Towards resilient rivers: holistic measures for integrated water resource management in changing scenarios

Rivers are increasingly exposed to climate extremes, characterized by more severe summer low flows and winter floods of increasing intensity. At the same time, pressures on water resources are intensifying, whether related to irrigation, biodiversity conservation, or urban cooling. This study develops and illustrates a holistic approach to enhance the hydrological resilience of small rivers facing these multiple pressures. It is based on the development of a conceptual catchment model that links stakeholders, uses, and current climatic conditions in order to better understand system functioning and interactions. Different scenarios can then be applied to anticipate their direct and indirect consequences on catchment components. This methodology is applicable to any type of catchment, regardless of its size or characteristics. It is explicit and visual, making it useful both for analyzing catchment dynamics and for communicating key issues to the public and decision-makers. It is complemented by operational tools to support the planning of concrete projects. The paper illustrates this approach through two small Swiss rivers affected by severe low flows, the Aire and the Drize. The results show that, by accounting for multiple needs, it is possible to identify integrated solutions that simultaneously address several challenges, including low-flow support, water quality improvement, restoration of ecological continuity, and urban cooling.