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74-455: Boca Chica has a popular beach with the same name, located about 30 kilometers east of Santo Domingo de Guzmán in the south-east region of the country. The community of Boca Chica was founded in 1779 during the government of Brigadier Don Isidro Peralta y Rojas with the name of San José de los Llanos. Boca Chica was later established by Dominican businessman and politician Juan Bautista Vicini Burgos , who developed sugar plantations there in

148-423: A beach depends on whether the waves are constructive or destructive, and whether the material is sand or shingle. Waves are constructive if the period between their wave crests is long enough for the breaking water to recede and the sediment to settle before the succeeding wave arrives and breaks. Fine sediment transported from lower down the beach profile will compact if the receding water percolates or soaks into

222-409: A beach tends to indicate the energy of the waves and wind in the locality. Constructive waves move material up the beach while destructive waves move the material down the beach. During seasons when destructive waves are prevalent, the shallows will carry an increased load of sediment and organic matter in suspension. On sandy beaches, the turbulent backwash of destructive waves removes material forming

296-409: A clay platelet has a slight negative charge where the edge has a slight positive charge when two platelets come into close proximity with each other the face of one particle and the edge of the other are electrostatically attracted." Flocs then have a higher combined mass which leads to quicker deposition through a higher fall velocity, and deposition in a more shoreward direction than they would have as

370-557: A cloudy water column which travels under the tidal influence as the wave orbital motion is in equilibrium. The Null-point hypothesis has been quantitatively proven in Akaroa Harbour, New Zealand, The Wash , U.K., Bohai Bay and West Huang Sera, Mainland China, and in numerous other studies; Ippen and Eagleson (1955), Eagleson and Dean (1959, 1961) and Miller and Zeigler (1958, 1964). Large-grain sediments transported by either bedload or suspended load will come to rest when there

444-519: A depth of −13 m relative to mean sea level at the 9 km point down the transect of the central axis. The predominant storm wave energy has unlimited fetch for the outer harbour from a southerly direction, with a calmer environment within the inner harbour, though localised harbour breezes create surface currents and chop influencing the marine sedimentation processes. Deposits of loess from subsequent glacial periods have in filled volcanic fissures over millennia, resulting in volcanic basalt and loess as

518-463: A filter for runoff from the coastal plain. If the runoff is naturally dispersed along the beach, water borne silt and organic matter will be retained on the land and will feed the flora in the coastal area. Runoff that is dispersed along the beach will tend to percolate through the beach and may emerge from the beach at low tide. The retention of the freshwater may also help to maintain underground water reserves and will resist salt water incursion. If

592-401: A gently sloping beach. On pebble and shingle beaches the swash is dissipated more quickly because the large particle size allows greater percolation , thereby reducing the power of the backwash, and the beach remains steep. Compacted fine sediments will form a smooth beach surface that resists wind and water erosion. During hot calm seasons, a crust may form on the surface of ocean beaches as

666-492: A lesser root ball. Erosion of beaches can expose less resilient soils and rocks to wind and wave action leading to undermining of coastal headlands eventually resulting in catastrophic collapse of large quantities of overburden into the shallows. This material may be distributed along the beach front leading to a change in the habitat as sea grasses and corals in the shallows may be buried or deprived of light and nutrients. Coastal areas settled by man inevitably become subject to

740-465: A necessary and permanent feature of beach maintenance. During beach nourishment activities, care must be taken to place new sediments so that the new sediments compact and stabilize before aggressive wave or wind action can erode them. Material that is concentrated too far down the beach may form a temporary groyne that will encourage scouring behind it. Sediments that are too fine or too light may be eroded before they have compacted or been integrated into

814-468: A rapid cycle of growth throughout the 1850s and 1860s. The growth was intensified by the practice among the Lancashire cotton mill owners of closing the factories for a week every year to service and repair machinery. These became known as wakes weeks . Each town's mills would close for a different week, allowing Blackpool to manage a steady and reliable stream of visitors over a prolonged period in

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888-435: A shoreline subject to constant erosion and loss of foreshore. This is often required where the flow of new sediment caused by the longshore current has been disrupted by construction of harbors, breakwaters, causeways or boat ramps, creating new current flows that scour the sand from behind these structures and deprive the beach of restorative sediments. If the causes of the erosion are not addressed, beach nourishment can become

962-422: A tidal surge or tsunami which causes significant coastal flooding , substantial quantities of material may be eroded from the coastal plain or dunes behind the berm by receding water. This flow may alter the shape of the coastline, enlarge the mouths of rivers and create new deltas at the mouths of streams that had not been powerful enough to overcome longshore movement of sediment. The line between beach and dune

1036-438: Is a significant source of sand particles. Some species of fish that feed on algae attached to coral outcrops and rocks can create substantial quantities of sand particles over their lifetime as they nibble during feeding, digesting the organic matter , and discarding the rock and coral particles which pass through their digestive tracts. The composition of the beach depends upon the nature and quantity of sediments upstream of

1110-506: Is because sediment grain size analysis throughout a profile allows inference into the erosion or accretion rates possible if shore dynamics are modified. Planners and managers should also be aware that the coastal environment is dynamic and contextual science should be evaluated before the implementation of any shore profile modification. Thus theoretical studies, laboratory experiments, numerical and hydraulic modelling seek to answer questions pertaining to littoral drift and sediment deposition,

1184-452: Is difficult to define in the field. Over any significant period of time, sediment is always being exchanged between them. The drift line (the high point of material deposited by waves) is one potential demarcation. This would be the point at which significant wind movement of sand could occur, since the normal waves do not wet the sand beyond this area. However, the drift line is likely to move inland under assault by storm waves. Beaches are

1258-404: Is due to the influence of hydraulic energy, resulting in a seaward-fining of sediment particle size, or where fluid forcing equals gravity for each grain size. The concept can also be explained as "sediment of a particular size may move across the profile to a position where it is in equilibrium with the wave and flows acting on that sediment grain". This sorting mechanism combines the influence of

1332-468: Is insufficient bed shear stress and fluid turbulence to keep the sediment moving; with the suspended load this can be some distance as the particles need to fall through the water column. This is determined by the grain's downward acting weight force being matched by a combined buoyancy and fluid drag force and can be expressed by: Downward acting weight force = Upward-acting buoyancy force + Upward-acting fluid drag force where: In order to calculate

1406-407: Is known as the hypothesis of asymmetrical thresholds under waves; this describes the interaction between the oscillatory flow of waves and tides flowing over the wave ripple bedforms in an asymmetric pattern. "The relatively strong onshore stroke of the waveforms an eddy or vortex on the lee side of the ripple, provided the onshore flow persists, this eddy remains trapped in the lee of the ripple. When

1480-448: Is made up partly of the microscopic calcium carbonate skeletons of marine plankton , the deposition of which induced chemical processes ( diagenesis ) to deposit further calcium carbonate. Similarly, the formation of coal begins with the deposition of organic material, mainly from plants, in anaerobic conditions. The null-point hypothesis explains how sediment is deposited throughout a shore profile according to its grain size. This

1554-455: Is the importing and deposition of sand or other sediments in an effort to restore a beach that has been damaged by erosion. Beach nourishment often involves excavation of sediments from riverbeds or sand quarries. This excavated sediment may be substantially different in size and appearance to the naturally occurring beach sand. In extreme cases, beach nourishment may involve placement of large pebbles or rocks in an effort to permanently restore

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1628-452: The seashore is most commonly associated with the word beach , beaches are also found by lakes and alongside large rivers. Beach may refer to: The former are described in detail below; the larger geological units are discussed elsewhere under bars . There are several conspicuous parts to a beach that relate to the processes that form and shape it. The part mostly above water (depending upon tide), and more or less actively influenced by

1702-487: The 1720s; it had been a fashionable spa town since a stream of acidic water was discovered running from one of the cliffs to the south of the town in the 17th century. The first rolling bathing machines were introduced by 1735. The opening of the resort in Brighton and its reception of royal patronage from King George IV , extended the seaside as a resort for health and pleasure to the much larger London market, and

1776-507: The 1940s, when dictator Rafael Leónidas Trujillo ordered the construction of a modern hotel named "Hotel Hamaca", which subsequently became an icon in the area. During the 1950s prominent families of the Dominican Republic built several summer properties along the beach only accessible by private transportation. The hotel also became more famous after Trujillo granted political asylum to the dictator Fulgencio Batista . After

1850-414: The Dominican Republic, especially on weekends and holidays. Boca Chica beach has immaculate fine sand. You can walk in the water and the depth will barely change, the water will be to your waist (or a little bit over) all the time. Boca Chica has two small islands, Los Pinos and La Matica, and two marinas . There are several bars, restaurants, pizza stands, souvenirs stalls and loud music throughout most of

1924-492: The all-covering beachwear of the period was considered immodest. By the end of the century the English coastline had over 100 large resort towns, some with populations exceeding 50,000. Deposition (geology) Deposition is the geological process in which sediments , soil and rocks are added to a landform or landmass . Wind, ice, water, and gravity transport previously weathered surface material, which, at

1998-428: The area. It was later reopened and the public beach remains popular among people of different classes. Boca Chica's proximity to the city of Santo Domingo , its clear blue waters and white sand have made it one of the busiest beaches in the Dominican Republic, especially on weekends and holidays , because it is 30 km away from Santo Domingo. Boca Chica has two small islands Los Pinos, which were made with sand from

2072-458: The assassination of Rafael Trujillo in 1961 the beach became more accessible to the public. The beach became increasingly more popular and public transportation helped to make Boca Chica a very crowded place in the 1960s and 1970s; it was no longer a secluded beach for the elites as it had been during the 1950s. The Hamaca hotel was closed after Hurricane David in 1979, and it remained closed and abandoned for years which caused an economic decline in

2146-435: The beach and into the sea. If the flow is constant, runoff from cleared land arriving at the beach head will tend to deposit this material into the sand changing its color, odor and fauna. The concentration of pedestrian and vehicular traffic accessing the beach for recreational purposes may cause increased erosion at the access points if measures are not taken to stabilize the beach surface above high-water mark. Recognition of

2220-457: The beach as a popular leisure resort from the mid-19th century was the first manifestation of what is now the global tourist industry. The first seaside resorts were opened in the 18th century for the aristocracy, who began to frequent the seaside as well as the then fashionable spa towns, for recreation and health. One of the earliest such seaside resorts, was Scarborough in Yorkshire during

2294-620: The beach became a centre for upper-class pleasure and frivolity. This trend was praised and artistically elevated by the new romantic ideal of the picturesque landscape; Jane Austen 's unfinished novel Sanditon is an example of that. Later, Queen Victoria 's long-standing patronage of the Isle of Wight and Ramsgate in Kent ensured that a seaside residence was considered as a highly fashionable possession for those wealthy enough to afford more than one home. The extension of this form of leisure to

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2368-401: The beach head, they may erode the beach creating a lagoon or delta. Dense vegetation tends to absorb rainfall reducing the speed of runoff and releasing it over longer periods of time. Destruction by burning or clearance of the natural vegetation tends to increase the speed and erosive power of runoff from rainfall. This runoff will tend to carry more silt and organic matter from the land onto

2442-523: The beach profile is higher in summer. The gentle wave action during this season tends to transport sediment up the beach towards the berm where it is deposited and remains while the water recedes. Onshore winds carry it further inland forming and enhancing dunes. Conversely, the beach profile is lower in the storm season (winter in temperate areas) due to the increased wave energy, and the shorter periods between breaking wave crests. Higher energy waves breaking in quick succession tend to mobilise sediment from

2516-404: The beach, and the speed of flow and turbidity of water and wind. Sediments are moved by moving water and wind according to their particle size and state of compaction. Particles tend to settle and compact in still water. Once compacted, they are more resistant to erosion . Established vegetation (especially species with complex network root systems) will resist erosion by slowing the fluid flow at

2590-1686: The beach. However, these natural forces have become more extreme due to climate change , permanently altering beaches at very rapid rates. Some estimates describe as much as 50 percent of the earth's sandy beaches disappearing by 2100 due to climate-change driven sea level rise. Sandy beaches occupy about one third of global coastlines. These beaches are popular for recreation , playing important economic and cultural roles—often driving local tourism industries. To support these uses, some beaches have human-made infrastructure, such as lifeguard posts, changing rooms , showers, shacks and bars. They may also have hospitality venues (such as resorts, camps, hotels, and restaurants) nearby or housing, both for permanent and seasonal residents. Human forces have significantly changed beaches globally: direct impacts include bad construction practices on dunes and coastlines, while indirect human impacts include water pollution , plastic pollution and coastal erosion from sea level rise and climate change . Some coastal management practices are designed to preserve or restore natural beach processes, while some beaches are actively restored through practices like beach nourishment . Wild beaches, also known as undeveloped or undiscovered beaches, are not developed for tourism or recreation. Preserved beaches are important biomes with important roles in aquatic or marine biodiversity, such as for breeding grounds for sea turtles or nesting areas for seabirds or penguins . Preserved beaches and their associated dune are important for protection from extreme weather for inland ecosystems and human infrastructure. Although

2664-413: The beach. Compacted sediment is more resistant to movement by turbulent water from succeeding waves. Conversely, waves are destructive if the period between the wave crests is short. Sediment that remains in suspension when the following wave crest arrives will not be able to settle and compact and will be more susceptible to erosion by longshore currents and receding tides. The nature of sediments found on

2738-562: The central axis of the harbour, or if classified into grain class sizes, "the plotted transect for the central axis goes from silty sands in the intertidal zone to sandy silts in the inner nearshore, to silts in the outer reaches of the bays to mud at depths of 6 m or more". See figure 2 for detail. Other studies have shown this process of the winnowing of sediment grain size from the effect of hydrodynamic forcing; Wang, Collins and Zhu (1988) qualitatively correlated increasing intensity of fluid forcing with increasing grain size. "This correlation

2812-452: The character of underwater flora and fauna in the coastal shallows. Burning or clearance of vegetation on the land adjacent to the beach head, for farming and residential development, changes the surface wind patterns, and exposes the surface of the beach to wind erosion. Farming and residential development are also commonly associated with changes in local surface water flows. If these flows are concentrated in stormwater drains emptying onto

2886-444: The dangers of loss of beach front flora has caused many local authorities responsible for managing coastal areas to restrict beach access points by physical structures or legal sanctions, and fence off foredunes in an effort to protect the flora. These measures are often associated with the construction of structures at these access points to allow traffic to pass over or through the dunes without causing further damage. Beaches provide

2960-516: The day; all this along the beach sand very close to the shore. In the evening, Boca Chica transforms itself into a town of party bars. Notes Beach A beach is a landform alongside a body of water which consists of loose particles. The particles composing a beach are typically made from rock , such as sand , gravel , shingle , pebbles , etc., or biological sources, such as mollusc shells or coralline algae . Sediments settle in different densities and structures, depending on

3034-427: The down-slope gravitational force of the profile and forces due to flow asymmetry; the position where there is zero net transport is known as the null point and was first proposed by Cornaglia in 1889. Figure 1 illustrates this relationship between sediment grain size and the depth of the marine environment. The first principle underlying the null point theory is due to the gravitational force; finer sediments remain in

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3108-406: The drag coefficient, the grain's Reynolds number needs to be discovered, which is based on the type of fluid through which the sediment particle is flowing, laminar flow, turbulent flow or a hybrid of both. When the fluid becomes more viscous due to smaller grain sizes or larger settling velocities, the prediction is less straightforward and it is applicable to incorporate Stokes Law (also known as

3182-527: The dredging of the Andrés port in the 1950s and La Matica and La Piedra, mangrove cays, submerged vascular plants and habitat for various species of birds. The beach has a natural breakwater, as well as a fresh water spring, coming from the Brujuelas underground river. The short distance from the capital city (19 miles), the crystalline waters and the white sands turned Boca Chica into the most crowded beach of

3256-628: The early 1900s. Boca Chica was developed by the Dominican state through the Boca Chica sugar company in 1916 and throughout the 1920s. In 1926 the highway was built that would connect it with the city of Santo Domingo. In November 1932, by order of Dominican dictator Rafael Leónidas Trujillo , Boca Chica was separated from the province of San Pedro de Macorís to form part of the National District. The golden era of Boca Chica began in

3330-504: The effects of human-made structures and processes. Over long periods of time, these influences may substantially alter the shape of the coastline, and the character of the beach. Beachfront flora plays a major role in stabilizing the foredunes and preventing beach head erosion and inland movement of dunes. If flora with network root systems (creepers, grasses, and palms) are able to become established, they provide an effective coastal defense as they trap sand particles and rainwater and enrich

3404-434: The established vegetation. Foreign unwashed sediments may introduce flora or fauna that are not usually found in that locality. Brighton Beach, on the south coast of England, is a shingle beach that has been nourished with very large pebbles in an effort to withstand the erosion of the upper area of the beach. These large pebbles made the beach unwelcoming for pedestrians for a period of time until natural processes integrated

3478-417: The feature. Where wind is the force distributing the grains inland, the deposit behind the beach becomes a dune . These geomorphic features compose what is called the beach profile . The beach profile changes seasonally due to the change in wave energy experienced during summer and winter months. In temperate areas where summer is characterised by calmer seas and longer periods between breaking wave crests,

3552-559: The fines are suspended and reworked aerially offshore leaving behind lag deposits of the main bivalve and gastropod shells separated out from the finer substrate beneath, waves and currents then heap these deposits to form chenier ridges throughout the tidal zone, which tend to be forced up the foreshore profile but also along the foreshore. Cheniers can be found at any level on the foreshore and predominantly characterise an erosion-dominated regime. The null point theory has been controversial in its acceptance into mainstream coastal science as

3626-414: The flow reverses, the eddy is thrown upwards off the bottom and a small cloud of suspended sediment generated by the eddy is ejected into the water column above the ripple, the sediment cloud is then moved seaward by the offshore stroke of the wave." Where there is symmetry in ripple shape the vortex is neutralised, the eddy and its associated sediment cloud develops on both sides of the ripple. This creates

3700-531: The frictional force, or drag force) of settling. The cohesion of sediment occurs with the small grain sizes associated with silts and clays, or particles smaller than 4ϕ on the phi scale. If these fine particles remain dispersed in the water column, Stokes law applies to the settling velocity of the individual grains, although due to seawater being a strong electrolyte bonding agent, flocculation occurs where individual particles create an electrical bond adhering each other together to form flocs. "The face of

3774-450: The heat of the sun evaporates the water leaving the salt which crystallises around the sand particles. This crust forms an additional protective layer that resists wind erosion unless disturbed by animals or dissolved by the advancing tide. Cusps and horns form where incoming waves divide, depositing sand as horns and scouring out sand to form cusps. This forms the uneven face on some sand shorelines . White sand beaches look white because

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3848-449: The height of the water table. Some flora naturally occurring on the beach head requires freshwater runoff from the land. Diversion of freshwater runoff into drains may deprive these plants of their water supplies and allow sea water incursion, increasing the saltiness of the groundwater. Species that are not able to survive in salt water may die and be replaced by mangroves or other species adapted to salty environments. Beach nourishment

3922-451: The individual fine grains of clay or silt. Akaroa Harbour is located on Banks Peninsula , Canterbury, New Zealand , 43°48′S 172°56′E  /  43.800°S 172.933°E  / -43.800; 172.933 . The formation of this harbour has occurred due to active erosional processes on an extinct shield volcano, whereby the sea has flooded the caldera, creating an inlet 16 km in length, with an average width of 2 km and

3996-547: The local wave action and weather , creating different textures, colors and gradients or layers of material. Though some beaches form on inland freshwater locations such as lakes and rivers , most beaches are in coastal areas where wave or current action deposits and reworks sediments. Erosion and changing of beach geologies happens through natural processes, like wave action and extreme weather events . Where wind conditions are correct, beaches can be backed by coastal dunes which offer protection and regeneration for

4070-449: The loss of enough kinetic energy in the fluid, is deposited, building up layers of sediment. This occurs when the forces responsible for sediment transportation are no longer sufficient to overcome the forces of gravity and friction , creating a resistance to motion; this is known as the null-point hypothesis. Deposition can also refer to the buildup of sediment from organically derived matter or chemical processes . For example, chalk

4144-478: The main sediment types available for deposition in Akaroa Harbour Hart et al. (2009) discovered through bathymetric survey, sieve and pipette analysis of subtidal sediments, that sediment textures were related to three main factors: depth, distance from shoreline, and distance along the central axis of the harbour. This resulted in the fining of sediment textures with increasing depth and towards

4218-445: The middle and working classes began with the development of the railways in the 1840s, which offered cheap fares to fast-growing resort towns. In particular, the completion of a branch line to the small seaside town of Blackpool from Poulton led to a sustained economic and demographic boom. A sudden influx of visitors, arriving by rail, led entrepreneurs to build accommodation and create new attractions, leading to more visitors and

4292-632: The naturally occurring shingle into the pebble base. Even in Roman times, wealthy people spent their free time on the coast. They also built large villa complexes with bathing facilities (so-called maritime villas) in particularly beautiful locations. Excavations of Roman architecture can still be found today, for example on the Amalfi Coast near Naples and in Barcola in Trieste. The development of

4366-621: The permanent water forming offshore bars, lagoons or increasing the area of the beach exposed at low tide. Large and rapid movements of exposed sand can bury and smother flora in adjacent areas, aggravating the loss of habitat for fauna, and enlarging the area of instability. If there is an adequate supply of sand, and weather conditions do not allow vegetation to recover and stabilize the sediment, wind-blown sand can continue to advance, engulfing and permanently altering downwind landscapes. Sediment moved by waves or receding floodwaters can be deposited in coastal shallows, engulfing reed beds and changing

4440-564: The quartz or eroded limestone in the sand reflects or scatters sunlight without absorbing other colors. The composition of the sand varies depending on the local minerals and geology. Some of the types of sand found in beaches around the world are: Beaches are changed in shape chiefly by the movement of water and wind. Any weather event that is associated with turbid or fast-flowing water or high winds will erode exposed beaches. Longshore currents will tend to replenish beach sediments and repair storm damage. Tidal waterways generally change

4514-415: The result of wave action by which waves or currents move sand or other loose sediments of which the beach is made as these particles are held in suspension . Alternatively, sand may be moved by saltation (a bouncing movement of large particles). Beach materials come from erosion of rocks offshore, as well as from headland erosion and slumping producing deposits of scree . A coral reef offshore

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4588-412: The shallows, keeping it in suspension where it is prone to be carried along the beach by longshore currents, or carried out to sea to form longshore bars, especially if the longshore current meets an outflow from a river or flooding stream. The removal of sediment from the beach berm and dune thus decreases the beach profile. If storms coincide with unusually high tides, or with a freak wave event such as

4662-487: The shape of their adjacent beaches by small degrees with every tidal cycle. Over time these changes can become substantial leading to significant changes in the size and location of the beach. Changes in the shape of the beach may undermine the roots of large trees and other flora. Many beach adapted species (such as coconut palms) have a fine root system and large root ball which tends to withstand wave and wind action and tends to stabilize beaches better than other trees with

4736-562: The shape, profile and location of a beach within hours. Destruction of flora on the berm by the use of herbicides, excessive pedestrian or vehicle traffic, or disruption to freshwater flows may lead to erosion of the berm and dunes. While the destruction of flora may be a gradual process that is imperceptible to regular beach users, it often becomes immediately apparent after storms associated with high winds and freak wave events that can rapidly move large volumes of exposed and unstable sand, depositing them further inland, or carrying them out into

4810-577: The summer. A prominent feature of the resort was the promenade and the pleasure piers , where an eclectic variety of performances vied for the people's attention. In 1863, the North Pier in Blackpool was completed, rapidly becoming a centre of attraction for upper class visitors. Central Pier was completed in 1868, with a theatre and a large open-air dance floor. Many of the popular beach resorts were equipped with bathing machines , because even

4884-425: The surface flow of the runoff is diverted and concentrated by drains that create constant flows over the beach above the sea or river level, the beach will be eroded and ultimately form an inlet unless longshore flows deposit sediments to repair the breach. Once eroded, an inlet may allow tidal inflows of salt water to pollute areas inland from the beach and may also affect the quality of underground water supplies and

4958-519: The surface layer of the dunes, allowing other plant species to become established. They also protect the berm from erosion by high winds, freak waves and subsiding floodwaters. Over long periods of time, well-stabilized foreshore areas will tend to accrete, while unstabilized foreshores will tend to erode, leading to substantial changes in the shape of the coastline. These changes usually occur over periods of many years. Freak wave events such as tsunami, tidal waves, and storm surges may substantially alter

5032-657: The surface layer. When affected by moving water or wind, particles that are eroded and held in suspension will increase the erosive power of the fluid that holds them by increasing the average density, viscosity, and volume of the moving fluid. Coastlines facing very energetic wind and wave systems will tend to hold only large rocks as smaller particles will be held in suspension in the turbid water column and carried to calmer areas by longshore currents and tides. Coastlines that are protected from waves and winds will tend to allow finer sediments such as clay and mud to precipitate creating mud flats and mangrove forests. The shape of

5106-438: The theory operates in dynamic equilibrium or unstable equilibrium, and many fields and laboratory observations have failed to replicate the state of a null point at each grain size throughout the profile. The interaction of variables and processes over time within the environmental context causes issues; "a large number of variables, the complexity of the processes, and the difficulty in observation, all place serious obstacles in

5180-400: The water column for longer durations allowing transportation outside the surf zone to deposit under calmer conditions. The gravitational effect or settling velocity determines the location of deposition for finer sediments, whereas a grain's internal angle of friction determines the deposition of larger grains on a shore profile. The secondary principle to the creation of seaward sediment fining

5254-408: The waves at some point in the tide, is termed the beach berm. The berm is the deposit of material comprising the active shoreline. The berm has a crest (top) and a face —the latter being the slope leading down towards the water from the crest. At the very bottom of the face, there may be a trough , and further seaward one or more long shore bars: slightly raised, underwater embankments formed where

5328-434: The waves first start to break. The sand deposit may extend well inland from the berm crest , where there may be evidence of one or more older crests (the storm beach ) resulting from very large storm waves and beyond the influence of the normal waves. At some point the influence of the waves (even storm waves) on the material comprising the beach stops, and if the particles are small enough (sand size or smaller), winds shape

5402-405: The way of systematisation, therefore in certain narrow fields the basic physical theory may be sound and reliable but the gaps are large" Geomorphologists, engineers, governments and planners should be aware of the processes and outcomes involved with the null point hypothesis when performing tasks such as beach nourishment , issuing building consents or building coastal defence structures. This

5476-544: Was demonstrated at the low energy clayey tidal flats of Bohai Bay (China), the moderate environment of the Jiangsu coast (China) where the bottom material is silty, and the sandy flats of the high energy coast of The Wash (U.K.)." This research shows conclusive evidence for the null point theory existing on tidal flats with differing hydrodynamic energy levels and also on flats that are both erosional and accretional. Kirby R. (2002) takes this concept further explaining that

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