As is always said - any natural body of water in Florida is going to have alligators in it.
There is a certain size they have to get to before they are moved, I believe it is around 5ft.
Actually, ANY decent sized water body in Florida can have an alligator or two. The man made water hazard behind our house in Miami (lived on a golf course) had one - we named him Freddie - and he moved from the one behind our house to the one near our neighbor's. As long as there is a ready supply of food (fish, the left over roasts the chef at the country would bring by, small mammals) in or nearby, they will come. Sadly, Freddie ended becoming a pair of shoes and handbag late one evening. R.I.P., Freddie.