Impacts of Hydropower Development on Downstream Fish Passage

摘要

Hydroelectric dams can have a significant impact on anadeomous species (e.g., Atlantic salmon and American shad) that spend most of their adult life in the ocean but return to freshwater to spawn. Mortality can result from turbine passage and delays in downstream migration caused by flow regulation. Minimization and compensation are two general approaches that can be employeed to reduce the adverse impacts of hydroelectric dams on downstream migrants. Mortality resulting from turbine passage can be minimized by (1) installation of intake diversion and bypass systems, (2) collection and transportation of downstream migrants around dams, and (3) controlled spills. Restoration of degraded spawning/nursery habitat, on the other hand, can be employed to compensate for losses in natural production reulting from the construction of new dams or the operation of existing hydroelectric dams. Close cooperation between developers and regulators of hydropower projects will be required to ensure the protection of anadromous fish stocks in regions such as the Northeast where hydropower resources are abundant. (ERA citation 08:040474)