The book provides a comprehensive account of an important sector of engineering—the hydro-power—that is renewable and potentially sustainable. It covers the entire scope of the subject in a lucid manner starting from the fundamentals of hydrology, to various hydraulic and civil structures to electrical and mechanical equipment as required for hydro-power projects. Many new issues and challenges voiced in the energy sector in general and water power in particular during the last decade have been addressed in the book. Recent innovations and developments in some areas like wave power, and new technologies in hydraulic structures, like the P-K weirs, fuse gates, stepped spillways, CFRD, RCC, etc., find place suitably in the book. The book is meant for undergraduate and postgraduate students of civil and electrical engineering and for the professionals interested in the subject.