Health and the Global Water Supply

Dennis P. Lettenmaier

Department of Civil and Environmental EngineeringUniversity of Washington

Seattle, WA

for presentation at

Lecture Series on Global Health Issues confronting the World Community

University of WashingtonExtension Service

November 8, 2004

Outline of this talk

• The global (and regional) water and energy cycles

• Human needs for potable water• Water and food• Water development• Water and climate• Water quality and health• Conclusions – the path forward

1. The global (and regional) water and energy cycles

Source: NRC 1975

From Bras, 1990

From Taikan Oki, AMS 2005

0

200

400

600

800

1000

1200

1400

1600

1800

Europe &Iceland

Asia Africa North &CentralAmerica

SouthAmerica

Australia World

(mm

/ye

ar) Precip

ET

Runoff

Annual Water Balance for Major Continental Land Areas

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Europe &Iceland

Asia Africa North &Central

America

SouthAmerica

Australia World

Mill

ion

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are

a)

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ou

sa

nd

cu

bic

km

(ru

no

ff)

Surface Area

Runoff Volume

Surface Area and Annual Runoff Volume of Major Continents

Column water balance (e.g. of a region)

Source: Kooiti Masuda, 2002

Water balance of major global rivers

Source: Kooiti Masuda, 2002

Water balance of major global rivers

Source: Kooiti Masuda, 2002

2. Human needs for potable water

• Domestic consumptive use (U.S.) is ~200-250 liters/day

• Compare with drinking water requirement (about 5 l/day). U.S. domestic consumption has declined slightly over the last two decades. Much of difference between potable water requirement and use is sanitation, laundry, etc.

• Industrial requirement in developed world is of same order as domestic

• Total water withdrawals are about 6000 km3/yr• Compare with global (land) precip ~150,000

km3/yr (or global runoff ~0.4 x runoff)

Table courtesy Peter Gleick

Table courtesy Peter Gleick

Table courtesy Peter Gleick

3. Water and food

Blue and Green water (after Falkenmark)

• Green Water is rainfall that is stored in the soil and available to plants. Globally, it makes up some 65 per cent of fresh water resources. It is the basis of rain-fed farming and all terrestrial ecosystems.

• Runoff, stream base flow and groundwater constitute blue water. Green water may be used only in situ: whereas blue water may be transported and used elsewhere – for irrigation, urban and industrial use, and as environmental flow in streams.

Courtesy Wageningen University

Figure courtesy of world soil information, Wageningen University

Figure courtesy of world soil information, Wageningen University

Notes• Rain-fed agriculture contributes most of the world’s farm

production: 95 per cent in Sub-Saharan Africa where it makes use of only 15-30 per cent of rainfall, the rest is lost, mostly as destructive runoff;

• The partitioning of rainwater is a dynamic process (governed by rainfall intensity, terrain, land cover and soil) that may be controlled by management of land cover, micro topography and soil conditions;

• Soils process several times more water than they retain; while soil erosion by runoff and bank erosion by peak flows contribute nearly all the sediment load of streams, leading to the siltation of reservoirs and water courses. This means that management of green water is also management of blue water;

• Finally, agricultural demand for water is in competition or, even, conflict with the needs of industry, urban populations and the environment.

Courtesy Wageningen University

(http://hydro.iis.u-tokyo.ac.jp/GW/result)

Global Runoff & Water useGlobal Runoff & Water use

(Oki, et. al, 2002, IHE-UNESCO)

CaribbeanCaribbean

NorthNorth AmericaAmerica

Central Central AmericaAmerica

South South AmericaAmerica

WestWest

AfricaAfrica

OceaniaOceania

East &East &South East AsiaSouth East Asia

SouthSouth

AsiaAsia

USSRUSSR

North WestNorth WestAfricaAfrica

WesternWesternEuropeEurope

MiddleMiddle

EastEast

1~5 5~10 10~15 15~20 20~30 30~50 50<

Importer based, over 5 km3/y

km3/y

(Based on Statistics from FAO etc., for 2000)

78.5

33.5

46.2

57.538.8

36.4

An Adaptation Strategy to Cope with Scarcity? “Virtual Water” flow in 2000 (cereals only)

4. Water development

Global Reservoir DatabaseGlobal Reservoir DatabaseLocation (lat./lon.), Storage capacity, Area of water surface, Purpose of dam, Year of construction, …

13,382dams,

Variation of Reservoir StorageVariation of Reservoir Storage (estimated by RS, 1992-2000)

Chad

050

100

150200250300350

400450500

日付

(mm

/mon

)平

均降

水量

024

68101214

161820

ΔV(

km3)

AVE_mm/ monΔ V(km3)

382 325 374 394 419 412 409 417 363

Chad

050

100

150200250300350

400450500

日付

(mm

/mon

)平

均降

水量

024

68101214

161820

ΔV(

km3)

AVE_mm/ monΔ V(km3)

382 325 374 394 419 412 409 417 363

Nasser

050

100

150200250300350

400450500

日付

(mm

/mon

)平

均降

水量

0

20

40

60

80

100

120

ΔV(

km3)

AVE_mm/ monΔ V(km3)

713 　 　 　 　 　 　 711　 　 　 　 　 　 　 801　 　 　 　 　 　 705　 　 　 　 　 　 728　 　 　 　 　 　 　 750　 　 　 　 　 　 　 767　 　 　 　 　 　 805　 　 　 　 　 　 665

Nasser

050

100

150200250300350

400450500

日付

(mm

/mon

)平

均降

水量

0

20

40

60

80

100

120

ΔV(

km3)

AVE_mm/ monΔ V(km3)

713 　 　 　 　 　 　 711　 　 　 　 　 　 　 801　 　 　 　 　 　 705　 　 　 　 　 　 728　 　 　 　 　 　 　 750　 　 　 　 　 　 　 767　 　 　 　 　 　 805　 　 　 　 　 　 665

Turkana

050

100

150200250300350

400450500

日付

(mm

/mon

)平

均降

水量

0

5

10

15

20

25

30

35

40

ΔV

(km

3)

AVE_mm/ monΔ V(km3)

954 　 　 　 965　 　 　 　 　 　 839 　 　 　 　 　 　 　 773　 　 　 　 　 　 　 923　 　 　 　 　 　 　 963　 　 　 　 　 　 　 995 　 　 　 　 　 　 693　 　 　 　 　 　 　 829

Turkana

050

100

150200250300350

400450500

日付

(mm

/mon

)平

均降

水量

0

5

10

15

20

25

30

35

40

ΔV

(km

3)

AVE_mm/ monΔ V(km3)

954 　 　 　 965　 　 　 　 　 　 839 　 　 　 　 　 　 　 773　 　 　 　 　 　 　 923　 　 　 　 　 　 　 963　 　 　 　 　 　 　 995 　 　 　 　 　 　 693　 　 　 　 　 　 　 829

Volta

050

100

150200250300350

400450500

日付

(mm

/mon

)平

均降

水量

- 25- 20- 15- 10- 5051015202530

ΔV(

km3)

AVE_mm/ monΔ V(km3)

887　 　 　 　 　 　 　 898　 　 　 　 　 　 　 1040　 　 　 　 　 　 　 960　 　 　 　 　 　 1037　 　 　 　 　 　 　 902　 　 　 　 　 　 1052　 　 　 　 　 　 1162　 　 　 　 　 　 　 948

Volta

050

100

150200250300350

400450500

日付

(mm

/mon

)平

均降

水量

- 25- 20- 15- 10- 5051015202530

ΔV(

km3)

AVE_mm/ monΔ V(km3)

887　 　 　 　 　 　 　 898　 　 　 　 　 　 　 1040　 　 　 　 　 　 　 960　 　 　 　 　 　 1037　 　 　 　 　 　 　 902　 　 　 　 　 　 1052　 　 　 　 　 　 1162　 　 　 　 　 　 　 948

(1) Chad

(2) Nasser

(3) Turkana(4) Volta

　

Volta

Kainji

Chad

Tanganyka

Mweru

Kariba Cabora-Bassa

Malawi

Victoria

Turkana

Tana

Nasser

(1)(2)

(3)(4)

dV(km3) Precipitation (mm)

Global Water System Project

IGBP – IHDP – WCRP - Diversitas

Global Water System Project

IGBP – IHDP – WCRP - Diversitas

Human modificationof hydrological systems

Regulated Flow

Historic Naturalized Flow

Estimated Range of Naturalized FlowWith 2040’s Warming

Figure 1: mean seasonal hydrographs of the Columbia River prior to (blue) and after the completion of reservoirs that now have storage capacity equal to about one-third of the river’s mean annual flow (red), and the projected range of impacts on naturalized flows predicted to result from a range of global warming scenarios over the next century. Climate change scenarios IPCC Data and Distribution Center, hydrologic simulations courtesy of A. Hamlet, University of Washington.

0

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Up to1900

1901-1910

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Australia/New Zealand

Africa

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Europe

Central and South America

North America

Reservoir construction has slowed.

All reservoirs larger than 0.1 km3

Visual from Palmieri, NAS Sackler symposium, 2004

5. Water and climate

Global Climate ChangeSelected Basins

1　MacKenzie2　Mississippi3　Amazon

4　Severnaya　Dvina5　Yenisei

6　Amur7　Yellow8　Xi9　Mekong

-90

-60

-30

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-150 -120 -90 -60 -30 0 30 60 90 120 150

1

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789

Selected BasinsBasin Characteristics

River　Basin Predominant　Climatic　Zones

Area　(km2)　upstream　of　gauge

Amazon Tropical 4.62　106

Amur ArcticMid-Latitude　rainy

1.73　106

Mackenzie Arctic 1.57　106

Mekong Tropical 0.55　106

Mississippi Mid-Latitude　rainy 2.96　106

Severnaya　Dvina Arctic 0.35　106

Xi Mid-Latitude　rainy 0.33　106

Yellow Arid-coldMid-Latitude　rainy

0.73　106

Yenisei Arctic 2.44　106

GCM Predicted Climate ChangeChange in precipitation and temperature for selected basins

GFDL_CGCMCCCMA-CGCM1

HCCPR-CM2CCSR-CGCM

HCCPR-CM3CSIRO-CGCM

MPI-ECHAM4DOE-PCM3

2025 2045 2095

-40　-30　-20　-10　

0　10　20　30　40　 Amazon Amur Mackenzie

-40　-30　-20　-10　

0　10　20　30　40　 Mekong Mississippi Severnaya Dvina

-40　-30　-20　-10　

0　10　20　30　40　

0　 1　 2　 3　 4　 5　 6　 7　 8　

Xi

0　 1　 2　 3　 4　 5　 6　 7　 8　

Yellow

0　 1　 2　 3　 4　 5　 6　 7　 8　 9　

Yenisei

Change　in　temperature　(C)

Ch

an

ge

　in

　pre

cip

ita

tio

n　(

%)　

Predicted Precipitation Changes2045

0

100

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mm

Amazon Amur

-50-25

02550

%　c

ha

ng

e

-50-25

02550

-50-25

02550

MacKenzie

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300

mm

Mekong Mississippi

-50-25

02550

%　c

ha

ng

e

-50-25

02550

-50-25

02550

Severnaya Dvina

0

100

200

300

mm

Xi

J F M A M J J A S O N D

Yellow

J F M A M J J A S O N D-50-25

02550

%　c

ha

ng

e

-50-25

02550

-50-25

02550

Yenisei

J F M A M J J A S O N D

HCCPR-CM2 HCCPR-CM3 MPI-ECHAM4 DOE-PCM3

Predicted Temperature Changes2045

-40-20

02040 Amazon Amur

-4

04

8

°C

-4

04

8

-4

04

8

MacKenzie

-40-20

02040

Mekong Mississippi

-4

0

48

-4

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48

-4

0

48

Severnaya Dvina

-40-20

02040 Xi

J F M A M J J A S O N D

Yellow

J F M A M J J A S O N D-4

0

4

8

-4

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8

-4

0

4

8

Yenisei

J F M A M J J A S O N D

HCCPR-CM2 HCCPR-CM3 MPI-ECHAM4 DOE-PCM3

°C

°C

°C°C

°C

Simulated Streamflow 2025

Baseline HCCPR-CM2 HCCPR-CM3

MPI-ECHAM4 DOE-PCM3

0

100000

200000

300000 Amazon

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15000

20000

25000 Amur

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30000

40000

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15000 Xi

J F M A M J J A S O N D0

1000

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J F M A M J J A S O N D0

25000

50000

75000

100000 Yenisei

J F M A M J J A S O N D

m3/s

m3/s

m3/s

Simulated Streamflow2045

Baseline HCCPR-CM2 HCCPR-CM3

MPI-ECHAM4 DOE-PCM3

0

100000

200000

300000 Amazon

05000

10000150002000025000 Amur

0

10000

20000

30000 MacKenzie

0

10000

20000

30000

40000 Mekong

01000020000300004000050000 Mississippi

0

5000

10000

15000

20000 Severnaya Dvina

0

5000

10000

15000 Xi

J F M A M J J A S O N D0

1000

2000

3000

4000 Yellow

J F M A M J J A S O N D0

25000

50000

75000

100000 Yenisei

J F M A M J J A S O N D

m3/s

m3/s

m3/s

GCM grid mesh over western U.S. (NCAR/DOE Parallel Climate Model at ~ 2.8 degrees lat-long)

Western U.S. regional study

PCM Business-as-Usual scenarios

Columbia River Basin(Basin Averages)

control (2000-2048)

historical (1950-99)

BAU 3-run average

PCMBusiness-As-Usual

Mean MonthlyHydrographs

Columbia River Basin@ The Dalles, OR

1 month 12 1 month 12

2040-2069

60

80

100

120

140

FirmHydropower

Annual FlowDeficit atMcNary

Pe

rce

nt

of

Co

ntr

ol

Ru

n C

lim

ate

PCM Control Climate andCurrent Operations

PCM Projected Climateand Current Operations

PCM Projected Climatewith Adaptive Management

2070-2098

60

80

100

120

140

FirmHydropower

Annual FlowDeficit atMcNary

Perc

en

t o

f C

on

tro

l R

un

Cli

mate

PCM Control Climate andCurrent Operations

PCM Projected Climateand Current Operations

PCM Projected Climatewith AdaptiveManagement

Central Valley Water Year Type Occurrence

0.0

0.1

0.2

0.3

0.4

0.5

0.6

Critically Dry Dry Below Normal Above Normal Wet

Water Year Type

Per

cen

t G

iven

WY

Typ

e

hist (1906-2000) 2020s 2050s 2090s

Total Basin Storage

Annual Releases to the Lower Basin

target release

Annual Releases to Mexico

target release

Vörösmarty, 2000

Crisis of Global Water Resources in 2025: Climate or Population Growth

Global assessmentof water scarcity

Global Water System Project

IGBP – IHDP – WCRP - Diversitas

6. Water quality and health

Material in this section courtesy of Pat Brezonik, University of Minnesota (presented at NAS Sackler Symposium, October 2004

The Global Picture● Water　resource　issues　will　have　large　effects　on　

many　of　the　world’s　major　decisions　in　the　next　50　years.

●　1　billion　people　live　on　less　than　$1/day.

●　More　than　1.2　billion　have　inadequate　drinking　water　(poor　quality,　insufficient　quantity,　but　still　priced　beyond　the　means　of　the　poorest),　and　twice　that　many　(2.5　billion)　lack　sanitation　facilities.　

●　Poorly　handled:　could　result　in　wars　and　will　result　　　　in　premature　deaths,　poor　quality　of　life　for　many,　　　　and　widespread　degradation　of　aquatic　ecosystems.

●　Well　handled:　opportunities　for　scientific　and　political　　　　creativity,　international　collaboration,　promoting　　　　cooperation　rather　than　discord.　

Global Water Quality: Problems and Issues

A. Definitions:　

Water　quality　has　many　dimensions.　In　general,　it　must　be　defined　in　relation　to　the　use　or　intended use　of　the　water

Important　uses　of　water　include:●　direct human use for drinking, cooking, bathing

●　recreational uses: both contact and non-contact

●　agricultural: irrigation from crop production, livestock watering

●　industrial uses: for manufacturing, cooling

●　maintenance of healthy aquatic ecosystems

●　fish production

Relative　to　these　uses,　water quality　is　defined　in　terms　of　desirableranges　for　numerous　physical,　chemical,　and　biological　attributes　(orallowable ranges　for　attributes　that　are　inherently　undesirable　for　some　use);　in　contrast,　water-quality problems　occur　when　values　for　theseattributes　lie　outside　those　ranges.

Disease Millions affected ____________________________________________

Diarrhea 900a

Roundworm 900Guinea　worm 　　　4Schistosomiasis 200____________________________________________

a　Number　of　episodes　per　year

Source: World Bank, 1992

B.　Effects　of　Poor　Water　Quality　and　Sanitation　on　Sickness　and　Disease

　　　　This　presentation　will　not　focus　on　enumerating　the　effects　of　poor　water　　　　　quality　on　human　health,　but　a　few　statistics　are　relevant　to　indicate　the　　　　　seriousness　of　the　problem.　

Global Water Quality Problems/Issues cont.

II. Global Water Quality Problems/Issues cont.

　　　　　　C.　Six　　major　categories　of　water　quality　attributes　for　which　　　　　　　　　　　there　are　global　issues　and　problems

1. Nutrients (primarily nitrogen and phosphorus)　　　　lake　and　coastal　eutrophication　　　　 hypoxia,　harmful　algal　blooms,　loss　of　desirable　fish　　　　　nitrate　contamination　of　ground　water

2. Microbial pathogens and other disease vectors　　　　bacteria,　viruses,　protozoa　　　　　higher　animal　vectors　(e.g.,　insects,　snails)

3. Persistent organic pollutants　　　　legacy　chemicals:　PCBs,　chlorinated　pesticides　and　solvents　　　　disinfection　by-products:　halomethanes　and　haloacetic　acids　　　　emerging　contaminants:　(mostly　associated　with　consumer　products)

polybrominated　phenylethers　(flame　retardants),　perfluorinated　compounds　(PFOS)　(“Scotchgard”),　MTBE

4. Unregulated, non- (or less) persistent bioactive compounds of consumer origin:

pharmaceuticals,　products　for　personal　care,　endocrine　disrupters,　antibiotics

5. Heavy metals and metalloids:arsenic,　lead,　chromium,　mercury

6. Habitat degradation/destructione.g.,　ecosystem　fragmentation,　siltation,　loss　of　riparian　or　littoralvegetation,　disruption　of　water　levels　and　natural　hydoperiod

II. Global Water Quality Concerns, cont.

Arsenic in sedimentary aquifers in Bangladesh. Map based on > 18,000 samples. McArthur et al.  Water Resources Research, in press. Arsenic Crisis Information Centre: http://www.bicn.com/acic/

http://phys4.harvard.edu/%7Ewilson/arsenic/arsenic_project_introduction.html

ARSENIC: a major water quality problem in parts of Bangladesh, West Bengal, Vietnam, and elsewhere—largely of natural geochemical origin,but exacerbated by human decisions regarding water management

Global and continent access to safe drinking water (DW) and sanitation, 2000*

　　　Urban　 　　　　DW　　　Sanit 　　　Rural 　　　　　DW　　　Sanit

Population　　　%　Served　 Population　　　　%　Served_　　　________________________________________________________Global 　　2,845 　　　　　94　　　　　　86　　　　　　　　　3,210 　　　　　　71　　　　　　38Africa 　　　　　297 　　　　　85　　　　　　85　　　　　　　　　　　　487 　　　　　　47　　　　　　45Asia 　　1,352 　　　　　93　　　　　　78　 　　2,331 　　　　　　74　　　　　　31Europe 　　　　　545 　　　　　99　　　　　　99 　　　　184 　　　　　　88　　　　　　74Latin　America 　　　　　391 　　　　　93　　　　　　87 　　　　128 　　　　　　62　　　　　　48North　America　 　　　　　239 　　　100　　　　　100 　　　　　　71　　　　　　　　100　　　　100Oceania 　　　　　　　21 　　　100　　　　　100 　　　　　　　　9 　　　　　　67　　　　　　78________________________________________________________

*Gleick,　P.H.　et　al.,　The World’s Water 2002-3,　Island　Press,　2002.

One　consequence　of　poor　sanitation　is　a　decline　indissolved　oxygen　(DO)　levels　in　low-income　countries　during　the　1980s;　in　contrast,　DO　increased　in　high-　income　countries　during　same　period.

Source:　World　Bank　(1992).

Data for rivers at the continental level mostly show little change in nitrate between the periods 1976-90 and 1991-2000; median values were not statistically different. European rivers had highest nitrate loads to the oceans. North American and European rivers remained fairly stable; major rivers in south-central and southeast Asia increased considerably.

Comparison of major watersheds between 1976-90 and 1991-2000 shows that northern Europe and North America had lower phosphate, but the Ganges and Brahmaputra watersheds in south-central Asia had higher values. Nutrient control programs in municipal and agricultural activities may explain the observed reductions.

The　only　information　on　biological　characteristics　of　global　water　quality　in　the　UNEP　report　shows　a　marked　decline　in　an　index　of　aquatic　species　populations　for　all　continents　except　North　America,　but　even　on　that　continent　there　has　been　a　declining　trend　since　1985.

7. Conclusions and the path forward

Material in this section courtesy of Dr. Peter Gleick, Pacific Institute

The Nature of the Resource

• 97.5 percent of all water on the planet is salt water.

• The vast majority of fresh water is inaccessible to humans.

• Water is unevenly distributed in both space and time.

• Massive infrastructure has been built in many part of the world, at huge cost.

The Nature of Water Issues

• The failure to meet basic human and environmental needs for water is arguably the greatest development failure of the 20th century.

• Huge numbers of water-related diseases occur every year, with millions of preventable illnesses and deaths.

• Aquatic ecosystems are under threat of destruction; deteriorating quality and quantity.

The Nature of Water Issues (cont.)

• Global climate change will affect water resources in new ways.

• New solutions are available, but not widely implemented.

Unmet Basic Human Needs for Water

• 1.1 billion people lack access to adequate drinking water (mostly in Africa and Asia).

• 2.4 billion people lack access to adequate sanitation services.

• 2.2 to 5 million die annually from preventable water-related diseases.

The “New Economy of Water”

• There is growing pressure to let private companies and markets address water needs.

• There are many forms of water privatization, with both potential benefits and risks to the public good.

• There is growing opposition to private involvement in water. Do we understand the risks and benefits?

Understanding the Risks of Climate Change

• Climate change is a real problem.• Some climate change – perhaps a lot of

climate change – is unavoidable.• Convincing evidence suggests that the

climate is already changing.• Some of the most significant impacts will

be on water resources.

Gleick 2001

The link between water use and economic growth can be broken

0

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$199

6 U

.S. G

NP

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ithd

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Widespread efficiency improvements are possible, in all sectors

•1930s: 200 tons of water per ton of steel

•1980s: 20-30 tons of water per ton of steel

•2002: 2-3 tons of water per ton of steel(and we are changing the structure of our economy…)

•Agricultural water use can drop and yields can increase with better irrigation technology.

Things are already changing…

• Our understanding of the true costs of traditional supply – the “hard path.”

• Our understanding of the potential to improve efficiency of use.

• The nature of our economies.

• Our whole way of thinking about water – “soft” vs “hard” path.