The release of waste materials from chemical plants or industries into river or atmosphere is a common phenomena. To control the contamination in a stream, or in atmosphere or coastal regions and to predict the levels of accidental pollution, the studies concerning the longitudinal dispersion of dissolved and suspended particles in natural flow is highly important. This book is written for the researchers and post graduate students who are working in the field of turbulent open channel flow. A clear view on turbulent flow is given in the first chapter of the book. Three research problems have been carefully chosen to understand the basic mechanism of the dispersion of suspended/settling particles due to convection and eddy diffusion.