Dams and fish
This is a photo of the river Lee dam. Work had begun on the River Lee at Inniscarra in Co. Cork, as a forerunner to a policy by the ESB to step up rural electrification in Ireland. Harnessing water power in the River Lee was in the plans of the ESB since the completion of the Shannon Scheme in 1927. Work started on the Lee Hydro Electric Scheme in 1952. The dam is owned and operated by the Electricity Supply Board (ESB Group).
Aquatic organisms, including fish such as salmon and river herring, depend on steady flows to guide them. Dams change the character of rivers, creating slow-moving, warm water pools that are ideal for predators of salmon. Low water velocities in large reservoirs also can delay salmon migration and expose fish to high water temperatures and disease. Many things have been done to reduce the impacts of dams on fish. Stagnant reservoir pools disorient migrating fish and can significantly increase the duration of their migration.