ABSTRACT
Bubble-plume diffusers are increasingly used to replenish hypolimnetic dissolved oxygen (DO) while preserving stratification. While bubble plumes are successful at adding oxygen, they also introduce energy which drives basin-scale transport and mixing processes. Plume-induced mixing, for example, changes the thermal structure of the reservoir, which, in turn, influences the plume performance. Here, we account for this complex plume-reservoir interaction by coupling a circular bubble-plume model with a three-dimensional hydrodynamic model. The coupled model is applied to assess the relative role of bubble-induced circulation in driving inter-basin exchange in Amisk Lake, which has two basins separated by a narrow and shallow channel. Model simulations accurately reproduced field observations. We argue that inter-basin exchange is predominantly driven, not by bubble-induced circulation, but rather by internal-wave pumping.
