Three-Dimensional Modeling of Eutrophication and Cyanobacteria Growth in Two Shallow Bays of Lake Champlain

Lake Champlain is a large, transnational lake located in the northeastern United States and Quebec. The eastern bays of Lake Champlain have experienced increased eutrophication and cyanobacteria blooms over the last century. This has led to significant interest in understanding the factors driving eutrophication and cyanobacteria growth in the lake.

In this work, we present calibration of a three-dimensional water quality model for the eastern portion of Lake Champlain using AEM3D with emphasis on Missisquoi Bay and St. Alban’s Bay, two shallow bays that have experienced water quality concerns. The model performance was evaluated against biochemical and physical data from years 2017–2019. Modeling results suggest a number of factors have led to eutrophication of the shallow bays, including internal loading despite the typically high measured dissolved oxygen levels at depth. This water quality model provides a framework to couple with hydrology, climate, and land-use models to run 100-year simulations that investigate the effects of future climate and land-use scenarios on water quality in the eastern bays of Lake Champlain.