http://www.examiner.com/architecture-de ... rom-floods
The Mississippi does have a tendency to flood!The mounds of the Southeastern Indians were generally associated with major rivers. All of these rivers at least occasionally flooded. Could it be that mounds were originally built to provide a safe haven for villages during a flood, and later were constructed to keep the temples and elite’s houses above water during floods? Over time the association between mounds and the elite would have become an architectural tradition within itself, regardless of the potential threat of flooding.