The paper takes up the physical features having deciding influence on design and construction of hydroelectric plants. It describes the mountain system of the region, the precipitation, the runoff, the streams suitable for power development, and the major characteristics of the development; then takes up a little more in detail the structural features, such as reservoirs and diversion dams, the conduit system, surge tanks and forebays, pressure pipes, power houses and equipment. The choice of impulse and reaction turbines is discussed and some performance curves given; this followed by conditions imposed upon modern plants by the transmission line; switch gear is briefly discussed, followed by a resume on transmission lines and their control. Finally, some results which have been obtained are related, and the paper ends up with the hope that hydroelectric developments and distribution will continue as in the past, rather than have it undertaken by competing municipalities, which by ambitious advertising of cheap power (tax free) would endeavor to attract industries and people to their crowded areas. It is felt that the hydroelectric power industry on the Pacific Coast has distributed the benefits of cheap electricity to the small and large community alike, tending to more stable development of the entire region.