Coasts

 Sample Exam Questions 

 

How can human activity lead to the need for managment within your chosen geomorphic environment? How successful are these strategies?

   There are a wide range of management strategies that deal with human activities on the coastline. Many strategies are expensive, eg hard engineering but are not always successful. Other strategies, eg soft engineering need a greater understanding of geomorphological processes but can bring better results. Human activity at Bournemouth, on the south coast of the UK, has caused an increase in coastal erosion at Barton-on-sea. The beach at Bournemouth is a major economic asset but in the 1960s the beach had nearly disappeared as long-shore drift washed away beach material. Hard engineering in the form of groynes were set up along the beach to trap the beach sediment. 26 groynes were set up costing £200000 per groyne. However, these groynes held beach sediment that would have otherwise travelled to Barton-on-sea. The beach there has now lost most of its sediment, so that wave energy now acts directly on the cliff, causing increased erosion.

   Lulworth Cove, as a World Heritage Coastline, is under serious threat due to the human impact of tourism.  The large number of tourists is increasing erosion by wearing away top soil, increasing subaerial erosion, leading to mass movement. It is a tourist honeypot site owned by the National Trust, but there are very few management strategies dealing with increased tourism. They need to reduce the number of people visiting; an increase in parking cost to £15 was the first step to do this. However, more serious restrictions are needed.

   Human activity has increased the need for management strategies due to global warming (release of green house gases). Global warming is causing a rise in sea level due to the thermal expansion of water and melting ice. This has been an increased problem in the last century and now, sea levels are rising 2mm per year. More people are moving to live by the coast for tourism, retirement or for economic activity. However, this increases the need for coastal protection. Global warming is also increasing the number of storms and the erosive power of waves.

   For example, in Galveston Texas on the 8th September 1900, a hurricane destroyed 4000 buildings and killed 6000 people. A very extensive hard management strategy was set up. A 6m tall sea wall of solid concrete 10 miles long was made. 4m was also added to the top of the whole island. This was done by placing houses on beams or just getting rid of the whole bottom floor of a building. This was very expensive but has been a success as it has defended Galveston for over a century. The area has a large port which works and the area is economically active. However, the beach has been eroded as storms remove the sand in front of the walls, reducing the tourist industry and damaging beach ecosystems as turtles have nowhere to lay their eggs.

   The increase in sea level has also caused increased coastal flooding at the town of Chiswell, behind Chesil beach. It has been overtopped increasingly as the sea level has risen, which cuts off the only road to Portland causing huge physical and economic problems. There are 4 prisons, 6 quarries and 20000 inhabitants at Portland and contains the largest port in the UK. Coastal management included a sea wall, gabions and a beach drainage system, costing £4 million for 1km of coastline. This seemed expensive but the cost-benefit analysis proves it was worth while. It used to be an economically depressed area, but now is an economic boom hot-spot. The defenses have been successful as Chesil beach has not been overtopped in 12 years. The Olympic Games have also increased house prices in this area, and people are buying second homes here now. This small selective site with management was expensive and not pretty but the change to the economy has been massive.

   Human activity has caused the need for the Thames barrage in the lower part of the Thames. Coastal flooding was increasing due to rising sea levels, prevailing wind direction and a high tide but humans made matters worse by reducing 95% of salt marshes and building on it. The barrage cost £600 million but this hard engineering was money well spent as it prevents the large problem of flooding for the Olympic Games.

   Miami Beach in Florida is a barrier island which undergoes sediment movement problems. In the 1960s, the beach was gone and it was no longer a dream holiday resort as it was economically dying and frequent hurricanes were getting more violent. Here, soft engineering was used Ė beach nourishment. In the 1970s, 40m of beach was added costing $67 million. Again, cost-benefit analysis approved as the economy boomed. This was a huge success and the tourist economy was increasing. Furthermore, the sea only displaced 5m in 30 years. They expected they would have to add more sand but only a bit had been taken away. It was worth the money due to the multi-million dollar land values behind the beach. This MEDC could afford this management but other countries, eg Bangladesh, canít afford any management. This management has worked and was sustainable as sediment was extracted from its own sea floor. But this is not a long term solution as there is only a limited amount of sand on the sea bed.

   Sea level rise is expected to increase and this is going to increase the need for coastal management. However, more people are moving to live by the coast (1 billion) which is extremely dangerous as more storms will occur. People are moving to danger zones. The other problem with sea level rise is that sea walls canít be moved, along with other forms of hard engineering. A 1m rise in sea level will inundate 25% of Bangladesh, affecting 60% of its population. To conclude, human activity increases the need for management strategies, but some strategies adopted can be very effective. These may however be very expensive and negatively affect the environment.