Problem: The growth of barrier islands depends upon Sand supply - when an abundance of sediment is supplied in the region, it will promote the growth of Barrier island The flatness of the surface: If the surface will be flat more sediment will accumulate to form the island Balanced wave energy - will make sure the proper supply of sand and prevent it from erosion Sea level rise - a gentle rise in sea level rise also promotes sand deposition. A sea level increase of one to two centimeters per year that occurred as the result of melting glaciers was simply too rapid for adequate barrier island development.