Climate change and its potential impacts are well documented in many literatures. Very little academic studies exists that systematically analyses how communities are vulnerable to change, what are their coping measures and, are these measures adequate enough in long run as an adaptation to the change. Thus, this book is about current assessments of climate variability, water diversion and their cumulative effect on adaptation of local people living downstream area in a watershed of Nepal. Derived from the "participatory vulnerability assessment approach" Smit and Wandel, the system approach was adopted in order to combine results after hydro meteorological parameters analysis with the results from qualitative enquiry to understand local people''s exposure to climate variability and risk of reduced downstream flow due to diversion of River water in the Melamchi- a mountain watershed of Nepal. This study is useful for development organizations, professionals, and individuals who are working in the field of climate change adaptation, particularly in water sector.