Just found this as I was looking up "alligator prevention" (LOL)
Alligators are most dangerous in water or at the water’s edge. They occasionally make overland forays in search of new habitat, mates, or prey. Concrete or wooden bulkheads that are a minimum of 3 feet (1 m) above the high water mark will repel alligators along waterways and lakes. Alligators have been documented to climb 5-foot (1.5-m) chain-link fences to get at dogs. Fences at least 5 feet high with 4-inch (10-cm) mesh will effectively exclude larger alligators if the top of the fence is angled outward.