From http://www.omaha.com/article/20110626/NEWS01/110629782#flood-wall-fails-at-fort-calhoun

FORT CALHOUN, Neb. — A berm holding back floodwater at the Fort Calhoun Nuclear Station has collapsed.

The U.S. Nuclear Regulatory Commission says it’s monitoring the Missouri River flooding at the plant, which has been shut down since early April for refueling.

The 2,000-foot berm collapsed about 1:30 a.m. Sunday, allowing the swollen river to surround two buildings at the plant. The NRC says those buildings are designed to handle flooding up to 1014 feet above sea level. The river is at 1006.3 feet and isn’t forecast to exceed 1008 feet.