ABSTRACT

Louisiana has the highest rates of coastal erosion and land loss in the United States. Rates of coastal land loss exceed 50 mi²/yr. Lousiana's barrier islands, whose presence creates and maintains an extensive estuarine system and protects the salt marshes from the wave energy of the open Gulf of Mexico are rapidly vanishing, decreasing in area and migrating landward at rates up to 65ft/yr. Between 1898 and 1978, Louisiana's barrier islands decreased in area by 41 percent, shrinking from 37 mi² to 22 mi². The life-expectancy of individual barrier islands systems ranges between 30 years for the Isles Dernieres and 225 years for the Chandeleur Islands. Disappearance of the barrier islands will result in destruction of the barrier-built estuaries and accelerated salt marsh deterioration. Such destruction will severely impact the fishery, fur, and waterfowl industries, valued at an estimated $1 billion per year, whose harvests depend on the habitat provided by these fragile estuaries.

Understanding the coastal geomorphological processes, both natural and human-induced, that control barrier island erosion, estuary deterioration, and salt march loss in the Mississippi River delta plain is essential in evaluating the performance of the various coastal protection methods currently envisioned or being employed. Previous attempts at coastal preservation and restoration have shown that an integrated approach that enhances natural processes, rather than combatting them, is the most effective. Highways are built with regularly scheduled maintenance programs and this same concept should be applied to the coastal zone. Preservation and restoration of our coastal environments requires a dynamic landscape maintenance program of regularly scheduled beach nourishment, barrier restoration, shoreface nourishment, vegetation, and coastal modification projects.