This book treats the problem of transient hydraulic computation, for hydroelectric plants and pumping stations, with an emphasis on numerical methods. The topics covered include: the waterhammer in hydraulic systems under pressure; experimental results concerning the waterhammer; protection of pumping stations with reference to the waterhammer; hydraulic resonance in hydroelectric power plant and pumping stations; mass oscillation in hydraulic surge systems; hydraulic stability of systems endowed with surge tanks; experimental results in the study of mass oscillations; hydroelectric power plants and pumping stations designed in complex hydraulic schemes; and computation of unsteady motions in the intermediate domain between rapid and slow motions. This book is not a standard monograph based on previously published material, but is primarily grounded on the theoretical and applied results obtained by authors during more than 20 years of practice. It considers the problems of hydraulic computation as encountered in the design of a significant number of hydroelectric power plants and pumping stations in Romania.