Barrier Island: Galveston Island

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Galveston Island is a barrier island formed during the Holocene after a major glacial melt. Since that time, the island has changed in size and geographic location based on numerous factors including sediment availability and various hydrodynamic reasons. The island also suffers from erosion due to major storms, like hurricanes, as well as other natural disasters. Much effort has been put in place to reduce the amount of erosion and/or migration, including a seawall and jetties. These efforts are not 100% effective and while the island will continue to transform; with human intervention, we hope to mitigate this change to a minimum. Barrier islands are seen mainly in coastal settings with three main characteristics. First, they usually have a low-gradient continental shelf next to a low-relief coastal plain. The second characteristic is an abundant sediment supply. Both shelf and plain are made up of unconsolidated sediments, typically providing the barrier islands with an abundant sediment supply. The third characteristic is a low to moderate tidal range. The Gulf of Mexico provides all three characteristics and, therefore, contains numerous barrier island formations (Reinson). The hypothesis presented in a paper titled, “Barrier Island Formation”(Hoyt 1130), is as follows: Along a sand shoreline, wind will form dunes or ridges (depending on the type of material the beach is composed of). If there is a relative submergence, the area landward of the dune/ridge will be flooded to form a lagoon and the ridge/dune then becomes a barrier island. This would most likely occur when a stable shoreline with a well-developed ridge is engulfed by a relatively sudden transgression that does not erode or push the ridge landward (Ot... ... middle of paper ... ...ansportation in the natural direction of the littoral drift. This particular jetty is responsible for the accretion of sediment immediately adjacent to the South Jetty (Kraus). The stability of barrier islands is dependent on numerous dynamic factors, hence the efforts taken to keep the island as stable as possible. The combination of structures used to “protect” the island from natural disasters and the normal “life” of a barrier island is crucial. Without these protections, the island could be significantly altered by a single major meteorological event. If another event similar to the mass melting during the Holocene, or if the amount of sediment increases or decreases; the island could disappear altogether. Learning how the island formed and what factors affect its’ stability are the fundamental links to keeping Galveston Island the paradise it is today.

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