In Spite of great importance and interest in limnological modeling which is an emerging field, today very little literature is available regarding this subject, and the need for such books has been keenly felt both by students and teachers. This book limnological modeling is meant to fulfill such a need. It will interest those who are involved with, and those who have a concern for, the control of limnological pollutions. This book consists of six chapters including a newly developed model to predict DO-BOD interaction. This model is a generalized one and can be used throughout the world in any river system. This book will help students, teachers, limnologists, researchers, academicians etc. in understanding the mathematical models.