Indian Journal of Science and Technology

Abstract

Over the past few decades, river water quality has been a critical issue in many parts of the world due to various domestic, industrial and agricultural pollutants. The challenge lies in developing mechanisms and tools, that will assist us to mitigate, prevent or possibly reverse deteriorating river water quality. Water quality models are the most useful tools in describing river ecological conditions, assessing effects of water pollution and assisting decision makers for water quality management. They can be used to predict the changes of the water quality parameters and also contribute in reducing the cost of labor and time needed to conduct field studies or experiments to some degree. As the Hybrid Cells in Series model a conceptual mixing cells based water quality model that has an advantage over the Fickian based advection dispersion equation model, this paper aimed to assess pollutant transport characteristics of Umhlangane River north of Durban using the proposed model. A main advantage with this model is that it deals with first order ordinary differential equation and which can accommodate any reaction kinetics without any complexity in model equation unlike the Fickian model. Thus this paper derives a new model component and investigates its ability to simulate decaying pollutant decay and dissolved oxygen concentration under predefined condition. The proposed model in this study yielded positive outcome at the lower reach of Umhlangane River with an average agreement between simulation results and the observed data. The work is concluded by rendering a future potential scope of the proposed model to incorporate nutrient dynamics and non-point source pollution.

Keywords: Biochemical Oxygen Demand, Chemical Oxygen Demand, Dissolved Oxygen, Peclet Number, Umhlangane River, WQ Model