Determination of Dispersion Parameters in Otamiri River, Owerri

Abstract

The dispersion pattern of Otamiri River was studied by means of a tracer-dye. Measured tracerresponse curves produced from the injection of 1kg of soluble Sulphur-Black (BR) dye was used to obtain the data for this study. The dispersion and mixing of the tracer took place in three dimensions of the river. Vertical mixing was rapidly completed within a distance of 50m from the initial point of tracer injection; lateral mixing was completed within a distance of 400m, while longitudinal dispersion continued downstream beyond 450m. The longitudinal dispersion coefficient as a fundamental parameter in hydraulic modeling of river pollution was determined with the statistical moment equation as 38m²/s. It was noted that longitudinal dispersion coefficient values are affected by the river flow velocity, hydraulic depth and cross-sectional width of the river.