Historical Shoreline Analysis of the Mississippi Gulf Coast

Olvanki, Stephen M.; Moody, Jack S.; Yassin, Barbara; ,

Historical Shoreline Analysis of the Mississippi Gulf Coast

by Stephen M. Olvanki, Mississippi Office of Geology, Jackson, United States,
Jack S. Moody, Mississippi Office of Geology, Jackson, United States,
Barbara Yassin, Mississippi Office of Geology, Jackson, United States,

Document Type: Proceeding Paper

Part of: Coastal Zone '93

Abstract:

Historical shoreline positions of the Mississippi mainland coast and the barrier islands were digitized for four periods of time. USGS T-sheets provided control for the 1850's, 1917, and the 1950's, while air photo interpretation was used for 1986 control. Data were transferred to ARC/INFO for analysis and display. The mainland coast shows moderate erosion near the border with Louisiana in Hancock County. Erosion rates there have averaged 7.4 acres per year for the past 136 years with resulting shoreline retreat rates as high as 4.49 meters (14.6 feet) per year. The central portion of the mainland shoreline is stabilized by a seawall and artificial beach, and shows only those changes effected by human modifications. The eastern shoreline near Alabama displays the highest rate of erosion where the Grande Batture Islands have been completely eroded away, exposing the previously protected marsh to higher wave energy. Land loss there has averaged 8.1 acres per year over the 136 year study period. The accompanying maximum shoreline retreat is 2.87 meters (9.42 feet) per year. The barrier islands south of the mainland coast are migrating from east to west in the direction of longshore drift, and are also showing a net 19.78 acre loss per year.

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