Presentation on theme: "Key terms Key termDefinition HydrosphereAll the water stored on the Earth’s surface and in the atmosphere. Hydrological CycleThe cycle of water transfers."— Presentation transcript:
Key terms Key termDefinition HydrosphereAll the water stored on the Earth’s surface and in the atmosphere. Hydrological CycleThe cycle of water transfers and stores around the hydrosphere. EvaporationWhen liquid water is converted to water vapour due to heat. CondensationWhen water vapour cools and turns back into liquid water. PrecipitationWhen water stored in clouds falls to Earth as rain, snow, hail or sleet. TranspirationWhen water is evaporated from the leaves of plants and trees. Surface waterWater stored on the Earth’s surface, for example in lakes and ponds. Surface runoffWater flowing along the Earth’s surface, for example in rivers. GroundwaterWater stored in the ground, for example in aquifers. Groundwater flowWater flowing through the ground, for example in underground rivers. InfiltrationWhen water soaks into the ground PercolationWater flowing downwards through soil and rock TransferProcesses where water is being moved from one store to another StoreWhen water is being contained in one place
Key terms Key termDefinition DroughtA prolonged period of abnormally low rainfall, leading to water shortage. SeasonalityChanges relevant to specific seasons. Water stressPressure on water supply DesertAn area experiencing under 250mm of rainfall per year. DesertificationWhen previously fertile land is changed to desert EutrophicationExcessive nutrients in a lake or river, which leads to growth of algae. Nutrient overloadAn oversupply of nutrients, leading to eutrophication. Algal bloomA large growth of algae on the surface of a body of water. OverabstractionTaking too much water from the ground. IrrigationThe supply of water to crops. Intermediate technology Technology appropriate to the people using it, making use of locally available resources.
Key facts: The hydrological cycle and climate change
Key facts: Water pollution sources Industrial: Warm water from power stations Acidic gases dissolved in water Chemical waste Heavy metals e.g. lead Industrial: Warm water from power stations Acidic gases dissolved in water Chemical waste Heavy metals e.g. lead Agricultural: Chemicals from pesticides and fertilisers Animal waste and manure Agricultural: Chemicals from pesticides and fertilisers Animal waste and manure Domestic: Sewage from homes Litter Domestic: Sewage from homes Litter Transport: Emissions from boats and ships Oil from engines Litter from tourists. Transport: Emissions from boats and ships Oil from engines Litter from tourists.
Named example of climate change and the hydrological cycle: South East Australia. http://www.youtube.com/watch?v=u9s_A0G7oUU http://www.youtube.com/watch?v=B5MuR_FvEvA 2007 – worst drought for 1,000 years. Reduction in levels of the Murray River – decreased irrigation and crop failure Increase in bush fires Wheat yields have fallen by half Winemakers being put out of business Ecosystems are suffering
Named example of an unreliable water supply: Somalia drought, 2005-6 Location: East Africa, on the Indian Ocean coast. Bordering Ethiopia and Kenya PHYSICAL causes: Failure of annual monsoon rainfall Some areas received as little as 10% of average rainfall for the time of year HUMAN causes: Deforestation, disrupting the water cycle Rapid population growth – pressure on water supplies Past conflict means little investment in water supplies Effects: Crop failure Dehydration and malnourishment People made homeless and become refugees 11.5 million people in need of food aid Wells run dry Death of livestock
Named example of an unreliable water supply: desertification in The Sahel Location: A narrow band immediately south of the Sahara desert, stretching from west to east Africa PHYSICAL causes: Naturally dry climate with prolonged drought Persistent high temperatures Dry, loose soil eroded by wind Naturally low water table HUMAN causes: Overgrazing by cattle, exposing loose soil to erosion Deforestation Overpopulation, leading to overabstraction of groundwater Effects: Exposed soil is easily eroded, leading to fewer nutrients Crops are therefore unable to grow Biodiversity is reduced – animals dry out Land eventually becomes a desert as the process repeats.
Named example of reduced water quality: The Rhine Various sources of pollution (see slide 6) One of the world’s most heavily industrialised rivers 1986 Sandoz chemical disaster at a chemical factory fire in Switzerland led to disastrous levels of pollution Caused by runoff from hoses of firefighters, which washed chemicals into the river. The Rhine Action Programme was put in place to restore biodiversity and reduce levels of pollution.
Named example of overabstraction of groundwater: Benidorm Location: South East Spain, on a stretch of coast known as the Costa Blanca. The issue: Benidorm is one of Spain’s main tourist resorts Water is being abstracted fromt he ground to cater for tourist needs e.g. Swimming pools and golf courses Water is being removed at a rate 2-3 times quicker than it can recharge Water is now being piped in from the River Tajo, 400km away Effects: Sea water is soaking into the soil near coastal areas, poisoning the groundwater supply and causing crops to fail Subsidence due to falling water levels, damaging buildings
Named example of diversion of river channels: The Aral Sea River channels feeding the Aral Sea diverted by the Soviet Union to irrigate cotton fields Lake level has decreased by 90% Salinity of water has increased, poisoning fish and affecting fishing industry Ports have shut down and are now located miles from the lake Wind blows dust polluted with chemicals from the lake into towns, reducing life expectancy
Named example of overabstraction and damming of rivers: The Colorado River, USA Causes: Growth of cities such as Los Angeles, Las Vegas and Phoenix 10 major dams built along the river, disrupting flow Increased irrigation due to higher food demand Inappropriate irrigation leads to high water wastage Consequences: Reduction in lake levels, such as Lake Mead River often dries up before it reaches the sea, causing political tension between the US and Mexico Lakes become more saline, damaging biodiversity
Named example of large-scale water management (LEDC): The Katse Dam, Lesotho Purpose is to supply water to Johannesburg, South Africa and to provide income for Lesotho Impacts Positive - Lesotho Negative - Lesotho Positive – South Africa Negative – South Africa Source of income for the country. South Africa pay for water supplied by the dam Provided jobs in construction and maintenance of dams Provided workers with new skills Flooded farmland, reduced income for farmers. Local people did not directly benefit from the income from the dam. People forced out of homes to make way for dams and reservoirs Provided water to Johannesburg, often to poor neighbourhoods which previously had a poor water supply. Cost of dam and transport of water meant increased water bills for the public and taxes to pay for the scheme
Named example of large-scale water management (MEDC): The Snowy Mountains, Australia Purpose is to divert water from the Snowy Mountains for use in agriculture and energy generation, then to be diverted back into the Murray river Benefits: Has allowed the development of farming along the Murray river. Provided employment to over 100,000 people. Energy produced, and water supplied, by the scheme, has allowed cities like Sydney to develop and improve their economies. Plays a vital role in the growth and the development of Australia’s economy. Crops produced die to irrigation from the scheme are worth around £1billion. Problems: Creation of storage lakes has destroyed valuable wildlife habitats. Record droughts in recent years have meant that the scheme is working well below its intended level. Flow of the Snowy River has fallen to 1% of its original level. Water in the Snowy River has become more saline (salty), affecting farms further downstream in the Murray floodplain. Issues between farmers and city dwellers, competing for falling water supplies.
Named example of small-scale water management: WaterAid (Tanzania) How does WaterAid operate in LEDC’s? WaterAid supply the technology, information and advice Villagers liaise with the local NGO. Then form a committee to decide where the well will go and organise the work. WaterAid works through local partners. (Local NGO’s/ charities in the area) The well is built by the villagers, using appropriate technology that they are able to maintain. Result: A sustainable, clean water supply. Some villagers are trained to look after the well and carry out repairs.
Named example of small-scale water management: WaterAid (Tanzania) IMPACTS: Increased irrigation for crops, leading to increased incomes for farmers Reduction in water-borne diseases, such as cholera Children spend less time collecting water, meaning that they can go to school (paid for by increased income) Women spend less time collecting water, allowing them to spend more time focusing on growing crops
Past GCSE questions Explain how water is transferred from the land to the atmosphere in the hydrological cycle. (4 marks) Describe how water is transferred from the oceans to the atmosphere and back again (4 marks) Outline the process of precipitation. (2 marks) State two impacts of deforestation on the hydrological cycle. (2 marks) Describe one impact of water shortages on people. (2 marks) Describe two impacts of water shortages on people. (4 marks) Outline why an unreliable water supply can cause problems for farmers (2 marks) Using examples, describe how human interference can disrupt water supply. (4 marks) For a named vulnerable area, describe one problem caused by an unreliable or insufficient water supply. (2 marks) Describe how one human activity can result in a decline in water quality. (2 marks) Describe two ways in which human activities can affect water quality (4marks) Give two effects of water pollution (2 marks) Using an example(s), explain why small scale solutions (intermediate technology) to managing water supplies are often sustainable in the developing world (6 marks) Using an example(s), explain why small scale solutions to managing water supplies are often sustainable. (4 marks) State two ways of using intermediate technology to manage water resources (2marks) Using examples, examine the costs and benefits of large-scale water management schemes. (6 marks) Describe the costs and benefits of a named large-scale water management project. (4 marks) For a named water management project, describe ways it has benefitted local people. (2 marks)