Water Quality Modeling of Phytoplankton and Nutrient Cycles of a Complex Cold-Region River-Lake System

Linking elemental processes in integrated modeling provides a means of handling emerging issues related to aquatic system management. In this study, an integral modeling strategy was used to develop a water quality model of the Qu'Appelle River, particularly for under-ice conditions, which is a topic that has not received much attention in the literature. Phytoplankton and nutrient cycles of the river and lake were coupled using the Water Quality Analysis Simulation Program (WASP) 7.52. Model calibration and validation were based on samples taken from six water quality stations during the period 2013 to 2016. The calibration and validation results show good agreement between model predictions and observed data for oxygen, organic nitrogen, and ammonium. This study demonstrates the development and use of a model connecting riverine and lake sections to study under-ice conditions and can be applied to similar systems in cold regions.