The Army Corps of Engineers is investigating “anomalies” underneath the apron of Gavins Point Dam, a corps official said Tuesday.
Bret Budd, chief of restoration for the corps' Omaha district, said the corps will conduct additional tests to see if the anomalies seen on radar are something to be concerned about.
“There's no visible stress on the concrete,” he said. “From what we see there is no danger to the dam.”
The apron is a concrete chute below the gates of the dam that water flows over as it leaves the reservoir.
To assess damage from last year's flood, the corps used ground-penetrating radar that probed all the way to bedrock, with some of the soundings bouncing back in an odd way.
Budd said the anomalies might have existed prior to construction of the apron, or developed since then or resulted from the flood.
As it stands now, repairs to Gavins Point Dam are expected to cost $10.5 million.
That includes spillway gate and concrete slab repairs, new trash racks for the powerhouse intake, erosion protection of cultural resource sites, erosion repair along the shoreline downstream of the dam, recreation area repairs and road repairs.
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