Transcript Transboundary exchange of groundwater knowledge: the

International Groundwater Resources Assessment Centre
Groundwater
and risk management
Las aguas subterráneas y el manejo de riesgos
Jac van der Gun
IGRAC
4th World Water Forum, Mexico, 21 March 2006
Session “Groundwater and risk management: coping with water scarcity, climate change and emergency situations”
International Groundwater Resources Assessment Centre
Functions of groundwater
Funciones de las aguas subterráneas
Domestic and industrial water supply
Irrigation water supply
Bridging dry periods (buffer function)
Supporting the environment
Support of
ecosystems
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Importance of groundwater
Importancia de las aguas subterráneas
Groundwater on the globe:
• 96% of all unfrozen fresh water
• 23% of irrigation water
• 53% of all public water supply
• 97% of all rural domestic water
Groundwater plays a
much larger role than
most people think
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Important risks related to groundwater
Riesgos importantes relacionados a las aguas subterráneas
Triggers
of
change
Changes in water system conditions:
Changes of groundwater level (higher/lower)
Reduction of groundwater stock
Deterioration of groundwater quality (pollution, salinization)
etc….
Direct impacts on people, nature and the environment:
Groundwater
functions often
are seriously
at risk
Reduced availability of or access to useable water
Higher price of groundwater
Increased water scarcity
Water-logging
Land subsidence
Affected ecosystems, etc…..
Impacts in the more general sense:
Economic decline, increased poverty
Decreased health/well-being of people and animals
Loss of nature values and of environmental quality
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Risk management
Manejo o control de riesgos
Risk = damage (“loss of functions”) x probability
Steps in risk management:
• Identifying and assessing risks
Clear understanding
& preparedness
• Risk management strategy
Options:
• Accepting risk
• Risk avoidance
• Risk reduction
• Risk mitigation
• Implementation and monitoring
How?
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First step: risk identification and assessment
Primer paso: identificación y evaluación de los riesgos
River Toyohiragawa alluvial fan
(Sapporo city)
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Causes of groundwater storage depletion
Causas del agotamiento de las aguas subterráneas
Technological
progress
Economic
development
& urbanization
Higher
rates
of
groundwater
abstraction
Groundwater
storage
depletion
Higher water demands
and/or less recharge
of groundwater
Gradual change (trend)
Climate change
Natural and
anthropogenic
disasters
Groundwater as
an emergency
resource
Sudden change
Demographic
trends
Loss of fresh
groundwater
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Reducing groundwater storage depletion
Reducir el agotamiento de las aguas subterráneas
Augmenting gw resource
Restricting gw abstraction
Artificial recharge:
Regulation:
• Licensing
• Charging for water use
• Energy supply restrictions
• Restricting credits
Adapting behaviour:
• Water saving techniques
• Conjunctive water use
• Water harvesting
• Land use planning
• Transformation to a less
water–dependent economy
Huge recharge
dams in Oman
Reducing
groundwater
storage
depletion
• Large and small dams
• Infiltration basins
• Injection wells
Induced recharge
Kenya sand dams
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Groundwater quality degradation
Deterioración de la calidad de las aguas subterráneas
Technological
progress
Economic
development
& urbanisation
Higher
rates
of
groundwater
abstraction
and
pollution
Groundwater
quality
degradation
Poor quality
grw recharge
Gradual change (trend)
Climate change
Natural and
anthropogenic
disasters
Saline intrusion
due to more
intensive
groundwater
abstraction
Sudden change
Demographic
trends
Flooding as a
source of pollution
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Emergency situations after disasters
Condiciones de emergencia después de desastres
Tsunamis
Floods
Groundwater as
a source for
emergency
water supply
Damaged water
supplies and/or
aquifers affected
by saline or
contaminated water
Labe (Elbe) study,
Czech Republic
Need for
aquifer
rehabilitation
UNESCO action in Tamil Nadu
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Contribution from international entities
Contribución de entidades internacionales
Complementary to and in support of local risk management
on groundwater (studies, local actions) there are many
international organisations and international projects that
may be a source of information, guidance or inspiration:
UNESCO
IAH
IGRAC
IASH
UNEP
FAO
IWMI
WB
GEF
WHYMAP
ISARM
GWES
GW-MATE
GRAPHICS
CPWC
WWAP
GEMS/Water
GRDC, etc.
Among others, they help disseminating
the approach and results of local activities
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Conclusions
Conclusiones
 Groundwater has many functions and is very important on
both global and local scales
 These functions are often at risk, partly due to human and
climate change pressures (trends - predictable), partly due to
sudden disasters (emergency situations - unpredictable)
 Adequate risk management includes: (a) diagnostics; (b) a risk
management strategy; (c) implementation.
 For each specific risk on groundwater, usually several
alternative measures for control can be identified. It is
extremely useful to exchange information on such measures
and their degree of success under different circumstances.
 Groundwater is not only exposed to risk, it may be also a
mitigating factor for risks affecting other water cycle
components.
 In addition to local action, international initiatives may also
contribute to proper risk management related to groundwater.
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Thank you
Gracias
Thank u…