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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 International Groundwater Resources Assessment Centre 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 International Groundwater Resources Assessment Centre 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 International Groundwater Resources Assessment Centre 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? International Groundwater Resources Assessment Centre First step: risk identification and assessment Primer paso: identificación y evaluación de los riesgos River Toyohiragawa alluvial fan (Sapporo city) International Groundwater Resources Assessment Centre 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 International Groundwater Resources Assessment Centre 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 International Groundwater Resources Assessment Centre 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 International Groundwater Resources Assessment Centre 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 International Groundwater Resources Assessment Centre 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 International Groundwater Resources Assessment Centre 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. International Groundwater Resources Assessment Centre Thank you Gracias Thank u…