Synopsis South Asia is associated with many types of natural hazards and over the years, some form of disasters have been taking place in one region or the other such as floods, drought, earthquakes, land slides and cyclones; with the exception of absence of frequent volcanic activities, practically all other forms of natural disasters have been visiting this region with regular frequency. It is hence but natural to focus attention on these aspects by researchers in these countries to problems being faced by the densely populated communities. This book brings into focus several case studies by experienced workers representing academic institutions, governmental and non-governmental agencies and active group of researchers. Special attention has also been given to understand the arsenic problem being faced by nearly 100 million people in the Bengal delta region with respect to transport processes from source to sink and controlling factors in its pathways through the vast alluvial basins.