The best way to prevent damage from flooding is to move before one occurs. Seriously, don’t live on a flood plain unless you have no choice. If you learned anything in the last decade or two, it should be floods can and do occur in low-lying areas previously thought safe. Rivers and streams rise to record levels, levy’s break, and there’s just too much concrete for the ground to absorb all that rain.
If a flood threatens, evacuate before it is too late. If you’re stuck in a flood, follow your instincts and move to the highest ground possible. Exercise caution when traveling because it doesn’t take much water to float a car or pick up truck. Use common sense and do not wade into moving water. Do not drink flood waters.
Sandbags are useful if you have time to fill them and place them before the flood arrives, but you may be better off spending your time and energy moving your belongings to higher ground.
The bottom line: Good survivalists should not live in a flood plane.