The U.S. Army Corps of Engineers says it will conduct a damage assessment of the spillway slabs at Gavins Point Dam on Wednesday.
The chief of the Omaha District hydrologic engineering branch says releases from the dam will be halted for no more than eight hours to dewater the uppermost portion of the spillway. John Remus says a preliminary assessment of damages sustained after the 2011 flood indicated minor damage to a number of areas on the spillway slab.
The investigation will include the use of ground penetrating radar and other methods. It's being conducted to develop and implement corrective measures by the spring of 2013.
Stage reductions at Yankton, Sioux City and Omaha are expected to last for about 12 hours, 24 hours and 48 hours, respectively.