The rumor going through the grapevine right now is that Herschend Family Entertainment Company has or will soon buy the now struggling 90 Outlet Mall (Red Roof Outlet Mall) that is behind White Water's parking lot for future expansion. The park has not commented on this as of yet, but it does seem that this is a done deal until proven otherwise.
White Water, which added the very successful slide complex Kalani Towers this past year, saw quite a surge in attendance. The park had not added a new slide since Raging River Rapids, which was added 2 years before.
To me, I would think that it would be most logical to move the parking lot to where the Mall is currently and then to use the parking lot (which is already flat) for the waterpark expansion.