Dispersion Prediction in the Uppanar River of South East Coast of India

P. Mullai, Bibin Oommen, M. K. Yogeswari



This paper presents the estimation of dispersion coefficient in a small segment of a natural river. The dispersion coefficient is a fundamental parameter in hydraulic modelling of river pollution and important to evaluate the characteristics of pollutants behaviour in a natural river. Based on the measured data of dissolved oxygen (DO), nitrate – nitrogen and reactive silica, the dispersion coefficient was determined along the three sampling stations I, II and III in the Uppanar River (11° 42’ 34”N 79° 46’ 88”E), Cuddalore district, Tamil Nadu, India. The calculated values of dispersion number (D/uL) along station I, station II and station III obtained for DO were 0.122, 0.136 and 0.152, for nitrate-nitrogen, 0.142, 0.136, and 0.163 and for reactive silica 0.114, 0.129 and 0.116, respectively. It was pragmatic that all the three sampling stations were having dispersion numbers less than 0.2. The experimental data obtained were modelled by adopting a dispersion model. The statistical quality of the dispersion modelling was high (R2 = 0.9992, 1.0 and 0.9983 for stations I, II and III respectively, between experimental and theoretical DO values). Furthermore, it was also observed that there was a one to one correlation among the theoretical and observed values. The results could show the superiority of the proposed model.


Keywords: Dispersion model; dispersion number; Uppanar River