Beach processes can vary dramatically from one end of a particular beach to the other. Site-specific factors such as extent and health of coral reefs, alterations to dune systems, sediment runoff from upland areas, and other human activities also affect coastal processes. Wave and current patterns change dramatically from season to season, and from swell to swell. Because of these variations, each segment of each beach will have its own history of erosion and accretion trends. Sand Dunes Dunes are accumulations of wind-blown sand.
Vegetation traps wind-blown sand and then grows up through the new sand accumulation.
This process is repeated to build larger dunes. Many dunes are host to burial sites and are legitimate environmental systems that support specific ecosystems. Because of their cultural and environmental sensitivity, many dunes are worthy of all due protection. During a storm or a large swell, waves attack and erode the Figure 2. Twenty foot high vegetated dunes, Spreckelsville, Maui.