Efforts to reduce the impacts of hydroelectric power production on reservoir fisheries in the United States

Abstract

Research into the environmental effects of hydroelectric power production in the United States has focused increasingly on resident and migratory fish populations. Hydropower dams and reservoirs can block fish movements in both upstream and downstream directions. These movements are essential for important stocks of anadromous and catadromous fish. In addition, some strictly freshwater fish may move long distances within a river during their life cycle.A dam can pose an impassable barrier for fish trying to move upstream unless mitigation measures in the form of ladders or lifts are provided. Fish moving downstream to the sea may become disoriented when they encounter static water within a reservoir. Both resident and migratory fish may be injured or killed by passing through the turbine or over the spillway. In the United States, a variety of organizations conduct applied research and development of measures to (1) enhance fish passage, (2) reduce the numbers of fish that are drawn into the turbine intakes, and (3) reduce the injury and mortality rates of fish that pass through the turbines. Examples of these efforts from a variety of river systems and hydroelectric power plants are described