text: Which Columbia river? The fact is using hydroelectricity is a wonderful resource, until you think about the fish. Salmon are migratory species which means they pass through rivers on their way to coastal feeding grounds and back to spawn. \nThis means that great big hydroelectric dams on the river stop the salmon from moving around and become trapped.\n\nBasically the fish stocks of salmon are going to be depleted from over fishing and dams soon anyway, so enjoy your fish while you got it. Its the tragedy of the commons.