Edexcel IGCSE Geography Chapter 1 - Pearson Schools

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<strong>Chapter</strong> 1: River environmentsFigure 1.32: Three stages in the supply of cleanwater – collection (reservoir), treatment(waterworks) and delivery (standpipe)Managing the supply of clean waterManaging the supply of clean water involves three main stages (Figure 1.32):Collection − Reference has already been made in Part 1.6 to the main sources ofwater, namely:●●●riversreservoirs and lakesaquifers and wells.This is where water is collected from.Treatment − It is very rare to use water that does not need some form ofpurification. Rivers are often highly polluted. Reservoir water can be polluted byfalls of acid rain and the seepage of pollutants from surrounding hillsides.Groundwater used to be thought of as being pure. However, it is now known thatsuch water can be badly contaminated by chemicals in the rocks. In parts ofBangladesh, groundwater is contaminated by arsenic, a highly toxic chemical.Water treatment aims to remove pollutants from the ‘raw’ collected water and soproduce water that is pure enough for human consumption (Figure 1.32).Substances that are removed during the process of drinking water treatmentinclude suspended solids (e.g. silt, soil), bacteria, algae, viruses, fungi, minerals (e.g.iron, manganese and sulphur), and synthetic chemical pollutants (e.g. fertilisers).A combination of processes is used worldwide in the treatment of water for humanconsumption. The combination varies according to the nature of the raw water.The processes include:●●●●●chlorination – to control any biological growth (e.g. algae)aeration – to remove dissolved iron and manganesesedimentation – to remove suspended solidsfiltration – to remove very fine sedimentsdisinfection – to kill bacteria.Delivery – In many countries, particularly HICs, water is delivered from thetreatment works to the point of consumption (the home, factory, etc.) by means ofpipes. The costs of installing pipe networks for the distribution of water are high, sotoo are the costs of maintaining the network. Unless the network is properlymaintained, there can be large losses of water from leaking pipes.In the urban areas of many LICs, water is more often delivered by standpipes (pipesthrough which water is pumped vertically) in the streets. In villages, wells areimportant water sources. Often well water is used untreated. Where water iscollected in buckets and carried from a well or standpipe into the home, there arefurther risks of pollution. Buckets and plastic containers may be dirty. Water left inopen buckets in the home are vulnerable to pollution by dust, insects and animals.A universal problem with the delivery of water by standpipes and wells is the timespent collecting the water (Figure 1.32).24
There is a fourth and relatively new way of delivering water – in plastic bottles filled at asource such as a spring. This is a very expensive way to deliver water because of thecost of the plastic containers, and of filling and transporting them to the point of sale. Itis interesting to note that the biggest sales of bottled water occur in HICs. Some peopleare worried that drinking piped domestic water might be risky. In other words, they areconcerned about water quality and the efficiency of water treatment, even in HICs.What do you think are the advantagesand disadvantages of bottled water?Water management is not just about ensuring a good supply of clean water. Damsand reservoirs can serve a number of different purposes, such as generatingelectricity, supplying irrigation water, flood control and improving navigation. Thismulti-purpose use of water, or river management is well illustrated by the ThreeGorges Dam project in China.Case study: The Three Gorges Dam project (China)The project, started in 1997, has been undertaken mainly for electricityproduction and flood control. Figure 1.33 shows the location of the project inthe middle of China and on its longest river, the Yangtze. The dam wasfinished in 2009 and is the largest in the world. It is 185 m high and almost2 km wide. The reservoir of water that will build up behind the dam isexpected to be up to 600 km long. Hydro-electric generators at the dam willproduce about 10% of China’s present electricity needs. China badly needsthis electricity if it is to continue to industrialise. In the interests of reducingglobal warming, China needs to burn less coal.NIn what ways will the Three GorgesDam project help the growth of industryin China?<strong>Chapter</strong> 1: River environmentsC H I N ABeijingYangtzeRiverThree Gorges Dam projectChongqingdamYichangWuhanShanghai0 500kmFigure 1.33: The location of the Three Gorges Dam projectThe major disadvantage of building such a massive reservoir is that more than1 million people have lost their homes and had to be resettled. By the time itis full, the reservoir will have drowned 13 cities, 140 towns and 1350 villages.The flooding of the Yangtze valley has meant losing some of the country’s bestand most fertile farmland. It is also likely that silt will be trapped behind thedam, making the farmland lower down the Yangtze less fertile over time.25
Page 1 and 2: Section A:The natural environment a
Page 3 and 4: ●●●●overland flow - most of
Page 5 and 6: shows the channel networks of two d
Page 7 and 8: There are a number of factors affec
Page 9 and 10: ErosionThere are several different
Page 11 and 12: KeyDifference inheight betweenX and
Page 13 and 14: As lateral erosion continues, the b
Page 15 and 16: The height of the drainage basin an
Page 17 and 18: ●●●The rising standard of liv
Page 19 and 20: uses less water (now 14%) (Figure 1
Page 21 and 22: 1.7 Water qualityIn Part 1.6, we lo
Page 23: Agriculture●●●Liquid from far
Page 27 and 28: FACTORPhysicalWeatherRockSoilRelief
Page 29 and 30: In the longer term, there is the co
Page 31 and 32: the monsoon climate with its heavy

Edexcel IGCSE Geography Chapter 1 - Pearson Schools

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