Hydropower is the energy derived from water that is falling or fast-running. It is a type of renewable energy. There are four types of hydropower, namely, run-of-river hydropower, storage hydropower, pumped-storage hydropower and offshore hydropower. Devices such as trompe and watermill run on hydropower. The electricity produced by hydropower is known as hydroelectricity. It can also be used to store potential energy between two reservoirs. Hydroelectric power plants, which include reservoir, are used to exploit the energy of falling water. Hydropower can be used for irrigation and operations such as carried out dock cranes, gristmills, textile mills, ore mills, etc. This book is a compilation of chapters that discuss the most vital concepts in the field of hydropower. It elucidates new techniques and their applications in a multidisciplinary approach. As this field is emerging at a rapid pace, the contents of this book will help the readers understand the modern concepts and applications of the subject.