Water Landforms And People Case Studies


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Water Landforms And People Case Studies

  1. 1. Case Study Examples: Water, Landforms and People Flooding: (i) Name and locate an area of an MEDC where flooding has taken place: Shrewsbury in Shropshire, UK, October 2000 (ii) Describe how the flood affected different groups of people: The flooding affected many groups of people including homeowners, businesses, children and transport. Homeowners were affected by flooding as homes in the Frankwell and Abbey Foregate areas of Shrewsbury were flooded. This caused damage to carpets, plaster and electrics in homes and took many months to repair. Some people had to move out of their homes into temporary accommodation. Over 400 homes were damaged and sandbags were given out to try to protect some homes from the flooding. Although many shops are located on higher land above the level of flooding in Shrewsbury, they were still affected by the 2000 floods. The flooding stopped some shoppers from visiting the town and therefore shops such as Boots and Marks and Spencer’s lost up to £925,000 in business due to the flooding. Transport was also cut off as the English and Welsh Bridges, the only transport routes into the town centre were flooded. This enhanced the losses to businesses in the town centre as deliveries could not be made to the shops. Social impacts were also caused by the floods. Children could not use playgrounds as parks such as the Quarry as these areas were flooded. (iii) Explain the causes of the floods. A depression moved across the British Isles in October 2000. This brought over four times the average amount of rainfall in just 24 hours. Therefore the river overflowed as a result of the excess water entering the river. Land use also contributed to the causes of the floods because towns such as Shrewsbury have impermeable concrete and tarmac surfaces. These caused the flooding because the rainwater cannot infiltrate into the ground and surface water is increased. Therefore the water reaches the river more quickly. Deforestation in the upper course of the River Severn contributed to the causes of the floods because the cutting down of the trees increased surface run off and decreased infiltration. Therefore the water reached the river more quickly and increasing the risk of floods.
  2. 2. A River Landform: (i) Name a place where you have studied a river landform. Name the type of landform ad state whether it was created by erosion or deposition. Niagara Falls Waterfall on the Niagara River on the border of the USA and Canada, created by erosion. (ii) Describe how the river landform was created. The waterfall at Niagara Falls was created when a layer of softer rock has been eroded away underneath an area of harder rock. The softer rock has been worn away through the processes of abrasion, when rocks have been wearing away the bed and banks of the river and hydraulic action, when air has been forced into cracks in the rock, forcing the rock to break away. The harder rock has been undercut by the softer rock leaving an overhang, which has eventually collapsed into the plunge pool at the bottom of the falls. The rocks in the plunge pool have continued to wear away the banks and bed of the falls through abrasion. Niagara Falls has continued to wear away backwards in this way creating Niagara Gorge. Goat Island, an area of more resistant rock, has been left in the middle of the river, while American Falls and Horseshoe Falls continue to wear away on either side of the gorge. From: http://content.answers.com/main/content/wp/en/thumb/4/48/350px-Waterfall_formation23.png (iii) Explain how the river landform has been or is being used by people and/or organisations. Niagara Falls is being used in a variety of ways by a number of different groups of people. The waterfall has become a major tourist attraction due to the size and spectacular sights of the waterfall. There are also boat trips and helicopter rides along the river. This has provided jobs for local people in hotels, restaurants and the tourist attractions alongside the falls. Therefore, the local council gains taxes from the falls which are used to provide better services and facilities for the area including hospitals and schools. There are a number of Hydro-electric power stations underneath the falls which produce vast amounts of energy for local towns and industries. However, the people using Niagara Falls have also had a negative impact on the local area and on the river landform. Local people’s lives have been spoilt by congested roads, illegal parking, graffiti, vandalism and crime as a result of the increased tourism caused by Niagara Falls. Local people cannot afford the houses in the area and are forced to leave the area because of the increased development by hotels and other tourist industries, which has increased house prices. The wildlife of
  3. 3. the area has been scared away except for those feeding off the tourists e.g. pigeons, which are a pest. Water Supply: (i) Name a place where the supply of water is being, or has been, changed by people. The Hoover Dam on the Colorado River, in Nevada, USA, is an example of where the supply of water has been changed by people. (ii) Describe how the supply of water was, or is being changed by people. In the 1930’s it was decided by the American Government that a dam needed to be built on Colorado River to provide electricity and water to the states of Nevada, Arizona and California. The Hoover Dam was constructed on the Colorado River in the Black Canyon. Diversion tunnels were first constructed to divert the Colorado through bedrock in order to construct the dam. This created a reservoir of 100 miles in length behind the dam called Lake Mead. The Colorado River was controlled to provide a much needed water supply for Las Vegas, located in an arid area with little rainfall, as well as highly populated areas such as California. However, the water supply downstream of the Colorado Dam was restricted and controlled by the Hoover Dam, reducing the water supply to states downstream including parts of Arizona. The river’s mouth is in Mexico and therefore water supply was also reduced here as a result of the changed in water supply from the Hoover Dam. (iii) Explain how the changing water supply is affecting or will affect different groups of people and organisations. The changing of the water supply by the Hoover Dam has brought advantages to states such as California and cities such as Las Vegas. Las Vegas is located in an arid area with little rainfall. Therefore the construction of the Hoover Dam has meant that the city of Las Vegas has been provided with a water supply. Therefore, there is less chance of drought and a reliable clean water source can be provided for the tourism and Casino industry in Las Vegas. Therefore, without this reliable water supply, the city of Las Vegas may not have prospered as well as it has. The Hoover Dam has also brought advantages to residents and tourism in the state of California. Many wealthy people live in California, many houses have swimming pools and there are numerous golf courses. Therefore, the change of water supply brought by the Hoover Dam means that there is a reliable water supply for residents and the tourism industry. The Hoover Dam has also benefited intensive agriculture in California and Nevada. Without the construction of the Hoover Dam, little agriculture, particularly arable farming, would take place because the climate is so hot and dry. However, the construction of the Hoover Dam and consequent changing water supply has enable farmers to irrigate their land, making larger profits from the crops they can produce. Hydroelectricity from the dam has also benefited the US government and people living and working in Las Vegas, California and the surrounding areas. This is because a cheap and renewable electricity supply is provided by the dam. However, the dam has also brought disadvantages to some people. Native Indian Tribes who have lived on the land surrounding the Hoover Dam have lost out from the changing water supply. This is because they have traditionally used the river for fishing and transport. However, due to the construction of the dam, the flow of the river downstream has been reduced, leading to less fish in the river, and therefore less food for the Indian Tribes. Their land has also been flooded and homes lost due to the construction of the dam. People living in Mexico, particularly farmers on the flood plain of the Colorado River in Mexico have also lost out because the flow of the river has been reduced and therefore there is less flooding and therefore the land does not receive nutrients from the fertile silt. There is also less water here to irrigate their crops.
  4. 4. A landform created by the sea (erosional) (i) Name a coastal landform created by the work of the sea. Old Harry Rocks in Dorset, on the south coast of the UK. (ii) Describe how the landform was created by the sea. Old Harry Rocks is a coastal landform created by the erosional processes of the sea. Firstly, processes such as abrasion, where rocks are hurled at the base of the cliff and together with the action of the waves, have carved away a wave cut notch in the cliff. Sea water and air has also been forced into cracks in the chalk cliffs, enlarging these cracks by the process of hydraulic action. The wave cut notch and cracks in the cliff have been eroded away to form a cave. The waves have worn through the headland to form an arch. Eventually, the waves have continued to enlarge the arch and together with sub-aerial processes such as biological and chemical weathering, have caused the arch roof to collapse, forming a stack – Old Harry. Over time, the waves have continued to erode the base of the stack, causing the stack to collapse into the stump, called Old Harry’s Wife. (iii) Explain any advantages and disadvantages the landform brings to the area around it. Old Harry Rocks have brought several advantages to this area in Dorset. Firstly, because the landform and surrounding area is scenic, it attracts tourists to visit Old Harry. Therefore the tourists bring money into the area, such as car park charges and cafes, allowing these tourist businesses to benefit from the coastal landforms. Money generated from tourism brings advantages, as it can be used to construct defences to protect Old Harry from the impacts of tourism, such as footpath management, fencing to make the cliffs safer, and better visitor facilities. Old Harry has also brought advantages for bird watches, because the cliffs around Old Harry create a habitat for nesting sea birds such as seagulls. However, the landform brings disadvantages to the area. Because there are so many visitors to the area, there are many problems. For example, the large number of visitors creates footpath and cliff top erosion as the tourists go nearer the edge to look at Old Harry. Old Harry also causes disadvantages due to litter, air pollution and congestion from tourist traffic due to Old Harry creating a honeypot site. As the rocks on the cliffs around Old Harry are so steep and unstable, tourists and walkers may be hurt by falling off the cliffs or by falling rocks.
  5. 5. A landform created by the sea (deposition) (i) Name a coastal landform created by the work of the sea. Hurst Castle Spit at Studland, in Dorset, UK. (ii) Describe how the landform was created by the sea. Hurst Castle Spit has been created by the process of deposition and longshore drift. Sand has been transported along the Dorset coast by the process of Longshore Drift, where the sand is transported along the beach in a zigzag movement. Swash carries sediment up onto the beach at an angle and then backwash drags some sediment back down the beach vertically, thus moving sand in the direction of the prevailing wind. The spit has formed over thousands of years as sediment is transported along the coast from west to east. Eventually the coast changes direction into the Solent Estuary and therefore the sediment has been deposited. Over time, the spit has extended into the estuary and the end has been curved due to the erosional force of the Solent river. Winter storms have also caused the end of the spit to curve. This has created a sheltered salt marsh behind the spit. (iii) Explain any advantages and disadvantages the landform brings to the area around it. Hurst Castle Spit brings many advantages to the area around it. The beach at Hurst Castle Spit has been built up over time and therefore provides a beach which attracts tourists to the area. Hurst Castle was built in the 1500s at the end of the spit because it provided a good site to defend the Solent estuary and surrounding coastline from invaders. In the Second World War, gun batteries and search lights were installed on Hurst Castle Spit to protect the coast from invasion by German Gun Ships. The salt marsh behind the spit has created a natural harbour and has therefore provided a harbour for local fishermen and tourist boats to moor their boats safely. The Salt Marsh also provides a unique ecosystem, and therefore provides a habitat for wading birds. However, Hurst Castle Spit also brings disadvantages to the area around it. As longshore drift is constantly transporting sediment along the coast, the beach at Hurst Castle Spit is under threat. This may cause a disadvantage to tourism as there will be no beach for recreation. Also the beach has provided a site for Hurst Castle, protecting it from erosion and storm waves. If the beach is removed by longshore drift, Hurst Castle may be at risk from erosion and flooding from storms. Therefore groynes have been installed along the beach to prevent sediment being moved by longshore drift and reducing the risk of further erosion. However, some people think these groynes are unattractive and may therefore reduce the amenity value of the beach. Boats mooring behind the spit may cause pollution to the water, therefore damaging the salt marsh ecosystem.
  6. 6. A Coastal Management Scheme (i) Name a coastal management scheme that protects the coast from the action of the sea. Hurst Castle Spit coastal defences, on the Dorset Coast in the UK. (ii) Describe the scheme. There are a number of different coastal defences used for coastal management at Hurst Castle Spit. In 1996, the local council decided to construct sea defences at Hurst Castle Spit after a cost-benefit analysis of erosion against cost of defences was completed. A rock breakwater and boulder armour were constructed close to Milford-on-Sea. Revetments and rock groynes were constructed along the beach at Hurst Castle. The main part of the scheme however, was beach nourishment, where 250,000 tonnes of shingle was pumped onto the beach at Hurst Castle to raise the beach by 7 metres above the high tide line. (iii) Explain why the scheme was, or is, necessary. There are two main reasons why these coastal defences were needed – erosion and coastal flooding. Firstly, a sea wall was built at Milford-on-Sea and this prevented sediment from being eroded and transported along the coast. Therefore, as a result of less sediment being transported by longshore drift, there was less deposition of sand at Hurst Castle Spit and therefore the beach and end of the spit was more susceptible to erosion from waves. Therefore, rock groynes were constructed along Hurst Castle spit to trap sediment being moved by longshore drift. Therefore the sediment was trapped between the groynes, building the beach up and therefore preventing further erosion and transportation of sediment from the beach at Hurst Castle. A rock breakwater and boulder armour were built to the west of Hurst Castle Spit and beach nourishment was used on Hurst Castle beach because beaches along the south coast of Britain are often eroded and the land behind flooded due to storm waves. Therefore these defences were used to absorb the energy of the waves, therefore reducing the erosional impact they have on the beaches and coastlines behind. In the 1980s, severe storms flattened the spit at Hurst Castle, eroding material from the beach, as well as flooding the salt marsh and damaging habitats behind the spit. Therefore, beach nourishment and boulder armour was necessary to reduce the impact of storm waves in the future, and to date have been successful in preventing the spit from being breached by waves since their installation.