Hurricane Frederic in 1979. The suggested Navarre Pass as designed by Baskerville-Donovan in 1975 is shown on the slide. Note that littoral drift would be trapped in a deposition basin behind the east jetty. A sea-level canal would mix fresher, warmer, lighter waters of the Sound with saline, cool, heavier waters of the Gulf. Flow through canal would affect water quality in Sound.
Bays are brackish, being fed by many fresh water streams and rivers.
There is an interchange of brackish Bay waters with saline Gulf waters by tidal action through Pensacola, Perdido and Destin East Passes. Tidal currents moving seaward through Passes tend to block alongshore littoral drift and create ebb tidal shoals. Tidal currents moving into Passes tend to sweep littoral sediment into the Bay creating flood tidal shoals. Because at water density differences, flood tides sweep sediment into Passes than ebb tides sweep out creating a larger inner bar than outer bar. Hence sediment that would normally move alongshore is trapped in the inlets and tidal bars.