The coexistence of development and the environment is achieved by technical and economic approaches. The technical approach takes into account such factors as air pollution measures, conserving energy, and recycling resources, while the economic approach is the costs of environmental disruption and providing safeguards such as wildlife conservation and management plans. The economic development of Japan in the 1950s required substantial electric power. As a result, environmental and industrial pollution increased. The economy of Japan reached a new high in the 1960s, and the generation of electric power was overtaken by thermal power; which in turn was superseded by natural gas and atomic power following the energy crisis of the 1970s. The Japanese economy was depressed during the 1990s, but has recently showed signs of a gradual recovery. Accordingly, the demand for electric power has increased over recent years. The energy sources that will replace oil in the future are atomic power, natural gas, and wind power. Hydropower stations discharge only minor carbon dioxide, and are therefore better for the environment than atomic and natural gas power stations. The environmental cost of the development of hydropower stations is discussed in this paper.