This book is for the benefit of readers in the fields of Environment, Thermofluid, Modelling and Simulation Do you know how important the water cooling system for large complexes? The cooling water after used it is discharged back into the lake or river, but what is going happen to it? And how it is dispersed? In this book you will find the answer for the above questions and many more. It is clearly showing the size and the mixing zone of the discharged heated water under the free surface of the receiving water. The mathematical process of deriving the equations that are predicting the size of the plume are discussed and presented. The applications of the derived model were applied in laboratory and on the real canal site with a detailed procedure of experimental set up and data collection.