An Improved Model for Water Quality Management Accounting for the Spatiotemporal Benthic Flux Rate

Abstract

Although water quality models provide useful interpretations for water quality management, it is critical to accurately input and simulate the flux rate, which varies with space and time. In the Environmental Fluid Dynamics Code model, the flux rate value set does not consider spatiotemporal variability. The water quality of the Saemangeum freshwater lake in Korea is poor despite quality improvement measures. In this study, the model was improved by considering the characteristics of flux rates that change spatiotemporally based on environmental conditions and factors influencing the benthic layer. An exponential relational expression was generated and applied to the model while considering the aerobic, anaerobic, and influencing factors. Results from four important sites in the Saemangeum Reservoir were compared with the RSR, %Difference, and AME results of the previous model for evaluating the reproducibility of the improved model. Calibration and verification of the model were performed in 2013 and 2016, respectively. The improved model yielded values close to the optimal value after computing the evaluation functions of both models. It had excellent reproducibility and simulated water quality by reflecting a reasonable value for the benthic flux rate. The improved model can be extended to evaluate other water bodies in the future.