Workers are breaching Klamath dams, which will let salmon swim freely for first time in a century / Thousands of US dams may be unprepared for extreme rain / US admits dams in Pacific north-west have devastated Native Americans / US acknowledges harm to tribes from Pacific Northwest dams / US government, for the 1st time, details how Northwest dams devastated the region's Native tribes / US acknowledges Northwest dams have devastated the region's Native tribes / Insights into water flow and fish passage through dams offer options for meeting energy, environmental needs / Dams being removed from California river, hoping to restore salmon population