Barrier Erosion Essay Research Paper The Erosion
Barrier Erosion Essay, Research Paper
The Erosion of Long Island & # 8217 ; s Barrier Beaches The barrier beaches, which line the south shore of Long Island are in a changeless province of alteration due to factor & # 8217 ; s such as air current, tides and beckon action. & # 8220 ; The term & # 8216 ; barrier & # 8217 ; identifies one that protects other characteristics, such as lagunas, salt fens, and bays from direct onslaught from the unfastened ocean & # 8221 ; ( Leatherman 1 ) . The pebbles and sand of which these beaches are made invariably lifted and deposited in other countries. Currents created by tides and moving ridges carry deposit and sedimentation it on beaches and in shallow H2O countries along the shoreline. In this paper I will discourse moving ridge activity, the most prevailing factor of beach eroding. In add-on, I will analyze the axial rotation of sand dunes and other ways of forestalling eroding. The job which many Long Island beaches face today is the component of eroding. More deposit is carried off from the shoreline than is deposited. These elements of nature make the barrier beaches really unstable characteristics of Long Island & # 8217 ; s south shore. Wave action, tides, and winds invariably change beaches and shorelines, and are the cause of the many annihilating effects of eroding. The barrier beach which I have chosen to concentrate my research on is TOBAY beach, a beach located merely E of Jones Beach. Like TOBAY, barrier beaches are normally the consequence of a sand bar which is built up and develops as an islands. They are continuously deriving and losing sand, and easy travel landward. This is known as barrier island migration. & # 8220 ; Sand from the ocean side of the barrier is transported by H2O and air current toward the rear of the island so that the whole landform bit by bit changes its location & # 8221 ; ( Leatherman 47 ) . The changeless motion of deposit from the forepart of the beach to the dorsum is known as rollover. IF the barrier beaches did non travel, they would finally be covered by H2O. In a manner, barrier island migration Acts of the Apostless against the effects of eroding. ( McCormick 23 ) Wave action is a major cause of beach eroding. The strength of these moving ridges is determined by the conditions. & # 8220 ; Waves are created by the air current blowing over the surface of the H2O, reassigning the energy of gesture from air to H2O & # 8221 ; ( Press 421 ) . Calm conditions creates smaller moving ridges which approach the shoreline at regular intervals. Stormy conditions creates big moving ridges which move at high velocities. The power if air current creates the power the moving ridges. If hebdomad air currents prevail, little ripplings signifier. However, if heavy air currents persist, big, destructive moving ridges are created. & # 8220 ; The tallness of moving ridges addition as the air current velocity additions, the air current blows for longer times, and the distance over which the air current blows is increased & # 8221 ; ( Press 421 ) . The breakage of moving ridges is an of import facet of wave action. Since moving ridges greatly consequence eroding and the status of our beaches, it is of import to understand how certain moving ridges & # 8220 ; interrupt & # 8221 ; . As a moving ridge moves closer to a shoreline they break. The moving ridge interrupting action occurs when the moving ridge becomes so steep it can no longer back up its weight. & # 8220 ; Gently inclining undersides cause moving ridges to interrupt farther off from the shore, and steeply inclining undersides make moving ridges interrupt closer to the shore & # 8221 ; ( Press 423 ) . Interrupting moving ridges fit the coastline transporting sand off and interrupting up solid stones. After the moving ridge interruptions, its tallness is reduced. This spreads more H2O into direct contact with the sand. This is when eroding takes topographic point. When the H2O spreads across the inclining forepart of the shoreline, it is called swash. Swash creates a slipstream of H2O fluxing back into the ocean. This backwash carries sand along with it. & # 8220 ; Fine sand can be moved by wave action in H2O up to about 20 inches deep & # 8221 ; ( Press 423 ) . This procedure is non merely capable of transporting sand grains, but little stones every bit good. At the beach, I built a hill of sand up near the H2O & # 8217 ; s border. As moving ridges came and smothered my heap, the hill began to acquire smaller and smaller. Within 5-6 moving ridges there was no hint of any hill that I had built. This experiment portrays & # 8220 ; swash & # 8221 ; and how sand is carried off. Another of import facet of wave action is refraction. Wave refraction is the bending of moving ridges as they approach the shoreline from an angle. The shallow underside, the portion of the moving ridge closest to the shore, hits foremost doing the moving ridge particles to go more egg-shaped. Therefore, the moving ridge and its atoms are slowed down. This procedure continues as the moving ridge approaches the shoreline, and do the moving ridge to flex its face landward. The swash so runs up the beach at an angle, and runs down in a similar mode. The repeat of this procedure consequences in the supplanting O
degree Fahrenheit sand atoms. Long shore impetus is the cause of this supplanting. Long shore impetus and long shore currents working together are powerful procedures in the conveyance of big sums of sand on beaches and in really shallow waters” ( Press 425 ) . Long shore current is a shallow watered current which runs analogue to the shoreline. It consequences from the angled nature of the waves’ attack. The job which the beaches of Long Island face is the motion of sand due west from Montauk Point. The currents which flow analogue to the shoreline run westward and transport deposit to beaches further down the seashore. The deposit will finally construct itself up once more, but their size, place and location will non be the same. The landward gesture of rollover will finally do portion of the beach to be lost to eroding ( Leatherman 47 ) . In reaction to the drastic sums of eroding which have taken topographic point, many attempts have been made to forestall this from go oning. Natural opposition to the effects of the tides and moving ridges comes from sand dunes. These big hemorrhoids of sand line the dorsum of the beach. They provide protection from gnawing air currents and supply a supply of sand to the blown down and replace the sand lost to beckon activity on the shoreline. Dunes are frequently held in topographic point by the flora which grows on them. This flora, known as American Beachgrass, stabilizes deposit which moves along the seashore. Its strength lies in its roots, which spread broad beneath the sand and assist give rise to new workss. The vigorous growing of American Beahgrass makes it able to turn up through heavy sedimentations of sand. Another signifier of dune stabilisation lies in the deposition of cast-off Christmas trees in the dunes. This is a reasonably new pattern which I have informants and taken portion in past old ages. The trees are placed on top of the sand dunes, and over clip their subdivisions become covered with sand deposited by air current and H2O. In actuality, he tree’s subdivisions have an consequence similar to that of American Beachgrass. In add-on to the protection provided by the dunes, many semisynthetic constructions provide options. The pattern of making these constructions is known as shoreline stabilisation. The most common illustrations of these constructions are breakwaters and inguens. Standing on the beach, I recognized that Jetties seem to forestall the happening of Long Shore Drifts. A moving ridge it merely every bit broad as the Jetties and Groins let them to be. A inguen is a shore protection construction built perpendicular to the shore to pin down deposit and idiot shore erosion” ( Leatherman 51 ) . Time has proven, nevertheless, that inguens and breakwaters have negative facets. An article in The New York Times provinces: Critics say the inguens and their longer sister construction, Jetties, tend to pin down sand traveling in currents running parallel to the shore and dam it on one side of the construction, making a fat beach there and a skinny, sand starved beach on the other side ( New York Times ) . Another signifier of bar of eroding is the shore beef uping constructions. Examples include bulkhead and breakwaters. These constructions are similar in that they shield land from eroding. However, the job is that they are believed to debar beckon energy instead than absorb it. Wave energy is deflected, non absorb, when it strikes a difficult surface so the force is merely redirected-energy defelcted downward, this can scour off sand under a wall. And storm moving ridges that wash around sea walls erode belongings at either terminal ( New York Times ) . In consequence sea walls cause eroding to happen on the beach next to the sea wall. The concluding and most recent development in shoreline stabilisation is known as GEOTUBE. The GEOTUBE is a “huge cloth tubing pumped full of wet sand, making a impermanent barrier” ( New York Times ) . It is placed underneath the bing sand dunes. It has chiefly been used to salvage main roads which run along many coastlines near beaches. Turning up on Long Island, I have seen the impairment of the beaches over many old ages. I ne’er thought twice about what causes this eroding, until I went and did my field survey. Looking at the ebaches from a scientific point of position made me recognize that beach eroding is a changeless factor in Long Island’s beaches. Every moving ridge has an consequence the status of our beaches.
Plants Cited 1. Hanley, Roberts. As beaches Erode, a Argument on Who & # 8217 ; ll Oay for Repairs. & # 8221 ; The NEW YORK TIMES. 20 Apr. 1998 2. Imperativeness, Frank. Siever, Raymond. Understanding Earth. New York. W.H. Freeman and Company. 1998 3. Leatherman, Stephen P. Barrier Island Handbook. Maryland. University of Maryland, 1982.