When I first started to work in Hartford way back in 1969 (I'm sure that is before many of you were born) fresh water was talked about as the factor that would limit migration to the south and west. FL was seen as having the biggest problem with all kinds of doomsday scenarios about needing to desalinate ocean water, and the cost that would put on growth. Agriculture in the area you mentioned is not irigation intensive since over the last 75 years cotton has been replaced with tree farms. As far as water for industrial, commercial and residential use is concerned, the area is dotted with large lakes that are used for hydropower and recreation. Few, with Lanier in GA being the main exception, are currently used to provide water for any other purpose. I would not hold my breath for a reverse migration based on lack of water.