Dissolved Oxygen Downstream of an Effluent Outfall in an Ice-Covered River: Natural and Artificial Aeration

Abstract

In ice-covered rivers, dissolved oxygen (DO) might fall below critical levels for aquatic biota in the absence of surface aeration, combined with low winter flow conditions and reduced photosynthesis rates. Open-water zones, however, can be created downstream of a diffuser by warm effluent discharges, resulting in an increase in surface aeration. In this study, we modeled the behavior of the effluent plume and the resulting open-water lead development in the Athabasca River, Alberta, Canada downstream of a pulp mill diffuser. The DO was found to increase by