Restoring and conserving the island's water system require actions both by the public and private sectors. On the public side, substantial capital outlays as well as moderate operational costs are required for improvements. Control of private development is also essential, and many of CF's recommendations were so oriented. The major natural hazard affecting occupation of Sanibel is the tropical hurricane. Sanibel shares with all other barrier islands of the Atlantic and Gulf of Mexico extreme vulnerability to hurricanes.
Evacuation is the major defense.
The rate at which automobile traffic can move over the causeway to the mainland limits the speed of evacuation and imposes a limit on population and therefore on residential density. In their absence, density allocations would have to be reduced to provide for the conservation of natural systems and natural resources. Recognizing that Sanibel is composed of several different zones with particular characteristics and varying tolerances, a separate set of standards is applied to each zone. Each type of residential development has the potential for a particular combination of environmental disturbances. The amount of natural systems damage that may result from any disturbance depends upon the characteristics and vulnerabilities of the specific subsystem involved.