Abstract
Groundwater drought denotes the condition and hazard during a prolonged meteorological drought when groundwater resources decline and become unavailable or inaccessible for human use. Groundwater drought risk refers to the combined physical risk and human vulnerability associated with diminished groundwater availability and access during drought. An integrated management support tool, GRiMMS, is presented, for the mapping and assessment of relative groundwater drought risk in the Southern African Development Community (SADC) region. Based on composite mapping analysis of region-wide gridded relative indices of meteorological drought risk, hydrogeological drought proneness and human groundwater drought vulnerability, the mapping results highlight consistent areas across the region with highest groundwater drought risk and populations in the order of 39 million at risk of groundwater drought at present. Projective climate-model results suggest a potentially significant negative impact of climate change on groundwater drought risk. The tool provides a means for further attention to the key, but neglected, role of groundwater in drought management in Africa.
Résumé
L’assèchement d’une nappe fait apparaître les risques d’une sécheresse prolongée avec la diminution des ressources en eau souterraine qui deviennent indisponibles ou inaccessibles pour l’utilisation humaine Le risque sécheresse concerne le risque physique combiné à la vulnérabilité humaine, associé à une diminution de la disponibilité et de l’accès à l’eau de la nappe. Un outil intégré, GRIMMS, est présenté pour cartographier et évaluer le risque d’assèchement de nappe dans la région de la Southern African Development Community (SADC). Basée sur l’analyse d’une grille composite régionale d’indices relatifs du risque météorologique de sécheresse, prédisposition de la nappe à la sécheresse et vulnérabilité humaine à l’assèchement de la nappe, la cartographie met en lumière à travers toute la région les zones présentant de façon constante le risque le plus élevé d’assèchement de nappe et des populations de l’ordre de 39 millions d’habitants exposées actuellement au risque de son assèchement. Les projections d’un modèle climatique suggèrent un risque potentiel significatif de changement climatique et d’assèchement de nappe. L’outil est un moyen d’apporter une nouvelle attention au rôle clef, mais négligé, de l’eau de nappe dans la gestion de la sécheresse en Afrique.
Resumen
La sequía del agua subterránea denota la condición y el peligro durante una prolongada sequía meteorológica cuando los recursos de agua subterránea disminuyen y se convierten en no disponibles o son inaccesible para el uso humano. El riesgo de sequía del agua subterránea se refiere al riesgo físico combinado con la vulnerabilidad humana relacionado con la disminución de la disponibilidad y acceso de agua subterránea durante la sequía. Se presenta una herramienta soporte de manejo integrado, GRiMMS, para el mapeo y la evaluación del riesgo relativo de sequía de agua subterránea en la región de la Comunidad Sudafricana para el Desarrollo (SADC). Sobre la base de un análisis de mapeos compuestos de una cuadrícula a escala regional de los índices relativos de riesgo de sequía meteorológica, de las tendencias hidrogeológicas a las sequías y de la vulnerabilidad humana a la sequía de agua subterránea, los resultados de los mapas resaltan áreas consistentes a través de toda la región con los más altos riesgos de sequía del agua subterránea y en poblaciones del orden de 39 millones en riesgo de sequía del agua subterránea en la actualidad. Los resultados de modelos climáticos proyectivos sugieren potencialmente un impacto negativo significativo del cambio climático sobre el riesgo de sequía del agua subterránea. La herramienta provee un medio para una ulterior atención del rol clave, aunque descuidado, del manejo del agua subterránea de la sequía en África.
Resumo
A seca das águas subterrâneas denota a condição e o risco durante uma seca meteorológica prolongada, quando os recursos de água subterrânea diminuem e se tornam indisponíveis ou inacessíveis ao uso humano. O risco de seca das águas subterrâneas refere-se à combinação do risco físico e do risco de vulnerabilidade antrópica associado à diminuição da disponibilidade de água subterrânea e ao seu acesso durante a seca. É apresentada uma ferramenta de apoio à gestão integrada, GRiMMS, para a cartografia e avaliação do risco relativo à seca das águas subterrâneas na região da Comunidade de Desenvolvimento da África Austral (SADC). Com base na análise de cartografia compósita de toda a região, dividida em quadrículas contendo os índices relativos de risco de seca meteorológica, propensão de seca hidrogeológica e vulnerabilidade humana à seca das águas subterrâneas, os resultados da cartografia permitem destacar, no presente, áreas consistentes com maior risco de seca das águas subterrâneas em toda a região e que as populações em risco por seca das águas subterrâneas são da ordem dos 39 milhões. Os resultados de modelos de previsão climática sugerem um impacte potencialmente negativo significativo resultante das alterações climáticas no risco de seca das águas subterrâneas. A ferramenta fornece um meio para uma maior atenção para o papel chave, mas negligenciado, das águas subterrâneas na gestão da seca em África.










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Acknowledgements
The work is a subcomponent within a larger project, funded by the Global Environmental Facility and the World Bank, on Groundwater and Drought Management in SADC (2007–2011), which is part of the Regional Groundwater Management Program (initiated in 1996) under the on-going Regional Strategic Action Plan (RSAP) for Integrated Water Resources Management and Development in SADC. The valuable inputs of SADC national representatives from central water resources management units are acknowledged.
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Villholth, K.G., Tøttrup, C., Stendel, M. et al. Integrated mapping of groundwater drought risk in the Southern African Development Community (SADC) region. Hydrogeol J 21, 863–885 (2013). https://doi.org/10.1007/s10040-013-0968-1
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DOI: https://doi.org/10.1007/s10040-013-0968-1