Profile of beaches Essay Example

Profile of beaches Essay Example Profile of beaches Essay Profile of beaches Essay Introduction General Introduction The universe s coastlines, spliting the land from the sea, are geological environments which are alone in their composing and the physical procedure act uponing them. The bulk of these coastlines have beaches made up of loose deposits like crushed rock, sand, or clay that are continuously being acted upon by moving ridges, currents and air currents, redefining their form without break. Nevertheless, in malice of the assorted moving ridge climes that prevail around the universe and the difference in the coastline composing, the nature and behaviour of the beaches are often really similar. The air currents blowing over immense extents of oceans provide the necessary energy and impulse to moving ridges. This is accumulated energy is dispersed in the breaker zone and the breakage of moving ridges in this zone is mostly responsible for the formation of turbulency, which traps and suspends the deposits from the beach. Therefore the beach profile form is due to the action of moving ridges and currents at the shoreline. The moving ridges besides form nearshore currents that transport the suspended deposits alongshore or crossshore. Nearshore currents can travel tremendous measures of deposits along the shoreline and in the cross shore waies in volumes every bit big as 100s of 1000s of three-dimensional metres of sand per twelvemonth in some parts of the universe. Longshore currents are formed by moving ridges that break neither perpendicularly nor parallel to the shoreline and flow in the way comparable to the wave way. Many times, longshore current turns seaward to go rip current which carry deposit offshore. This motion of deposit is termed as the litteral impetus and the measure of deposit set in gesture along the seashore is the littoral conveyance. During a twelvemonth, wave environment alterations and so does the conveyance waies. But there is a dominant way of the deposit conveyance that prev ails at most coastlines. The way that is coinciding with this dominant conveyance way is known as downdrift and updrift is the opposite way. The cross shore conveyance is besides caused by moving ridge or air current induced average cross shore flows and is chiefly responsible for the presence of sand bars and other beach profile alterations. These profile alterations are normally slow, on the order of old ages in continuance or can happen quickly during storms, on the order of hours. The profile of beaches is one characteristic of coastal countries that are frequently studied and analysed. These cross subdivisions through coastlines give a better thought as to the alterations happening over clip at one point on the seashore, either in the form or size of a beach. The survey of a figure of profiles from the different points can garner informations about the motion of deposit along a seashore and to compare one country from another. Data collected can be plotted as a graph to bring forth the physical representative of the form of the beach and can besides be analysed statistically. Major beach eroding occurs during big storms. These storms besides stir the sand from the deeper deepnesss and convey it towards the breaker zone. However, some beaches have sound pumps with over capacity and are capable of self fix during bad times. But if this ego fix mechanism becomes damaged, beaches are more reactive to endure conditions and clime rhythms. Beach eroding of Westhampton Beach ( USA ) over a period of 40 old ages is shown in the diagram below. This tendency is about similar for img: Typical beach erosionmany beaches all over the universe. While promontories and drops erode, beaches are able to impede the action of moving ridges on them therefore doing themselves a formidable defence against the choler of the sea. Its constituents of ego fix are: ( 1 ) Drying of beach sand because of withdrawing tide and by air current and sunlight ; ( 2 ) Blowing of sand inland by sea air current ; ( 3 ) Storage of sand in the dunes. Therefore a beach is able to hive away sand and grow during favourable meteoric conditions. During bad conditions conditions, beaches erode and lie flatter. The ocean s degree was about 120 m lower than today as the expiration of the last ice age blocked in the mountain and the polar ice caps. At that clip the beaches were near to the boundary line of the Continental shelf. When the clime started warming, the sea degree rose and moved the beaches landwards along with its sand. The ocean s degree took some 4000 twelvemonth to lift and this procedure was over about 6000 old ages ago. Description of Mauritius Coastal Zone. Mauritius is a little island province covering 1865 km2 of land. It is situated at latitude 200 South and longitude 580 East, around 1,242 stat mis off the South East seashore of Africa. The coastline of Mauritius is 322 kilometer in length, is bordered by fringing coral reefs which confine a lagoon country of 243km2 and has the above 93 stat mis ( 150km ) of white flaxen beaches. The state is invariably air currents throughout the twelvemonth, except for short periods in summer months ( November to April ) when tropical storms approach the island. These air currents are stronger in winter ( May to October ) due to the presence of strong anticyclones go throughing near to Mauritius. The island besides has protected bays and composure lagunas which have enabled the development of fishing and touristry. Marine and coastal resources are one of the chief pillar to the national economic system. In 2000 the population of Mauritius was about 1.14 million and had a Gross Domestic Product ( GDP ) of Rs101.7 billion ( Central Statistics Office, as reported in Halcrow 2003 ) . The touristry scheme ( Deloitte A ; Touche 2002 ) sees a growing from the existent 9,000 hotels suites to around 20,000 in 2020. The coastal zones have witnessed a rapid encouragement in development over the past old ages and have been extensively exploited for assorted activities. This is due to the enlargement in tourer reachings, lifting from 103000 in 1977 to 656450 in 2000. Coral sand remotion ( 800,000 tonnes/yr ) and sewage discharge in the lagunas mean that some beaches and lagunas have been badly impacted. Furthermore there is the absence of a proper planning with regard to coastal development and unequal enforcement have resulted in building of edifices everyplace and constructions such as breakwaters and br eakwaters along the seashore. Thus the coastal zone has become under terrible emphasis. Description of the 3 coastal sites chosen Blue Bay the bay with its nice deep blue colour in the sou-east of Mauritius. The colourss of the sea are improbably powerful and consist of a assortment of many different blues. The Blue Bay has a really nice public beach which is absolutely suited for swimming and loosen uping. Blue Bay, every bit good as the general country in the south and south-east is non so much touristically tapped. That is why the beach of Blue Bay is really quiet during the hebdomad. On weekends, nevertheless, one has the feeling that the half population of Mauritus pilgrims journeies here to pass some nice free yearss at seaboard. They are besides really quiet at the weekends. Blue Bay is peculiarly celebrated for its snorkeling trips. Since 1997, a 353-hectare country which is located in the sea merely in forepart of the public beach is appointed as the first and until now the lone Marine Park in Mauritius. The grounds for the foundation are the unusual and alone coral gardens, which are situated here. The marine ecosystem provides a rare beauty with its many different species of vegetations and zoologies. These are particularly the corals, which are in an improbably good status. Overall a figure of approximately 72 different corals and 32 different species of fishes are founded in this country. The corals are sometimes even up to 800 old ages old. The public beach of St Felix is another beautiful beach of Mauritius. St. Felix is located besides in the South between the towns of Belle Ombre and Soulliac. Actually St Felix has even two public beaches ; nevertheless, the 2nd beach from the way of Le Morne is much more beautiful. To acquire at that place you have to go on the route after the way mark to the public beach of St Felix a small spot until you reach a traffic circle where you have to take the 3rd issue. The beach is fantastic, the exceptionally white sand, which flows into the turquoise viridity of the Indian Ocean of Mauritius, gives a fantastic contrast to the verdant trees of the back land. The beach of St Felix is really lonely and offers an first-class chance to chill out and loosen up. However, a little disadvantage from the beach of St Felix in Mauritius is that bathing is debatable. First the land of the laguna is covered with corals in which one or the other fish from the household of the extremely toxic rock fishes can be founded. Second the current can be rather strong and should non be sneezed. AIMS AND OBJECTIVES Purpose The purpose of this survey is to give an history of the spacial and temporal alterations in beach profile informations for the country of St Felix, Gris Gris and Blue Bay and to function as a baseline for farther research on coastal eroding for these 3 beaches. Aims This independent survey has two chief aims: To turn out what alterations in beach profile form has occurred on a spacial graduated table, along the length of St Felix, Gris Gris and Blue Bay and to bring forth a description study of these alterations. To determine what alterations in St Felix, Gris Gris and Blue Bay beach profile s form have occurred on a temporal graduated table and to supply a longitudinal and descriptive study of these alterations. Methodology The Emery board method which was developed by the celebrated coastal scientist, K.O Ernery, is the simplest technique to mensurate a beach profile. The setup consists of two bets which are connected by a rope of known length ( 5 M or 10 M ) as shown in figure 1.4 This length initiates the measurings interval along the profile for single information points. Each interest has a measurement graduated table running from 0 at the top, down to the underside. When the beach is inclining downwards towards the sea, the perceiver positions across the top of the interest confronting the sea to the degree of the skyline and calculates the distance ( a ) from the top of the board lying towards the land to the position afforded. On the contrary, if the beach is inclining upward off from the shore, so ( a ) is determined on the seaward board and the screening is with the skyline of the inland board. The deliberate distance ( a ) must be equal to the distance ( B ) even if the beach has either ris en or dropped within the horizontal distance between the bets ( Komar, 1998 ) . This attack has the advantages of holding cheap and light equipment which can be easy transported to hanker study sites for rapid studies, and provides really accurate informations for beach profiles. Fieldwork After holding selected the site for the beach profile measuring when geting at the beach, the first work is to tag a baseline ( a line in the sand which runs analogue to the shoreline ) . Measurement of beach profile ( lifts ) will be carried out along the baseline at specific intervals. These intervals will be labeled as the horizontal distance ( along the coastline ) ( ten ) . A landward surveyor, a offshore surveyor and a information recording equipment will be required to transport out the study. The landward surveyor is appointed for keeping the landward board, sing over the offshore board towards the skyline and shouting out the measuring ( centimeter ) to the informations recording equipment. The latter must observe down these measurings in an organized mode which includes the horizontal distance ( x ) of lift ( a ) and a cumulative alteration in all lifts for one profile measuring. The offshore board and do certain that the rope is flat between the 2 bets when extended by traveling the cringle up or down. Cross-shore information points of lifts are measured at the specific sampling intervals determined by the length of the rope when to the full extended, get downing at the landward extent of the base. If the beach is broad, more than 5 cross shore informations points should be collected. Datas Analysis A cumulative perpendicular lifts ( y-axis ) v/s the horizontal place ( x-axis ) must be plotted utilizing the beach profiles informations recorded. The existent beach profile will be revealed. If the horizontal and perpendicular graduated tables are equal, the beach profile may non look to be thrilling ( about like a horizontal line ) . If that is the instance, a technique called vertical hyperbole is used, ( to change perpendicular graduated table by a known factor e.g a factor of 5 or 10 ) . This technique is chiefly used by geographers, geologists and map makers. LITERATURE REVIEW A immense sum of informations refering several facets of beach profile informations exists around the universe. Sing measuring of beach profiles, Delgado and Lloyd ( 2004 ) elaborated one of the simplest technique of mensurating beach profiles in their paper ; explicating the method, and its pros and cons. The set-up is light and simple, can be conducted by one individual entirely, does non necessitate sighting of the skyline and can run in different conditions conditions. The lone equipment needed is a horizontal and perpendicular rod attached sheer to each other and, a graduated standing pole from which measurings can be taken. Besides systematic mistakes ( somewhat bent rods ) can be reduced by standardization on a level surface. This technique has been used in assorted locations and consequences have shown that mistakes associated with the Delgado and Lloyd method have an norm of 0.024m with respects to 50 m long profiles and a preciseness of 0.014 m when used by a individual pro filer. When compared to the usage of electronic methods ( transits ) to transport out the same study, the DL method shows a preciseness of 99.76 % . In malice of indicating out the truth of this method with regard to the beginnings of instrumented mistakes, Emery ( 1961 ) did non take into history the influence of the belongingss of different deposit surfaces on his method. Krause G ( 2004 ) showed that this consequence can non be disregarded as it can better the overall truth of the information. Furthermore it was proved that Emery method is sensitive to systematic mistakes introduced ( little divergences between the graduated tables of the 2 measuring poles ) . In order to accomplish 90 % truth with mistakes introduced, the minimal beach incline should non drop below 125 centimeter for a 100 m long profile. Increased trying spacing from 2 m to 10 m in order to speed up the study and cut down mistakes was deemed inacceptable if sampling intervals is in the order of hebdomads or months. Cooper et Al ( 2000 ) laid accent on the fact that coastal monitoring informations sets should be up-to-date and accurate because these informati ons will enable a better designation and apprehension of alterations happening at the shoreline. As shown above, the Emery method holds both because it is accurate on a dynamic beach. With added alterations to the original method, this technique is best suited for a good beach profile measuring.