INVESTIGATION OF THE DIFFUSION PROCESS IN RIVERINE SYSTEMS

Abstract

Many biological and chemical processes, in which environmental engineers and scientists are interested are governed by diffusion/ dispersion phenomena. A detailed knowledge of diffusion process is needed in solving problems in gaseous as well as liquid phases. An important predicator, IL, which is called as longitudinal dispersion coefficient bears the effect of diffusion (mixing due to turbulence and brownian motion) with dispersion (mixing yhhanced by velocity fluctuations across the stream) . Some of the relavent fields necess-itating use of tL have been highlighted below. Upon accidental discharge of an appreciable quantity of a lethal chemical or radioa ctive material into a river, an inmedia to forecast regarding the fate i.e. the anticipated concentration level,- and residence times downstream, if made enables the authorities and the public to take emergency measures to mitigate the damage caused. The efficiency of such forecasting models depends on how the mixing and dilution processes are simulated. Aquatic lives are sensitive to temperature changes. The anpli-cation of TL, could be made in the prediction of water temperature variation downstream of the source of thermal discharges, such as from steam or nuclear power plants using water for cooling, The use of 1l., can al so be made to know the variation of reaeration rites of 1 rivers,