A pedestrian bridge connecting Umatilla’s South Hill with downtown partially collapsed sometime late Saturday night or early Sunday morning.
The bridge spans the Umatilla River about one-half mile west of Umatilla High School, and many students use it to walk to school. The next closest bridge is another half mile west where Highway 730 crosses the river.
Umatilla city manager David Stockdale said engineers are coming out Tuesday to make an official determination, but staff believe it is a total loss. Demolition and replacement costs will likely be in the millions of dollars and take at least a year — probably more like three to five years, he said.
On Sunday morning a section of the bridge dipped down toward the water, which was rushing just below the bridge as spring runoff pushed the river higher than usual. A tangle of branches was caught under the break in the bridge.
Scott Coleman, city public works director, said when rivers are swollen with floodwaters, debris tend to collect against the bridge and form a natural dam, magnifying stress and pressure on the structure.
“That’s what we had going on here,” he said.
A water main runs along the bridge, carrying water to South Hill residents. Coleman said the water had been rerouted and was being delivered through a different pipe. No one lost their water service but they may see a drop in pressure, and there would be a major problem if the backup line broke.
Umatilla Police Department posted on Facebook that anyone trying to cross the broken bridge would be subject to criminal trespass charges. Stockdale said the bridge is “unusable and unsafe.”
“Go ahead and be curious — from a distance,” he said. “If nature is taking out a structure like that, it’s definitely lethal to humans.”
The Umatilla City Council plans to make an emergency declaration regarding the bridge during their meeting at 8 p.m. Tuesday evening at city hall, following a budget work session at 6 p.m.
On Saturday the Umatilla River continued to run high elsewhere, including the rapids formed along Umatilla River Road and the flooding that continued through Riverfront Park in Hermiston.