Water World Flashcards
What are the possible effects of climate change on water supplies in South-west USA?
- very arid area with Colorado river as main water source, including irrigation
- climate change may make it drier
- restrictions of taking water from Colorado river, less water for irrigation, fewer crops
- less water will create problems for rapidly increasing population
What are the possible effects of climate change in Asia?
- China/India/Vietnam depend on water from melting glaciers in Himalayas
- Long-Term Impacts: all Himalayan glaciers melting leading to severely reduced water supplies
- Short-Term Impacts: increase in glacial melt leading to seasonal stress on agriculture
What are causes of river pollution?
Threats to hydrological cycle
- untreated sewage pumped into river can lead to cholera and typhoid
- intensive agriculture/fertilisers/pesticides/herbicides poison wildlife and affect water quality
- waste chemicals leaked from factories can get into water sources
- plastic bags and non-biodegradable waste can kill wide life
How can we manage river pollution?
- sewage is treated before it can be pumped into rivers
- farmers regulate their use of fertilisers
- factories dispose of waste before returning water to river
- plastic and other waste is recycled and not dumped in rivers
Why may water supplies be unreliable?
- distinct wet and dry seasons(sahel in Africa have long dry periods which causes ground to harden so lots of surface run off)
- weather cycles where an area may get several dry years followed by several wet years(sahel has loads of drought)
- evidence of global warming+continuing rise in temperatures(sahel gets hotter n UK gets wetter)
What are large-scale water management schemes?
- are expensive to build and maintain
- cover large areas
- are organised by local or national government
- usually consist of dams and reservoirs being created
What are the benefits of the dam in The Colorado River?
- Reduces flooding that would normally occur in the summer, and reduces drought that would normally occur in the winter
- Electricity is produced by the dam for local towns, farms and factories
- Water is stored behind the dam which can be used for irrigation and for supplying growing cities such as Las Vegas.
- There is year-round supply of clean water for US cities.
What are the disadvantages of dam in The Colorado River?
- Land is lost to flooding when making the dams.
- Sediment has built up behind the dams which affects the -workings of the Hydroelectric Power (HEP) generation.
- Less sediment flowing down the river has disrupted the habitat for native fish.
- Also, the lack of sediment means sandbanks have shrunk which is also impacting animals and their habitats.
- Less water downstream in Mexico
What are the benefits of The Three Gorges Dam, China?
- Reduced risk of flooding for homes, farms and factories along the Yangtze River
- Water stored behind the dam is available for irrigation
- Hydroelectric power (HEP) is generated by turbines in the dam. It’s the world’s largest capacity HEP station.
- The electricity it produces means China saves 31 million tonnes of coal each year and their overall greenhouse gas emissions has reduced
- The river is deeper and more navigable for ships, so it has improved transport and trading in China
What are the disadvantages of The Three Gorges Dam, China?
-Good farmland has been lost because of the dam.
-Over 1 .3 million people were forced to move their homes as towns and villages disappeared under water.
-Important cultural and archaeological sites were lost.
-There is an increased risk of landslides in some places.
-The project was very expensive, $US 22.5 billion, but some people estimate the actual cost to be as high as $US 50bn.
-Sediment is building up behind the dam.
-There is no sediment to maintain river banks resulting in downstream areas becoming more at risk to flooding.
Important wetland areas have been destroyed.
What is a Small Scale Water Management Scheme?
- Small scale, intermediate technology solutions to any unreliable water problems.
- relatively cheap to build and maintain, cover small areas
- organised by the local people in conjunction with charities and local organisations
- help local people access clean water and increase water storage safely.
What are examples of Small Scale Water Management Schemes?
- Wells - Wells are dug to reach underground water supplies. They are lined with concrete and have a concrete lid to prevent pollution by sewage.
- Hand pumps - A more efficient way of reaching underground water where there is less chance of water becoming contaminated.
- Rain barrel - Water barrels collect rainwater from gutters and roofs can can be stored and used in times of droughts. This is called water harvesting. The water stays clean in the covered barrel.
