Barrier island

Barrier islands are coastal landforms and a type of dune system that are exceptionally flat or lumpy areas of sand that form by wave and tidal action parallel to the mainland coast. They usually occur in chains, consisting of anything from a few islands to more than a dozen.They are subject to change during storms and other action, but absorb energy and protect the coastlines and create areas of protected waters where wetlands may flourish. A barrier chain may extend uninterrupted for over a hundred kilometers, excepting the tidal inlets that separate the islands, the longest and widest being Padre Island of Texas.[1] The length and width of barriers and overall morphology of barrier coasts are related to parameters including tidal range, wave energy, sediment supply, sea-level trends, and basement controls.[2] The amount of vegetation on the barrier has a large impact on the height and evolution of the island.[3]

Chains of barrier islands can be found along approximately 13-15% of the world's coastlines.[4] They display different settings, suggesting that they can form and be maintained in a variety of environmental settings. Numerous theories have been given to explain their formation.

Accreting coast Image6
Barrier island contrasted with other coastal landforms.

Constituent parts

Lower shoreface

The shoreface is the part of the barrier where the ocean meets the shore of the island. The barrier island body itself separates the shoreface from the backshore and lagoon/tidal flat area. Characteristics common to the lower shoreface are fine sands with mud and possibly silt. Further out into the ocean the sediment becomes finer. The effect from the waves at this point is weak because of the depth. Bioturbation is common and many fossils can be found here.

Middle shoreface

The middle shore face is located in the upper shoreface. The middle shoreface is strongly influenced by wave action because of its depth. Closer to shore the grain size will be medium size sands with shell pieces common. Since wave action is heavier, bioturbation is not likely.

Upper shoreface

The upper shore face is constantly affected by wave action. This results in development of herringbone sedimentary structures because of the constant differing flow of waves. Grain size is larger sands.


The foreshore is the area on land between high and low tide. Like the upper shoreface, it is constantly affected by wave action. Cross bedding and lamination are present and coarser sands are present because of the high energy present by the crashing of the waves. The sand is also very well sorted.


The backshore is always above the highest water level point. The berm is also found here which marks the boundary between the foreshore and backshore. Wind is the important factor here, not water. During strong storms high waves and wind can deliver and erode sediment from the backshore.


The dunes are typical of a barrier island, located at the top of the backshore. Dunes are made by the wind. See Coastal Dunes for more information. The dunes will display characteristics of typical aeolian wind blown dunes. The difference here is that dunes on a barrier island typically contain coastal vegetation roots and marine bioturbation.

Lagoon and tidal flats

The lagoon and tidal flat area is located behind the dune and backshore area. Here the water is still and this allows for fine silts, sands, and mud to settle out. Lagoons can become host to an anaerobic environment. This will allow high amounts of organic rich mud to form. Vegetation is also common.



Moreton Bay, on the east coast of Australia and directly east of Brisbane, is sheltered from the Pacific Ocean by a chain of very large barrier islands. Running north to south they are Bribie Island, Moreton Island, North Stradbroke Island and South Stradbroke Island (the last two used to be a single island until a storm created a channel between them in 1896). North Stradbroke Island is the second largest sand island in the world and Moreton Island is the third largest.

Fraser Island, another barrier island lying 200 km north of Moreton Bay on the same coastline, is the largest sand island in the world.

United States

They are seen most prominently on the United States' East Coast and Gulf Coast, where every state, stretching from Maine to Florida and Florida to Texas on each coast has at least part of a barrier island, stretching to more than twenty-five for Florida. However, this chain is international. It starts in Quebec's Magdalen Islands and ends in Mexico. No barrier islands are found on the Pacific coast of the United States due to the rocky shore and short continental shelf, but barrier peninsulas can be found. Barrier islands can also be seen on Alaska's Arctic coast.


Barrier Islands can also be found in Maritime Canada, and other places along the coast. A good example is found at Miramichi Bay, New Brunswick, where Portage Island as well as Fox Island and Hay Island protect the inner bay from storms in the Gulf of Saint Lawrence.


Mexico's Gulf Coast has numerous barrier islands and barrier Peninsulas.

New Zealand

Barrier islands are more prevalent in the north of both of New Zealand's main islands. Notable barrier islands in New Zealand include Matakana Island, which guards the entrance to Tauranga Harbour, and Rabbit Island, at the southern end of Tasman Bay. See also Nelson Harbour's Boulder Bank, below.


Barrier islands can be observed in the Baltic Sea and are a distinct feature of the Wadden Islands, which stretch from the Netherlands to Denmark. The Lido di Venezia is a notable barrier island which has for centuries protected the city of Venice in Italy.


Barrier Islands can be observed on every continent on Earth, except Antarctica.


Migration and overwash

Water levels may be higher than the island during storm events. This situation can lead to overwash, which brings sand from the front of the island to the top and/or landward side of the island. This process leads to the evolution and migration of the barrier island.[5]

Critical width concept

Barrier islands are often formed to have a certain width. The term “critical width concept” has been discussed with reference to barrier islands, overwash, and washover deposits since the 1970s. The concept basically states that overwash processes were effective in migration of the barrier only where the barrier width is less than a critical value.The island did not narrow below these values because overwash was effective at transporting sediment over the barrier island, thereby keeping pace with the rate of ocean shoreline recession. Sections of the island with greater widths experienced washover deposits that did not reach the bayshore, and the island narrowed by ocean shoreline recession until it reached the critical width. The only process that widened the barrier beyond the critical width was breaching, formation of a partially subaerial flood shoal, and subsequent inlet closure.[6] For the present discussion, critical barrier width is defined as the smallest cross-shore dimension that minimizes net loss of sediment from the barrier island over the defined project lifetime. The magnitude of critical width is related to sources and sinks of sand in the system, such as the volume stored in the dunes and the net long-shore and cross-shore sand transport, as well as the island elevation.[7] The concept of critical width is important for large-scale barrier island restoration, in which islands are reconstructed to optimum height, width, and length for providing protection for estuaries, bays, marshes and mainland beaches.[8]

Formation theories

Long Island Landsat Mosaic
Outer barrier in Long Island.
Baie de Mobile
The Mississippi-Alabama barrier islands guarding Mobile Bay and Mississippi Sound.

Scientists have proposed numerous explanations for the formation of barrier islands for more than 150 years. There are three major theories: offshore bar, spit accretion, and submergence.[2] No single theory can explain the development of all barriers, which are distributed extensively along the world's coastlines. Scientists accept the idea that barrier islands, including other barrier types, can form by a number of different mechanisms.[9]

There appears to be some general requirements for formation. Barrier island systems develop most easily on wave-dominated coasts with a small to moderate tidal range. Coasts are classified into three groups based on tidal range: microtidal, 0–2 meter tidal range; mesotidal, 2–4 meter tidal range; and macrotidal, >4 meter tidal range. Barrier islands tend to form primarily along microtidal coasts, where they tend to be well developed and nearly continuous. They are less frequently formed in mesotidal coasts, where they are typically short with tidal inlets common. Barrier islands are very rare along macrotidal coasts.[10] Along with a small tidal range and a wave-dominated coast, there must be a relatively low gradient shelf. Otherwise, sand accumulation into a sandbar would not occur and instead would be dispersed throughout the shore. An ample sediment supply is also a requirement for barrier island formation.[4] The last major requirement for barrier island formation is a stable sea level. It is especially important for sea level to remain relatively unchanged during barrier island formation and growth. If sea level changes are too drastic, time will be insufficient for wave action to accumulate sand into a dune, which will eventually become a barrier island through aggradation. The formation of barrier islands requires a constant sea level so that waves can concentrate the sand into one location.[11]

Offshore bar theory

In 1845 the Frenchman Elie de Beaumont published an account of barrier formation. He believed that waves moving into shallow water churned up sand, which was deposited in the form of a submarine bar when the waves broke and lost much of their energy. As the bars developed vertically, they gradually rose above sea level, forming barrier islands.

Spit accretion theory

American geologist Grove Karl Gilbert first argued in 1885 that the barrier sediments came from longshore sources. He proposed that sediment moving in the breaker zone through agitation by waves in longshore drift would construct spits extending from headlands parallel to the coast. The subsequent breaching of spits by storm waves would form barrier islands.[12]

Submergence theory

Isles Dernieres
Isles Dernieres in 1853 and 1978. Wave action detaches Isles Dernieres from the mainland.

William John McGee reasoned in 1890 that the East and Gulf coasts of the United States were undergoing submergence, as evidenced by the many drowned river valleys that occur along these coasts, including Raritan, Delaware and Chesapeake bays. He believed that during submergence, coastal ridges were separated from the mainland, and lagoons formed behind the ridges.[13] He used the Mississippi-Alabama barrier islands (consists of Cat, Ship, Horn, Petit Bois and Dauphin Islands) as an example where coastal submergence formed barrier islands. His interpretation was later shown to be incorrect when the ages of the coastal stratigraphy and sediment were more accurately determined.[14]

Along the coast of Louisiana, former lobes of the Mississippi River delta have been reworked by wave action, forming beach ridge complexes. Prolonged sinking of the marshes behind the barriers has converted these former vegetated wetlands to open-water areas. In a period of 125 years, from 1853 to 1978, two small semi-protected bays behind the barrier developed as the large water body of Lake Pelto, leading to Isles Dernieres's detachment from the mainland.[9]

Boulder Bank

An unusual natural structure in New Zealand may give clues to the formation processes of barrier islands. The Boulder Bank, at the entrance to Nelson Haven at the northern end of the South Island, is a unique 13 km-long stretch of rocky substrate a few metres in width. It is not strictly a barrier island, as it is linked to the mainland at one end. The Boulder Bank is composed of granodiorite from Mackay Bluff, which lies close to the point where the bank joins the mainland. It is still debated what process or processes have resulted in this odd structure, though longshore drift is the most accepted hypothesis. Studies have been conducted since 1892 to determine the speed of boulder movement. Rates of the top-course gravel movement have been estimated at 7.5 metres a year.[15]

Ecological importance

Barrier islands are critically important in mitigating ocean swells and other storm events for the water systems on the mainland side of the barrier island, as well as protecting the coastline. This effectively creates a unique environment of relatively low energy, brackish water. Multiple wetland systems such as lagoons, estuaries, and/or marshes can result from such conditions depending on the surroundings. They are typically rich habitats for a variety of flora and fauna. Without barrier islands, these wetlands could not exist; they would be destroyed by daily ocean waves and tides as well as ocean storm events. One of the most prominent examples is the Louisiana barrier islands.[16]

See also


  1. ^ Garrison, J.R., Jr., Williams, J., Potter Miller, S., Weber, E.T., II, McMechan, G., and Zeng, X., 2010, "Ground-penetrating radar study of North Padre Island; Implications for barrier island interval architecture, model for growth of progradational microtidal barrier islands, and Gulf of Mexico sea-level cyclicity:" Journal of Sedimentary Research, v. 80, p. 303–319.
  2. ^ a b Davis Jr., p. 144.
  3. ^ Durán Vinent, Orencio; Moore, Laura J. (2015). "Barrier island bistability induced by biophysical interactions". Nature Climate Change. 5 (2): 158–162. doi:10.1038/nclimate2474.
  4. ^ a b Smith, Q.H.T., Heap, A.D., and Nichol, S.L., 2010, "Origin and formation of an estuarine barrier island, Tapora Island, New Zealand:" Journal of Coastal Research, v. 26, p. 292–300.
  5. ^ Lorenzo-Trueba, J.; Ashton, A. (2014). "Rollover, drowning, and discontinuous retreat: Distinct modes of barrier response to sea-level rise arising from a simple morphodynamic model". Journal of Geophysical Research: Earth Surface. 119 (4): 779–801. doi:10.1002/2013JF002941.
  6. ^ Leatherman, S.P (1976). "Barrier island migration: an assessment of the overwash process". Geological Society of America Abstracts with Programs. 8: 215.
  7. ^ Rosati, J.D (2009). "Concepts for Functional Restoration of Barrier Islands" (Engineer research and development center vicksburg ms environmental lab).
  8. ^ Rosati, J.D; Dean, R.G; Stone, G.W (2007). "Morphologic evolution of subsiding barrier island systems". Proceedings 30th International Coastal Engineering Conference, World Scientific Press, in Press.
  9. ^ a b Davis Jr., p. 147
  10. ^ Boggs, S., Jr., 2012, Principles of Sedimentology and Stratigraphy: New Jersey, Pearson Education, Inc., 585 p.
  11. ^ Coastal Services Center, NOAA’s Coastal Services Center Barrier Islands: Formation and Evolution Archived August 8, 2010, at the Wayback Machine. Accessed April 10, 2011.
  12. ^ Davis Jr., pp. 144–145
  13. ^ Davis Jr., p. 145
  14. ^ Morton, p. 2
  15. ^ M. R. Johnson (2001). "Nelson Boulder Bank". New Zealand Journal of Geology and Geophysics. 44: 79–88. doi:10.1080/00288306.2001.9514924.
  16. ^ Stone, G.W., and McBride, R.A., 1998, "Louisiana barrier islands and their importance in wetland protection: forecasting shoreline change and subsequent response of wave climate:" Journal of Coastal Research, v. 14, p. 900–915.


Assateague Island National Seashore

Assateague Island National Seashore is a unit of the National Park Service system of the U.S. Department of the Interior. Located on the East Coast along the Atlantic Ocean in Maryland and Virginia, Assateague Island is the largest natural barrier island ecosystem in the Middle Atlantic states region that remains predominantly unaffected by human development. Located within a three-hour drive to the east and south of the Richmond, Washington, Baltimore, Wilmington, Philadelphia major metropolitan areas plus north of the several clustered smaller cities around Hampton Roads harbor of Virginia with Newport News, Hampton, Norfolk, Portsmouth, Chesapeake and Virginia Beach. The National Seashore offers a setting in which to experience a dynamic barrier island and to pursue a multitude of recreational opportunities. The stated mission of the park is to preserve and protect “unique coastal resources and the natural ecosystem conditions and processes upon which they depend, provide high-quality resource-based recreational opportunities compatible with resource protection and educate the public as to the values and significance of the area”.

Assateague Island encompasses a 37-mile-long barrier island, adjacent marsh islands and waters in Maryland and Virginia, and the Assateague Island Visitor Center on the Maryland mainland. 41,346 acres of land and water are within the seashore’s boundaries. The island consists of three public areas; Assateague Island National Seashore (managed by the National Park Service), Assateague State Park (managed by the Maryland Park Service of the Department of Natural Resources) and Chincoteague National Wildlife Refuge (managed by the U.S. Fish and Wildlife Service).

Bank (geography)

In geography, the word bank generally refers to the land alongside a body of water. Different structures are referred to as banks in different fields of geography, as follows.

In limnology (the study of inland waters), a stream bank or river bank is the terrain alongside the bed of a river, creek, or stream. The bank consists of the sides of the channel, between which the flow is confined. Stream banks are of particular interest in fluvial geography, which studies the processes associated with rivers and streams and the deposits and landforms created by them. Bankfull discharge is a discharge great enough to fill the channel and overtop the banks.The descriptive terms left bank and right bank refer to the perspective of an observer looking downstream, a well-known example of this being the sections of Paris as defined by the river Seine. The shoreline of ponds, swamps, estuaries, reservoirs, or lakes are also of interest in limnology and are sometimes referred to as banks. The grade of all these banks or shorelines can vary from vertical to a shallow slope.

In freshwater ecology, banks are of interest as the location of riparian habitats. Riparian zones occur along upland and lowland river and stream beds. The ecology around and depending on a marsh, swamp, slough, or estuary, sometimes called a bank, is likewise studied in freshwater ecology.

Banks are also of interest in navigation, where the term can refer either to a barrier island or a submerged plateau, such as an ocean bank. A barrier island is a long narrow island composed of sand and forming a barrier between an island lagoon or sound and the ocean. A submerged plateau is a relatively flat topped elevation of the sea floor at shallow depth (generally less than 200 m), typically on the continental shelf or near an island.

Caladesi Island State Park

Caladesi Island State Park is a Florida State Park located on Caladesi Island in the Gulf of Mexico, across St. Joseph Sound to the west of Dunedin, Florida, and north of Clearwater Beach.

It is accessible by passenger ferry, or by private boat, from a dock on Honeymoon Island, provided primarily for convenience of access from the north (Dunedin area). Alternatively, the state park can be walked to via Clearwater Beach from the south; it is only separated by a "welcome" sign. Thus, Caladesi Island is not its own island, but shares its island geography with Clearwater Beach.

Amenities include a three-mile nature trail, a marina, picnic pavilions, bathhouses, a park concession stand, and a beach. In 2005 the Caladesi Island beach was listed as having the fourth-best beach in the country, in 2006 and 2007 the second-best, and in 2008 the best beach in the United States by Dr. Beach.Originally part of a large barrier island, Caladesi Island and Honeymoon Island, north of Caladesi, were formed in 1921 when a hurricane created Hurricane Pass, splitting the barrier island into two parts.

Although Caladesi is still referred to as an island, Hurricane Elena filled in Dunedin Pass in 1985, making Caladesi "Island" accessible by walking northward from North Clearwater Beach.In the 1880s, homesteader Henry Scharrer and his daughter Myrtle lived on the island. Later in life, at the age of 87, Myrtle Scharrer Betz penned the book Yesteryear I Lived in Paradise, telling of her life on the barrier island.

Capers Island, South Carolina

Capers Island is a state-owned barrier island on the Atlantic Ocean in Charleston County, South Carolina about 15 miles north of the city of Charleston. It is separated from the mainland by salt marshes and the Intracoastal Waterway. To the southwest it is separated from the barrier island Dewees Island by Capers Inlet. To the northwest, it is separated from the barrier island Bulls Island by Price Inlet.The island is named for Bishop William Theodotus Capers, a native of South Carolina.

Flight Hauraki

Flight Hauraki is a small regional airline based in Ardmore, in New Zealand. in December 2014, the airline began an "Island Hopper" service offering two return daily flights from Ardmore to Waiheke Island and on to Great Barrier Island. The airline offers scenic flight tours around Central Auckland and the Hauraki Gulf islands Rangitoto and Motutapu.

Great Barrier Aerodrome

Great Barrier Aerodrome (IATA: GBZ, ICAO: NZGB) is the major airfield of the three on Great Barrier Island. It is a small, uncontrolled aerodrome 1 nautical mile (1.9 km) north-east of Claris on Great Barrier Island in the Hauraki Gulf off the North Island of New Zealand. Fuel is not available.

The town of Claris is a short walk to the north east, and there are rental car and bicycle hire services available at the airport. Landing fees were previously payable at Council offices, but are now billed direct to aircraft operators.

Great Barrier Island

Great Barrier Island (Māori: Aotea) lies in the outer Hauraki Gulf, New Zealand, 100 kilometres (62 mi) north-east of central Auckland. With an area of 285 square kilometres (110 sq mi) it is the sixth-largest island of New Zealand and fourth-largest in the main chain. Its highest point, Mount Hobson, is 627 metres (2,057 ft) above sea level. The local authority is the Auckland Council.

The island was initially exploited for its minerals and kauri trees and saw only limited agriculture. In 2013, it was inhabited by 939 people, mostly living from farming and tourism. The majority of the island (around 60% of the total area) is administered as a nature reserve by the Department of Conservation. In 2009 the island atmosphere was described as being "life in New Zealand many decades back".

John da Silva

John Walter da Silva (born 11 June 1934) is a former New Zealand wrestler and boxer.

He represented New Zealand in wrestling at the 1956 Olympics and at the 1958 British Empire and Commonwealth Games. In 1955 he held both the New Zealand Heavyweight Wrestling title and the Auckland Heavyweight Boxing title. His family was of a mixed race, being Portuguese, African, English and French Tahitian. Paul Silva, a competitive wood chopper, was his uncle.An amateur from 1953, he turned professional after the 1958 Commonwealth Games in Cardiff. He wrestled throughout New Zealand and around the world.

He retired in 1977, and subsequently worked with disadvantaged youth. He was awarded the Queen's Service Medal for community service in the 1994 New Year Honours.He now lives on Great Barrier Island. He is the father of boxer Garth da Silva.

Little Barrier Island

Little Barrier Island, or Hauturu in Māori language (the official Māori title is Te Hauturu-o-Toi), lies off the northeastern coast of New Zealand's North Island. Located 80 kilometres (50 mi) to the north of Auckland, the island is separated from the mainland to the west by Jellicoe Channel, and from the larger Great Barrier Island to the east by Cradock Channel. The two aptly named islands shelter the Hauraki Gulf from many of the storms of the Pacific Ocean.

Settled by Māori sometime between 1350 and 1650, the island was occupied by those people until the New Zealand government declared the island a wildlife sanctuary in 1897. Since the island came under control of the government, it has been under limited access, with only a few rangers living on the island. In the Māori language, the name of the island name means "the resting place of lingering breezes". Along with its larger neighbour Great Barrier, it was given its English name by Captain James Cook in 1769.The island is a nature sanctuary which has been described by the MBIE as "the most intact [native] ecosystem in New Zealand". However, several invasive species were introduced by both Maori and European settlers, including cats, which were destructive to local small bird and reptile species until they were eradicated between July 1977 and June 1980 in what was possibly New Zealand's costliest pest control programme.

Long Beach, New York

Long Beach is a city in Nassau County, New York. Just south of Long Island, it is on Long Beach Barrier Island, which is the westernmost of the outer barrier islands off Long Island's South Shore. As of the 2010 United States Census, the city population was 33,275. It was incorporated in 1922, and is nicknamed The City By the Sea (as seen in Latin on its official seal). The city of Long Beach is surrounded by Reynolds Channel to the north, east and west, and the Atlantic Ocean to the south.


Ngātiwai or Ngāti Wai is a Māori iwi of the east coast of the Northland Region of New Zealand. Its historical tribal area or rohe stretched from Cape Brett in the north to Takatū Point on Tawharanui Peninsula in the south and out to Great Barrier Island, the Poor Knights Islands and other offshore islands.Descendants of Ngātiwai include brothers Jim, Ian and Winston Peters, artist Shona Rapira Davies, and writer Paula Morris.

North Frisian Barrier Island

North Frisian Barrier Island is the collective term for three barrier islands (outer shoals) due west of the German Halligen in the North Frisian Islands archipelago. The shoals act as natural breakwater for the Halligen and other islands closer to land. Uninhabited, they remain one of the few areas in the Wadden Sea that are unaffected by direct human activity.

The shoals from north to south are:

The shoals are subject to constant change and are slowly moving towards the mainland coast to the east. This changes both their location and surface area. During the last 50 years, all three shoals benefitted from their increasing area but their individual development was very diverse. In total, 43.5 million m3 of sand were eroded by wind and water on the west coasts of the shoals, whereas 32.4 million m3 were deposited at the eastern shorelines. Especially Japsand, which is the youngest and smallest of the three shoals, could thereby gain volume and was the fastest moving shoal. Numerical simulations by the University of Kiel have shown the likelihood of a merger between Japsand and Norderoogsand until 2050. This would cover Hallig Norderoog in sand, as well as large areas of mudflats which are still east of the sands as of today.The peak heights of the shoals reach about one metre above the average high tide. In summer, the dry sand is sometimes piled to dunes of several metres height. These are occasionally settled by Elymus grasses. Since 1999 though, an increasingly stable and diverse vegetation has been observed at the northern edge of Norderoogsand. The plant carpet helps to accumulate ever more sand, and so the peak dune of Norderoogsand was recorded with 3.50 metres in 2013. Because of this development, Norderoogsand has been called a new island.All three shoals are nature reserves and constitute an important resting area for migratory birds, harbour seals, and grey seals. Together with the Hooger Loch and Rummelloch-West gats, as well the Halligen of Norderoog and Süderoog, the shoals are a popular resort for seals and form one of the main moulting areas of the common eider.The shoals are part of the core zone of the Schleswig-Holstein Wadden Sea National Park and must not be entered except for the northern areas of Japsand. In 1985, a light beacon was erected on Süderoogsand on a wooden framework. The device is solar powered and has a shelter for shipwrecked sailors.

Okiwi Airfield

Okiwi Airfield (ICAO: NZOX), also called Okiwi Station Airfield, is a small airfield located near the village of Okiwi on Great Barrier Island. It has a single bitumen runway, and a small terminal in the form of a wooden hut. The airfield is owned by Auckland Council and is used for both general aviation and commercial flights operated by Barrier Air and Fly My Sky.

Outer Barrier

The Outer Barrier, also known as the Long Island and New York City barrier islands, refers to the string of barrier islands that divide the lagoons south of Long Island, New York from the Atlantic Ocean. These islands include Coney Island, Long Beach Barrier Island, Island Park, Jones Beach Island, Fire Island and Westhampton Island. The outer barrier extends 75 miles (121 km) along the South Shore of Long Island, from the Rockaway Peninsula in New York City to the east end of Shinnecock Bay in Suffolk County.

The lagoons enclosed by the barrier islands are Jamaica Bay, Brosewere Bay, Hewlett Bay, Reynolds Channel, Middle Bay, East Bay, South Oyster Bay, Great South Bay, and arms of the Great South Bay that have their own geographic names: Great Cove, Nicoll Bay, Patchogue Bay, Bellport Bay, Narrow Bay, Moriches Bay, Quantuck Bay, Tiana Bay, and Shinnecock Bay. East Rockaway Inlet, Jones Inlet, Fire Island Inlet, Old Inlet, Moriches Inlet, and Shinnecock Inlet pierce the barrier, forming the individual sandy islands. The resort communities of Atlantic Beach, Long Beach, and Westhampton Beach; the Fire Island National Seashore, Robert Moses State Park, Jones Beach State Park, and other recreational areas are found there. The low-lying islands are subject to wave erosion, and, during storms, they are sometimes inundated and cut through.

Sampsons Island

Sampsons Island is a 15-acre (6.1 ha) uninhabited, undeveloped barrier island at the mouth of Cotuit Harbor in Barnstable, Massachusetts. It is the location of the Massachusetts Audubon Society's Sampsons Island Wildlife Sanctuary, and it forms part of the Sampsons Island/Dead Neck Island barrier beach system. The island is only accessible by private boat, and is used for recreation and wildlife viewing and preservation.As a barrier island, Sampsons Island and Dead Neck Island protect Cotuit Harbor and nearby coastal areas. The island is a nesting site for piping plovers, least terns, and common terns and a habitat for many other shore birds. It is designated an Important Bird Area. Access to the island is limited during nesting season.

Sapelo Island National Estuarine Research Reserve

The Sapelo Island National Estuarine Research Reserve is a 6,110-acre (2,470 ha) coastal plain estuary, located in the U.S. State of Georgia, protected on its seaward side by a Pleistocene barrier island. It was established in 1976.

Sapelo Island is the fourth largest Georgia barrier island and one of the most pristine. The reserve is made up of salt marshes, maritime forests and beach dune areas. Not only is the island rich in natural history, but also in human history dating back 4,000 years.

Strand plain

A strand plain or strandplain is a broad belt of sand along a shoreline with a surface exhibiting well-defined parallel or semi-parallel sand ridges separated by shallow swales. A strand plain differs from a barrier island in that it lacks either the lagoons or tidal marshes that separate a barrier island from the shoreline to which the strand plain is directly attached. Also, the tidal channels and inlets which cut through barrier islands are absent. Strand plains typically are created by the redistribution by waves and longshore currents of coarse sediment on either side of a river mouth. Thus, they are part of one type of wave-dominated delta.Examples of strand plains:

Western Louisiana

Eastern Texas

West coast of Namibia

South-east and south-west coasts of Australia, and in the Gulf of Carpentaria

Letea and Caraorman, Danube Delta, Romania

Tidal marsh

A tidal marsh (also known as a "tidal wetland") is a marsh found along rivers, coasts and estuaries which floods and drains by the tidal movement of the adjacent estuary, sea or ocean. Tidal marshes experience many overlapping persistent cycles, including diurnal and semi-diurnal tides, day-night temperature fluctuations, spring-neap tides, seasonal vegetation growth and decay, upland runoff, decadal climate variations, and centennial to millennial trends in sea level and climate. They are also impacted by transient disturbances such as hurricanes, floods, storms, and upland fires.

Venetian Causeway

The Venetian Causeway crosses Biscayne Bay between Miami on the mainland and Miami Beach on a barrier island in south Florida. The man-made Venetian Islands and non-bridge portions of the causeway were created by materials which came from the dredging of the bay. The Venetian Causeway follows the original route of the Collins Bridge, a wooden 2.5 mi (4 km) long structure built in 1913 by John S. Collins and Carl G. Fisher which opened up the barrier island for unprecedented growth and development.

The causeway has one toll plaza (administered by the Miami-Dade County Public Works department) on Biscayne Island, the westernmost Venetian Island. The toll for an automobile is $3.00 (US).The causeway has two bascule bridges.

At the Downtown/Western Beginning of the causeway travelers are greeted by two columns vertically saying "VENETIAN WAY" along with a sign indicating that there is a weight limit .

At the South Beach/Eastern Terminus, drivers must choose whether to go north onto Dade Boulevard or eastbound onto 17th Street to Ocean Drive, Collins Ave/A1A, Lincoln Road, City Hall, The Convention Center, Jackie Gleason Theater and the beach .

The Venetian Causeway was re-dedicated in 1999 after the completion of a $29 million restoration and replacement project.A popular use of the causeway is for exercising, which includes both jogging and bicycling.


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