An Integrated Modeling Approach for Managing Transboundary Lakes

Lakes are essential for ecological integrity, water supply, hydropower production, and recreation, yet they are increasingly threatened by the combined impacts of human activities and climate change. Urbanization and agriculture intensify nutrient loading, while rising temperatures accelerate biogeochemical processes that promote harmful algal blooms. At the same time, the increasing frequency and intensity of extreme precipitation events elevate the risk of flooding, posing serious threats to lakeshore communities and infrastructure. Transboundary lakes are particularly vulnerable to these compounded pressures, as their management is often fragmented across political boundaries with differing priorities, regulations, and data availability. Addressing these challenges requires integrated, forward-looking tools capable of representing both natural processes and human interventions. This study develops an integrated modeling framework that couples water quantity, water quality, and management practices to support sustainable lake management under current and future climate conditions. We focus on Lake Memphremagog (102 km²), a transboundary lake shared between Canada and the United States, which exemplifies these challenges. Using a multi-model approach, we simulate lake volume to characterize current hydrological conditions and associated uncertainties. Preliminary analyses reveal strong variability and emerging trends in hydroclimatic, hydrological, and thermal datasets. This study provides a solid foundation for impact assessments and provide a critical step toward management of transboundary lakes under changing conditions.