NUMERICAL ANALYSIS OF RIVER WATER QUALITY

摘要

With the increase in water consumption to satisfy the different demands, the quantities of waste waters to be disposed are increasing rapidly. The continued release of the waste waters has had serious impact on the water quality of the river. In this paper major types of pollutants and their sources are presented. All water quality investigations have to start with measurements, but afterwards models become important tools for abstracting more information from these measurements. At present, with increasing environmental controls, important river water quality projects can not any more be conducted without proper modeling of quality. In this research, the water quality (WQ) module in MIKE 11 is applied to one catchment in Belgium. Concentrations of dissolved oxygen (DO), biochemical oxygen demand (BOD), ammonium-nitrogen (NH_4-N) and nitrate-nitrogen (NO_3-N) are modeled in MIKE11 by taking into consideration advection, dispersion and the most important biological, chemical and physical processes. Model calibration was done on the basis of available measured water quality data. Continuous simulation over a period of 8 years is used to create CDF-curves (Concentration-Duration-Frequency) to gain an insight in the duration and the frequency of the occurrence of events with inadmissible concentrations of the modeled parameters. Moreover, comparisons with both Flemish and British standards are presented in this paper.