Stress testing landscapes’ response to climatic extremes with and without sponge measures

With global climate change, it is not only getting warmer but precipitation patterns are also shifting. This leads to more intense or prolonged precipitation as well as periods with reduced or no precipitation. Stress testing, a technique originally from engineering, assesses the stability of an object under adverse conditions and has been widely used in the financial sector to evaluate the impact of interacting drivers of change and to plan actions to minimize risks in a standardized and transparent manner.  In the water sector, stress testing has also recently been employed in the Netherlands to map out the vulnerabilities of landscapes and the assets in it to weather extremes. This research aims to advance this stress testing methodology to aid dialogues on improving climate resilience of landscapes. The developed framework serves as a systematic evaluation process designed to assess a system’s behaviour under progressively increasing stress levels linked to a wider variety of hydro-meteorological events. It lists key stressors driving the system and proposes indicators to evaluate performance under stress, including system responses expressed as extend of floods and droughts, shifts in water quality and biodiversity values, and socioeconomic impact. In this research, the methodology is applied by conducting hydrological model experiments to simulate flood and drought scenarios in transboundary catchments. Using a range of stress tests, we explore landscapes’ sensitivity to variations in precipitation patterns and initial conditions. Additionally, the study evaluates potential sponge measures designed to mitigate system stress and enhance its resilience before critical failures occur. By testing these measures, the study assesses their capacity to reduce system pressure, improve adaptability, and enhance resilience to extreme events to limit critical failure or significant operational disruptions.