Edexcel IGCSE Geography Chapter 1 - Pearson Schools

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The River Tay shows many of the typical estuary features that can be found atthe mouths of rivers (Figure 1.21). They include:●●a wide channel – up to 2 kmsand and mud banks (Abernethy Bank)● some areas of marsh (in grid square 2119)●channels of deeper water (North Deep).1.6 Water uses, demand and supply<strong>Chapter</strong> 1: River environmentssalt water 97%other 0.5%atmosphere0.05%rivers and lakes0.45%soil androck 22%Figure 1.22: The world’s waterFresh water 3%glaciers andice sheets77%How might global warming changeFigure 1.22?UsesOnly 3% of all the water on Earth is fresh water; the rest is saltwater in the seas(Figure 1.22). Over 75% of the fresh water is locked up in glaciers and ice sheets,and 20 per cent is groundwater. The world’s remarkably small amount of freshwater is:●●●essential to all life,vital to the process of economic development,unevenly distributed with some areas ‘water-rich’ and others ‘water-poor’.Freshwater is needed for the following purposes:●●●●domestic use − e.g. bathing and showering; flushing toilets; drinking andcooking; washing clothes and dishes; watering the gardenindustrial use − e.g. producing a litre of beer uses 300 litres of water; producinga hamburger uses on average 2400 litres of water; the production of one tonneof paper uses 400 000 litres of water. See also Figure 1.29 on page 21agricultural use − e.g. irrigating crops; providing drinking water for livestockleisure use – e.g. sport fishing on rivers; sailing on lakes and ponds; wateringgolf courses.All forms of water use involve two key elements:●●demand – this is the need for water for a range of uses. It is also often referredto as consumption. In other words, the amount of water consumed reflects thelevel of demandsupply – that is meeting the demand for water by tapping various sources, suchas groundwater, lakes and rivers.For any country or area within it, it is possible to compare water demand and watersupply. This comparison is known as the water balance (Figure 1.25 on page 18).16DemandWater demand and consumption have increased dramatically during the last 100years with global demand doubling every 20 years (Figure 1.23). The major factorbehind the rising demand has been the continuing growth of the world’s population.Between 1990 and 2010, the world population grew from 5.3 billion to an estimated6.8 billion. However, the rise in the demand and consumption of water is not just dueto growing numbers of people. Development also plays an important part.
●●●The rising standard of living that is part of developmentincreases the domestic use of water. More houses with pipedwater, flush toilets, showers and baths, washing machines,and even swimming pools mean much higher waterconsumption.The rise in agricultural productivity needed to feed agrowing population increases the use of water, particularlyfor irrigation.Industrialisation is a key part of development. Most factoriesare large consumers of water. Water is used for coolingmachinery. It is also used in the generation of electricity forpowering industry.Given the link between development and water consumption, wecan recognise two ‘worlds of water’. There are big differencesbetween water consumption in high-income countries (HICs)01950 1960 1970 1980 1990 2000and in low-income countries (LICs). Water consumption in HICs Figure 1.23: World water consumption, 1950−2000is very high. On average, each person in an HIC uses about 1200cubic metres of water each year. This is about three times as much as a person in aLIC where consumption is around 400 cubic metres per year.There are also some big differences in the use of that water (Figure 1.24). In LICsmost water is used by agriculture and relatively little by industry or in the home. InHICs industry uses the most water followed closely by agriculture. Domestic use ofwater is relatively small, but the percentage is over three times greater than in LICs.SupplyHaving looked at one side of the water equation, let us now look at the other –water supply. In many parts of the world, the water needed to meet the increasingdemand comes from three main sources:●●●rivers and lakes – possibly this was the source of supply used by the earliesthumansreservoirs – these are artificial lakes created by building a dam across a valleyand allowing it to flood. The water collected and stored behind the dam canbecome an important water supplyaquifers and wells − much of the world’s fresh water supply lies underground.It is stored in porous rocks known as aquifers. This groundwater can beextracted by drilling wells or boreholes down to the aquifer. The water is thenraised to the surface by buckets, pumps or under its own pressure.Cubic Km/year50004000300020001000AgricultureIndustryDomesticLIC water consumption4%5%HIC water consumption14%91%AgricultureIndustryDomestic39%<strong>Chapter</strong> 1: River environmentsWater surplus and deficitIf we were to draw up two world maps, one showing the distribution of waterdemand or consumption and the other, water supply, we would find that the twomaps show quite different patterns. If we laid one map on top of the other, wewould be able to pick out three types of area:●●areas where the water balance is negative – in other words where water demandexceeds supply. These are referred to as water-deficit areasareas where the water balance is positive – in other words water-surplus areaswhere the supply or availability of water exceeds demand47%Figure 1.24: Water consumption in LICs and HICs17
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: The height of the drainage basin an
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 and 24: Agriculture●●●Liquid from far
Page 25 and 26: There is a fourth and relatively ne
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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