CANNON BEACH - If an earthquake or a tsunami occur in Cannon Beach, students at the elementary school have two options for escape.
They can walk on the bridge across Ecola Creek to higher ground, which takes five minutes, or they can hike down Spruce Street to the south end of midtown, which takes 22 minutes.
But, say state and city officials, let's get real. If an earthquake and tsunami occur, the Ecola Creek bridge, which, they note, has inadequate footings, will collapse, just like it did during the tsunami in 1964.
Wary of the cost to replace the current vehicular bridge across the creek, Cannon Beach officials are beginning to explore the possibility of constructing a pedestrian bridge that will withstand an earthquake and provide an escape route. But preliminary figures show that it won't be cheap.
Depending on the design and the alignment, the bridge could cost between $1.6 million and $2.9 million, according to rough estimates prepared by engineers contacted by the city.
OBEC Consulting Engineers, of Eugene, estimated the cost to build a bridge with a 12-foot wide deck that will carry the load of an emergency vehicle and withstand a 1,000-year interval earthquake and a "higher level" tsunami wave.
According to the preliminary design, the bridge would be constructed of precast slab spans and anchored to concrete-filled steel pipe piles. The pilings of the current vehicular bridge are wood.
The difference between cost estimates is based on the proposed bridge's alignment.
Option 1 would have the bridge aligned with an extension of Spruce Street north to Fifth Street west of Cannon Beach Elementary School. The alignment, the engineers note, is closer to the ocean and crosses a wider section of Ecola Creek than the current bridge does, and the north end of the bridge must span the wetlands of Logan Creek, which flows south into Ecola Creek.
The Option 1 bridge would be 650 feet long. It would have to be designed to withstand a large earthquake and, being close to the ocean, it would receive more debris than a bridge farther to the east. In addition, the engineers say, the structure's height might impede ocean views for residences to the east of the bridge. Estimated cost of Option 1: $2.95 million.
The Option 2 bridge would be parallel to and downstream from the existing bridge. It would begin at the northeast corner of the school and end directly west of the Fir Street-Fifth Street intersection to the north. Much shorter than the Option 1 bridge, the Option 2 bridge would be 250 to 300 feet long.
Because it would be farther from the ocean, the bridge would have less tsunami resistance than Option 1. Some private land might have to be purchased to complete the right-of-way.
However, the engineers note, the shorter bridge might attract federal or state funding, and a sidewalk to connect the vehicular bridge to the Option 1 bridge wouldn't be needed. In addition, the Option 2 bridge provides the shortest evacuation route. Estimated cost of Option 2: $1.58 million.
Cannon Beach Public Works Director Mark See presented the two options to the city's emergency preparation committee recently. See said he would contact more engineering firms for estimates.
"There could be some really interesting proposals, and the prices could be pretty good. Now is a good time to be doing that," because construction of public projects has slowed, See said.
Committee members said they wanted to contact the Cannon Beach Conference Center and the Seaside School District to discuss the possibility of building a pedestrian bridge. Both of those organizations should have an interest in the bridge, since they would probably use it in an emergency, committee members said.