Disasters have increased in frequency and their impact has been intensely felt on the continent. This frequently results in damage to the resources and infrastructure on which humans rely on for survival and quality of life. When disasters strike, large segments of the population are faced with devastating consequences, which include food shortages, limited shelter and inadequate health services. Disasters are a result of a complex mix of natural and other hazards, including human actions and vulnerabilities. They consist of a combination of factors that determine the potential for people to be exposed to particular types of hazards. The frequency and impact of disasters in South Africa has increased significantly, the most common type of disaster being drought. Droughts are the result of reduced amounts of rain received over a long period of time, but it includes delays at the beginning of the precipitation season that affects crops that depend on the rain. For the purpose of this study, agricultural and socioeconomic drought received attention. Agricultural drought is when the humidity in the soil is not sufficient to assist crop production and growth in the area. Socio-economic drought arises when economic activities aligned with other elements do not meet the population demand. Agricultural droughts often have the latent effect of reducing agricultural production to such an extent that the livelihoods of the communal farmers are threatened. Drought effects often result in shrivelling crops, loss of water resources, vegetation and a decrease in livestock forage for communal farmers. This, in turn, leads to a decreased availability of food and the overall loss of livelihoods. In addition, activities such as crop growing and grazing conditions for livestock remain vulnerable, yet rural communities rely on these to generate income. The most severe impact of droughts do not simply include the absence of food supply for the community, but rather correlates directly with the severity and the duration of droughts. This often increases the community’s vulnerability. The empirical findings were concluded from focus groups interviews and semistructured interviews as data collection for the study. The data collected from the field was compared to the Sustainable Livelihood Framework. The analysis revealed that drought mitigation in South Africa only exists in governmental policy documents. Moreover, the lack of a disaster management plan for Setlagole makes it difficult to prepare for drought. An inadequate relationship between farmers and the government also makes it difficult to create a sense of shared vision and mission for drought alleviation. One prominent issue that makes the effects of drought so severe is the process of relief; it takes too long for the government to give assistance to the farmers. This shows that mitigation measures are needed to prepare both the farmers and the government for drought. / M Development and Management, North-West University, Potchefstroom Campus, 2015

Disasters have increased in frequency and their impact has been intensely felt on the continent. This frequently results in damage to the resources and infrastructure on which humans rely on for survival and quality of life. When disasters strike, large segments of the population are faced with devastating consequences, which include food shortages, limited shelter and inadequate health services. Disasters are a result of a complex mix of natural and other hazards, including human actions and vulnerabilities. They consist of a combination of factors that determine the potential for people to be exposed to particular types of hazards. The frequency and impact of disasters in South Africa has increased significantly, the most common type of disaster being drought. Droughts are the result of reduced amounts of rain received over a long period of time, but it includes delays at the beginning of the precipitation season that affects crops that depend on the rain. For the purpose of this study, agricultural and socioeconomic drought received attention. Agricultural drought is when the humidity in the soil is not sufficient to assist crop production and growth in the area. Socio-economic drought arises when economic activities aligned with other elements do not meet the population demand. Agricultural droughts often have the latent effect of reducing agricultural production to such an extent that the livelihoods of the communal farmers are threatened. Drought effects often result in shrivelling crops, loss of water resources, vegetation and a decrease in livestock forage for communal farmers. This, in turn, leads to a decreased availability of food and the overall loss of livelihoods. In addition, activities such as crop growing and grazing conditions for livestock remain vulnerable, yet rural communities rely on these to generate income. The most severe impact of droughts do not simply include the absence of food supply for the community, but rather correlates directly with the severity and the duration of droughts. This often increases the community’s vulnerability. The empirical findings were concluded from focus groups interviews and semistructured interviews as data collection for the study. The data collected from the field was compared to the Sustainable Livelihood Framework. The analysis revealed that drought mitigation in South Africa only exists in governmental policy documents. Moreover, the lack of a disaster management plan for Setlagole makes it difficult to prepare for drought. An inadequate relationship between farmers and the government also makes it difficult to create a sense of shared vision and mission for drought alleviation. One prominent issue that makes the effects of drought so severe is the process of relief; it takes too long for the government to give assistance to the farmers. This shows that mitigation measures are needed to prepare both the farmers and the government for drought. / M Development and Management, North-West University, Potchefstroom Campus, 2015

Un sistema de gestión de sequías apropiado requiere de la anticipación de los posibles efectos que un episodio de este tipo tenga sobre el sistema de recursos hídricos. Esta tarea sin embargo resulta más complicada de lo que parece. En primer lugar, debido al alto grado de incertidumbre existente en la predicción de variables hidrológicas futuras. Y en segundo, debido al riesgo de sobrerreacción en la activación de medidas de mitigación generando falsa sensación de escasez, o sequía artificial. A este respecto, los planes especiales de sequía proveen de herramientas para la gestión eficiente de situaciones con escasez de recursos y la preparación de cara a futuros eventos. De todos modos, las diferentes estrategias de operación seguidas en cada sistema de recursos hídricos hacen que las herramientas que en algunos casos resultaron altamente útiles no lo sean tanto cuando se aplican en sistemas distintos. Debido a la falta de tiempo y/o al exceso de confianza en los trabajos realizados por terceros, con excelentes resultados en sus respectivos casos, a veces se cae en el error de implementar metodologías no del todo apropiadas en sistemas con requisitos completamente distintos. El desarrollo y utilización de metodologías generalizadas aplicables a diferentes sistemas y capaces de proporcionar resultados adaptados a cada caso es, por tanto, muy deseable. Este es el caso de las herramientas de modelación de sistemas de recursos hídricos generalizadas. Estas permiten homogeneizar los procesos mientras siguen siendo los suficientemente adaptables para proporcionar resultados apropiados para cada caso de estudio. Esta tesis presenta una serie de herramientas destinadas a avanzar en el análisis y comprensión de los sistemas de recursos hídricos, haciendo énfasis en la prevención de sequías y la gestión de riesgos. Las herramientas desarrolladas incluyen: un modelo de optimización generalizado para esquemas de recursos hídricos, con capacidad para la representación detallada de cualquier sistema de recursos hídricos, y una metodología de análisis de riesgo basada en la optimización de Monte Carlo con múltiples series sintéticas. Con estas herramientas es posible incluir tanto la componente superficial como la subterránea del sistema estudiado dentro del proceso de optimización. La optimización está basada en la resolución iterativa de redes de flujo. Se probó la consistencia y eficiencia de diferentes algoritmos de resolución para encontrar un balance entre la velocidad de cálculo, el número de iteraciones, y la consistencia de los resultados, aportando recomendaciones para el uso de cada algoritmo dadas las diferencias entre los mismos. Las herramientas desarrolladas se aplican en dos casos de estudio reales en la evaluación y posibilidad de complementación de los sistemas de monitorización y alerta temprana de sequías existentes en los mismos. En el primer caso, se propone un enfoque alternativo para la monitorización de la sequía en el sistema de operación anual del río Órbigo (España), complementándolo con la utilización de la metodología de análisis de riesgo. En el segundo caso, las herramientas se emplean en un sistema con una estrategia de operación completamente distinta. Se estudia como el análisis de riesgo de la gestión óptima puede ayudar a la activación anticipada de los escenarios de sequía en los sistemas de los ríos Júcar y Turia, cuya operación es hiperanual. En esta ocasión, el sistema de indicadores existente goza de una gran confianza por parte de los usuarios. La metodología de análisis de riesgo es, sin embargo, capaz de anticipar los eventos de sequía con mayor alarma, aspecto que es deseable si se quiere evitar que los episodios en desarrollo vayan a más. En ambos casos se muestra como la evaluación anticipada de las posibles situaciones futuras del sistema permiten una definición confiable de los escenarios de sequía con suficiente antelación para la activación efectiva de medidas de prevención y/o mitigación en caso de ser necesarias. La utilización de indicadores provenientes de modelos frente a indicadores basados en datos observados es complementaria y ambos deberían utilizarse de forma conjunta para mejorar la gestión preventiva de los sistemas de recursos hídricos. El empleo de modelos de optimización en situaciones de incertidumbre hidrológica es muy apropiado gracias a la no necesidad de definir reglas de gestión para obtener los mejores resultados del sistema, y teniendo en cuenta que las reglas de operación habituales pueden no ser completamente adecuadas en estas ocasiones. / Haro Monteagudo, D. (2014). Methodology for the optimal management design of water resources system under hydrologic uncertainty [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/45996 / TESIS