Geomorphologic Evolution of a Rapidly Deteriorating Barrier Island System with Multiple Sediment Sources: Eastern Isles Dernieres, Louisiana, 1887 to 2006

Benjamin Kirkland, Ioannis Georgiou, and Mark Kulp
[email protected]

Trinity, East, and Wine Islands comprise the eastern half of the Isles Dernieres, a barrier island system along south-central Louisiana. The system formed following the abandonment of the Lafourche delta complex, and relative sea level rise and erosion, primarily generated by large storms, have led to rapid deterioration of the system. Since 1887, the land area of the islands has decreased 77%, and the gulf shoreline has retreated landward slightly more than 1 km. Wave erosion on the shoreface of the islands is primarily responsible for the sediment loss; liberated sediment travels longshore and can be intercepted by tidal inlets. Dominant ebb tidal currents transport sediment to ebb tidal deltas or it is carried westward, out of the system, by littoral transport. A large lobe of sediment bypassing Cat Island Pass is entering the system from the eastern lower shoreface, which helps replace some of the sediment lost through wave erosion to the upper shoreface.

AAPG Search and Discovery Article #90167©2013 GCAGS and GCSSEPM 63^rd Annual Convention, New Orleans, Louisiana, October 6-8, 2013