A model was created to study how sand moves along the coast of Alabama and Mississippi. The study found that there are six different areas where sand moves westward. On Dauphin Island, sand moves eastward towards Mobile Pass. The size of the sand grains changes along the coast, with coarser sand found further down the coast. The sand on the islands contains more shells and heavy minerals, and erosion rates are highest where the direction of sand movement changes. Some areas act as sinks for sand, meaning they don't exchange much with other areas. Overall, the study shows that sand movement along these barrier islands is complex and influenced by various factors.