT engineers needed to consider a variety of other factors.
For instance, the school district buses Head Start students on the route beginning in mid-June and running for three weeks, through the first week of July. And the 2017 school year begins on Aug. 28.
“The school district representative explained that closures of the highway on or after Aug. 28 would result in significant impacts to the district’s busing schedule for that area,” DeHart said.
State officials have already been in contact with businesses in the affected area, and hope to mitigate the impacts. For example, the Discovery Center is planning to direct tourists and tour buses from the touring river boats to take a different exit to reach the facility during bridge reconstruction. That might work for The Dalles Country Club as well.
“We’ve had conversations with ODOT about the closure, and they have assured us they will provide adequate signage to direct people to the Rowena exit,” Buce said. “We have notified the tour boat companies about the anticipated closure. It remains to be seen what their decisions are.”
DeHart said shutting down the site to allow unimpeded work is a much more effective way to tackle the project. He pointed out that if the full closure does not happen, there could be lane closures and other delays at the bridge that would last for a much longer time.
“This option quickly came to be the best, and we hope this will be the least amount of impact,” DeHart explained. “Otherwise, we could be out there working for two years.”
ODOT plans an open house on Wednesday, Oct. 26, to discuss the bridge replacement project with local residents. The event, at the Discovery Center, will run from 5 p.m. to 7 p.m. DeHart said there will not be a formal presentation, and citizens can drop in at any time to comment or ask questions.