Al it's funny how often a 100 year flood occurs here in Texas. I have lived in the Dallas area now for twenty years and we have already had two of them. The last one happened about four years ago when we got nine inches of rain in a very short period of time. My pond went two feet above full pool and two feet over the emergency spillway. After that I had Mike Otto construct for me another emergency spillway for the next 100 year flood. My only point is that I would make sure that if you continue to raise the water level you are feeling fairly secure that if a 100 year flood does happen your spillway can handle it and take the water away from the back side of the dam.
