Why a crawl space slab? If you have ever had a crawl space, you know they are typically dirt, wet, moldy, smelly and allow moisture to pass from the ground up into the home. We are sealing the crawl space to prevent and eliminate this. First, with a six mil vapor barrier. Second, four inches of 4000 psi concrete with fiber. Since the slab floats between the block walls, the edges are sealed with a waterproof polymer.
Second and third pictures show rebar pads that are inserted into the footings for the new piers.
Dickman Legacy Lodge 
We did the same thing in our basement. We significantly cut down on radon vapors. We also installed a sump can. Will you need one sump pump so near the water?
LikeLike
Sorry for the late reply. I just learned how to reply to comments. No sump pump needed as we are basically above ground level.
LikeLike