I guess my first question is an overly simple one: is your concept to stay in the house during the flood, or bug out early and let the house tend to itself during the flood, while you and family are safe and sound somewhere else?

It sort of sounds like you feel reasonably "safe" to stay in the house, at least for a while. But you point out, due to the drainage ditch, it might be bad to try and get out if you wait too long.

I think that you need to set a point, a safe a secure bug out point, by looking at your escape route, that when the water reaches here, we bug out now!

In my thinking, no matter how secure the house is, if the flood is so high that it is unsafe to leave, you stayed too long. Junk floating down on the flood could destroy the foundation of the house even if you are actually above the water itself.

Seems to me the best policy is to get while you can, and hope to come back to an intact house.