Disaster officials say the levee system today is stronger than in 1993 when the Missouri River damaged nearly every floodwall and inundated thousands of homes, farms and businesses.
The 1993 disaster prompted a massive effort to rebuild floodwalls and relocate houses to higher ground.
Now that the river is rising again, the question is, will the better built levees hold, especially if the water stays high for weeks? That's one of the greatest tests of any levee: whether it can survive pressure from a prolonged flood.
The flood of 2011 could be a long one as the Army Corps of Engineers releases record amounts of water from upstream dams because of heavy rains and snowmelt.
Officials hope the levee breach threatening Hamburg, Iowa, just across from Missouri, is the exception, rather than a harbinger of things to come.
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