Health and the Global Water Supply
description
Transcript of Health and the Global Water Supply
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
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Asia Africa North &CentralAmerica
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Annual Water Balance for Major Continental Land Areas
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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
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60
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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
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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
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35
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ΔV
(km
3)
AVE_mm/ monΔ V(km3)
954 965 839 773 923 963 995 693 829
Turkana
050
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150200250300350
400450500
日付
(mm
/mon
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均降
水量
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(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.
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1990-1998
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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
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-150 -120 -90 -60 -30 0 30 60 90 120 150
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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
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%)
Predicted Precipitation Changes2045
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% c
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Mekong Mississippi
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Severnaya Dvina
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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
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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
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8
°C
-4
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-4
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8
MacKenzie
-40-20
02040
Mekong Mississippi
-4
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-4
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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
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-4
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-4
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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
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J F M A M J J A S O N D0
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J F M A M J J A S O N D0
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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
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01000020000300004000050000 Mississippi
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J F M A M J J A S O N D0
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J F M A M J J A S O N D0
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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
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FirmHydropower
Annual FlowDeficit atMcNary
Pe
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of
Co
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ol
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lim
ate
PCM Control Climate andCurrent Operations
PCM Projected Climateand Current Operations
PCM Projected Climatewith Adaptive Management
2070-2098
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FirmHydropower
Annual FlowDeficit atMcNary
Perc
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on
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un
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PCM Control Climate andCurrent Operations
PCM Projected Climateand Current Operations
PCM Projected Climatewith AdaptiveManagement
Central Valley Water Year Type Occurrence
0.0
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Critically Dry Dry Below Normal Above Normal Wet
Water Year Type
Per
cen
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iven
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Typ
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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
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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.