DamA dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aquaculture, and navigability. Hydropower is often used in conjunction with dams to generate electricity. A dam can also be used to collect or store water which can be evenly distributed between locations.
Fish migrationFish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousands of kilometres. Such migrations are usually done for better feeding or to reproduce, but in other cases the reasons are unclear. Fish migrations involve movements of schools of fish on a scale and duration larger than those arising during normal daily activities.
Columbia RiverThe Columbia River (Upper Chinook: Wimahl or Wimal; Sahaptin: Nch’i-Wàna or Nchi wana; Sinixt dialect swah'netk'qhu) is the largest river in the Pacific Northwest region of North America. The river forms in the Rocky Mountains of British Columbia, Canada. It flows northwest and then south into the U.S. state of Washington, then turns west to form most of the border between Washington and the state of Oregon before emptying into the Pacific Ocean. The river is long, and its largest tributary is the Snake River.
SalmonSalmon (ˈsæmən; : salmon) is the common name for several commercially important species of euryhaline ray-finned fish from the family Salmonidae, which are native to tributaries of the North Atlantic (genus Salmo) and North Pacific (genus Oncorhynchus) basin. Other closely related fish in the same family include trout, char, grayling, whitefish, lenok and taimen. Salmon are typically anadromous: they hatch in the gravel beds of shallow fresh water streams, migrate to the ocean as adults and live like sea fish, then return to fresh water to reproduce.