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Dams and the World’s Water
International Commission on Large Dams Name of presenter
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The ICOLD BookletThe ICOLD Booklet
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The World’s WaterThe World’s Water
By the end of the 21By the end of the 21stst century watercentury waterwill be the most imperiled natural resource in the worldwill be the most imperiled natural resource in the world
Presently water quantity, qualityPresently water quantity, qualityand availability concerns occur regularlyand availability concerns occur regularly
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ICOLD Mission
ICOLD advances the art, science and engineering for the planning, design, construction, operation, and maintenance of safe dams to ensure sustainable development and management of the world's water resources.
This is accomplished by:
– Providing an international forum for the exchange of knowledge and experiences on dam engineering and construction
– Technical committees that address emerging issues
– Raise the level of public awareness of the beneficial role of dams
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WaterRemains the vital resource to sustain civilization
Not evenly distributed by season or locationImbalance between availability and demandCareless use and contamination of what is available
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Main Issues with Water
Quantity
Quality
Demand versus availability
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The World’s Water
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The World’s Water
Cycle
79% of the rain79% of the rainfalls on the oceanfalls on the ocean
Of the water that falls on land
59% - evaporation38% - runoff
2% 2% -- groundwatergroundwater
It is critical that we store some of therunoff in reservoirs
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Distribution of the World’s Water
Dry river bed in India Flooding in China
Water is not evenly distributed by season or location
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GroundwaterNot Always Available at the Locations and in the Quantities Meeded
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World Population Date
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A perspective onDomestic Water Requirements
Purpose liters/person/dayDrinking 5Sanitation 20Bathing 15Cooking 10
Total 50
Equates to 4,281 gallons/person/yearor 18.25 cubic meters/person/year
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A perspective onDomestic Water Requirements
For example:
A city of 500,000 people requires 25 million liters per day
A town of 1,000 people requires 50,000 liters per day
A small village of 500 inhabitants requires 25,000 liters per day
Where there is a significant demand for water dams and reservoirs are our
most realistic option
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History of Dams
Marib Dam, YemenBuilt in 750 BC and upgraded in 1968
For almost 5000 years, dams have enabled civilization to collect and store water.
Throughout the world dams have been successful in maintaining and enhancing the quality of life.
They have become an integral part of our societies’ infrastructure.
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Dams of Today
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Dams of Today
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Dams of Today
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The Benefits We Receive From Dams
Water supply – domestic, agricultural & industrial
Flood controlHydropowerInland navigation
Recreation is usually included in all projects
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Domestic Water Supply
A typical water supply dam
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Industrial Water Supply
It takes 246,000 liters or 65,000 gallons of water to produce one ton of steel
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Irrigation
Food Grows Where Water Flows
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Flood Control
Flooding in Europe Flooding in Africa
Floods represent 30% of all natural disasters
Between 1975 and 2000 there were 95 significant floods in the world
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Flood Control
Dams provide storage for flood control
After the flood season is overthe water is released to maintain river flows
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Hydropower
Hydropower is a source of renewable energyAll water is passed downstream
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Inland Navigation
The capacity of 1 tow equals 15 jumbo rail cars or 55 normal trucks
A 15 barge tow making a passage at a lock and dam
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Dams and the Environment
EnvironmentalBenefits
EconomicBenefits
“A balance is needed”
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Environmental Conservation
Creating a wetland environment in shallow reservoir water
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2005 World Summit of the United Nations
UN presented 8 Millennium Development Goals and stated that:
Water as a resource is an essential ingredient for all goals
Sound water resources development and management underpins attainment of each goal
Requirements to meet the Goals will vary across regions
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Looking to the Future
Planning process for water resources projects
Accomplished on a watershed basis that includes wise use of multipurpose dams and reservoirs
Must address and mitigateResettlement and relocationSocio-economic impactsEnvironmental impactsSedimentation issues
Public involvement and coordination
Increased use of integrated water management in the watershed
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Summary
Historically, dams and reservoirs have provided the water and other benefits to sustain life and support economic development in all parts of the world
Current conditions in the world present many “opportunities” where water & energy are needed to sustain life, support additional development and reduce poverty
In those countries and regions of the world where there is a demand for significant quantities of water and energy , what realistic options do we have?
Groundwater, wind and solar must be pursued but people must realize that it has limitations and are not stand alone solutions
Conservation measures and improving efficiency must be applied,however, they are also not “stand-alone” options
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Summary
The realistic option:
Comprehensive planning must be accomplished on a river basin or watershed basis with involvement of all technical disciplines and stakeholder involvement
We have the technology and can use it wisely
The result:Better multipurpose dam projects can be built
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ICOLD wants to help nationsto prepare to meet tomorrow’s
technical challenges to developand manage their water resources
