Population and I HWater Resources: fA Delicate Balance

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• subject to drought, extreme seasonal fluctuations in rainfall, and other wate|I resource problems. Many of these countries also have rapidly grc wing |p populations that must compete for limited water resources. This PopulatitmMf'<<: Bulletin explains how environmental precondition*, like climate ; nd geogr»-$I phy, limit human access to water; and how human activities affec; the global!?I.- water systems. With a harsh hydroclimate and growing populatio 1 pressure,I;; arid and semi-arid regions of Africa are already living on the hyd ological i| ; margin. By 2025, <wer 1 billion people worldwide will be living in are*||i subject to extreme water scarcity. Slower population growth, con lerva*|? appropriate agricultural policies, and increased storage facilities ire ami;•. the many ways water-scarce areas can maintain the balance betwt en popula-Ift-tion and water resour«w«i.?is l"""'"""1""""""'"" '"" ""' ' ' " ' ' ''''

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Population Reference Bureau. For information on becoming a PRB member or lj> order MjK••~ » K i i a i s , s e e i n s i d e b a c k c o y « • - - • . > . • . . • - : • • . — . • . . • • - - . - • • • •••• - ^ l » .,,........,..w..,i=,.:...i

e suggested citation, if you quote fr©oa this publicali©*, is: Matin Falkenmar'idstrand. "Population and Water Resources: A Delicate Balance," Population Bulletin,

No. 3 (Washington, DC: Population Reference Bureau, Inc., November 1992). I »|For permission to reproduce .substantial portions from the Population Bulletin, wriferfPopulation Reference Bureau, Inc., Permissions, 1875 Connecticut Aye., N.W., Si)Washington, D,C. 20009-5728. s v ?*•; •

1992 b)' the Population Reference Bureau,«N0OS2-468X ; '•"•'--x^^-ei.**''-^*-'*

Population and Water Resources: A Delicate BalanceInt.roduci.irtn oLifeblood of the Biosphere ^Water and Civilization 5Limits on Human Access to Water gPopulation Pressure on Water Resources joWater Availability vs. Demand 25Ways Out of the Predicament '.' ' " " " " " " ' " ! " 27(Conclusion „„References 04Suggested Readings L,Discussion Questions ^g

Tables1. Selected Countries by Source of Available Water 172. Management Approaches for Different Water Source Combinations 173. Population and Water Resources in World Regions and Selected Countries

1990 and 2025 ' 2 Q

4. Demographic Indicators for World Regions, 1992 '.'.'.'.'.'.'.'.'.'.. '.'".'. 215. Water-Resource Situation by Distance to Water Availability Ceiling'""""""'""'""^ 27

Figures

1. How Water Enters and Leaves the landscape 72. Evaporative Demand | g

3. Share of Rainfall Going to Recharge Gronndwater 104. Levels of Human Development ij5. How Human Activities Disturb the Water Cycle ,'„', 126. Growing Seasons and Drought Risk in Africa ","". 157. Agricultural Potential of Land in Developing Regions"""!"."""""'"'""''""''' ]g8. Population Pressure and Water-Resource Problems '.'.'.'.'.'.'.'.'.'.'. 199. Water Availability and Demand «!}

Boxes1. Myths About Water .2. Genuine vs. Human-Induced Water Scarcity jg3. Urban Population Growth, Pollution, and Safe Water ......,,,,. 224. The Population and Water Predicament ....,,.,.,. 245. The River Jordan Basin :The Politics of Sharing a Scarce Resource """""" 30

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POPULATION BULLETINVol. 47, No. 3November 1992

Matin Falkenmark is f/rofessor ernerila atthe Swedish Natural Science Research Coun-cil, and chair of the Swedish Committee farthe International I lydrological Programmeand of the Scientific Program/me Committee,for the Stockholm Water- Symposia. She is alsoa visiting professor al Sweden's University ofTjnkeifnng. She participates in internationalorganizations, including the InternationalUnion for the Conservation of Nature, and isscientific advisor to the joint World Bank/UNEP/UNDP Global Envimnriw.nl Facility,She has written extensively on global waterresource issues and, in 1991, was named aUN Environment Programme Global 500Laureate.

Carl Widstrand is professor, University ofLinki'yfnng, Sweden and adjunct researchprofessor at Carleton University, Ottawa,Canada. He holds a Ph.D. in Anthropologyfrom Uppsala University, Sweden, and was

Population andWater Resources:A Delicate Balance.By MaUn Falkenmark and Cati Whdstrand

Director of the Scandinavian Institute ofAfrican Studies in Uppsala from 1962 to1984. He has taught at the University ofDares Salaam, Tanzania, and worked in Kenyaand Burkina Faso. Professor Widstrand hasserved as consultant for Swedish and Cana-dian international development agencies andthe World Health Organization, among otherorganizations. His recent research focuses onhygiene and the relationship between healthand water.

Their colleagues Irene Johansson andUna Berglbffalso rrixule valuable contribu-tions to this fmblicalion.

This Population Bulletin is an edited,abridged version of a longer manuscript,"Water—A Finite Resource, " ijy MatinFalkenmark and Carl Widstrand.

Water is one of our most plentifulresources. Covering more than two-thirds of the Earth, water travels fromthe sea into the air to the land and backto the sea in a seemingly endless cycleol renewal. Yet water is a finite resource,and the tiny fraction suitable fordrinking or irrigating crops is distrib-uted unevenly throughout the world'sregions. At the same time, the humanneed for water is escalating because ofrapid population growth and industrial-ization, especially in the world regionswhere water is most scarce.

The world's population lives at themercy of the water cycle. Humaninnovative talents can make the bestpossible use of the water that passesthrough the territory of a country, buttechnology cannot influence the rate atwhich water is naturally renewed fromthe global water circulation system.Further, human activities, such as theclearing of land, disposal of wastes, andwithdrawal of freshwater, introducedisturbances in the water cycle thatresonate throughout the Earth'senvironmental systems. These distur-bances are accelerated by the world'scontinuing population growth. Nearlyone-third of the world's inhabitants livein countries with severe water problems.The world's most poverty-strickencountries tend to lie within the climaticzones most subject to drought, andother water problems.1 These regionsalso boast some of the highest rates ofpopulation growth. The populations ofKenya, Ethiopia, and Iran may welldouble within 25 years. Yet, the amountof water available to these countries willremain the same.

In water-scarce countries, populationsize and consumption patterns will de-termine the quality of life. Where popu-lation pressure on available water is toohigh, it sets off a risk spiral which dimin-ishes the water available per person,and may degrade water quality, andthreaten human health. Scarcity of wa-ter also limits the ability to develop eco-nomically and to attain self-sufficiencyin food production. Water is a necessarylubricant for industry; the lack of it mayalso be the ultimate constraint.

Getting enough water has alwaysbeen a challenge. Access to water ha.s

Box IMyths About Water

Myth: Water is an endlessly renew-; i b l e r e s o u r c e . :••" •-,'•

Fact: Water is renewed within theglobal cycle, but the renewal rate ofwater is fixed and extremely slow.The amount oi water entering an;n ea each season depends on itsgeography and climate. There areno untapped reserves of water, butthere may be unused flows thatcould be developed.

Mvth: Waif r is a static resource.

Fact: Wilier is a dynamic, not staticresource. The renewal rate, not theglobal volume of water at a giventime determines how much water isavailable for use. The volume ofwater in a lake gives no informationon the amount of water that can bewithdrawn from thai. lake.

Myth: Water and the availability ofwater is a purely technical issue.Fact: Many of our economic andresource problems have been solvedby technology, but. water is not:solely a technological issue. Iftechnology makes it possible toproduce rain over- one country, aneighboring country is deprived ofit.s rainfall. If Ethiopia builds a damnear the source of the Nile andwithdraws water for agriculture andother uses, the supply of water forEgypt, thousands of miles down-stream, will diminish.

Myth: The availability of water ismainly an economic question. It isgoverned by market, forces.

Fact: Ninety percent of the world'savailable water is not amenable tometering and thus eludes currentmarket economics. However, themanagement of the water that ispiped to users may be an economicissue subject to market forces.

generated political and militaryconflicts throughout world history.Often people have devised sometechnological wonder to overcomethese problems—by building dams,canals, and pipelines to bring waterfrom far away, or by making sea waterdrinkable. But such solutions areexpensive, especially for the low-incomecountries suffering the worst shortages.And ultimately even the most ingeniousmethods may not supply enough waterfor the number of people expected toinhabit the Earth's thirstiest regions incoming decades.

The management of water scarcity isfurther complicated by the tendency totreat water as a commodity rather thanas a finite natural resource. Engineersand politicians, not physical scientists,traditionally govern the use or misuse ofwater, often with little understanding ofthe intricacies of the water cycle or thelong-term environmental impacts oftheir projects.

Irr the scientific community, popula-tion and water, along with otherresources, are studied within separatedisciplines, each with their ownterminology and priorities. Thisdispersion of effort: has caused a kind ofscientific paralysis which has blockedprogress irr solving current, and impend-ing water problems.

An integrated, interdisciplinaryapproach to water management wouldallow the traditional question "howmuch water do we need and how muchwill it cost to get it", to be more appro-priately reformulated as "how muchwater is available, and how can we use itmost efficiently?"

Most water management systemswere developed in the relatively water-abundant temperate climates of theindustrialized countries. The whole-sale transfer of these methods andtechnologies to the fragilehydroclimates of the tropical ThirdWorld denotes a type of "waterblindness" and "temperate bias"among the development specialistswho so often advise developingcountry governments and industries.

This Population BulMin looks at.water's role in the Earth's life systems,and how it relates it to human society.

I

It shows how society is both a manipula-tor of the water cycle and a consumerdependent on a constant supply; andhow its needs vary with population sizeand consumption patterns.

lifeblood of theBiosphereWater is the lifeblood of the bio-sphere—that part of the Earth and itsatmosphere in which all living thingsexist. life on Earth exists within one ofits three main systems: the atmosphere,the land, and water (including both theoceans and bodies of freshwater). Life isonly possible because of the solar-drivencirculation of water from tile ocean tothe atmosphere, from the atmosphereto die land, and back to the ocean.

Water has many remarkable physicaland chemical characteristics. Within thehuman body, water carries nutrients tothe cells and evacuates their wasteproducts. It fulfills similar functions forplants and other animals. Its capillarityand surface tension leave water hangingbetween the mineral particles in thesoil, making moisture accessible to plantroots. Water's ability to absorb heatmakes it not only a cooling agent forplants and animals, but also gives itgreat influence over the world's climate.Its properties as a unique solvent and ofunderground mobility make water acanier of nutrients and minerals fromland into the groundwater, rivers, lakes,and other water bodies.

Water is also a carrier of disease.Human and animal wastes flowing intorivers or reservoirs introduce pathogensthat cause a myriad of serious water-related diseases, including typhoid,cholera, amoebic infections, bacillarydysentery, and diarrhea. These accountfor over three-quarters of all disease indeveloping countries, and a large shareof deaths. Treatment of water destinedfor household consumption caneliminate these diseases, but safe waterfor drinking and personal hygiene andsewage systems to control waste are aluxury in much of the world. In manydeveloping countries, less than 20percent of the population has access toclean drinking water.2

Water and CivilizationNot only is water necessary for humansto live, close proximity to water mayhave been a precondition for theearliest human settlements. Largewaterways like the Nile and theEuphrates and Tigris, the Indus, and theDanube Rivers have been the source foragricultural and drinking water formillennia. Energy generated by differ-ences in the water levels in rivers andstreams was used to operate mills andfactories, providing an early base forsmall industries. Lakes, rivers andoceans provided food and offeredhumans their most efficient meansof transport.

The problem of getting enoughwater for growing populations andincreasing agriculture and industry hasfrequently caused conflict. Irrigationsystems in Mesopotamia and ancientEgypt, in the Roman Empire, China,and Medieval Europe all faced similarproblems of distribution of water, ofcommunal labor and collective responsi-bility for water courses. Conflicts overwater use and extraction and over waterrights occupied Roman lawyers andmedieval judges in Valencia's Tribunal delas Aguas—a tribunal which has metnearly every Thursday for almost 900years! For centuries, government plansfor central control of waterways andirrigation water have been in conflict,with farmers and their ideas of agricul-ture. Bickering over irrigation water wasa permanent factor in Chinese life andquarrels over die measurement ofirrigation time were not unheard of inmedieval Spain.3

After the Romans designed methodsof lifting water or conducting it fromdistant sources, Roman subjects wereable to congregate in denser settle-ments. The Roman aqueducts made theuse of marginal land possible but theirconstruction ushered in political andlogistical problems of their operationand maintenance.

The history of water and populationsis also a history of power in society.There is extensive debate among socialand political scientists about theconnection between irrigation systems,political organization, and modes of

Environmental conditions, along with political unrest, limit water access in Somalia.

production.'1 The importance of waterto the societies that developed along theEuphrates, the Tigris, and the Nile ledhistorian Karl Wit.tfogel to propound atheory that control of water was afoundation for early civilizations.Wilifogel defended and promoted theargument that waterworks for agricul-tural purposes were so extensive andimportant that a well-organized coop-erative effort was needed for theirconstruction, administration, andmaintenance.'1 This, in turn, led to aneed for centralized decisions fromwhich a certain type of political central-ization and hierarchy developed.

Other researchers have proposed,conversely, that power is the basis forcontrol of water rather than the controlof water being the basis for power,6

Some argue that the managerialfunctions implicit in irrigation maybeperformed through communityleadership rather than a centralauthority.7

Political conflicts about the controlof water and water-ways are with ustoday. Almost 150 of the world's 200major river systems are shared by at leasttwo countries.8 Conflicts over interna-tional rivers such as the Danube or theRhine encompass both extraction andpollution. The 1.991 war in the PersianGulf underscored lire strategic positionof Turkey in controlling the sources of

the Tigris and Euphrates Rivers. Recentirrigation/agriculture developments inTurkey, such as the SoutheasternAnatolia Project will cut the flow of theTigris by 20 percent and that of theEuphrates by some 40 percent. TheTigris carries about 1V billion cubicmeters of water into Iraq and theEuphrates about. 31 million cubicmeters into Syria.

limits on HumanAccess to Water jAs numbers of people multiply andagricultural and industrial activitiesintensify, the amount, of water used bysociety escalates. But access to this mostvital resource is limited by environmen-tal preconditions, such as the climateand geography, and through humanactivities that pollute or otherwisedisturb the water systems. The key tounderstanding how population affectsand is affected by the global watersystems is an understanding of how thewater system operates.

Understanding the Water CycleThe presence of the water cycle is thefundamental difference between Earthand the other planets.'1 Water bindstogether and dominates many of

Earth's subsystems. About 113,000 cubickilometers of" water fall on the conti-nents each year.1" This precipitation isthen partitioned into a long or shortbranch of the water cycle (see Figure 1).Most of the water remains in the shortbranch, returning quickly to theatmosphere from the surface of theEarth where it evaporates from moistsurfaces and water bodies or is con-sumed by plants whose leaves return itto the air.

Water in the long branch of the cycleseeps into the soil and replenishes theunderground aquifers, joining under-ground flows, and finally the rivers andseas. Groundwater eventually seeps tothe surface in springs, or flows intorivers. The groundwater table may liefairly close to the surface, where it iseasily pumped out, or remain trappedin rock formations far under the earth.Some aquifers contain enormousamounts of water deposited thousandsof years ago. The world's largest knownaquifer, the Ogallala, lies beneath eightstates in the central plains of the UnitedStates, Water pumped from the Ogallalahelped transform a vast prairie intoAmerica's most productive farmland.

Environmental LimitsSociety's access to water is complicatedby the inequitable distribution of freshwater throughout the globe. Theamount of renewable freshwater thatpasses through the aquifers and rivers ofa country and is available for human useis defined by that country's position inthe global water cycle and is composedof two complementary components:endogenous and exogenous. Endog-enous water is produced locally fromrain or snow. Most local precipitation isreturned to the atmosphere as evapora-tion from wet surfaces and the transpira-tion of vegetation. Any surplus watergoes to recharge the groundwater orflows into rivers or streams. Exogenouswater is produced from rain or snowelsewhere and carried into a region byrivers or groundwater systems.

The share of water that enters andremains in an area naturally (that is,without human intervention) is gov-erned by the characteristics of the

Figure 1How Water Enters and Leaves the Landscape

Air Moisturefrom Other

Areas

River flow

Groundwaterseepage

O Partitioning points for longer and shorter branches of the water cycle.

Source: Adapted from Malin Falkenmark, "Fresh-Water-(1986): 192-200.

-Time for a Modified Approach," Amblo 15, no, 4

landscape: rock formations beneath thesurface, soil type, mountain ridges,vegetation. Most of all, it is regulated bythe hydroclimate, especially the timingof the annual precipitation, the risk ofrecurrent droughts, and the evaporativedemand of the atmosphere. Evaporativedemand is a measure of the maximumamount of moisture that the atmo-sphere can absorb. Its value dependsprimarily on the temperature andlatitude of a given area. Generally,evaporative demand is higher in warmareas, and is especially high at certainlatitudes, as shown in Figure 2.

Because the temperature is higher inthe Earth's low latitudes surroundingthe equator—which receive the fullbrunt of the sun's rays—evaporativedemand is higher there. But even in thewarmest latitudes, the amount of waterconsumed in the production of vegeta-tion, or biomass, varies between wet and

Figure 2Evaporative Demand

Potential Evaporation (mm per year)

|Low (0-499mm) DModerate (500-1500mm) uHigh (>1500mm)

Note: Evaporative demand is the potential or maximum amount of moisture a region's atmosphere can absorb (in millimeters of water per year). One millimeter (mm) equals 0.04 inches.

Source: Malin Falkenmark and Tom Chapman, eds., Comparative Hydrology: An Ecotogkai Approach w Land and Water Resources (Paris: UNESCO, 1989).

dry climates. In the humid tropicssupporting layers of lush foliage, onlysome 200 cubic meters of water returnsto the atmosphere for every ton ofbiomass produced. In the arid tropics,where the atmosphere is hot and dryand the vegetation sparse, about 1,000cubic meters of moisture are consumedper ton of biomass produced.

In the Scandinavian hydroclimate inthe northern latitudes, for example,fewer than 500 millimeters of moistureper year evaporate into the atmosphere.The evaporative demand is twice thislevel in southern Europe and threetimes as large in the Sahel region ofAfrica. As a result, 1,000 millimeters ofrainfall could create quite wet condi-tions in Scandinavia, but dry conditionsin the Sahel.

Also, the annual precipitation isevenly distributed throughout the yearin areas such as Sweden or the PacificNorthwest of the United Slates. But inother regions, especially in the drytropics, a year's worth of rain may fallwithin a few weeks. In India, forexample, 90 percent of the annualrainfall occurs between June andSeptember, the monsoon season.11 Inmonsoon areas, weeks of heavy,intensive rain often follow a vety dryperiod. The parched soil can absorbonly a small portion ol the rainfall andmuch of die area's annual water supplyescapes downstream, often causingsevere floods and heavy siltation indownstream regions.

The risk of drought varies greatly byregion. Low latitude climates arc oftencharacterized by highly fluctuatingamounts of rainfall.la While most worldregions occasionally experience dryyears or even severe drought, tropicaland sub-tropical areas often suffer fromrecurring drought years. Thesedroughts and fluctuations are linked toatmospheric conditions and globalweather patterns. For example, unusu-ally warm surface currents in the PacificOcean—dubbed the El Nino current—occur in intermittent years arrd create apool of warm water that disruptsweather patterns throughout thecountries in the Pacific region, and,possibly, throughout the globe.11 ElNino may cause flooding in normally

arid areas, such as in western SouthAmerica, and drought in normallyhumid areas, such as Indonesia. Possiblylinked to the El Nino weather' phenom-enon, mote than 20 African countriesexperienced drought in 1984 and 1985,contributing to widespread famine.14

Renewed drought, hit southern andeastern Africa during the 1991 -1992growing season, ensuring enormousdeficits in grain and other foods. Kenya,which usually exports food, will have toimport 500,000 tons of food in 1992.There have been reports of peoplebegging for water from passing vehiclesin western Kenya, which is suffering thebrunt of the drought. In parts ofZimbabwe, drought has caused indus-tries to shut down. Collapse of the watersystem in the Zimbabwean city ofBulawayo may cause residents to beevacuated. Arrd poor rains in Ethiopiawill affect not only that country, but alsoEgypt, because the major source of theNile River' is in western Ethiopia.'-'Drought has exacerbated alreadyexcruciating conditions in war-tornSomalia—forcing thousands ol Somalisto leave their homes, many movingacross national borders.

The hydroclimate, along with thesoil, geographic features and thelatitude, dictate the type of nativevegetation a landscape can support.Depending on the amount of rainfall,evaporative demand, and temperature,the landscape may support forests,grasslands (savannahs), or deserts (seeFigure 3, page 10). An area's groundwa-ter systems are replenished from anysurplus water.

The vegetation growing within eachtype of ecosystem varies with localgeologic conditions as well as lirelatitude. Forests range from the lushrainforests of Brazil containing thou-sands of species of plants and animals totire less diverse evergreen forests of theCanadian Rockies. Where water isinsufficient to support forest growth, lessdense woodlands grow, which give wayto grasslands as conditions becomemore dry. Grasslands or savannahs mayconsist entirely of grasses, or may beinterspersed with shrubs and trees.Where water' is scarce, the entirelandscape may be desert.

Figure 3Share of Rainfall Going to Recharge Groundwater

High

Low

Ecotyitem:Desert Savannah WoodlandsPrecipitation = Twice the evaporative demand

Precipitation = Evaporative demand

Rainforest:

nLow

Share of precipitation that

^ | Recharges aquifers and rivers

Humidity

I Returns to atmosphereI via evapotranspi ration

The transition regions between thetropics and temperate climates, latitudesof about. 20 to 30 degrees north andsouth of the equator tend to be thedriest on Earth. Included in this bandsoui.li of the equator are the KalahariDesert in southern Africa, the deserts ofCentral and western Australia, and theAtacama Desert in northern Chile.Between 20 and 30 degrees north of theequator lie the Sahara Desert in Africaand the Chihuahua Desert, in Mexico.

At these latitudes, dry cool airtransferred from the atmosphereabove the equator falls from the upperatmosphere leaving little moisture forprecipitation in those areas. The highevaporative demand, limited andfluctuating rainfall, and risk ofdrought in these regions constituteenvironmental preconditions that limitthe capacity to produce lucrativeagricultural products for export andfrustrate the search for self sufficiencyin food. As a glance at Figure 4 willshow, the countries with the lowestindex of human development aredisproportionately concentrated in thesemi-humid to arid tropics. Oftenthese areas also have the greatestconstraints on available water and thefastest growing populations.

Human-Induced limitsHydrological preconditions place abso-lute limits on society's access to waterresources. However, society's activitiescreate another form of limitation towater quality and supply. Human civili-zation requires the manipulation ofnatural systems. To obtain food andshelter and to manufacture tools andother products, men and women havealways tilled the soil, dug wells, and cuttrees to harvest timber and fuelwood.Just as during the first millennia of hu-man life on Earth, further economicand social development will require useof water and other natural resources.While some manipulation of the envi-ronment is unavoidable to meet domes-tic, industrial, and agricultural needs,certain human interventions are tech-nologically driven and can be avoided.Avoidable human interventions thatharm the environment can be identi-fied and mitigated by policy.

The United States and other indus-trial countries have long faced waterquality and quantity problems createdby their own waste and industrial andagricultural activities. These relativelyrich countries have begun to clean upsome of the old man-made problemsand are attempting to head off or atleast minimize future disruption oftheir freshwater systems. But the task re-mains a formidable one.

Many developing countries haveonly begun large-scale alteration oftheir natural environment in theattempt to achieve security in foodproduction, modernize their econo-mies, arid improve their standards ofliving. With the importation of technol-ogy, pesticides, and fertilizers from thealready developed countries, themagnitude and environmental impactsof these development projects areescalating.

All these human interventions havehigher order effects on flora and fauna;first, through the water cycle, whichpropagates any disturbance onward likea chain reaction, and second, becauselife is based on a myriad of water Hows.Chemical or physical disturbance ofthese flows has ecological effects on theflora and fauna, in many less developed

10

Figure 4Levels of Human Development

Human Development Index

Low • Moderate • High | | No DataNote: The Human Development [ndexis computed from measures oflife expectancy, educations] attainment, and gross domestic product per capita for each country.

Source: United Nations, Human Envelopment Report 1992 (New York: Oxford University Press, 1992), Table k

Figure 5How Human Activities Disturb the Water Cycle

1 HUMANUCTIVITI

Wastegases

Manipulationof soil/vegetation

ATMOSPHERE

Precipitation Net seaEvapo- evaporationtranspiration

LAND

1 T ijroiW a t e r flowsupply I ^

Groundwater Flood flow

Waste-waterflow

BODIES G. .. Riverflow

OCEAN

Source: Adapted from Malin Fatkenmark, "The Ven Te Chow Memorial Lecture," Water International 16, no.4(1991): 229-240

countries, the incipient poverty andrush to modernize in the lace ofcontinuous population increase hasencouraged the adoption of thecheapest, most expedient methods ofextracting minerals, raising crops,building dams or roads. Concern about,environmental degradation generatedby these actions is often pushed to thebackground.

Human activities that disturb thecirculation and character of water arepropagated through the water cycle asdepicted in Figure 5. They causesecondary effects on the groundwatertable, the fertility of the soil, theseasonality of river flows, and thechemical and biological characteristicsof the moving water.

A common example of a chemicaldisturbance with far-reaching effects isthe overuse of nitrogen-rich fertilizers toincrease agricultural yields. Thedissolved surplus nitrate is carried togroundwater aquifers, lakes, and rivers,generating rapid growth of algae,robbing the water of oxygen, andcreating water supply problems.Eventually the water cannot support thenative fish population arid otherindigenous aquatic life. Once thenutrient-enriched river flow reachesestuaries and coastal waters, the sameprocess—termed eutrophication—begins there. The Baltic and North Seasare showing the effects of (his process,raising public concerns about the water

12

quality and fishing industry in Scandina-vian countries.

Acid rain is another man-inducedchemical disturbance that enters thewater cycle from the atmosphere ratherthan the landscape. Energy production,traffic, and other human activitiesproduce acidifying gases that dissolve inwater droplets in the atmosphere,transforming the precipitation into adilute acid. Once on the land, the acidwater seeps into the root zone, damag-ing the vegetation and contributing toforest dieback. This process has harmedforest growth in the AdirondackMountains of the northeastern UnitedStates and ravaged the forests ofCzechoslovakia.

Once the buffering capacity of thesoil has been surpassed, an "arid front"moves down into the groundwater,dissolving metals and other ph-sensitivematerials in the soil and washing theminto the water systems. In Scandinaviaand Canada, acids that accumulate allwinter in the snow pack are released allat once during the snow-melt, sending ashock to the river systems. These acidfloodwaters also cany aluminumdissolved from the soil, which, incombination with the high acidity, istoxic to fish.

Air pollution also affects the watercycle through the warming effect of"greenhouse gases" building up in theEarth's atmosphere. One of the mostprevalent of these is carbon dioxidecreated by the burning of fossil fuelsin automobiles and factories. Thefuture effects of global warming,indeed the estimated extent of it, arevigorously debated, but some changeis certain to occur. Warmer tempera-tures could intensify lire evaporationfrom the ocean and thereby increasethe amount of water vapor carriedtoward the land. The shifting paths ofatmospheric water vapor would alterprecipitation patterns over thecontinents. The evaporative demandof the atmosphere may rise—someareas will become wetter, others drier.

Changes in the moisture content ofthe soil would alter biological systems;groundwater recharge and thereforewater tables would be affected.Eventually the water levels of rivers,

lakes, and other water bodies will bechanged. The chemical composition ofground and suiface water could beaffected, eventually inlluencing theaquatic and coastal ecosystems. The typeand yield of agricultural production willmost certainly change—especially inareas that are heavily dependent onirrigation.

Overpumping of groundwater canalso set off a chain of events. Whenwater is pumped from the ground fasterthan it can be renewed, the water tablesinks and aquifers are depleted. Thisprocess is occurring with the Ogallalaaquifer in the United Stales. Someexperts estimate that the aquifer may bedepleted within the next quartercentury. In India's Tamil Nadu region,excessive pumping has lowered thelocal water table by 30 meters in just afew decades.

Agricultural practices, especially thetraditional burning and clearcuttingrelied on in many developing societies,can alter the water systems. When landis cleared or overgrazed, water thatwould otherwise infiltrate the soil tofeed the plants, remains on the surface,often carrying away nutrients and soilwith it. This desiccation, or extremedrying, of the land may create desert-like conditions.

Storing water behind some man-made barrier is another' intentionalmanipulation of the water cycle toimprove the accessibility of water for

social use. Water stored behind damscan be used when needed to grow dryseason crops or generate electricity, forexample. The building of dams ofteninvolves flooding a river valley whichalters natural habitat and the composi-tion of animal and plant species bothbehind and downstream from the dam.Alteration of groundwater systems andriver deltas is an unavoidable outcomeof building a dam. However, othernegative effects commonly associatedwith large dams and reservoirs can belessened or avoided altogether. Theseinclude the spread of water-bornediseases affecting humans and livestockand salinization or waterlogging of soildownstream. The rapid silting ofreservoirs which can shorten the usefullife span of a dam, can also be avoided.With proper foresight, dam reservoirscan provide new desirable habitats.Fisheries, boating, flood control, andrecreational activities can be developedin conjunction with the building of adam and hydropower plant, counterbal-ancing the unavoidable side-effects ofthis form of human intervention.

In sum, human manipulation of thewater cycle is unavoidable, but many ofdie most harmful effects of humanactivity can be avoided. How much waterdoes human society rreed? Agairr, theanswer depends on both the environ-mental preconditions, the way a givensociety uses water, and of course thenumbers of people to be served.

ACID RAIN KILLS RIVERSTHIS RIVER IS DYING

THIS PHDJECT SPONSORED BY THE

ATLANTIC SALMON FEDERATIONAND THE

NOVA SCOTIA SALMON ASSOCIATION

Air pollutants can enter the water through acid rain, harming flora and fauna.

13

Patterns of Water UseIrrigated agriculture consumes most ofthe water used by people—nearly 70percent worldwide. Industry accountsfor about. 23 percent of worldwide wateruse; and households only about 8percent. Within a specific area, therelative importance of each of thesethree competing uses depends on thehydroclimate, population size, and thenature of economic activities. Theamount of water used also varies withcultural expectations and demands. InAsia, 82 percent of the estimated waterwithdrawals from rivers or aquifers isused to irrigate crops. Irrigated agricul-ture accounts for 68 percent of wateruse in Africa, 41 percent in the UnitedStates, and 30 percent in Europe."' Theamount used for industry increases withdevelopment level and by type ofindustry, but. also can reflect changes inindustrial processes.

Domestic or household use nearlyalways accounts for the smallest share ofwater used, except in the few countrieswith little agriculture or industry. In the

city-state of Singapore, for example,domestic use accounts for 45 percent ofthe water used, and industry 51 percent.

Domestic water use is the onlycategory that has a practical minimum.To assure adequate health, people rreeda minimum of about 100 liters of waterper day for drinking, cooking, andwashing. Of course many limes thisamount is necessary to carry out theactivities necessary to sustain an eco-nomic base in a community. In water-abundant or affluent, societies, peopleuse many times the personal dailyminimum.

Industry is the next largest usagecategory for water. Water has long beena basic lubricant of industrial develop-ment. Water is used in factories forcooling, processing, generating steam torun equipment, and as a transportingagent. Certain industries are particularlywater intensive. Pulp and paper manu-facturing, petroleum refining, and foodprocessing are prime examples. Butdepending on the methods used,especially the reuse of water within theplant, the amount, of water needed to

People need a minimum of 100 liters of water per day for personal health and hygiene.14

manufacture a given product can varyby a factor of 40. In Sweden, industrialwater use declined markedly in the1970s because new economic incentivesmotivated industries to introduce in-plant recirculation of water.1'

Agriculture, which accounts for thelargest share of water use, is also theleast efficient. In the 1980s, approxi-mately 270 million hectares of land wereirrigated,1" almost hall' oi it in thedeveloping countries. But a large shareof irrigation water is wasted. It is notuncommon for 70 to 80 percent of thewater diverted i.o irrigation systems to belost to the atmosphere or seep into theground before reaching the fields. Inthe lower Colorado River basin in theUnited States, about half of the irriga-tion water is wasted in this manner.

Country Use PatternsThe amount of water per capita used ina specific region depends not only onhow much is easily accessible, but alsoon the nature of water needs and theliving standards of the population.Irrigation consumes the lion's share ofwater resources. It is no surprise thatwater usage would be highest, incountries that must irrigate agriculturemost, of the year, such as in MiddleEastern countries.

Data on water availability arrddemand from the time of the UN 1977Water Conference irr Mar del l'lata,Argentina, indicate that, in the 1970s,Iraq used 4,400 cubic meters per yearper person, while Pakistan used 2,200;Syria, 1,200; Egypt, 1,200; and India,800. Israel stands out as an industrial-ized country in a semi-arid /one with alow gross water-demand level orr arelative scale. By practicing efficientwater management, Israel uses only 500cubic meters annually per person.19

For countries in these arid /ones,access to exogenous water—specifi-cally, freshwater flowing into a countryfrom rivers—can determine whetherthey are self-sufficient in agriculture.Irr semi-arid areas with no exogenouswater, such as Libya and Saudi Arabia,agricultural production is limited bythe amount of water in the root zoneunless irrigation is possible. Soil

moisture, replenished during the rainyseason, determines the length of thegrowing season. A growing season ofthree months (about 75 to 90 days) isconsidered the lower limit, for cropcultivation. Where the soil contains lessmoisture than required for a three-month growing season, only pasture ispossible. Where the atmosphere is hotand dry, as it is in the dry tropics, it iscapable of rcabsorbing some 100 to150 millimeters of water per month, orat least 300 to 450 millimeters duringthe growing period. In areas where theamount of water in the root /.one limitsthe growing season to three to sevenmonths (90 to 210 days), agriculture ishighly vulnerable to droughts.

Large stretches of land in Africahave so little root-zone water availablethat little or no agriculture can bepracticed. While some countries,such as Sudan and Kthiopia, haveaccess to irrigation water, most of theseareas must adapt to low levels offarming or raising livestock (see Figure6, page 16).

In these areas, crop yield can beincreased by drought-proofing agricul-ture through rainwater harvesting,runoff collection, and catchmentmanagement. Irrigation can beminimized by limiting it to criticalperiods during the growing season.Experiments with such water conserva-tion methods are being carried out inIndia.2" Some areas pump water fromgroundwater trapped in aquifers, apractice known as "mining" groundwa-ter. But this is a temporary solution.The renewal rate of aquifers is so slowthat groundwater mining can quicklydeplete an aquifer.

The situation can be quite differentin arid regions that have access to largerivers, such as Egypt. In such regions,irrigated crop growth may be practicedfor as marry seasons as the water flowmay support. Since early human history,farmers have made skilllul use ofexogenous water to irrigate crops,thereby expanding the growing season.Ancient Mesopotamian, Egyptian, andChinese cultures provide classic ex-amples of how access to drought-prooiing water made social develop-ment possible.

75

Figure 6Growing Seasons and Drought Risk in Africa

210

210

Growing Season

H over 210 days

| y 75 to 210 clays

1 to 74 days

less than 1 day

Note: When: iht: growing season is negligible or less than 75 days, (90 days in North Africa) vegetation tends to be drought-prone pasiurdsnd. No agriculture ispossible without irrigation. Where the growing season is 75 to 210 days, agriculluu; is limiicd by rccurrcm droughis mid lnrg« srasoiuil fiLH:iiiaiionis in rainfall.

Source: UN Food and Agriculture Organization (FAO), Irrigation ant} Water Resources Potential for Africa ALG/MISC/II /87 (Rome: FAO, 1987).

16

The presence of exogenous waterexplains the different, situations oi theSahel, in northern Africa, and thePunjab, in India. Both regions have aridclimates, yet the Sahel relies on endog-enous water produced by local rainfall.The Punjab is enriched by exogenouswater generated by rain and snow onthe I Iiinalayan slopes, miles away.Egypt's access to the Nile River gives it agreat advantage over Libya, for ex-ample, which has no large rivers (seeTable 1). Dramatic increases in agricul-tural production in southern Asiaduring the past few decades may in factlargely be due to the widespread accessto exogenous water in that region.

1 lumid areas fed by local rainfallhave different soils of water manage-ment problems (see Table 2). Theymust deal with drainage problems andeutrophication, that is, the depletion oiwater's oxygen content from excessiveorganic matter. Eutrophication is oftengenerated by the leaching of excessfertilizers from agricultural land. Humidlandscapes largely fed by exogenouswater' sources often sutler from waterpollution introduced upstream. Thewater supply for the Netherlands, lorexample, is vulnerable to huge amountsoi pollutants carried in by the RhineRiver from the upstream countries ofSwitzerland, France, and Germany.

While all areas face water manage-ment challenges, absolute water scarcitythreatens the large group of low latitudecountries whose climates place them onthe hydrological margin. Their prob-lems have somewhat different origins,predict a very different future, anddictate unique remedies.

living on the HydrologicalMarginThe hydroclimatc of much of the ThirdWorld makes it particularly subject to"genuine" water scarcity stemming fromenvironmental conditions and thehydrological cycle (see Box 2, page 18).At the same time, overgrazing,overcutting of woodlands, traditionalagricultural methods, arrd growingpopulation pressure in these same areasoften create an ideal environment forhuman-induced modes of scarcity.

Table 1Selected Countries by Source of Available Water

^t Share of^V water from

^V exogenous^V sources

Share o f ^Vwater from ^Vendogenous ^ ^ ^sources ^ ^

Small

Medium

Large

Small

Saudi ArabiaAustraliaTunisia1 ibya

ChinaSpainMexico

NorwayColombia

Medium

NigerIraqPakistan

Paraguay

YugoslaviaUruguayCongo

Large

Mauritania

Botswana

Gambia

HungaryNetherlands

Table 2Management Approaches for Different Water SourceCombinations

w Share of^V water from

^ ^ Sdurces

Share of >^water from ^Vendogenous ^Vsources ^ ^

Small

Medium

Large

Small

storage;rain waterharvesting;protectiveirrigation; runoffcollection

reduce causes ofcu jt.rofi cation

introduceir.ffcczt'wcdrainage: iyalcrfii,

Medium

irrigf

Large

ition.

international cooperation to controlwater pollution

Note: Exogenous water is imported from elsewhere, such as a river water. Edogenous water is fromlocal precipitation.

The severe drought and widespreadfamine in Africa during 1984 and 1985can be linked to both genuine andhuman-induced water scarcity. Thegenuine water scarcity, exacerbated bydrought, created a "hunger crescent"through part oi' sub-Saharan Africa,passing through the gradient zonebetween the arid desert and the humidtropics. The most critically affectedcountries, such as Mali, Kenya, orTanzania, are located in a region that

17

Figure 7Agricultural Potential of Land in Developing Regions

IOO

80

60

40

20

Sub-Saharan Africa Near East and Asia excluding Latin AmericaNorth Africa China

I High potential land 9 Low potential land E3 Problem land

Source: Adapted from data in UN Food and Agriculture Organization, World Agricu/ture." Toward 2000 {London:Belhove Press, 1989).

has, first, a short growing season,making crops particularly vulnerable torecurrent droughts, and second, ashortage of water in aquifers and rivers.

The hydroclimate and environmen-tal preconditions make these arid andsemiarid landscapes particularlyvulnerable to the deterioration of soilpermeability. Soil in tropical andsubtropical areas deteriorates easilyfrom either chemical or physicaldisturbances. The virulent action ofintensive monsoon rains washes awaytopsoil, especially where the plant coverhas been cleared by overgrazing,deforestation, or iuelwood harvesting.In certain areas, the chemical makeupof the soil helps the topsoil becomenearly impermeable to rainwater andeasily eroded. Where the rainwatercannot infiltrate, the main avenue forrecharging local groundwater thatprovides water dining the dry season isblocked. This deterioration of the soilaggravates the genuine, or natural,water supply problems.

Because there is so little surplus ofwater (that is, water left after evapora-tion) in these regions, limited changesin vegetation can produce noticeableshifts in the surplus available forrecharging aquifers and watercourses.

18

Box 2Genuine vs. Human-InducedWater ScarcityThe water scarcity predicament fac-ing society maybe expressed in fourdifferent modes. Two modes arenatural or genuine in that: they arerelated to the hydroclimate. Theseare 1) the short growing season and2) intermittent droughts. I he othertwo are human-induced: 3) desicca-tion, or extreme drying, of the landso that the soil can no longer absorbwater, and 4) high population pres-sure with limited water availability.

The production of vegetation—and therefore self reliance in food;livestock fodder, fuelwood, and tim-ber—is limited by the genuine waterscarcity linked to the hydroclimate.Unless irrigation water from else-where is available, both modes ofwater scarcity dictate plantingdrought-resistant crops and storinggrain or' water surplus from wet yearsfor use during dry years.

Biomass production is also harm-ed by the third, human-induced, typeof water scarcity: soil desiccation.When the soil surface becomes im-permeable to water infiltration, theroot /one dries out; nothing growsand groundwater is not recharged.The water table in local wells de-creases and local populations experi-ence what they think is a drought.This phenomenon is widespread—not only in dry regions, where it isknown as dryland degradation, orless precisely as desert ifreal •on—butalso in water-rich areas like the Ethio-pian highlands or the Himalayanslopes. Inhabitants may complain ofdrought despite ample rail fall.

Human water supply is alsothreatened by population expansionin areas with limited water availabil-ity. In such areas, rapid populationgrowth' constitutes a particular threatto both biomass production andhuman water supply, lessening theability to be sell sufficient, (j^ercom-ing these threats poses greatchallenges to all those involved withwater management.

In parts of Australia and South Africa,large-scale vegetation changes severelyaltered the recharge rates of aquifersand rivers. In southwestern Australia thesalinity ol streams has increased asformer woodlands are cleared loragricultural development, especially inareas that receive the least rainfall.21 InSouth Africa, reforestation is considereda major water consumer, evaporatingwater that would otherwise feed thelocal rivers.*

The experiences in water-scarceareas drive home the point thatdevelopment following the model of thewater-abundant northern countries isinappropriate in areas living on thehydrological margin. Sub-SaharanAfrica is a prime example of such anarea. The Food and AgricultureOrganization (FAO) estimates that over35 percent of the total harvested land inAfrica is "low potential land," primarilybecause of its limited and uncertainrainfall. The share of low potential landis greater in Africa than in other majordeveloping regions (see Figure 7).Almost half the land could not supportits population given the low-yieldagricultural techniques generallypracticed. In 1975, 22 African countrieswere not self-supporting in agriculture.21

Agricultural production must at leastdouble within 20 years in order to justreduce famine and keep pace withpopulation growth.

Population Pressure onWater ResourcesWe have seen that water availability islimited by certain environmentalpreconditions—more severe in someareas than others—and by man-induced alterations of the naturalwater systems. Population size alsogoverns the amount oi water availableon a per capita basis.

The number of flow units of water ina given country (where one flow unitequals 1 million cubic meters of waterper year) fluctuates between wet anddrought years and between the rainyand dry seasons, but as long as theclimate does not change, the averageremains finite. The point at. which a

country passes irr to a position of waterscarcity or stress is related to populationpressure as well as water consumptionpatterns.

If the population per flow unitremains low—below 100, the lowestcategory in Figure 8—water supply isgenerally not a problerrr. As populationpressure increases, better water manage-ment is required to assure quality arrdequal distribution. Central and southernEuropean countries are subject to thislevel of water resource competition—about 300 persons per flow unit. As theamount ol water per capita dwindles,however, especially where there aremore than 000 persons per flow unit,signs of stress begin to appear—unlesswater is efficiently managed. Whenthere are over 1,000 persons per flowunit, a country invariably experienceschronic: water shortage. Under currenttechnology, extreme scarcity occurs ifthe ratio exceeds 2,000. The crucialissue in such countries is the amount ofwater that can be used for irrigation—relatively little is needed for domesticuse, and often even that can be reusedin agriculture.

Irr Africa and southern Asia, rapidpopulation growth will push manycountries into higher stress /ones andeventually to chronic water shortages. Insome countries, the population isexpected to double between 1990 and

Figure 8

Population Pressure and Water-Resource Problems

Personsper flow unit 100 1000 2000

Note: 1 flow unit = 1 million cubic meters per year

Source: Adapted from Malin Fatkenmark, "The Ven Te Chow Memorial Lecture,1* Water International 16, no. 4(1991): 229-240

19

TabledPopulation and Water Resources in World Regions andSelected Countries, 1990 and 2025

Region

North Africa

EgyptLibyn

Sub-Saharan AfricaKenya

SomaliaZaire

North AmericaCentral America/Caribbean

El SalvadorMexico

South AmericaBrazilPeru

Western AsiaTurkey

Southern AsiaAfghanistanBangladesh

Other Asia

EuropeOceaniaFormer USSR

Note: 1 cubic: uif.lf.i (m

Population(millions)

1990

140525

492249

37276

1475

8429414922

13256

1,19117

1 141,794

50927

281

2025

2807313

1,2766423

105360

25010

137452220

3728693

2,10046

2232,476

54241

344

is) ^ 1.35 cubic yards

Renewablewater (m3)

85,00057,000s

1,0003,575,000

15,00012,000

1,019,0005,379,000

1,330,00019,000

357,00010,377,0005,190,000

40,000253,000196,000

3,980,00050,000

1,357,0008,737,0002,321,0002,011,0004,384,000

Persons per1 million m3

1990

1,650900

6,500140

1,5907604050

110270240

3020

540520•12030033050

200

2201060

2025

3,2901,600

18,-100360

4,3102,040

10070

1905103904030

9301,130

690530920100280230

2080

Source: UN, World Population Prospects: The 1992 Revision (New York: UN. 1992); and World ResourcesInstitute, World Resources /992-1993 (New York: WRI. 1991), Table I I .

2025 (see Table 3). Because of Kenya'sexpanding population, its populationper flow unit grew from 905 in the1970s to 1,600 in 1990. This index willeasily surpass the 2,000 threshold by2025 when Kenya's population will benearly five times the 1975 figure. By2025, over 1 billion people in Africa andsouthern Asia will live under conditionsof water scarcity. Many North Africanand Middle Eastern countries arealready faced with absolute waterscarcity. In Jordan and Israel, over 3,000people compete for every flow unit ofrenewable water. By 2025, virtually allNor ih African countries will be facedwith high levels of population pressureon their scarce water resources. And,

20

except for Turkey, all of Western Asiawill also experience the highest levels ofwater scarcity.

These high growth rates are drivenby die persistently high birth rates inmost of these countries. In sub-SaharanAfrica, women have an average of sixchildren each; in southern Asia, theyaverage between four and five childreneach. Because death rates have fallen inmany parts of the developing world—inlarge part as a result of immunizationcampaigns, antibiotics, and otherimported health technologies—thetraditionally high fertility levels causedthe growth rate to escalate in the 1960s.Growth rates have fallen only slightlysince then.

Although birth rates have declinedin recent years, the young age structureof the population—created by decadesof high fertility—provides a tremendousmomentum for future growth. About 45percent of sub-Saharan Africans areunder age 15, compared with 20percent in Europe (see Table 4). Theseyoung people will be starting their ownfamilies within the next quartercentury. Even if the average number ofchildren per couple declined immedi-ately to two—the "replacement level"—the populations of these countries willcontinue to grow for decades becausesuch a large share of the population willbe moving into the childbearing ages.

Africa's population is expected togrow by at least 2.8 percent annuallyuntil the errd of the century. The total isprojected to more than double between1990 and 2025, expanding from 650million to 1.6 billion, even assuming arise in mortality from the AIDS epi-demic and a further decline in birthrates. The population of western Asiacould expand from 139 million to 313million, and that of southern Asia from1.2 billion to 2.2 billion over the sametime period.

Tire average water resource competi-tion levels for these broad regions maskthe total number of people subject towater scarcity because of wide fluctua-tions in precipitation or water flowsover the year, or between drought andwet years. In the humid zones, acompetition level of 600 might signalthe beginning ol water allocation

Table 4Demographic Indicators for World Regions, 1992

•i

North AfricaSub-Saharan AfricaWesLem AsiaSouthern AsiaSoutheast AsiaEast AsiaNorth AmericaLatin AmericaEuropeFormer USSR

Oceania

Population1992

(millions)

147507139

1,231451

1,386283453511284

28

Annualgrowth rate

(percent)

2,63.12.82.21.91.20.82.10.20.71.2

Totalfertility

rate (TFR)

4.86.54.74.33.42.12,03.41.62.22.6

Lifeexpectancy

in years

6152665862717667

757072

Percentunderage 15

4245413837272136202626

Percenturban

432662262934

7570756671

1990GNP

per capita

$1,070520

-440

..2,910

21,5802,170

12,990-

13,190

Note: Total fertility rate (TFR) = average total number of children born per woman under rvirrenl. hirlh rates.Source: Carl Haub and Machiko Yanagishita. 1991 Wor/tf Population Data Sheet (Washington, DC: PRB, 1992).

problems. Tn arid conditions, theproblem is more complex because ofconsiderable seasonal variations inrainfall. The largest need for irrigationwater is during the diy season when thewater accessible to people can be as lowas 10 percent of the annual flow. Evencountries with an average annualcompetition level of only 50, such a.sBangladesh, have considerable alloca-tion problems during the dry seasonwhen the water competition level mightrise to 500 persons per flow unit.24

But. national figures do not reflectthe stress on water resource quality inlocal areas exerted by rapid urbaniza-tion and industrialization. The averagepopulation pressure on water resourcesappears moderate in most LatinAmerican countries, for example. But amajority of Latin Americans live incities, which are often plagued byserious water pollution from industrialand household wastes. Recurrentdrought in northeastern Brazil hascontributed to the rapid urbanization inthat country. Unable to eke out a livingfrom land degraded by decades ofdrought and poor fanning techniques,farmers have flocked to Brazil's cities,reflecting the pattern of rural to urbanmigration that is occurring throughoutthe Third World. By the end of thecentury, a majority of the Earth'sinhabitants will live in urban areas, with

most of the growth occurring in thedeveloping countries.

The most immediate impact, of thisstream of migration into urban areas isthe growth of informal squatter settle-ments, or shantytowns. A lack ofhousing and jobs forces many recentmigrants, as well as longer-term resi-dents, to fashion shelters on vacant land,often land deemed unsuitable forhousing or development. Theseshantytowns have no sanitation or otherservices—both contributing to andsuffering from the health consequences

Ecuador has ample water, but not always where it is most needed.

21

Box 3Urban Population Growth, Pollution, and Safe Water

Thanks to b6th international anddomestic efforts, clean drinkingwater was made available to 1.3billion people and sanitation servicesto an additional 748 million peoplein the 1980s. These efforts grew, inpart, out of the United Nationscommitment to improving access tosafe water, demonstrated by thedeclaration of the 1980s as the CleanWater Decade.

These efforts were most successfulin the rural areas of the Third World.In urban areas, the number ofresidents without access to watergrew by 31 million during thatdecade, while those without sanita-tion grew by 85 million. By 1990, atleast 377 million urbanites lackedbasic sanitation services. Given therapid urbanization in the developingworld, these numbt'rs are expectedto swell. :: •: : '

The lacfc of adequate safedrinking water and sanitation is oneof the major health and economicconsequences of surging worldurbanization. Increasing popiilationconcentration in urban areas hascontributed to die depletion andcontamination of fresh water. Thecosts of treating and providing deanwater has escalated exorbitantly inmany Third World cities. TheIlaungpu Kiver, Shanghai's majorsource of drinking water has becomeso polluted near the "urban area thatthe water transmission main had tobe moved 40 kilometers upstream—at a cost of US$450 million. In lima,Peru, upstream pollution hasincreased treatment costs by 30percent. The rivers passing throughmany major cities have become opensewers devoid of aquatic life.

Much of the pollution is tied tothe'explosive growth of the informalsquatter settlements on ihe periph-ery of most Third World cities. Thesesettlements often spring up on low-

lying land and along waterways, theirwastes flowing directly into the urbanwater source. In Manila, a recentassessment showed that: the mostimportant sources of urban pollutionwere the uncollected solid waste,flooding, and river bank erosionaround the squatter settlements thatcontain some 38 percent of themetropolitan population.

Many municipal governments haveavoided improving the services tothese poor communities, eitherbecause they simply could not affordit or because they did not. want toencourage or legitimize these- illegalsettlements. The shantytown residentsoften pay inflated prices for waterbrought: in by enterprising vendorsand suffer high rates of infant,mortality and parasite infest a liondirectly resulting from the unsanitaryliving conditions.

These health and environmentalproblems spill over into the widercommunity. The low-income settlemerits of Lima, for example, were theorigin ofa cholera epidemic in 1991that eventually spread throughout theregion. In addition to higher health?care costs, the epidemic cost Peru anestimated US$460 million in tourism.Protecting the health of the urbanpoor in illegal squatter settlementsthrough the provision of basicservices may appear to be prohibi-tively expensive, but the health and'environmental consequences ofallowing these populations to live insqualor will eventually prove :-venmore expensive.

ReferenceUN Center for Human Settlements,"Urbanization: Water Supply and

: i: Sanitation Sector Challenges." Paperpresented at the Water Supply andSanitation Collaborative CouncilForum, Oslo,'Norway, 1.8-20 September1991.

22

of an unsafe water supply (see Box 3).Between 30 and 60 percent of the urbanpopulations of developing countries livein such informal settlements. At currentrates these shantytown populations willdouble every 10 to 15 years.25

Urban growth in the Third Worldhas created new megalopolises that aresurpassing the si/.e of the world capitalsin developed countries. In I960, only 3of the world's 10 largest cities were inthe developing countries: Shanghai,Buenos Aires, and Calcutta. In 1990, allexcept three (Tokyo, New York, and LosAngeles) were in the developing world.Although urbanization is spreadingthroughout the Third World, the urbanscene in many developirrg countries isdominated by a few large cities. Aboutone-quarter of Nigeria's city dwellerslive in either Lagos or Ibadan, forexample, and one-half of Egypt's urbanpopulation reside in Alexandria orCairo.'-'1 The populations of such citiesare soaring because of the rapid naturalincrease and the constant stream ofmigrants from the countryside. Thisexplosive growth is exacerbating theproblems of providing clean drinkingwater and disposing of human andindustrial wastes.

Unless per capita consumptiondeclines, the ratio of population to

water reaches stressful levels eitherbecause people dwell in areas withextremely scarce resources or becausedie population increase is too rapid forthe available water resources. Thecountries in the worst position are, ofcourse, those experiencing bothpredicaments as demonstrated in Box 4,page 24>'7

The pressure of rising populationssets off a cycle that reinforces the effectsof other sources of water scarcity: fluctu-ating rainfall, short growing seasons,and land degradation. Without bettermanagement, this risk spiral can cause acomplete collapse of basic services andfood supplies during recurrentdroughts. For example, severe famineoccurred during the African drought in1984 and 1985. At least four types ofrisks warrant attention:1. Inadequate water quantity. When

growing expectations cannot be met,frustration mounts among regionsand population groups. Disputesand conflicts arise concerning accessto water.

2. Deteriorating water quality. Withgrowing populations, industrial andother waste-water pollution increasesthe risk of water-borne or water-related diseases. The poor generallyabsorb the brunt of these problems,

Even water-abundant countries face problems of water quality.

23

r™1 ' 'wwW

Box 4

The Population and Water Predicament

Australia/IndiaEgypt

- Nigeria

Zimbabwe

Israel

SwedenCentral Europe

Low Medium High

Population Pressure

The interplay between the three lac-tors most affecting the water availabil-ity in a given country may be visual-ized in the three dimensional cubeabove, depicting evaporative demand,aridity of.'the hydroclimate, and popu-lation pressure. Evaporative demandol the atmosphere in an area (thevertical axis) governs the efficiency ofan area's rainfall For example, wherethe evaporative demand is low as it isin Scandinavia (below 500 millimetersper year), 1,000 millimeters of pre-cipitation corresponds to quite wetconditions. Where evaporative de-mand is high as it is in the tropics—often above 1,500 millimeters peryear—that same 1,000 millimeters ofrainfall falls short of the annualevaporative demand.

in moire arid climates, evaporativedemand exceeds by far the annualprecipitation. The result is desert orsemi-desert, Where it is subhumidand only part of. the year remainsarid, grasslands or savannah grow.Where it is humid*'•forests are thenatural vegetation.

Population pressure on availablewater is the third .major variabledetermining a country's watersituation. While the other variablesare expected to remain constant,population pressure may increase,moving some countries to higherstress levels over time.

If we visualize the cube as a, house,many of the industrialized countriescould be said to have developed inthe humid/subhumid corner of thebasement. Their hydfocli.ma.te andenvironmental conditions favoredeconomic development.

The most water-stressed of moredeveloped countries, such as Israel,are on the second floor. Most of the

Third World countries are in the hotattic of the predicament house. Inthese Third World countries, highlyefficient water use is required fordevelopment to occur in spite of highevaporative demand—a legacy oftheir hydroclimate-—-and increasingpopulation pressure—a result of highbirth rates and stable or decliningdeath rates.

24

especially in urban areas. Withoutadequate sanitation, populationgrowth in these environmentsincreases morbidity, as well ashuman suffering.

3. Failures in food security. During dryyears, crop yields may collapse.Unless there is an organized systemfor food distribution, large scalefamine can follow.

4. Land degradation. When popula-tion pressure increases, manipula-tion of the land intensifies. Withoutproper management this can lead todesiccation of the soil, lowering ofwater tables, erosion, and conse-quent, siltation and flooding ofdownstream areas.

How can diis risk spiral be avoided?Slowing population growth can head offa future crisis in some areas; however, it

cannot relieve pressure from currentpopulation size. And even with slowergrowth rates the number of peoplecontinue to swell, especially in ThirdWorld countries with young popula-tions. Slowing population growth is onlypart of the solution.

Water Availability vs.DemandPopulation pressure can be eased bycither accepting a lower per capitademand or increasing the percentage ofwater accessible. As Figure 9 depicts,demand is ultimately constrained by afinite availability ceiling: the waterresources available in each countrythrough the global water cycle. Esti-mates of the amount of annuallyrenewable water available in a country

Figure 9Water Availability and Demand

100

Water availability per capita (cubic meters/year)

S00 1,000 2,000 10,000 50,000

100% 50% 20%

Percent of water mobilizedNotes:1. Countries above the ceiling are using more water than is renewed each year through rainfall or inllow from upstreamcommies. Tliis ™ ess wnN'T TTI;IV < ome from ancirnl, nonrrnewabU: aquifers or be transported from other areas,2. Household need (H)equals 100 liters per day, per person.3. Resei"voir storage allows countries to mobilize mot e than 100 percent of the available water.

Source; Based on data from J, Forkasiewicz and J. Margat, Tableau Mondial de Donnees Nationals D'Economie de L'Eau, Resources etUiilrsoiions (Department Hydrogeologie, 79 SGN 784 HYD, Orleans, 1980).

25

include both internally producedsurface and groundwater and riverwater flowing into an area from anothercountry. Deep underground aquifersare important sources of water in someareas, but the extremely slow renewalrate may classify these as nonrcncwableresources.

Seldom is all available water in acountry used, either1 because there ismore water than needed, or because thecosts of extraction are higher than thepot.em.ial economic benefits of theadditional water. There is an tipperlimit to the amount available, but. thisceiling is reached only if eveiy flow unitof water in aquifers and rivers can beused, or "mobilized." A 100 percentmobilization level can be achieved onlyif all the water surplus during wetseasons and wet years can be stored andput to use during the dry seasons ordrought years, when the demand is

Seldom does a country use all of its available water.26

highest. The possibility of mobilizing100 percent of the water depends ontopography (which limits location ofreservoirs), climate (which affects waterlosses from reservoirs), and geology(which may permit or prohibit moreefficient underground water storage).In hot countries with a flat landscape,20 to 30 percent mobilization ofavailable water may be the upper limitunder present technology.

The position of Tunisia on Figure 9,page 25, for example, shows that, about35 percent of the available water isbeing utilized. This allows an averagewater demand of only five times thepersonal minimum, less than 200 cubicmeters per person. This is only one-tenth the typical water demand indeveloping countries thai, irrigateagricultural land.

Tn a few countries, with favorablegeology, the mobilization level of avail-able water can reach 100 percent. But itis seldom realistic to use all potentiallyavailable water. Where topography isflat, dams cannot be built. Where theclimate is hot and dry, large reservoirsare not cost-effective because they loseso much water to evaporation. Waterstorage below ground eliminates theloss through evaporation, but. such un-derground water must be easily retriev-able to be practical.

Economics is another limiting factor.Large darns are costly to build. The si/.eof a dam is determined by the size ofthe river, usually a function of theclimate and the drainage basin, and ofhow far up a river's valley or basin adam is built. The huge Aswan Dam inEgypt is an example of the enormoussize of dam required so far down in alarge river basin.

The mobilization level needed tosatisfy the demand for water also re-flects the overall water availability situa-tion (see Table 5). In a water-rich coun-try such as Sweden, a mere 3 percent ofavailable water need be mobilized toprovide a high standard of living for thecountry's 8 million inhabitants. Manydeveloping countries have relatively lowper capita water demands comparedwith Sweden. These countries could stillremain far below the availability ceilingand absorb the much higher water use

needed to facilitate socioeconomicgrowth. They may, in other words, stillbe in a slate of water under use. Thepotential increase in overall water use ina society will be limited by irrigation andindustrial needs as well as populationgrowth in coming decades.

At the same time, other areas areoverusing their available water. Libyauses more than 100 percent of itsrenewable water. It is buying rime bymining groundwater from its hugeNubian Aquifer. This can continue onlyuntil the aquifer is depleted or pumpingbecomes too expensive. In southernCalifornia, cities are green gardens in adesert climate. Thirsty crops, such ascotton and alfalfa, form an importantpart of the region's economic base.Decades of subsidized water haveallowed the urea to plant inappropriatecrops and use more than twice theavailable water resources.

Ways Out of thePredicamentAs populations continue to grow, wateris becoming scarce—often criticallyscarce—in arid countries. Even humidareas are caught in the population andwater predicament because humanactivities threaten both the quality andamount of the water available.

There is no doubt that the scarcity ofwater and the deterioration of waterquality severely complicate socioeco-nomic: development and efforts toimprove living standards. And itcontributes to the rampant povertyencountered in large parts of thedeveloping world. The tropical andsubtropical climates of much of theThird World, in combination withrecurrent risk of droughts, make themhighly vulnerable environments. Thetraditional slash-and-burn agriculturalpractices and reliance on wood for fuelin many countries contribute to thedegradation of soils by disturbing theplant cover.

The problematic environments ofdeveloping countries must be acceptedas givens and treated as challenges.These environmental preconditions arenot in themselves problems because

Table 5Water-Resource Situation by Distance to Water AvailabilityCeiling

Demandlevel

High

High

Low

Low

High

Distanceto ceiling

Low

High

Low

High

Above

Situation

Critical

Approachingcritical

Highlycritical

No immediatedanger

Unsustainable

Solution

Reduce demand byrationing/conservation

Develop waterresources to maintaincurrent demand level

Enlarge storage

No changenecessary

Ration/conserve

Example

California

Mexico

Jordan

Denmark

Libya

Source: Based on data and concepts in Figure 9, page 25.

they are the norm for those populations.However, they are new to the technicalassistance personnel from temperatecountries that advise developing countrygovernments. Often these personnel donot fully appreciate the consequences ofhydroclimatic differences between thetropical and temperate zones.

In areas where there are alreadywater-supply difficulties and land fertilityis already degraded, major threats toboth quality of life and basic health aremounting. The threats arc twofold:insufficient food supply and increasedpollution. Where local governmentscannot treat the increased waste andcannot provide safe household waterand food supplies, an area can slip intowhat some scholars have labeled thedemographic trap.28 They warn thai, aspopulation pressure continues tomount, health will deteriorate becauseof poor sanitation and malnutrition.Ultimately, slower population growthwill result, but at the cost of increasingdeath rates. Such doomsday scenariosoften overstate the case in an attempt toforce the public and policymakers to payattention to the very real problems. Onedanger of this approach is that it can becounterproductive, causing widespreadfeelings of defeat and hopelessness. On

27

Better management of waste water helped clean up the Potomac River, which flowspast Washington, D.C. ,

the other hand, a balanced assessmentof the situation may noi. create enoughdrama to interest, the media, and themessage is ignored. Also ignored are thesigns of slow progress in dealing withthe population/water predicament.

Slow ProgressSerious work in water-resources man-agement, sanitation and public hygiene,and family planning have improved thebalance between water and populationin many areas. Progress in these fields isslow and often frustrating. Lastingimprovements often begin at the locallevels arid involve local dccisioimiakersand nongovernmental organizations, afact that is only now gaining recognitionat the top levels of developmentorganizations. Bui. support and coopera-tion at all levels of government andthroughout society are necessary tobalance population needs and waterresource availability.

Limiting Population PressureA crucial step in averting a water crisis isto slow the unprecedented populationgrowth occurring in so many of theworld's countries. Many countries nowhave explicit policies to slow population

growth as well as to improve the healthand longevity of their citizens. In 1976,61 percent of governments sur-veyed bythe United Nations provided directsupport for family planning, whether itwas for health reasons or expressly tolower birth rates. In 1989, some 72percent of country governmentsprovided such support.2'1

Several nations have set target birthrates and death rates. Nigeria had a1990 total fertility rate (TFR—theaverage total number of children perwoman) just above six. The governmenthopes to achieve a TFR of four childrenper woman by 2000, and at the sametime lower its infant mortality. Ugandais also touting the advantages of limitingfamily size to four children. While thisaverage seems high by American andEuropean standards, where the TFR inmost countries has been below four formost of the 20th century, such areduction would avert millions of births.Meeting these goals by the end of themillennia, however, are optimistic andunlikely. Large families are highlyvalued in many traditional cultures andsuch deeply rooted social norms areslow to change. Couples require boththe motivation and means to limit theirfamily size.

28

Governments and other communityorganizations tan encourage couples tohave small families and ensure access tofamily planning information andmethods. They can support bettereducational and job opportunities forwomen, factors related to lower fertilityrates. But population growth rates willnot fall until individuals change theirbehavior. Few countries will follow thestringent population-control policies ofChina, which lowered that country'saverage family si/e to just over twochildren in the 1980s from about six inthe 1960s.'"

In much of the developing world,family planning has become moreacceptable and available. Fertilityrates—the driving force in the popula-tion boom—have fallen. In India, whichwas the first country lo formally pro-mote family planning, nearly one-half ofthe couples used a family planningmethod in the late 1980s. India's fertilityhas fallen since the 1960s, but it leveledoff at about 1.5 children per woman onaverage in the 1970s and 1980s. Recentevidence indicates that Indian fertilitymay be declining further. Nevertheless,its current growth rate ensures a totalpopulation greater than 1 billion by theyear 2000.31

In Africa, where contraceptive usewas practically nil thirty years ago, nearly20 percent of couples use familyplanning in the early 1990s, Fer tilily hasfallen in a few countries, offering somehope that the region can aver I the worstconsequences of the crisis in food andwater availability. In Kenya, the averagefertility rate is still nearly six childrenper womarr in the early 1990s, downfrom about an eight-child averagebefore 1980. About 27 percent ofKenyan women of reproductive agewere using contraception in 1989, wellbelow the level even of India.

In the Middle East, already sufferingfrom severe water stress, the specter ofcontinuous waves of new people paintan especially bleak picture (see Box 5).Adding to these problems, somecountries favor continued populationgrowth in hopes of outnumbering theirpolitical rivals.

Egypt, which has long relied on theNile for the vast majority of it.s water, has

slowed its population growth rate.However, the population is still increas-ing by over 1 million per year. Eightypercent of the growth occurs in therelatively few urban areas. The hugecities of Cairo and Alexandria areencroaching on the limited supply ofgood agricultural land. At the sametime, countries upstream in the Nilebasin may begin siphoning oil more ofEgypt's freshwater.

In the lorrg term, slowing populationgrowth will help avoid or at least slowthe risk spiral of resource depletion andsoil degradation. But demographicchange occurs slowly—in part because acountry's age structure containsmomentum for continuing growth, andin part because change originates at thehousehold level. In the short, term, theimpending crisis can be ameliorated byadopting management techniques toincrease the amount of accessible waterand use water more efficiently.

Water Management SolutionsWhere growing numbers of peopledepend on limited water availability,societies seek the most efficient ways tomanage their water resources. Evenwhere water is relatively abundant, theymust find ways to avoid polluting theirclean water or disrupting local watersystems. The type of managementapproach that is appropriate dependson the local conditions. The approachadopted is often dictated by the politicaland economic situation.

How can water use be adapted to itsavailability in countries trying to developeconomically, or trying at least toachieve agricultural self-sufficiency?

In semi-arid countries with onlyseasonal shortage problems and rapidpopulation increase, the main task isstoring water during the dry seasons. SriLanka, Iran, and Pakistan, with 300 to500 persons per flow unit, are examplesof developing countries with thesecharacteristics. Water conservation byrainfall accumulation, infiltration, andunderground storage seems to be theideal instrument to supply areas incountries far from rivers. In the south-western United States, water from theColorado and other large rivers is stored

29

The River Jordan Basin: The Politics of Sharing a Scarce Resource

The Middle East has less wateravailable per capita than any othermajor world region. Control of theJordan River, which collects the rainfrom four countries, is at the centerof a political controversy.' Thelimited rainfall in the northern andcentral parts of the river basin tailsmainly in the winter, The southremains dry year round. Rain fallingover northern Lebanon, Syria, andIsrael drains into the Sea of Galileeand flows into the Dead Sea, a closedlake basin. Rain over the eastern partsol the river basin in Jordan andsouthwestern Syria drain into themain river through the Yarmouk, atributary that forms the borderbetween'these two countries.

The plans for sharing the JordanRiver's water have caused conflict formillennia, but perhaps never soviolently as during the past 50 years,after the splitting of. Palestine and thecreation of the states of Israel andJordan. After gaining independencein 1948, Israel immediately started todevelop the water supply of the newstate, envisaging large-scale immigra-tion and agricultural expansion. Thecentral trunk ollsrael's system is theNational Water Carrier, a pipelinebringing water from the Sea ofGalilee down the coastal plain towardthe Ncgev Desert. Israel securedcontrol of the Yarmouk River, theJordan's largest, tributary, all the way

to the water divide after the 1967 war—a conflict sparked, in part, by waterresource disputes.2 Later, Israelexpanded its control to include theremaining tributaries.

The West Bank of the Jordan River,occupied in the same war, was animportant, recharge area for themountain aquifer that brings ground-water to 3 million urban inhabitantsalong the coast. To protect its urbanwater supply, Israel restricts thePalestinians in the West Bank fromdrilling new wells or irrigating crops,adding to the frustration and turmoil inthe occupied territory.

The past and even present disputesmay appear minor in the future. It isdifficult: to foresee a water sharingscheme that will satisfy all parlies. Nocountry has surplus water, and all aresubject to rapid population increase:Israel from immigration, the othersfrom high birth rates.

Israel's water use per capita is verylow for such a developed country.Water conservation is recognized as amatter of national defense. But Israel'swater demands already exceed itsavailable supply, and the nation faces a30 percent water deficit within adecade, threatening its politicalsecurity.3 The severe drought in theearly 1970s generated arr avalanche ofinternal criticism and charges ofmismanagement of Israel's nationalwater system.4

in reservoirs and redistributed to aridareas through canals and pipelines. Theviability of such efforts in other regionsis limited by economic costs andtechnology, as well as climate andtopography.

Countries with chronic shortages arethe most difficult to manage. Underconditions of water scarcity, smalleramounts may be allocated for eachindividual. In addition, each unit ofwater will have to be reused as many

30

times as possible. Sequential water useinvolves capturing, treating, andremoving pollutants from water used inone sector so that it can be directed toother uses. Because domestic userequires the cleanest water, the idealorder of reuse would be household first,then industry, then agriculture.Agricultural use would be last because,even in water-efficient irrigation, rrrostirrigation water returns to the atmo-sphere through evapotranspiration.

! I

Population Pressure in Jordan River Basin Countries

Persons per1 million cubic meters

1990s

3,0703,910

3504,000 (>

2025

4,6001 1,910

91013,300)

Currentwater usecirca 1990

(cubic meters)

375200

140

Water useceiling

(cubic meters)

1990s

310256

2,840250

202S

21784

1,100(<7S)

IsraelJordanSyriaWest Bank

Note: 1 cubic meter = 1.35 cubic yards.Sources: Wor l d Resources Institute, WoridResources 1991-92 (New York: Oxford University P«ss, 1991); and J. Forkaslweici and].Margat, Trjblpou Mondial dC DortncCS Nationals D'Eajno*riie dt: L'Laa, Ressourtes el Utilisations DGpaftement hydrog^ologie, 79 SGN 784HYD, Orleans, 1980.

The increasing population pressureon water resources in Jordan River basincountries hastens the need to findadditional sources of water, betterStorage facilities, and more efficientwater use.

Possible remedies to the region'swater problems include temporarysolutions such as a pipeline from theNile to the Gaza strip and the Negev fora defined period of 50 years. With NileRiver water to meet the extreme waterdeficits predicted for the near future,longer-term projects might include apeace pipeline transferring river waterfrom some of Turkey's rivers to Israel,Jordan, and the Palestinian communi-ties. Another longer term solution couldinclude construction of a desalini/.ationplant. Any of these solutions will requireunprecedented cooperation among thefiercely independent political factions.

References1. Sic V Lonergan and B. Kavanagh,

"Climate Change, Water Resources andSecurity in the Middle East," (ilolmlEnvironmental Chang? (September 1991)j:H. Shuval, "Approaches to Solving WateResources Conflicts in Arid Areas—Israel and Her Neighbors as a Case ;:Study," Second Consultation of theWHO/FAO Working Croup on LegalIssues in Water Supply and WaMewatcrManagement, Geneva, 10-12 September|1991; and George Mofrett III, "MiddleEast Water: Time Running Out," a four- •part series in The Christian ScienceMrmilar, appearing 8, 13, 14, and 16March 1990.

2. Jonathan C. Randal, "Euphrates DamAids Turkish Rebels," The WashingtonPost, IT) May 1992.

3. George Molfett III, "Middle East Watei."4. M. Bcn-Vaini, "Israel's Water Crisis

Deepens," World Wain andEnvirpnrrwntaEngineer (March 1991): 29.

Reducing the waste incurred inirrigation offers the greatest singlereduction of water demand in manyareas. Since 85 percent of water used inCalifornia goes into irrigation, forexample, even a limited improvementin irrigation efficiency would save hugeamounts of water for municipal andindustrial use.'2 Overall demand couldbe brought down to equal currentsupply and still allow ample water forirrigating crops.

Various agricultural techniques canreduce the amount ol water needed forirrigation and conserve the soil. Theseinclude planting drought-resistantcrops, capturing and reusing runofffrom irrigation systems, and drylandplowing. A strain ol chickpea that needsonly one hall the usual amount of water'has been introduced successfully in theMiddle East.1' In the drought-strickenMaharashtra State of India, a socio-Lechniral system for rainwater harvest-

31

More efficient techniques can cut down on the wate, neeaed for irrigation.

ing, accumulation, artificial aquiferrecharge, wells for retrieving the storedwater, and allocation of water inrelation to family size has been quitesuccessful. Subsistence food security hasbeen achieved for the local populationin an area that receives only 150millimeters of rainfall annually.34

Countries with chronic watershortages must also resort tononconventional methods to augmentfreshwater availability. The massivedesalinization projects in several Arabcountries and in southern California area current, example. Under presentmethods and technology, however,desalinization is too costly for wide-spread use. Water from desalinationaccounts for a minor share of all watereven in the areas that use it.3" Newmethods of transporting water are beingexplored. A system of towing water tosome Mediterranean countries is being-developed, for example.31'

Some countries with a chronicscarcity of endogenous water arefavored by international rivers whichprovide the core of their water re-sources. Egypt is the classic example;Jordan is another such case. But thesecountries arc prisoners of upstreamcountries. Large-scale agricultural

32

development in Ethiopia or Sudan, forexample, is likely to divert water fromthe Nile and could seriously reduce theflow to Egypt. For these countries, watermanagement must involve internationalcooperation.

ConclusionThere are many ways to soften theeffects of both the current crisis inselected world regions and the morewidespread problems that loom ahead.These require active management ofexisting water resources and a slowingof the population growth in water-scarce areas. Water systems transcendnational boundaries. Their manage-ment will require the cooperation andcommitment of local, national andinternational governments, industries,and other organizations.

In every country, development—indeed all human activities—mustinvolve careful and successful balancingof unavoidable manipulations of thelandscape and the likewise unavoidable"environmental impacts" of thosemanipulations. Conditions of environ-mental sustainability17 must encompass,for instance, protection of land produc-tivity, groundwater potability, and

biodiversity. These factors may restraindevelopment, but. they must be dealtwith either in the short term, byadopting methods to proLect naLuralsystems, or in the long term, by correct-ing the damage already done andminimizing future problems.

Balancing society's growing needs forclean water with the finite amount ofwater available also requires an under-standing of the demographic forces at

work in each country. Rapid rural tourban migration, high fertility rates, andshifting patterns of internationalpopulation movement will affect futurewater needs at regional, national, andlocal levels. With a heightened aware-ness of the global water systems and :demographic trends, as well as the activemanagement of resources, the delicatebalance between population and watercan be maintained.

33

References

1. Malin Falkenmark, "The Vcn Te Chow Memorial Lecture: Environment and Development:Urgent Need for a Water Perspective," Water International 16, no. 4 (1991): 229-240.

2. Norman Myers, "Population and the Environment: Issues, Prospects and Policies," Paperprepared for the United Nations Population Fvind. November 1990.

3. T.F. Glick, Irrigation and Society in Valencia (Cambridge, MA: Harvard University Press, 1971);and j . Needham, elal, Science and Civilization in China: Civil Engineering and NauticsWol. 4, no.3 (Cambridge: Cambridge University Press, 1971).

4. E. Leach, "Hydraulic Society in Ceylon," Past and Present 15 (1959).5. Karl A. WiLlibgel, Oriental Despotism: A Comparative Study of Total Power (New Haven, CT: Yale

University Press, 1957); see also Julian II. Steward, "Introduction," in Irrigation Civilizations: AComparative Study. A Symposium on Method and Result in Cross-Cultural Regularities. SocialScience Monographs I (Washington, DC: Pan-American Union, 1955).

6. Goran Djurfeldt and S. Lindberg, Behind Poverty: The Social Formation in a Tamil Village,Scandinavian Institute of Asian Studies Monograph 22 (Lund/London: Curzon Press, 1975);and T.F. Click, Irrigation and Society.

7. Ralph Bcals, "Discussion: Symposium on Irrigation Civilization," in Irrigation. Civilizations: AComparative Study. A Symposium on Method and Result in Cross Cultural Regularities. SocialScience Monographs I (Washington, DC: Pan-American Union, 1955); and K.W. Burner,Early Hydraulic Civilization in Hgypt: A Study in Cultural, h'.cology (Chicago: University of ChicagoPress, 1976).

8. G. Tyler Miller, Jr., Living in the Environment: An Introduction, to Environm.en.tal Science, 4th ed.(Belmont, CA: Wadswort.h Publishing Company, 1985), p. 187.

9. G.A. Soften, "Water: The Key to Global Change," 39th Annual Congress of the InternationalAstronautical Federation, Bangalore, India, September/October 1988.

10. M.I. I.'vovich, World Water Re.smiri.es and. their Future, English translation (Chelsea, MI:American Geophysical Union, 1979), p. 250.

11. Miller, Living in the Environment, p. 188.12. Malin Falkenmark and Tom Chapman, eds., Comparative Hydrology. An Ecological Approach to

Land and Water Resources (Paris: UNESCO, 1989); and UN Food and Agriculture Organiza-tion (FAO), Irrigation and Water Resources Potential, fm-Africa AGL/M1HC/11/87 (Rome: EAO,1987).

13. Michael H. Glantz, "On the Interactions between Climate and Society," Population andDevelopment Rniimo 16 (Supplement) 1991: 179-200; and Jane I'erlez, "Southern Africa Hit byIts Worst Drought of the 20th Century," New York. Times, 7 March 1992, p. 1.

14. Malin Falkenmark, "Fresh Water—Time for a Modified Approach," Ambio 15, no. 4 (1986):192-200.

15. Perlez, "Southern Africa."16. World Resources Institute, World Resources 1991-92 (New York: Oxford University Press,

1991).17. Malin Falkenmark, "Water and Mankind—A Complex System of Mutual Interaction," Ambio

6, no. 1 (1977): 3-7.18. Nikos Alexandratos, ed,, World Agriculture Toward 2000 (New York: UN Food and Agriculture

Organization, 1988).19. For a discussion of the conference sec Malin Falkenmark, "Global Water Issues Confronting

Humanity," Journal ofPeace Research 27, no. 2 (1990): 177-190.20. M. Falkenmark, J. Lundqvist, and C. Widstrand, "Macro-Scale Water Scarcity Requires Micro-

Scale Approaches. Aspects of Vulnerability in Semi-Arid Development," Natural ResourcesForum. 13, no. 1 (1989): 258-207.

21. Water Authority of Western Australia, "Stream Salinity and its Reclamation in South-WesternAustralia," Watf.r Resources Directorate Report, No. WS f)2, 1989.

22. South Africa, Management of Water Resources of the Republic of South Africa (Pretoria, SouthAfrica: Department of Watei Allah's, 1986).

23. J.M. Higgins, el ai, Potential Population Supporting Capacities of Lands in the Developing World,technical report for UN Food and Agriculture Organization (FAO), UN Fund for PopulationActivities, and International Institute lor Applied Systems Analysis (Rome: FAO, 1982).

24. Falkenmark, "Water and Mankind."25. United Nations Center for Human Settlements (Habitat), "Urbanization: Water Supply and

Sanitation Sector Challenges." Paper presented at the Water Supply and SanitationCollaborative Council Global Forum, Oslo, Norway, 18-20 September 1991.

26. United Nations, World Urbanization Prospects 1990 (New York: United Nations, 1991).27. Falkenmark, "Water and Mankind," p. 200.

34

28. Maurice King, "Health is a Sustainable State," The lancet 336, no. 8716 (September 1990):664; see also Susan Kalish, "Child Survival and the Demographic: 'Trap'," Population Today{Washington, DC.!: Population Reference Bureau) February 1992: 8-9.

29. Peter Donaldson and Amy Ong Tsui, "The International Family Planning Movement,"Population Bulletin 45, no. 3 (Washington, DC.: Population Reference Bureau, 1990).

30. H. Yuan lien, et ai, "China's Demographic Dilemmas," Population Bulletin 47, no. 1 (Washing-ton, DC: Population Reference Bureau, 1992).

31. United Nations, World Population Prospects 1990 (New York: United Nations, 1991); and CarlHaub and Machiko Yanagishita, 1992 World Population Data Slieel (Washington, DC: Popula-tion Reference Bureau, Inc., 1992).

32. Mohamet 1T. El-Ashry and Diana C. Gibbons, Troubled Waters, New Policies for Managing Waterin the American West. Study 6 (Washington, DC: World Resources Institute, 1986).

33. George. D. Moffett III, "Pouring Oil on Troubled Middle East Water," The Christian ScienceMonitor, 16 March 1990, p. 5.

34. Falkcnmark, "Water and Mankind."35. World Resources Institute, World Resources 1992-93 (New York: Oxford University Press, 1992),

p. 164.36. Falkenmark, "Water and Mankind."37. Malm Falkenmark and R. Adiwoso Subrapto, "Population-Landscape Interactions in

Development: A Waler Perspective to Environmental Sustainability," Ambit) %\, no. 1 (1992):31-36.

35

Suggested Readings

Butzer, K.W. Early Hydraulic Civilization in Egypt: A Study in Cultural Ecology. Chicago: University ofChicago Press, 1976.

El-Ashry, Mohamed T. "Sustainable Resource Management in Sub-Saharan Africa,* Annual Reportof the WarMftismirr.es Institute. Washington, DC: World Resources Institute, 1986.

- and Diana C. Gibbons. Troubled Waters: New Policies for Managing Water in tlie American West.Washington, DC: World Resources Institute, 1986.

Falkenmark, Malin. "The Ven Te Chow Memorial Lecture, Environment and Development:Urgent Need For a Water Perspective." Water International 16, no. 4 (1991).

- and Tom Chapman, cds. Comparative Hydmlogy: An licolngiral Approach to land and WaterResources. Paris: UNESCO, 1989.

, Jan Lundqvist, and Carl Widstrand. "Macro-Scale Water Scarcity Requires Micro-ScaleApproaches: Aspects oi Vulnerability in Semi-Arid Development." Natural Resources Forum 13,no. 4(1989).

- and R. Adiwoso Subrapto. "Population-Landscape Interactions in Development: A WaterPerspective to Environmental Sustainability." vlmAio 21, no. 1 (1992).

Ijeonard, H.Jeffrey and contributors. Environment and the Poor: Development StrategOs for a CommonAgenda. New Brunswick, N|: Transaction Books, 1989.

World Resources Institute, World Resources, 1992-1993. New York: Oxford University Press, 1992.

Discussion Questions

1. Outline the environmental conditions and human activities that limit access to clean water inyour community.

2. Discuss the impact that rural to urban migration may have on water use, water availability,and water quality in both urban areas and rural areas in developing countries.

3. The authors describe a series of water scarcity risks that may be exacerbated by populationgrowth. Give examples oi regions or countries that are experiencing any or all of theseproblems. Provide background on environmental conditions and human activities thatcontributed to this outcome.

1 I . ••

4. How will economic development in poorer countries alter the demand for water and changewater-use patterns?

5. During the United Nation's Clean Water Decade (1981-1990), the number of residents inurban areas without access to drinking water grew by 31 million even though clean drinkingwater was made available to 1.3 billion people. What led to this phenomenon?

6. Give examples of how population growth in specific countries (i.e., Kenya, United States,China) might affect the different phases of the water cycle as outlined in Figure 5.

7. Examine the relationship between water scarcity and poverty. Is it positive or negative? Isthere a direct correlation?

8. The authors state that about 150 of the world's 200 major river systems are shared by at leasttwo countries. Consider conflicts involving water rights, within or between countries. Whatroles does population growth play in such conflicts?

Prepared by Kimberly A. Crews

36

ulation Reference Bureau, Inc. (PRB)gathers, interprets, and disseminates information on the facts and

plications of national and world population trends. Founded in 1929,UjU> private, nonprofit educational organization that is supported by grants^ J contracts, individual and corporate contributions, memberships, and salespublications. It consults with other groups in die United States and abroad,aerates information and library services, and issues a variety of publications.S B also assists the development of population education through formal and^ r m a l programs.

Jiarles S. TidbaH, M.D., Chairman of the BoardSJarbara Boyle Torrey, President^Michael P. Bentzen, Secretary of the Board and CounselH k r t . T . Edwards, Treasurer of the Board

SVIice C. Andrews' lglissa Ashabranner^ g S. Blaiock[ojjjtld B. Conroyanneal J. Henderson, Jr.udith E.Jones

Gretchen S. KolsnulJuanita Tamayo LottWesley C. McClureF. Ray MarshallJessica T. MathewsRobert Parke

Martha H. PhilipsErol R. RickettsRafael ValdiviesoCharles F. WestoffMary M. WohlfordMarvin Zonis

red Marcy, Chair Emeritap d Taeuber, Chairman Emeritus and Demographic Consultant

Volume 45 (1990)

| ' No. 4 Germany's Population: Turbulent Past, UncertainFuture, by Gerhard Heitig, Thomas Biittner, andWolfgang Lutz

I ' No. 3 The International Family Planning Movement,by Peter J. Donaldson and Amy Ong Tsui

I 1 No. 2 Metropolitan America: Beyond the Transition,by William H. Frey

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O N O . 1 Two Hundred Years and Counting: The 1990 Census,by Bryant Robey

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Volume 42 (1987)

I I No. 4 Understanding Population Projections, by Cart Haub

! I No. 3 Redefining Procreation, Facing the Issues, by Stephen L.Isaacs and ReneeJ. Holt

j | No. 2 Population, Resources, Environment: An UncertainFuture, by Robert Repetto (updated reprint July 1991)

j , No. 1 Europe's Second Demographic Transition, by Dirk J.van de Kaa

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Volume 47 (1992)

QJ No. 3 Population and Water Resources: A Delicate Balance, byMalm Falkenmark and Carl Widstrand

| | No. 2 New Realities of the American Family, by Dennis A. Ahlburgand Carol J. De Vita

f I No. 1 China's Demographic Diiemmas, by H. Yuan Tien, withZhang Tianlu, Ping Yu, Lijingneng, and Liang Zhongt/mg

Volume 46 {1991)

[7] No. 4 The Challenge of World Health, by W. Henry Mosley andPeter Cowley

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