I'm sorry but I can't seem to find the other posts your referred to and would like to make a comment.
My comment or rather question is if we cannot build in a flood plain why is it okay to build in the middle of the darned river? That makes no sense. So, we go out in the middle of the river and fill in a part of the flow basin. That flow basin is going to have to be provided for or flooding could be the end result.