CANNON BEACH A proposed pedestrian bridge over Ecola Creek could either be a way for people to quickly evacuate to higher ground as a tsunami approaches or it could be a fatal funnel leading to a crossing over the jaws of death.
The Cannon Beach City Council heard both of those scenarios during a special meeting Tuesday night when emotions rose to the surface as the bridge came up once again for discussion.
This time, the question was whether the council should spend $5,000 more to study whether a wooden pedestrian bridge could be built that would withstand a magnitude 9 Cascadia earthquake and provide an evacuation route, or whether it could collapse and trap possibly hundreds of people in an oncoming tsunami.
After a lengthy discussion, the council voted 3 to 2 to approve the study, with the caveat that a bridge may not be built. Councilors Wendy Higgins and Melissa Cadwallader voted against the motion.
OBEC Consulting Engineers of Eugene will be asked to do the study. The company reviewed options for a pedestrian bridge last year.
Although it still has 20 years of useful service, the existing bridge isnt expected to withstand either an earthquake or a tsunami, and the north side of town would be cut off. Because it would cost several millions of dollars to replace the two-lane concrete bridge, a 10-foot wide wooden pedestrian bridge that would stand up to an earthquake but collapse in a tsunami has been proposed to evacuate people quickly.
But a pedestrian bridge could be a fatal funnel for people who are going to the bridge that is crossing across the jaws of death, said Bill Vanderberg, a consultant hired by the city to advise on emergency preparations.
I just dont think its a good scenario, Vanderberg said.
The bridges narrow width wouldnt allow people to cross quickly, he added.
All it takes is one person to fall down and one or two people to trip, to create a back-up, he said.
But retired engineer Les Wierson, who has spearheaded the effort to build the pedestrian bridge, said the study would tell the city if the bridge would be worthwhile.
Is 700 lives worth $5,000? he asked the council.
People are going to move to that bridge whether we have a replacement or not, said Wierson. But if we have a bridge, people will be safer than those in any school in Seaside.
The request for the study came from the citys Emergency Preparations Committee, which is backing a proposal that the bridge could be built for about $600,000 and could save as many as 700 lives, including students at Cannon Beach Elementary School.
In its 2011 report, OBEC reviewed several bridge options for the creek on the north side of Cannon Beach, which would quickly lead to higher ground and away from a tsunami. Among those options was a fixed timber bridge with a 6-foot-wide deck and steel pile foundations. The estimated cost was $1.05 million.
But Wierson, a member of the emergency committee, has suggested that construction costs could be reduced if the bridge wasnt as long as previously proposed and if it was built adjacent to the existing bridge.
Much of the original estimate, Wierson said, included the cost of building a temporary bridge as a launching point for constructing the permanent pedestrian bridge about 30 feet from the existing bridge. However, Wierson is proposing that the existing bridge be used as the preparation area for the new bridge, which would be constructed adjacent to the existing bridge.
He also proposed that the new bridge be 10 feet wide, which he estimated would enable 144 people to cross it per minute.
Another study, also issued last year, by an OSU engineering professor who made computer models of potential evacuation routes in the city, estimated that, on a typical summer day in Cannon Beach, at least 1,080 people would head toward bridge after the earthquake.
Adding to Tuesday nights debate were letters sent to the council by Patrick Corcoran, a coastal hazards specialist for the Oregon Sea Grant who has studied the potential effects of a Cascadia event.
Corcoran suggested that the city push hard on the state and the Oregon Department of Transportation to replace the current bridge with one that would withstand an earthquake.
A pedestrian bridge, he said, strikes me as something that when needed, will not perform and wouldnt be stable enough for many people to simultaneously cross on foot.
It seems like a half-measure, Corcoran wrote. If perceived as such when built, it could become the butt of jokes, which, he added, would be counter-productive.
On the other hand, former Cannon Beach mayor and local architect Jay Raskin, who has been in the middle of tsunami preparation efforts for many years, suggested that a low-cost pedestrian bridge that could survive the earthquake and allow people to evacuate is better than the current situation.
Mayor Mike Morgan called the debate a real conundrum. Even if a new school is built elsewhere and the students are moved away from the tsunami zone, it will take two to three years to make that move, he said. The Cannon Beach Conference Center also is located close to the creek, and visitors who drove across the creek will rush back to it in an emergency, Morgan added.
If OBEC said a pedestrian bridge could be built, the City Council would still have to make a decision, he noted.
Its a gamble, its a crap shoot. Its a head-scratcher, Morgan added. I dont think its black and white.
Cadwallader noted that the council had agreed during a retreat earlier this year not to pursue the pedestrian bridge but to concentrate on replacing the existing bridge. She suggested that Oregon Department of Transportation officials be requested to talk to the council about their plans for the U.S. Highway 101 bridge that also goes across the creek and probably wouldnt withstand an earthquake.
I would like to know where they would put a new bridge in their list of priorities, Cadwallader said. I get caught up in the fact that we might be putting people in dangerous places. Im not sure we will ever come up with the right answer, one that we can sleep with at night.
In its study done early last year, OBEC said that the wooden pedestrian bridge could possibly survive both mild and severe earthquakes, but it wouldnt survive a tsunami and its 6-foot width would be too narrow to adequately move a large number of evacuees in a short time period.
The OBEC report estimated then that about 72 persons per minute would be able to cross a 6-foot-wide bridge. However, a 12-foot-wide bridge would accommodate 216 evacuees per minute. It also questioned whether state environmental laws would allow a timber bridge to be placed in the creek.