The book is written for UG & PG students of civil and environmental engineering and earth sciences. Teachers, researchers and policy makers dealing with water will find it a useful reading material. The book introduces the subject of numerical groundwater flow and solute transport modeling followed by relevant review of literature. Chapter 3 looks to finite difference, finite element, random walk and modified method of characteristics models for groundwater flow and solute transport simulation. Chapter 4 considers validation and implementation of these models for various test cases. Chapter 5 examines the adequacy of best performed coupled model for field problem.