Sediment oxygen demand investigation and CE-QUAL-W2 model calibration in the Athabasca River

Mathematical modeling of dissolved oxygen (DO) concentrations in the Athabasca River has been used to set effluent standards for pulp mills. Sediment Oxygen Demand (SOD) is a component of the oxygen balance that has previously been poorly understood and represented in the Athabasca River. In order to achieve more accurate DO predictions, a sediment core incubation method was developed in this study and compared to the in situ closed chamber method commonly employed in most SOD evaluations. The study showed that the sediment core incubation method provided convenient, reliable, yet cost-effective means for quantifying SOD in some habitats.;This study indicated that the largest source of error in SOD determinations is correctly representing turbulence in the water column. The sediment core incubation method developed in this study allowed the opportunity to test the effects of mixing rates on SOD determination. This study further indicated that actual SOD rates could be as much as 2-fold higher than originally reported due to inadequate mixing in chamber methods. (Abstract shortened by UMI.)...