The largest river restoration project in U.S. history is underway along the Klamath River. One aging hydroelectric dam along the river’s Lower Basin was decommissioned last fall, and three more are being removed this year. The largest river restoration project in U.S. history is underway along the Klamath River. One aging hydroelectric dam along the river’s Lower Basin was decommissioned last fall, and three more are being removed this year. Environment Phys.org – latest science and technology news stories