Operational Seasonal Water Supply and Water Level Forecasting for the Laurentian Great Lakes

Abstract

Seasonal water supply forecasts are a critical component of regional water resources management planning. Across the United States, multiple modeling tools and operational protocols have evolved over time to address this need. Here, the authors document, assess, and recommend improvements to the current operational water supply forecasting protocols employed in managing flows through, and water levels across, Earth’s largest lake system: the Laurentian Great Lakes. The water resources management actions for this massive system are critically linked to North America’s economy, and to human health and safety, through planning and policy decisions related to hydropower management, commercial navigation, and water level fluctuations. The authors’ assessment indicates that existing operational seasonal water supply forecasting systems for the Great Lakes have moderate skill and that there are several high-priority areas for improvement, including improved representation of initial hydrological conditions, aligning variability in future meteorological forcings with climate-scale projections, and robust representations of forecast uncertainty.