Presenting a review of the state of water quality prediction models currently available to the practitioner, this book provides a broad-based understanding of the water quality prediction process and evaluates the merits and cost effectiveness in using water quality models under field conditions. This book builds on and revises the chapter on water quality modelling from the World Bank's Pollution Prevention and Abatement Handbook 1998. Surface water quality is a key to life, yet in many developing countries municipal and industrial pollution continues to pervade sources due to competing demands on scarce resources. Elementary environmental controls are being applied, but the optimal allocation of limited financial resources requires sophisticated analytical approaches. This volume provides an introduction to analytical tools, specifically water quality modelling, used in determining the quality of surface waters.