DECATUR, Neb. - Officials say several problems are "readily apparent" on the Highway 175 bridge over the Missouri River, but gave no timetable for reopening the bridge that's been closed due to flooding.
The bridge near Decatur was closed in June due to erosion of the abutment on the Iowa side of the bridge. Crews stabilized the roadway with rock, but the bridge has not been reopened and state transportation officials have since expressed concerns about additional erosion underwater.
The Iowa Department of Transportation said in a statement Friday the bridge's slope had become unstable and created concerns about the bridge's substructure. The river current has also caused erosion around critical structural elements and the highway approach.
Bob Younie, the Iowa DOT's state maintenance engineer, said sonar indicated a 56-foot-deep scour hole in the river bed on the east side of the bridge. However, he said officials won't know how much other damage the bridge suffered until the water recedes.
"The scouring is still going on, more than likely," Younie said.
Iowa DOT engineers won't be able to perform a more detailed analysis of the damage until at least the end of the month when the Army Corps of Engineers is scheduled to reduce flows from Gavins Point Dam to 90,000 cubic feet per second.
On Friday, the dam near Yankton, S.D., was still discharging 150,000 cfs. The corps plans to begin daily reductions of 5,000 cfs early next week.