Integrated modeling of climate risks and Nature-based Solutions in the Riviere du Nord watershed, Quebec

Anthropogenic climate change at the global scale is causing rapid shifts in weather patterns and hydrological regimes regionally and locally. As the magnitude, frequency and intensity of extreme weather events are getting more severe, this has direct impacts on humans, hydrology, infrastructure, and ecosystems. Additionally, the cumulative and compound impacts of climate change on hydrological systems over time poses added risks to socio-economic and socio-ecological structures due to integrative and synergistic effects. These effects, and their underlying mechanisms, are more complex than those of single extreme weather events and the severity of the impacts depend both on the combination of hazards and on how the surrounding human-water system reacts, adapts and evolves with changing hydrological conditions. Nature-based solutions (NbS), such as wetland conservation and restoration, re-meandering of waterways and reforestation are examples of adaptation measures that are gaining increasing attention due to their potential to buffer hydrological extremes whilst also providing ecological and human well-being benefits.

Understanding these cumulative impacts of climate change, and the role of NbS in supporting multifunctional adaptation, require holistic models that account for the co-evolution of social, ecological and hydrological systems. System dynamics (SD) is a modeling paradigm with a long history in integrated systems modeling that is well suited for this purpose due to its explicit focus on endogenous representation of complex feedback processes.

In this research, we apply SD to study the cumulative impacts of climate change in the Riviere du Nord watershed, Quebec, Canada. We present a scalable and modular hydrological simulation model with a daily timestep. Down-scaled climate scenarios from CanDCS-M6 are used as forcing data to study impacts of future hydrological flows and water levels on local communities. The hydrological model is designed to be seamlessly integrated with additional social and ecological modules to capture cascading effects on long-term human well-being and biodiversity indicators, supporting the design of robust multifunctional nature-based climate adaptation strategies.