Klamath River Dam and Sediment Investigation

The State Coastal Conservancy (Conservancy) and the Ocean Protection Council (OPC), two agencies of the State of California, initiated this study to characterize sediment behind four dams of the Klamath River Hydroelectric Project on the Klamath River, and examine the possibility of dam removal. This study investigates removal of the four most downstream dams: Iron Gate, Copco 2, Copco 1 and J.C. Boyle.

The Klamath River is located in northern California and southern Oregon on the Pacific coast of the United States. The Klamath River Hydroelectric Project, owned by PacifiCorp, consists of six generating developments along the mainstem of the Upper Klamath River. The project also includes a re-regulation dam with no generation facilities, and one generating development on Fall Creek, a tributary to the Klamath River. The Klamath River Project is now undergoing relicensing proceedings before the Federal Energy Regulatory Commission (FERC). Separate from the formal FERC relicensing process, a Settlement Group has explored future project management alternatives, and its Dam Removal Subgroup has investigated dam removal as a project management alternative.

Previous dam removal studies have suggested that downstream erosion of sediment to the marine environment would be a feasible approach to dam removal and sediment management, but this conclusion was limited by the lack of information characterizing sediment quantity, quality, and management options. Therefore, the Subgroup asked the Conservancy to conduct a detailed reservoir sediment study and dam removal investigation. The Conservancy entered into contracts with Gathard Engineering Consulting (GEC) and Shannon and Wilson, Inc., (S&W) to characterize sediment located behind the four lowermost dams, and to conduct preliminary dam removal studies.