Processes of Dimictic Lakes

In the spring the lake is about the same temperature and density therefore it has no resistance to mixing. In the summer the upper portion is heated by the sun and becomes less dense, and floats on the bottom more dense layer. As the temperatures cool in the fall, the surface waters become cooler and more dense than the bottom waters and sinks, this happens until a uniform temperature and density is shared by the entire lake. In the winter as temperatures drop further, ice forms on top of the lake, and stops any further mixing.

Map of Gatineau Park.