Over time, erosion occurs everywhere along the seaward side of barriers and along the cliffed shore. One determining factor as to where storm wave erosion occurs is the configuration of the adjacent seafloor. Shoals and bars offer protection from wave erosion by causing storm waves to break and dissipate their energy before reaching the shore. The configuration of the nearby seafloor is ever changing and changes in the location of shoals and bars may cause the locus of beach or cliff erosion to change position along the shore. Erosion on the seaward side coupled with deposition on the landward side has caused North Beach to migrate westward. In the long run, this rate of migration is the same as the rate of shoreline retreat for the cliffed part of the lower Cape to the north. The smooth arcuate shoreline from Provincetown to the south end of North Beach is evidence of this.
Breaching does not always occur in the same place. The most likely place for a breach to occur is where the barrier is narrow and where previous storm waves have washed across the barrier and removed the dunes. These conditions were present at the site of the 1987 breach in South Beach. On some barriers, beach dwellers have removed the dune to have a sea view. Once the protection offered by the dunes is gone, the barrier is more easily washed over and more subject to breaching.
east coast—showing probabilities of collision (in which waves erode dune fronts), overwash (in which waves wash over dunes and transport sand inland), and inundation (in which beach and dunes are completely submerged) along the sandy beaches of Long Island, New York.
Long Point Provincial Park | Ontario Camper
USGS scientists and collaborators have systematically mapped the thickness of sand deposits near the coast through seismic surveys and jet-probing. The first phase was a regional mapping with widely spaced geophysical and sample data that found that most beach quality sand is concentrated in active ebb-tidal deltas located just off tidal inlets and in long, linear ridges found on the inner shelf. Across the entire study area, bottom samples and core samples have been collected and are being analyzed to develop a map of sea-floor sediment types. This research indicates that although there is coarse, biogenic carbonate sand being produced in the modern environment, there is little or no modern source of beach-quality quartz sediment in this region.
Eroding North Topsail Beach turns to sandbags to save …
Coastal erosion is the wearing away of land or the removal of beach or dune sediments by wave action, tidal currents, wave currents or drainage. Waves generated by storms, wind or even fast-moving motorcraft traveling close to shore cause coastal erosion. Erosion may take the form of long-term losses of sediment and rocks or merely the temporary redistribution of coastal sediments. In other words, erosion in one location may result in a larger beach nearby, as the sand is veritably "moved" from one stretch of beach to another.
Eroding North Topsail Beach turns to sandbags ..
The beaches of North Carolina's coastline face an ongoing threat: coastal erosion. Though mostly gradual and relatively unnoticeable over the course of a year or two, the rising sea level combined with a season of storms or can cause anywhere from a few feet to hundreds of feet of this delicate shoreline being stripped away. Solutions are constantly being studied and discussed, but often, the solution to erosion can be just as damaging as erosion itself. While vacationers are all but guaranteed to enjoy decades of happy beach days in the future, the issue of coastal erosion and its potentially devastating effects on our shorelines remains on the minds of locals and visitors.
How Barrier Island Formation Occurs Through Beach …
Beach erosion and loss of protective dunes have left the coast susceptible to damage from storms and hurricanes. A 1992 report issued by the Florida Department of Natural Resources designated 65% of west Florida beaches as "critical erosion areas." In response, several sections of the coast have undergone nourishment projects to restore beach widths to previous dimensions. This method of beach maintenance is expensive, typically costing well over a million dollars for each mile of beach, and needs to be repeated as often as every 4 years. While beach nourishment is becoming the most common means of addressing beach erosion, it may not provide a cost- effective long-term solution, as sand resources for nourishment are limited along much of the west Florida coast.