Drought and climate change impacts on water resources: management alternatives

During the last decades water resources are facing severe challenges all over the world and the trends of decreasing precipitations and increasing temperatures in the Mediterranean region intensify this situation. The large climate variability of the region‐ makes drought events appear as a recurrent phenomenon in the area, causing important damages in both the economy and the environment. Water resources planning is part of complex, multi‐disciplinary processes overarching a wide range of stakeholders with different interests, technical expertise, and priorities. Successful planning requires effective Integrated Water Resource Management models that can solve these complex problems. The purpose of this study is to provide a framework for effective and systematic risk management of water resources during drought. This management framework integrates hydrological, agricultural and water planning models. The methodology has three components: first, the statistical properties of drought are analysed and thresholds of drought alert are determined to serve as triggers for management actions. Second, water demand for agriculture is determined during the normal and drought periods. Third, a water planning model is used to integrate water availability and demand and evaluate the range of possible management actions that minimise the risk of water deficit. This methodological approach links the dynamic aspects of water availability and demand and its statistical properties needed for risk analysis to operational aspects of water management at the basin level. The methods are tested in two contrasting case studies in the Tagus basin in Spain. The results presented show the differential impacts of drought in physically similar systems that are subject to different regulation levels and the convenience of designing modified drought management plans in order to minimise the social and economic impacts of drought depending on the characteristics of the system. The results of the study also reveal its applicability for integrated analysis of drought that incorporate a demand analysis approach and the evaluation of climate change scenarios