Modeling Artificial Aeration Kinetics in Ice-Covered Lakes

Abstract

A lake hydrodynamic model has been enhanced to simulate ice cover and artificial aeration during ice cover periods. Artificial aeration using mechanical surface aerators (“splashers”) and point-source bubblers (“bubblers”) is examined. Applying the model to two lakes in Alberta, Canada, indicate the model's capacity to handle a range of lake conditions and aeration operations. The sediment bed is found to be an important source of both heat and biochemical oxygen demand to the water column, during both natural conditions and artificial mixing periods. The ice cover thickness is shown to be a function of snow weight and insulation effects. The effects of an opening in the ice cover are a net gain in dissolved oxygen and a net loss of heat. The design and placement of aerators in the lake, as well as their operation schedules, are shown to determine the volume of mixed water and aeration effectiveness. This model is suitable for designing lake aeration systems to prevent winterkill in subarctic lakes.