I’d imagine that the location was seen as useful during the Cold War years due to being far inland in a rural area away from likely targets of a nuclear attack.

I’d imagine that the location was seen as useful during the Cold War years due to being far inland in a rural area away from likely targets of a nuclear attack. As for flood mitigation, I’m sure it’s the same as it is anywhere: risk assessments probably considered the likelihood of ‘really bad’ flooding, and the potential impacts, too low to be worth the cost. (As to whether that was wise or not, I’ve got no idea.) (Edit— from Wikipedia: ”Secretary of the Air Force Stuart Symington chose to locate the Air Force's crucial long-range atomic strike force at Offutt primarily because the base was centrally located on the North American continent, placing it well beyond the existing range of long-range, nuclear-armed bombers to (then) stay safely out of range of hostile missiles or bomber aircraft.”)