The hydrological cycle is a system of waterflows and storages that may be disrupted byhuman activity.

Discuss human impact on the hydrologicalcycle.

Construct and analyse a hydrotogical cyclediagram.

Solar radiation drives the hydrological cycle.

Fresh water makes up only a small fraction(approximately 2. 6% by volume] of the Earth'swater storages.

Storages in the hydrological cycle includeorganisms and various water bodies, includingoceans, groundwater [aquifers], lakes, soil,rivers, atmosphere and glaciers and ice caps.

Flows in the hydrologicat cycle includeevapotranspiration, sublimation, evaporation,condensation, advection (wind-blown

movement), precipitation, melting, freezing,flooding, surface run-off, infiltration, percotationand stream-flow or currents.

Human activities such as agriculture,deforestation and urbanization have a significaimpact on surface run-ofFand infiltration.

Ocean circulation systems are driven bydifferences in temperature and satinity. Theresulting difference in water density drives theocean conveyor belt, which distributes heataround the world, and thus affects climate.

198

. ;.. ?. i?''i'1C?lUCT!CS "i'C U'A'. '3R 2"S?"i'<iS

The Earth's water budgetThe Earth is not referred to as the 'Blue Planet' without due reason.

From space the presence of water on Earth is very obvious. About 70%of the Earth's surface is covered by water.

o About 2.6% of all water is fresh water and

97% of the water on the planet is ocean water (salt water).

Fresh water is in quite short supply.

About 68. 7 % of this water is in the polar ice caps and glaciers,

30. 1% in ground water.

^ Water on the surface of the Earth in lakes, rivers and swamps is onlyabout 0.3% of the total.

You may think the atmosphere holds a lot of water but:

Only 0. 001% of the total Earth's water volume is as water vapour inthe atmosphere.

According to the US Geological Survey, if all of the water in theatmosphere rained down at once, it would only cover the ground toa depth of 2. 5 cm.

fresh water 3%

Distribution of Earth's water

other 0. 9% rivers 2%

saline

{oceans}97%

groundwater

30 1%

surface

water 0. 3% iswamps 11%

Earth's water freshwater fresh surface

water [liquid)

Figure 4. 1.1 Distribution of Earth's water

ie turnover times (time it takes for a molecule of water to enter andave that part of the system) are very variable.

In the oceans, it takes 37, 000 years

Icecaps 16, 000 years

Groundwater 300 years

Rivers 12-20 days

Atoaosphere only 9 days.A'ater can be considered either a renewable resource or a non-ewable resource depending on where it is stored. See Figure 4. 1. 2.

The water budget is aquantitative estimate of the

amounts of water in storagesand flows of the water cycle.

Using the data given,construct a table to list fresh

water storages on Earth indecreasing order of size.

199

Renewable Middle ground Non-renewable

Atmosphere

Rivers

Groundwater aquifers

An aquifer is a layer of porous rock, sandor gravel underground that holds water.In aquifers, it takes longerthan a humanlifetime to replenish the water extracted

Oceans

lcecaps

A. Figure 4. 1.2 Status of water storages

The water (hydrological) cycleEnergy from solar radiation and the force of gravity drive thewater cycle. The water cycle drives the world's weather systems.

water . "agein ice a,

^..s0"^..

clouds &water vapour

precipitation

transport

evapotranspiration

condensation

evaporation

A Figure 4. 1. 3 The water cycle

The water cycle consists of storages of water and the flows of waterbetween the various storages. These flows may be transfers ortransformations.

Transfers, when it stays in the same state, are:

Advection (wind-blown movement)

Flooding

Surface run-off

200

4. ?, ir'TROCUCT'Or: TO ^ATE ̂ SYSm-tS

Infiltration and percolation (when water runs into and through soilor rocks)

Stream flow and current.

Transformations, when it changes state to or from liquid water, are:Evapotranspiration - liquid to water vapour

Condensation - water vapour to liquidFreezing - into solid snow and ice.

The storages include the:

oceans,

soil,

groundwater (aquifers),

lakes,

rivers and streams,

atmosphere, and

glaciers and ice caps.

1. Draw a systems diagram of the water budget and cycle showing thestorages and flows given in the table. Make your storage boxes and widthof flow arrows correspond to the proportions of these volumes. Label allstorages and flows.

Storages

Snow and ice

Ground water and aquifersLakes and rivers

Oceans

Atmosphere

Soil

Flows

Precipitation over oceans

Precipitation over landIce melt

Surface run-oflF

Evapotranspiration from landEvaporation from sea

Water volume (km3 x 103]

2?,000

9, 000

250

1,350,000

13

35,000

385

110

2

40

7Q

425

There are six storages of water shown in the diagram. List them in order ofdecreasing size (largest size first) and calculate the percentage of the totalhydrosphere stored in each

Which of these storages can humans use and what percentage of all wateris this?

The hydrological cycle isrepresented as a systemsmodel. To what extent

can systems diagramseffectively model reality,given that they are onlybased on limited observablefeatures?

Z01

Observe and record on yourjourney to school what thesurfaces of the land youcover are made of. Could

they absorb water? Whathas been done to channel

the water and to where?

Human impact on the water cycleHumans change the landscape and interrupt the movement of water by:

1. Withdrawals - for domestic use, irrigation in agriculture and industry

2. Discharges - by adding pollutants to water, eg chemicals fromagriculture, fertilizers, sewage.

3. Changing the speed at which water can flow and where it flows:

a. In cities by building roads and channelling rivers underground orin concreted areas.

b. Canalizing: straightening large sections of rivers in concretechannels to facilitate more rapid flow through sensitive areas.

c. With dams, barrages and dykes, making reservoirs.

4. Diverting rivers or sections of rivers:

a. Many are diverted away from important areas to avoidflood damage.

b. Some are diverted towards dams to improve storage.

Examples of major changes caused by humans:

Aral Sea - intense irrigation has almost stopped river flow into thesea and lowered the sea's level (it has shrunk in area by 90% in thelast 50 years).

Ganges basin - deforestation increases flooding as predpitation is nolabsorbed by vegetation.

Run-off from urbanized areas causing local flooding.

Urbanization and flash floodsMore and more humans live in cities and there are more of us than

ever before. Flash floods occur when rainfall or snowmelt cannotinfiltrate the soil and runs off on the surface. This could be due to land

being hard-baked in hot, dry areas but more and more it is due toimpermeable surfaces in cities.

In Manila, capital of the Philippines, 50% of the city was flooded in 20after record rainfall.

Investigate two otherexamples (one local, oneglobal] of where humanactivity has significantlyimpacted surface run-ofFand infiltration of water.

Go to http://www. fao. org/nr/water/aquastat/countries regions/jordan/index. stm

Read the information on Jordan and answer these questions.

a. Describe where most of the population live and explain why.

b. Summarize the agricultural industry of Jordan.

c. List the water supply sources available to Jordan. Explain which aresustainable.

d. Describe the political and the environmental issues around Jordan'swater supplies.

e. Explain the water management strategies that Jordan is adopting.

20^

! CyUCT:C;" 73 r'ATSi1 SYSI-E..-S

Ocean currents and energy distributionOcean currents are movements of water both vertically and horizontally.They move in specific directions and some have names, and they arefound on the surface and in deep water.

Ocean currents have an important role in the global distributionof energy. Without an understanding of ocean currents we cannotunderstand the global atmospheric energy exchanges.

Surface currents (upper 400 m of ocean) are moved by the wind.

The Earth's rotation deflects them and increases their circular

movement.

Deep water currents, also called thermohaline currents, make up 90%of ocean currents and cause the oceanic conveyor belt (figure 4. 1. 4).

They are due to differences in water density caused by (a) salt and(b) temperature.

Warm water can hold less salt than cold water so is less dense

and rises.

Cold water holds more salt, is denser so sinks.

When warm water rises, cold has to come up from depth to replaceit. These are upwellings.

. When cold water rises, it too has to be replaced by warm water indownwellings.

. In this way, water circulates.

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203

<! ''

1. Explain how the issues offreshwater availability are ofrelevance to sustainabilrtyor sustainable development.

2. With reference to a named

ecosystem, to what extenthave the solutions emergingfrom water resources been

directed at preventingcauses of environmental

impacts or problems, limitingthe extent of impact fromthese causes, or restoringsystems in which impactshave already occurred?

3. In what ways might thesolutions to freshwater

resource use alter yourpredictions for the state ofhuman societies and the

biosphere some decadesfrom now?

Cold ocean currents run from the poles to the equator, for example:

the Humboldt Current (off the coast of Peru)

the Benguela Current (off the coast of Namibia in southern Africa)

Warm currents flow from the equator to the poles, for example:

the Gulf Stream (in the North Atlantic Ocean)

the Angola Current (off the coast of Angola)

Ocean currents and climate

Water has a higher specific heat capacity (the amount of heat needed t'raise the temperature of a unit of matter by 1 °C) than land. This meanthat water masses heat up and cool down more slowly than landmasseAs a result, land close to seas and oceans has a mild climate with

moderate winters and cool summers.

Ocean currents also affect local climate:

The warm Gulf Stream/North Atlantic Drift moderates the

climate of Northwestern Europe, which otherwise would have asub-arctic climate.

The cold Benguela Current, under the influence of prevailingsouthwest winds, moderates the climate of the Namibian desert.2

The Humboldt Current impacts the climate in Peru.(see ENSO below)

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http://www. pbs. org/edens/namib/earth2. htm.

204

4. & I^TROOUCTiOM TO WAIB^ SYSTEMS

El Nino Southern Oscillation (ENSO)The El Niho Southern Oscillation (ENSO) is aphenomenon in the Pacific Ocean that has globalconsequences. Normally, air pressure in the easternPacific Ocean (South America] is higher than that inthe western Pacific Ocean (Australia, Indonesia). Thisresults in the trade winds that blow westward for most

of the year. The trade winds blow the warm surfacewater westward.

-;.. "- convective loop

equator -

^-_

thermocline

120°E 80°W

Figure 4. 1.6 Trade winds blowing warm surfacewaters of the Pacific westward in a non-ENSO year

In some years however, the pressure difference acrossthe Pacific Ocean is reversed.

'quator

thermocline

'E 80°W

Figure 4. 1.7 An ENSO year when the winds bloweastward across the Pacific

3e pressure reversions are the Southern Oscillation.:hanged pressure difference alters both thetions of the wind and of the warm surface current.^enomenon was first discovered by Peruvianr"en, who called it 'El Nina', the Boy Child, as it

usually occurred just before Christmas. Because thereversal of sea and air currents is caused by the changedpressure difference, the whole phenomenon is oftencalled ENSO: El Nino Southern Oscillation. El Nino events

occur about every two to eight years and last for abouttwo years. They may be either weaker or stronger. StrongEl Nino years are usually followed by several years of'LaNina', when the ocean temperature of the eastern Pacificis unusually cold after being unusually hot in the El Ninayears, as the system swings back and forth.

El Nino has local and global effects. Local effects includecollapse ofanchovy fish stocks, massive death of seabirds and storms and flooding in the coastal plain of Peru.

The anchovy fishery off the coast of Peru is extremelyrich because of the occurrence of an upwellingwhencold nutrient-rich waters come up from the ocean depths.Normally, productivity in oceans is quite low becauseof one of two limiting factors: light level and nutrientconcentration. In the upper water levels light intensityis high, but nutrient levels are low and limit productivity.The available nutrients are taken in by phytoplanktonand travel down the food chain. Dead organisms that arenot eaten by some other organism sink and the nutrientsstored within them end up on the ocean bottom. The lowerwater layers are therefore nutrient-rich. But here, theabsence of light makes photosynthesis impossible. Westof the Peruvian coast, the prevailing eastern trade windspush the surface water westward. This water is replacedby cold nutrient-rich water from the deep HumboldtCurrent, which originates in the Antarctic region andfollows the South American coast to the north. The

appearance ofnutrient-rich water at the surface allowsfor high productivity, hence the high numbers of fish andtheir predators, the seabirds. During El Nirio events, theupwelling disappears and the fish and seabirds starve.

During El Nino events the Peruvian coastal plain issubject to severe storms, accompanied by excessiverainfall. This is caused by the warm, extremely moist airbeing forced upward by the Andes Mountains.

The warm ocean waterthat moves east during El Nirioevents contains tremendous amounts of energy. Theamount of energy is large enough to alter major air currentslike the jet streams and, as a consequence, El Nino affectsglobal weather. Examples of these changes are:

Droughts in Australia, Indonesia, the Pacific Northwestof the United States and British Columbia [Canada].Forest fires are common in these areas.

205

Heavy storms often resulting in flooding in Californiaand the Midwest of the United States, Central Europeand eastern Asia.

Absence of the monsoon in India. The Indian

population depends on the monsoon rains for itsfood production.

While ENSO is a natural phenomenon, its effects areexacerbated by human pressures on the environment.

The Gulf Stream/North Atlantic Oscillation

The Gulf Stream is a current in the Atlantic Ocean that

comes from the Gulf of Mexico across the Atlantic, where

it is known as the North Atlantic Drift to western Europe.It carries warm waters in a current about 100 km wide

and 1000 m deep on average. It makes Northern Europewarmer than it otherwise would be. As this water flows,

some evaporates so its saltiness increases. By the timeit reaches north of Britain and Scandinavian coasts, it

is so much saltier, and so much more dense, than the

surrounding sea water that it sinks and returns in theconvey or belt as the North Atlantic Deep Water back towhere it started.

There is some evidence that the Gulf Stream current is

slowing down, possibly due to global warming. Some

think it may stop completely in a few decades. Meltingof the Greenland ice sheet may be adding so much ft^water to the North Atlantic that the saltiness of the North

Atlantic Drift is reduced and the sinking and return of thewater to the Gulf of Mexico is slower. If this were the casi

climate in Western Europe would be getting cooler but itis warming instead.

The North Atlantic Oscillation (NAO) is a weatherphenomenon in the Atlantic as ENSO is in the Pacific. Inhigh index NAO years, there is low pressure over Icelandand high over the Azores so westerly winds blow andwinters are mild and summers cool and wetter. In low

index NAO years, the pressure differences are lower, thewesterlies reduced and winters are colder and summershave heat-waves. There is also an influence on easternNorth America from the NAO.

Research the latest data on ENSO and NAO. Find out if

there is an ENSO event now. What is the reduction in the

Gulf Stream current now?

If human activity is altering climate, as most scientistsbelieve, we are also exacerbating the effects ofENSOevents as we put more pressure on the natural system'

If the Gulf Stream were to stop suddenly (which wethink has happened in the past], what would be theimplications?

206

4. 2 ACCESS TO F!IESH';.'HYE?!

The supplies of freshwater resources areinequitably available and unevenly distributed,which can lead to conflict and concerns over

water security.

Freshwater resources can be sustainablymanaged using a variety of different approaches.

Evaluate the strategies which can be used tomeet increasing demand for freshwater.

Discuss, with reference to a case study, howshared freshwater resources have given rise tointernational conflict.

"> Access to an adequate supply of freshwatervaries widely.

-^ Climate change may disrupt rainfall patterns andfurther affect this access.

-> As population, irrigation and industrializationincrease, the demand for freshwater increases.

-» Freshwater supplies may become limitedthrough contamination and unsustainable

'* abstraction.

Water supplies can be enhanced throughreservoirs, redistribution, desalination, artificial

recharge ofaquifers and rainwater harvesting. Waterconservation (including grey-water recycling) canhelp to reduce demand but often requires a changein attitude by the water consumers.

The scarcity of water resources can lead toconflict between human populations particularlywhere sources are shared.

Vater as a critical resource

These facts are from the World Water Council:

9 1. 1 billion people live without clean drinking water.

2 6 billion people lack adequate sanitation [20Q2, UNiCEF/WHO JMP 2004).18 million people die every year from diarrheal diseases.3,900 children die every day from waterborne diseases (WHO 2004].Daily per capita use of water in residential areas:

" 350 litres in North America and Japann 200 litres in Europea 20 litres (or less] in sub-Saharan Africa.--. er 260 river basins are shared by two or more countries mostly without:= equate legal or institutional arrangements.

"entity of water needed to produce 1 kg of;wheat: 1,0001"ce: 1,4001beef:l3, 0001.

20?

1. Assumingthereare6.6billionpeople alive on Earth, what isthe percentage of the world'spopulation that have no cleandrinking water?

2. How many children dieper year from waterbornediseases?

3. What is the percentageof daily per capita use ofwater in sub-Saharan Africa

compared with that in Japanand North America?

4. How many days of wateruse by one person in Europewould it take to produce onekilogramofbeef?

5. How many kilograms of wheatwould be produced by theequivalent of one year ofwater consumption by oneperson in sub-Saharan Africa?

Although there is a lot of water on Earth, most of it is saline. We canremove the salt from water in desalination plants but the costs interms of energy (especially burning fossil fuels) are large and it is onlycurrently possible in wealthy countries which are water-stressed andnear the sea, for example Israel, Australia, Saudi Arabia. A major issuewith desalination is that salt is a by-product and is often returned tothe ocean, increasing the density of the water which then sinks anddamages ocean-bottom ecosystems. Unless we can find the technologydesalinate water cheaply, it is not a viable proposition at the moment.

The freshwater available to us is limited and the UN has applied theterm 'Water Crisis' to our management of water resources today. Thereis not enough usable water and it can be very polluted. Up to 40% ofhumans alive today live with some level of water scarcity. This figurewill only increase.

Humans use fresh water for:

domestic purposes - water used at home for drinking, washing, cleanir

agriculture - irrigation, for animals to drink;

industry - including manufacturing, mining;

hydroelectric power generation;

transportation (ships on lakes and rivers);

marking the boundaries between nation states (rivers and lakes).

The WHO (World Health Organization) states that each human shouldhave access to a minimum of 20 litres of fresh water per day but Agen21 says this should be 40 litres. Much of the world has access to far lesthan this recommended minimum whilst other areas have far more.

Water scarcity is not just a measure of how much water there is but olhow we use it. There may be enough water in a region but it is divertsfor non-domestic use. Agriculture uses water for irrigation and toprovide water for livestock - usage rates are tens of times higher thandomestic use. As human population expands, we need water to growmore food but, like food, it is not that there is not enough worldwide,is that the distribution of it is uneven.

Egypt, for example, imports more than half its food as it does not havi

enough water to grow it, and in the JVLurray-Darling basin in Australithere is water scarcity for humans as so much is used for agriculture.Adding droughts and climate change, soil erosion and salinization to ?story, you can see that water is and will become a major issue for naGand international organizations.

Many major rivers run through several countries.

The Danube River basin is shared by 19 countries and 81 million pec

The Tigris and Euphrates rivers carry water that is extracted by &cIraq and Syria.

One country pollutes - the next country suffers, the question is whoowns the water? Another Tragedy of the Commons. And so warshave been and will continue to be fought over water as it become5increasingly needed and increasingly scarce.

208

4. 2 ACCESS TO FRESHWATER

Sustainability of freshwater resource usageSustainable use of resources allows full natural replacement of theresources exploited and full recovery of the ecosystems affected by theirextraction and use.

;| little or no water scarcity

!| physical water scarcity

[-] approaching physicalwater scarcity

I] economic water scarcity

iI not estimated \l

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Sources of freshwater are surface freshwater (rivers, streams,reservoirs and lakes) and underground aquifers. The water can beextracted directly from surface or via wells from aquifers.

An aquifer is a layer of porous rock (holds water) sandwiched betweentwo layers of impermeable rock (does not let water through). They arefilled continuously by infiltration of precipitation where the porous rock-caches the surface, but this is only in limited areas.

Vater flow in aquifers is extremely slow (horizontal flows can be astow as 1-10 metres per century). 1 As a result, aquifers are often usednsustainably. Many aquifers are also 'fossil aquifers' - meaning thecharge source is no longer exposed at the surface and so they areever refilled. These can never be used sustainably.

Alt water on Earth

recharge area forartesian well

surface waterartesian

well

spnng^

ard

"e 4.2. 2 Aquifer structure

unusable99%

water usable by humans 1%

lakes 0. 86% -I L rivers 0. 02%

A Figure 4. 2.3 Water to humans

^ Ecology of a Changing Planet, 3rd ed., Prentice Hall, Upper Saddle River, Z003, pages 187-188.209

Aid agencies often useemotive advertisements

around the water securityissue. To what extent

can emotion be used to

manipulate knowledge andactions?

Global freshwater consumption is increasing strongly because the humanpopulation is increasing and because the average quality of life is improving.This increased freshwater use leads to two types of problems: water scarcityand water degradation. Degradation means that water quality deteriorates,makuig it less suitable for use. Let's have a more detailed look at theproblems related to freshwater use and possible solutions:

Issues:

Climate change may be disrupting rainfall patterns, even changingmonsoon rains, causing further inequality of supplies.

Low water levels in rivers and streams. The Colorado River in the

USA, once a major river, now is not much more than a tiny streamwhen it enters the Gulf of Mexico, making navigation impossible.

Slow water flow in the lower courses of rivers results in sedimentation,which makes the already shallow river even shallower and may extenddeltas further into the sea.

Underground aquifers are being exhausted. This simply meansthat the aquifer cannot be used anymore, which strongly affectsagriculture. Buildings can be damaged when the soil is shrinkingbecause the water has been taken away.

Pumping rates from the aquifers are too fast; this causes a cone ofexhaustion making the well unusable.

Freshwater becomes contaminated and so unusable.

Irrigation often results in soil degradation, especially in dry areas.JVtuch of the water used in irrigation evaporates before it is absorbedby the crops. Dissolved minerals remain in the top layer of the soil,making it too saline (salty) for further agriculture. This process iscalled salinization.

Fertilizers and pesticides used in agriculture often pollute streamsand rivers.

Industries release pollutants into surface water bodies.

Industries and electricity plants release warm water into rivers.Warm water can hold less dissolved oxygen than cold water, soaquatic organisms that take their oxygen from the water (fish,crayfish) are negatively affected. Warm water outflow from powerstations changes the species composition in the water.

Solutions:

Increase freshwater supplies by

reservoirs

redistribution

desalination plants removing salt from seawater

rainwater harvesting systems - large and small scale

artificially recharging aquifers.

Reduce domestic use of freshwater by using more water-effidentshowers, dishwashers and toilets.

210

4. 2 ACCESS TO FRESHWATER

Wash cars in car washes with a closed water system. Not washing thecar in the street also reduces pollution by oil.

Grey-water recycling - grey water is water from showers, baths,household laundry, kitchen sinks etc. which can be reused on site forflushing WC s, garden irrigation.

Irrigation: selecting drought resistant crops can reduce the needfor irrigation. (Some areas may simply be unsuitable for growingcrops; cattle grazing may be better. ) Closed pipes instead of opencanals and trickle systems instead of spraying water can both reduceevaporation. Alternatively using subsurface drip irrigation.

Reduce the amount of pesticide and fertilizer used (using the smallestpossible amount at the most appropriate time).

Replace chemical fertilizers with organic ones - the release ofnutrients is slower and more likely to be absorbed by the crop plants.

Prevent over-spray, eg spraying pestidde or fertilizer directly in a stream.

Use highly selective pesticides instead of generic pesticide, or usebiological control measures.

Industries can remove pollutants from their wastewater with watertreatment plants. Often, they are forced by law to do so.

Regulate maximum temperatures of released cooling water. Insteadof releasing the warm cooling water, cooling towers that evaporatethe water can be used.

Pra&tol ¥wr"~

.K Uroqual access -to fr&&lnwa+^r6an 6ause. i^onfli6+ bfrtwfr&ncoun+nas that haw anabundan&e. of fre-shwatf-r andthose, who have. not t2.fse.arch

two mmple-s, wbm conflirihas ansan over water supplie-s

* 6valuate. the s-tra+e-gieswhich can be ua,ed to m&e-t

our ina-e-asing dwnand forfre.shwa+e.r

.» Imsstiga+e the. vokim& ofwat&r ̂ fou use (a) dirertlfand (b) indim+lf per daf6omparf- this wrth othfrr u&e.rslocallf and globall<(

Grey waterIf you live in a house with running water, only purified and treated freshwater entersyour home in one pipeline. This water is used for all the many processes in thehome that need water. But it does not all have to be as clean as our drinking water.

Black water or sewage contains human waste and may carry disease-causingbacteria and other organisms (eg worms].

Grey water can be very lightly used water. Do you keep the tap runningwhen you clean your teeth or run a glass of water? If so, most of this wateris perfectly clean yet goes down the pipes and mixes with black water ina shared sewerage system. All this water is then cleaned to the higheststandards before being recycled back into our piped water system.

This is a crazy waste of clean water and the two types, black and grey could beseparated before they leave our homes. Grey water could be used to irrigategardens, clean cars, flush WCs and anywhere that requires water but not drinking-quality water. It must be used at once though to avoid build-up of bacteria.

/aterwarsscarcity of water resources can lead to conflict between human

°Pulations particularly where sources are shared.

211

1. The geopolitics of Israel's watershortage

7International border

Coastal aquifer

Mountain aquifer

..tofan \ SYRIAHeights

^ Sea ofGalilee

I JORDAN

Tel Aviv

^Wt.3

Jerusalem

Be'er ShevaDead Sea

EGYPT

A Figure 4.2.4 Aquifers of the region

Water shortage looms in Israel after prolongeddrought, but supply to Jordan continuingInternational Herald Tribune. Posted on

March 21st, 2008.

"Israel is suffering its greatest drought in the pastdecade and will have to stop pumping from oneof its main drinking water sources by the end ofthe summer, an official said Wednesday. WaterAuthority spokesman Uri Schor said when Israelhas to stop pumping from the Sea of Galilee -the source of about 40 percent of its drinkingwater - it will have to step up extraction fromalready-depleted aquifers, underground water-bearing seams of rock. The situation is very, verybad/ Schor said. 'As we pump more from theaquifers, the quality of the water will go down/

Israel's water problem stems from populationgrowth and an improvement in quality of life thatbrings a greater desire to water lawns and gardens,Schor said. This winter was the fourth that Israel

got less than average rain, with only about 50-60percent of the average in most areas, he said. Criticsof government policy note that agriculture uses alarge proportion of Israel's water, receiving heavilysubsidized water rates. Since Israel in any eventdoes not grow much of the food it needs, they sayirrigation for farming should be drastically curtailed.Israel's rainy winter season ends this month,

though there can be occasional rainy days througtJune. The rainy season begins around October.

Despite the shortage, Israel wiU probably not reducethe amount of water supplied to Jordan according tothe peace treaty between the countries, Schor said.Jordan's drought is much worse than Israel's, he saidWater is a contentious issue in the dry region, and 01of the disputes IsraeU and Palestinian negotiators ho{to overcome in talks to work out a peace agreement.

In an effort to stem a serious shortage of water, Israewffl launch a conservation campaign, targeting mosthousehold use. As part of the efforts, Israel has inrecent weeks reduced by more than 50 percent thedrmkmg water suppUed to farmers, increasing theirneed for req/ded water, Schor said. Water officials wthis weekend debate raising the cost of drinking watiin another attempt to cut household me, he said.

Israel has two desalination plants that supply abouione-third of water needed by municipalities andhouseholds, Schor said. Three other plants schedulto be completed by 2013 will double that amount.The next one is due to be operational in 2009."

1. List Israel's water sources (stores) and deman(flows) on this water.

2. What are the long-term environmentalproblems of overuse of water? Can you explathis in terms of your water cycle diagram?

3. What are the reasons fur strained relations

between neighbouring countries over watersupplies?

4. How could Israel solve these problems in bf;the short term and the long term?

5. If some countries in the region can afford todesalinate sea water but others cannot, shou

they share the water?

6. In your opinion what would be a sustainasolution to water management in this pan cthe world?

Research the water politics of the Nile basin in Northeast Africa. The Nile flows through 10 countries whicall extract water from it.

1. Evaluate the claims of Egypt and Sudan fortheiiuse of Nile water.

2. Suggest solutions to the tensions.

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*.. 2 ACCESS TO FR6SKWATER

2. China's Three Gorges dam update

^

A Figure 4. 2. 5 Yangtze River and Three Gorges dam,China-where do you think the dam is located?

The Three Gorges hydroelectric dam on theYangtze River, China was one of the largestengineering projects and the largest power stationin the world. Its estimated cost was US$30 billion.i }dit opened in 2012. The hydroelectric powerreduced from the dam could provide 9% of all

. lina's output so the saving in carbon emissions5 u Id be huge. Up to a quarter of a millionirkers built the dam and 1. 3 million peopleere re&ettled as the flood waters covered their

melands. Apart from electricity generation, the, n is designed to stop the river flooding. These. >ds have drowned up to 1 million people inpast 100 years and flooded the major city ofh.an for months.

Criticisms of the dam are that it will cause

rinvironmental degradation, refugees, destroyrchaeological sites, threaten some wild speciesnd silt up.

Siberian Crane is critically endangered and. winter habitat is the wetlands that the dam

t'?. The Yangtze River dolphin is probably'<T in the wild due to pollution and loss of

.-'- flow downstream. The Yangtze sturgeon is^;ed as well.

.^avo. of the dam, siltation will increase asM.. will get caught behind the dam. This not^creases the danger of clogging the turbinesleans it does not flow downstream. Lack of^y make the downstream river banks more

<. ro erosion. Shanghai, at the mouth of the~'L;'-e, is built on a silt bed and this may erodeeasingly without replacement from upstream.

Behind the dam, the water level rose by up to100 metres and historical and cultural sites were

flooded. The Ba people settled here 3,000 years agoand buried their dead in coffins in caves on cliffs.

Pollution by toxic wastes and materials used inbuilding the dam may make the waters unsuitablefor drinking and minimal sewage treatment mayincrease algal blooms and eutrophication in thedammed waters.

There is a risk of energy security as well. Havingso much power from one dam means that, ifit is> destroyed, by terrorism or earthquake, allthis power generation is lost. It also has to betransmitted long distances to where it is used.

To have information is useful. To turn it into knowledgeis difficult. This information age feeds us a massiveglut of information, but for all this information thereis also a vast amount of misinformation. As a critical

thinker, always be aware of what is not written asmuch as what is written. Omitting essential facts thatdo not support the case you are arguing for is an easything to do. Consider either the Three Gorges damor any other project to manage water (eg the Aswandam, Aral Sea, Ogallala Aquifer).

Either

Put together a case FOR the project and AGAINSTthe project using the information you research.You can omit some facts and exaggerate others.Pseudoscience does just this.

OR

Set up a class debate for and against the project.

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