Evaluation of Methods for Determination of Dispersion Coefficient for Utu Etim-Ekpo River, Nigeria

Abstract

This study was conducted to evaluate methods for the determination of the longitudinal dispersion coefficient of Utu Etim-Ekpo River. Rihodamine-B was used in the tracer dye study. The variable distance – variable time method of sample collection was adopted. The samples collected were immediately transferred to the laboratory for analysis. Three approaches were adopted for the computation of dispersion coefficient with respect to this study, namely: Leverspiel & Smith method; Agunwamba’s method; and Ojiako’s method, respectively. The first two methods are analytical while the third is numerical. The dispersion coefficients obtained were 16.24, 19.679 and 14.68 m2/s with respect to Leverspiel & Smith method, Agunwamba’s method and Ojiako’s method, respectively. Agunwamba gave a higher value than the other methods due to the fact that the model is best suited for when tracer experiments are done using variable distance – variable time method which was not the case in Utu Etim-Ekpo tracer dye study.