In the past, the development of hydroelectricity predominantly involved the construction of large dams. These massive structures, comprising concrete, rock, and earth, created artificial lakes and provided reliable power supplies, irrigation, and flood control. However, the construction of such dams came at a high cost. It resulted in the flooding of extensive areas of fertile land and the displacement of numerous local inhabitants. Over time, these dams faced challenges such as rapid silting, which reduced their productivity and lifespan. Additionally, interference with natural river flows caused various environmental issues.Recognizing the significance of hydroelectric power and its potential, the book "Hydro Power" offers an overview of global energy consumption and projections for energy demand. It delves into the utilization of hydraulic resources for electricity generation and highlights advancements in the field of hydroelectric power. This book serves as a valuable source of information for researchers, academics, policymakers, and practitioners interested in renewable hydropower technologies. Moreover, it has been designed to be a supplementary textbook for students studying hydropower plants, providing them with comprehensive insights into the subject matter. As we continue to explore and develop hydroelectric power, it is essential to prioritize environmentally benign technologies that minimize disruption to natural river flows and maximize the benefits for communities worldwide.