Nez Perce National Forest officials are working on a $400,000 project to repair a bridge that washed out earlier this month when the Little Salmon River south of Riggins flooded.

Mike Cook, head of the forest’s engineering department, said the 130-foot White Bird Ridge bridge, about a mile and a half north of Pinehurst, where the worst flooding was, at first did not appear to be heavily damaged.

Some fill around the bridge support had washed out, temporarily stranding about seven families. As logs, brush and other debris washed downriver from where it had been lodged near the Pinehurst bridge, the stream was partially blocked and powerful flows cut away one of the forest bridge piers.

Forest engineers planned to replace a 45-foot span, but further investigation showed a second pier also had been undermined and was beginning to tip, Cook said.

It now appears at least 90 feet of the bridge will have to be replaced at a cost of about $400,000, Cook said. If damage is more extensive the entire bridge will need to be rebuilt.