A numerical mixing zone model for water quality assessment in natural streams: Conceptual development

A mixing zone is an area of a water body contiguous to wastewater disposal site in which the water quality does not comply with the water quality standards. The zone has been considered as one of the water quality characteristics for the protection of indigenous aquatic biota and regulated by the in-zone quality and the volumetric configuration. This paper presents the conceptual development of a numerical model which can predict the in-zone quality and volumetric configuration in natural streams. The model is based on the transformed advection-dispersion equation where transverse distance is replaced by dimensionless cumulative discharge.