Methodology for Drought Risk Assessment in Within-year Regulated Reservoir Systems. Application to the Orbigo River System (Spain)

Drought occurrence and its related impacts are a major concern in many river basins throughout the world. In the last years, drought management procedures have moved from a crisis approach towards a more sensitive preparedness approach. Drought plans development has arisen as an effective way of providing measures and actions to manage drought situations. However, due to each river basin has different operation characteristics, drought management requires a different approach in order to be efficient. Decision support tools are a great ally of water managers, especially in situations of high water stress and hydrologic uncertainty, allowing them to in-deep analyze the system and finding the best measures to minimize the risk of a system failure. This paper studies the difficulties of only using an indicator system based in current and past data to assess the drought risk in within-year regulated reservoir systems. It proposes the complementary use of a general risk assessment methodology to anticipate the future probable status of the system and defining the current drought scenario. It shows how the complementary use of a monitoring system and a risk assessment decision support system may improve the drought detection process allowing water managers optimizing the selection of mitigation measures and minimizing the probability of overreaction during a drought situation. Copyright The Author(s) 2014