A tombolo is a sandy or shingle isthmus . A tombolo, from the Italian tombolo , meaning 'pillow' or 'cushion', and sometimes translated incorrectly as ayre (an ayre is a shingle beach of any kind), is a deposition landform by which an island becomes attached to the mainland by a narrow piece of land such as a spit or bar . Once attached, the island is then known as a tied island .
27-534: Several islands tied together by bars which rise above the water level are called a tombolo cluster . Two or more tombolos may form an enclosure (called a lagoon ) that can eventually fill with sediment. The shoreline moves toward the island (or detached breakwater ) owing to the accretion of sand in the lee of the island, where wave energy and longshore drift are reduced and therefore deposition of sand occurs. True tombolos are formed by wave refraction and diffraction . As waves near an island, they are slowed by
54-430: A beached shipwreck can change the way that waves move, leading to different deposition of sediments. Sea level rise may also contribute to accretion, as material is pushed up with rising sea levels. Tombolos are more prone to natural fluctuations of profile and area as a result of tidal and weather events than a normal beach is. Because of this susceptibility to weathering, tombolos are sometimes made more sturdy through
81-539: A lake is hu ( 湖 ), and a lagoon is xihu ( 潟湖 ). In the French Mediterranean several lagoons are called étang ("lake"). Contrariwise, several other languages have specific words for such bodies of water. In Spanish, coastal lagoons generically are laguna costera , but those on the Mediterranean coast are specifically called albufera . In Russian and Ukrainian, those on
108-422: A regular flow of fresh water an "estuary". Davis does state that the terms "lagoon" and "estuary" are "often loosely applied, even in scientific literature". Timothy M. Kusky characterizes lagoons as normally being elongated parallel to the coast, while estuaries are usually drowned river valleys, elongated perpendicular to the coast. Coastal lagoons are classified as inland bodies of water. When used within
135-521: Is a shallow body of water separated from a larger body of water by a narrow landform , such as reefs , barrier islands , barrier peninsulas, or isthmuses . Lagoons are commonly divided into coastal lagoons (or barrier lagoons ) and atoll lagoons . They have also been identified as occurring on mixed-sand and gravel coastlines. There is an overlap between bodies of water classified as coastal lagoons and bodies of water classified as estuaries . Lagoons are common coastal features around many parts of
162-458: Is actually the third-largest lake by area in the country. The brackish water lagoon may be thus explicitly identified as a "coastal lagoon" ( laguna costera ). In Portuguese, a similar usage is found: lagoa may be a body of shallow seawater, or a small freshwater lake not linked to the sea. Lagoon is derived from the Italian laguna , which refers to the waters around Venice ,
189-502: Is also noted for its duck and goose hunting. 36°17′01″N 75°52′14″W / 36.28361°N 75.87056°W / 36.28361; -75.87056 This article about a location in Currituck County , North Carolina is a stub . You can help Misplaced Pages by expanding it . This City of Virginia Beach, Virginia state location article is a stub . You can help Misplaced Pages by expanding it . This article about
216-892: Is separated from the Atlantic Ocean by the Currituck Banks Peninsula (formerly Bodie Island ), part of the Outer Banks . On the northeast, it extends to Back Bay in northeast Virginia Beach, Virginia . A fork on the northwest leads to the Albemarle and Chesapeake Canal , which is a part of the Atlantic Intracoastal Waterway that connects the sound to Hampton Roads and the Chesapeake Bay . It ranges from 1 to 3 feet deep. Although several inlets connected it directly to
243-547: Is the major force that moves water. Currituck County 's Mackay Island and Currituck National Wildlife Refuge as well as Back Bay National Wildlife Refuge and False Cape State Park in Virginia Beach border the sound and are winter habitats on the Atlantic Flyway . Many watersports activities occur in the sound, including parasailing , sea kayaking , and jet skiing . An area of barrier beaches , it
270-626: The Black Sea are liman ( лиман ), while the generic word is laguna ( Лагуна ). Similarly, in the Baltic , Danish has the specific Nor [ da ] , and German the specifics Bodden and Haff , as well as generic terms derived from laguna . In Poland these lagoons are called zalew ("bay"), in Lithuania marios ("lagoon, reservoir"). In Jutland several lagoons are known as fjord . In New Zealand
297-522: The Isle of Portland , which it has reached. In this and similar cases like Cádiz , while the strip of beach material connected to the island may be technically called a tombolo because it links the island to the land, it is better thought of in terms of its formation as a spit , because the sand or shingle ridge is parallel rather than at right angles to the coast. Tombolos demonstrate the sensitivity of shorelines . A small piece of land, such as an island, or
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#1732791969301324-523: The Māori word hapua refers to a coastal lagoon formed at the mouth of a braided river where there are mixed sand and gravel beaches, while waituna , an ephemeral coastal waterbody, is neither a true lagoon, lake nor estuary. Some languages differentiate between coastal and atoll lagoons. In French, lagon [ fr ] refers specifically to an atoll lagoon, while coastal lagoons are described as étang [ fr ] ,
351-610: The Venetian Lagoon . Laguna is attested in English by at least 1612, and had been Anglicized to "lagune" by 1673. In 1697 William Dampier referred to a "Lagune or Lake of Salt water" on the coast of Mexico. Captain James Cook described an island "of Oval form with a Lagoon in the middle" in 1769. Atoll lagoons form as coral reefs grow upwards while the islands that the reefs surround subside, until eventually only
378-458: The Wadden Sea , have strong tidal currents and mixing. Coastal lagoons tend to accumulate sediments from inflowing rivers, from runoff from the shores of the lagoon, and from sediment carried into the lagoon through inlets by the tide. Large quantities of sediment may be occasionally be deposited in a lagoon when storm waves overwash barrier islands. Mangroves and marsh plants can facilitate
405-752: The Atlantic at one time or another, they have all since closed and there is now no direct access to the Ocean from the Sound. Thus contemporary salinity levels are very low, usually around 2-3 ‰ at the north end and 4-5‰ at the sound. Currently, the only access to the ocean is through the Albemarle Sound , which joins the Currituck to the South, meaning that the sound has no lunar or solar tides. Instead, wind
432-402: The accumulation of sediment in a lagoon. Benthic organisms may stabilize or destabilize sediments. Currituck Sound Currituck Sound ( / ˈ k ʊr ɪ t ʌ k / ) is a lagoon located in northeastern part of North Carolina and extreme southeastern Virginia . 36 miles (58 km) long north-south and 8 miles (13 km) at its widest, this shallow, island-filled sound
459-437: The construction of roads or parking lots. The sediments that make up a tombolo are coarser towards the bottom and finer towards the surface. It is easy to see this pattern when the waves are destructive and wash away finer grained material at the top, revealing coarser sands and cobbles as the base. Some of these may be simple isthmuses, and not have the deposition creation that defines a true tombolo. Lagoon A lagoon
486-626: The context of a distinctive portion of coral reef ecosystems, the term "lagoon" is synonymous with the term "back reef" or "backreef", which is more commonly used by coral reef scientists to refer to the same area. Many lagoons do not include "lagoon" in their common names. Currituck , Albemarle and Pamlico Sounds in North Carolina , Great South Bay between Long Island and the barrier beaches of Fire Island in New York , Isle of Wight Bay , which separates Ocean City, Maryland from
513-597: The generic word for a still lake or pond. In Vietnamese, Đầm san hô refers to an atoll lagoon, whilst Đầm phá is coastal. In Latin America, the term laguna in Spanish, which lagoon translates to, may be used for a small fresh water lake in a similar way a creek is considered a small river. However, sometimes it is popularly used to describe a full-sized lake , such as Laguna Catemaco in Mexico, which
540-630: The lagoon. Lagoons with little or no interchange with the open ocean, little or no inflow of fresh water, and high evaporation rates, such as Lake St. Lucia , in South Africa , may become highly saline. Lagoons with no connection to the open ocean and significant inflow of fresh water, such as the Lake Worth Lagoon in Florida in the middle of the 19th century, may be entirely fresh. On the other hand, lagoons with many wide inlets, such as
567-556: The land along the coast). Coastal lagoons do not form along steep or rocky coasts, or if the range of tides is more than 4 metres (13 ft). Due to the gentle slope of the coast, coastal lagoons are shallow. A relative drop in sea level may leave a lagoon largely dry, while a rise in sea level may let the sea breach or destroy barrier islands, and leave reefs too deep underwater to protect the lagoon. Coastal lagoons are young and dynamic, and may be short-lived in geological terms. Coastal lagoons are common, occurring along nearly 15 percent of
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#1732791969301594-407: The reefs remain above sea level. Unlike the lagoons that form shoreward of fringing reefs, atoll lagoons often contain some deep (>20 m (66 ft)) portions. Coastal lagoons form along gently sloping coasts where barrier islands or reefs can develop offshore, and the sea-level is rising relative to the land along the shore (either because of an intrinsic rise in sea-level, or subsidence of
621-627: The rest of Worcester County, Maryland , Banana River in Florida , US, Lake Illawarra in New South Wales , Australia, Montrose Basin in Scotland , and Broad Water in Wales have all been classified as lagoons, despite their names. In England, The Fleet at Chesil Beach has also been described as a lagoon. In some languages the word for a lagoon is simply a type of lake: In Chinese
648-407: The shallow water surrounding it. These waves then bend around the island to the opposite side as they approach. The wave pattern created by this water movement causes a convergence of longshore drift on the opposite side of the island. The beach sediments that are moving by lateral transport on the lee side of the island will accumulate there, conforming to the shape of the wave pattern. In other words,
675-426: The waves sweep sediment together from both sides. Eventually, when enough sediment has built up, the beach shoreline, known as a spit, will connect with an island and form a tombolo. In the case of longshore drift due to an oblique wave direction, like at Chesil Beach or Spurn Head , the flow of material is along the coast in a movement which is not determined by wave diffraction around the now tied island , such as
702-522: The world's shorelines. In the United States, lagoons are found along more than 75 percent of the Eastern and Gulf Coasts . Coastal lagoons can be classified as leaky, restricted, or choked. Coastal lagoons are usually connected to the open ocean by inlets between barrier islands. The number and size of the inlets, precipitation, evaporation, and inflow of fresh water all affect the nature of
729-582: The world. Lagoons are shallow, often elongated bodies of water separated from a larger body of water by a shallow or exposed shoal , coral reef , or similar feature. Some authorities include fresh water bodies in the definition of "lagoon", while others explicitly restrict "lagoon" to bodies of water with some degree of salinity . The distinction between "lagoon" and "estuary" also varies between authorities. Richard A. Davis Jr. restricts "lagoon" to bodies of water with little or no fresh water inflow, and little or no tidal flow, and calls any bay that receives
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