PORTLAND — Seven years after the start of planning, the height of a proposed Columbia River Crossing is still up in the air as planners face a permit deadline for the new Interstate 5 toll bridge between Portland and Vancouver.
Engineers are redesigning the bridge to increase the clearance for ship and barge traffic. Changing the height affects other aspects of construction such as highway grades, size of onramps, and even Pearson Airfield flight paths. In addition, construction costs increase with the height of the bridge.
Planners must settle on a height before the Jan. 30 deadline to file the permit application with the Coast Guard, The Oregonian reported.
In March, after $140 million had been spent, the Coast Guard said the proposed 95-foot clearance was too low and would block some ships or loads carried on barges.
The Coast Guard must approve the height of bridges on navigable waterways.
Planners have been analyzing possible bridge clearances, calculating effects and costs at each increment. They’re narrowing in on a decision of 115 or 116 feet, the newspaper said.
At those clearances, light-rail and I-5 grades would increase slightly. Bridge foundations might have to expand, but not enough to require a new environmental impact statement, planners said.
Still, the $3.5 billion price tag would jump $30 million, not including mitigation expenses to cover upriver businesses. The river now has more than 2,600 commercial users, and between nine and 11 might be affected at the 115-to-116-foot clearance, officials said. Managers are talking to the businesses.
At 116 feet, the dredging vessel Yaquina could pass below the bridge. But at 115 feet, the bridge could block the dredge used to maintain shipping channels.
Project managers were confident at a legislative hearing Tuesday.
“This is ... a massive project," said Pat Egan, chairman of the Oregon Transportation Commission. “We’re going to keep after it, and this is a project that’s going to move forward."