Understandably, the "pre-drainage" image…

Understandably, the "pre-drainage" image has several uncertainties. I've heard it speculated by some of the experts that (1) the custard apple swamp that fringed the lake may have only developed after human alterations to the system and (2) what's labeled rocky glades and marl prairie in the southern Everglades was actually slough. Perhaps the biggest difference is land subsidence due to peat loss. It ranges from anywhere between a foot to over ten feet depending on where you are in the Everglades.