Students' Traveling to the South Coast - Essay Example

Students' Traveling to the South Coast on Field trips are the happy part of learning and I am sure every student always looks forward to them. Therefore, all of us were so excited when we were told that we were going for a one day trip to the South Coast on . We were a group of Coastal Engineers and we knew that we were in for a very interesting trip. When the day arrived we took the and we chatted animatedly on whatever we already knew about the place. When we arrived at the Southern coast of England we happened to pass through Brighton. The city is a delightful, coastal city and has often been called “London by the sea.” The Brighton Marina is the biggest complex of its kind in Europe and testifies to the great engineering skills of modern times which have converted what was an open sea 40 years ago, into a commercial and residential settlement. The coastline from Brighton to Eastbourne is a delight for any coastal engineer, and I am no exception, for it features almost all the important innovations of coastal engineering, along with old and new techniques used in the preservation of the beaches and harbors, endangered by natural and human encroachment. In other words such a place is an engineer’s delight! Walking along the Brighton Marina is an exhilarating experience and I was once again struck by the way in which this development has been made possible. Economic activities and urbanization though, have had some very adverse effects on the environment and coastal erosion is the cause of great concern. The Brighton Marina caused depletion of the beaches because it altered the long shore drift, and Seaford that was already suffering from erosion was further affected. The Groynes had been built as early as 1836 to combat this problem and increase the amount of shingle. A groyne can be built of wood, concrete or rocks, which are placed at right angles to the sea, and help to create a wider and well nourished beach, since it catches the shingle on the updrift side, and protect the coast because the filtered sand absorbs the wave energy. But there is loss of beach material on the down drift side creating the need for another groyne there. At Brighton a sea wall and promenade were built at the foot of the cliffs in the 1930s, with the sea wall constructed of concrete blocks and the space between the wall and the cliff was packed with the chalk rubble, which was removed from the cliff, while constructing the wall. A splash wall and promenade were laid on top of this and Groynes were constructed at right angles to the sea wall, which trapped the shingle, and was further extended to Saltdean. At Brighton and Hastings the groynes are made of stone and cement and are much more elaborate. (Bosworth, 1909) These hard engineering techniques were successful to a certain extent, in combating the coastal erosion which has grown considerably. A number of breakwaters have been built to defend the coast and to prevent anchored yachts and ships from the effects of long-shore drift. The caisson unit is used here and they are characterized by vertical sides, where the mass of the caisson and the filling inside is used as a resistance against the waves. This is also effective in those places where one or more vessels are berthed on the breakwater’s inner sides. (N.W.H. Allsop (2002). The effect of the waves, leading to soil erosion have been checked by the dollos, near the Marina, and this is highly resistant to wave action and there was much better results when compared to the enormous concrete blocks which were earlier sunk offshore to catch the impact of the waves and tides. The breakwater at Newhaven, built more than hundred years back, has been effective in countering the eastward littoral drift of the shingle. The shingle buildup on the west of the breakwater has strengthened the cliffs below the Newhaven Fort, but the erosion in the bay led to breaches of the sea wall at Seaford. Beach nourishment, as a method of coastal defense is being accepted because of its positive side-effects, like supporting recreational activities and the “protection of fresh water lens induced by consolidation of dunes.”(Coastal erosion – Evaluation of the needs for action” January, 2004) This involves importing similar quality sand and piling it on the sand already on the beach, so that in time it integrates with the original. At Seaford this technique was employed and involved a number of other allied techniques. The existing beach was scraped until the solid underlying chalk became visible, on which a foundation of small rocks was placed. The old sea wall was fortified using 50,000 tonnes of granite blocks and finally 3,000,000 tonnes of shingle was poured in till it reached the promenade. The shingle used was taken from the seabed, about 15 km away from the shore. A new groyne, measuring 160 m was constructed at the eastern end of the beach which protects the shingle from being lost due to the long shore drift. The shingle which builds up is used to replenish the beach. The only negative implications here are for the chalk cliffs of Seaford Head, which due to exposure are eroding rapidly. (Think Energy) The distance from Eastbourne promenade to Burling Gap is about 7 km and a little away part the cliffs at Beachy Head, which at 150 m are the highest in Britain. The view of the coast from here is breathtaking. Burling Gap is owned by the National Trust, and the walk down the steps to the beach gives a wonderful view of the Seven Sisters, a group of chalky cliffs. These cliffs developed under the sea about 70, 200 million years ago, and gradually came up again covered in silt and sand. It is this, which is visible in the top layer of the cliff even today. These cliffs between Brighton and Beachy Head are receding at an average rate of 0.6m per year. (Think Energy) As we moved from Brighton to Newhaven, a similar pattern of erosion is seen, and the stone and wood groynes at Rottingdean and Peacehaven too are affected. References Breakwater (structure) http://dic.academic.ru/dic.nsf/enwiki/510119 Case study 5 > Ages 16-18 > Think Energy http://www.think-energy.co.uk/ThinkEnergy/16-18/case-studies/case-study-5.aspx N.W.H. Allsop (2002) - [http://www.google.fr/books?id=0XtfQ_iW0_YC&pg=PA198&dq=%22rock+manual%22&sig=Md2PBRHD8-15d5phk0lD_4z69fY#PPP1,M1 Breakwaters, coastal structures and coastlines] . Coastal erosion – Evaluation of the needs for action” Directorate General Environment European Commission ( January, 2004) SUSSEX by GEORGE F. BOSWORTH, F.R.G.S. Read More