2008 Joint Meeting of The Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, Gulf Coast Association of Geological Societies with the Gulf Coast Section of SEPM

Paper No. 17
Presentation Time: 8:00 AM-4:45 PM

Dune Profiles and Restoration on South Padre Island Texas

CONTRERAS, Mara, DEL ANGEL, Diana, CARDENAS, Andres and HEISE, Elizabeth A., Chemistry and Environmental Sciences, University of Texas at Brownsville, 80 Fort Brown, Brownsville, TX 78520, maramirza@hotmail.com

The Texas General Land Office has mandated that the Town of South Padre Island, TX have a continuous dune line. Currently there are large breaks in the dune line. Natural sand dunes are structures which maintain sediment deposition. Sand dunes store sand and protect property. Beach nourishment projects are routinely implemented to replace the sediment which has been washed away by the waves. The Town of South Padre Island has spent millions of dollars on beach nourishment, but still has structures that are impacted by large storm events in the Gulf of Mexico.

This study established a baseline and strategy for establishing a continuous dune line on South Padre Island and also was used to educate the public about the importance of the dune line. Utilizing ArcGIS software to compare aerial imagery from 1994 and 2005, we estimated the total area of vegetation cover and unvegetatated areas. We harvested Panicum amarum (bitter panicum), Sesuvium portulacastrum (sea purslane), Distichlis spicata (spike grass), Ipomoea pes-caprae (railroad vine) and other natural dune vegetation to re-vegetate areas on the dune line.

Impact of re-vegetation for beach stabilization was measured through beach profiling. The beach was profiled in three locations which had been re-vegetated, three locations without vegetation, and three locations that had existing vegetation. Beach profiles were completed before and after storm events to monitor the beach sedimentation change. Understanding the natural nourishment of the beach will create the framework which can protect the beach, allow for recreation and establish long-term management of the beach.