Author(s): Eduardo Paredes; Alvaro Sordo-Ward; Paola Bianucci; Maria Dolores Bejarano; Luis Garrote

Linked Author(s): Paola Bianucci

Keywords: Water resources systems; Climate change; Long term; Water scarcity; Water availability

Abstract: Ensuring adequate water supply to meet societal needs while maintaining good ecosystem status is becoming increasingly difficult. This task is particularly challenging in areas characterized by water scarcity and with unfavourable projections due to change climate. This is the case of the Iberian Peninsula, where many water resources systems have already achieved high water use efficiency. If environmental water requirements are increased, it is very likely that, in the medium and long term, current water reliability standards will be impossible to maintain. The main objective of this study is to generate knowledge that contributes to the design and implementation of climate-change adaptation policies in water management. The goal is to achieve sustainability of the management of water resources systems in the medium and long term. Our focus is decision making to prioritize water allocation among different activities, accounting simultaneously for technical, economic, social and environmental aspects. To achieve this, we considered conceptual, methodological and operational innovations. First, we collected and processed geographic, hydrological and socioeconomic data for the Iberian Peninsula. Second, we estimated the future availability of water in the region (medium and long term) and quantified its uncertainty. We conducted a numerical experiment with the WAAPA model (Water Availability and Adaptation Policy Assessment) by combining hydroclimatic scenarios and management alternatives. Water availability is defined as the maximum demand that can be supplied at a given point of a river network under certain reliability requirements. The calculation was carried out in dam locations, confluences of the main rivers and basin outlets. The periods analysed were: control (1960-1990), short (2020-2059) and long-term (2060-2099). The study included 720 dams with reservoir storage greater than 1 hm3. Model topology was obtained from the HYDROSHEDS topographic database. The climate models were taken from the EURO-CORDEX initiative. Third, we evaluated the performance of water resources systems under the range of scenarios by comparing water availability to water needs. The comparison provides decision makers with information to optimize water allocation in conditions of scarcity, when a large number of demands fail to meet the reliability criteria. Our results showed a great sensitivity of the regulation capacity of the dams to the interannual variability of the runoff, which constitutes a challenge for the future management of the water resources in the different hydraulic systems.

DOI: https://doi.org/10.3850/IAHR-39WC252171192022431

Year: 2022