This refers to the construction of seawalls, jetties, offshore breakwaters and groins intended to hold shorelines in place. Although it is well understood by scientists that armoring beaches destroys beaches on a decadal time scale, this fact is still widely unrecognized by the general public or ignored by coastal developers and engineers. The demand for armoring will become even more widespread as the rate of sea-level rise and shoreline retreat increases. A few political entities (North Carolina, USA, North Sea Coast of Holland) have outlawed armoring (with moderate success) and more should be urged to do so. There are large numbers of salesmen with “unique” types of seawalls and groins (Holmberg Device) that need to be refuted.
Definitions of Shoreline Armoring Terms
- The addition of sand to a beach allowing it to widen and build out seaward.
- Groin is a structure built perpendicular to the shoreline usually of rock or metal designed to trap sand that moves in the long shore current
- Hardened beach structures
- A general term referring to groins, jetties, offshore breakwaters, sea walls, tombolos, or any other engineered
- A jetty is a hardened structure built at an inlet usually made of rock or metal designed to keep navigation channels from filling in with sediment
- Longshore drift
- Long shore drift carries sand and sediment parallel to the shore and serves as the sand source for many beaches. On the east coast of the US, the long shore current is from the north to the south.
- Offshore breakwaters
- An engineered structure placed offshore and parallel to the beach. Breakwaters mimic sandbars to cause waves to break, lessening erosion on the beach behind the breakwater, but interrupting the longshore drift.
- Shoreline armoring
- The use of groins, jetties, offshore breakwaters, sea walls, tombolos or other hardened beach structures on the shore
- Sea wall
- A sea wall is designed to protect the land from erosion particularly during storms and usually made of metal, wood, or rock. One of the most famous seawalls is the Galveston seawall in Galveston, TX built after the 1900 hurricane killed 6,000 people on the island.
- Tombolos are a special type of groin built perpendicular to the shore to trap sand, but with an end parallel to the shore designed to reduce wave energy.
Surfing in / Shoreline Armoring
Proposed new rules will make it easier for beachfront land owners to build sandbag walls and leave them in place for longer periods. Members of the state panel directed by the N.C. General Assembly to create the rules expressed fears that the new, looser restrictions could result in hardened beaches along the entire N.C. coast.
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Is North Topsail Beach the most poorly managed beach community in the country? If not, it certainly seems to be taking a good shot at it. I have watched in dismay as the town has struggled to preserve a small stretch of oceanfront property at all costs.
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Are concrete seawalls actually affecting what salmons eat, and by how much? Researchers measured the types of prey in the water along armored shorelines and along restored beaches.
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Groins don’t really work. They stop or slow erosion in the immediate vicinity, but worsen erosion farther down the beach by halting the natural flow of sand. Beach sand migrates, especially as ocean levels rise. Trying to stop its natural course is potentially expensive folly.
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Some legislators are once again trying to expand the number of certain erosion-controlling structures allowed by law along the North Carolina coast. This time, they’re trying to do it through the state budget.
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Rapid coastal population growth and development are primary drivers of marine habitat degradation. Although shoreline hardening, a byproduct of development, can accelerate erosion and loss of beaches and tidal wetlands, it is a common practice globally. 22,842 km of continental U.S. shoreline, 14% of the total, has been hardened.
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As the 2015 summer storm season approaches, has the Gold Coast City Council got the right plan in place to protect the beaches luring the 11.5 million tourists, residents and investors to Australia’s playground each year?
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California Coastal Armoring Report: Managing Coastal Armoring and Climate Change Adaptation in the 21st Century
In response to erosion and storm events, Californians have built seawalls, revetments, and other “coastal armoring” structures along significant portions of California’s coast. Coastal armoring now occupies more than 110 miles, or at least 10 percent, of the overall California coastline. This coastal armoring has diminished California’s beaches and habitat, irreversibly altered bluffs, caused increased erosion to neighboring properties, and marred the natural beauty of the coast.
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The pristine beaches of Hopkins, on Belize eastern coast, have always attracted visitors, but recently the region’s appeal has drastically changed due to accelerated beach erosion. It has been determined that the problem was being caused by a groyne built by Hopkins Bay.
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