Dam Design and Construction

Removal completed on Copco No. 2 dam in western U.S.

Removal completed on Copco No. 2 dam in western U.S.
(photo courtesy Shane Anderson, Swiftwater Films)

Crews have finished removal of the Copco No. 2 dam and its diversion infrastructure, on the Klamath River on the California-Oregon border.

Copco No. 2 is part of the Lower Klamath Hydropower Project, which occupies about 400 acres of federal land administered by the U.S. Department of Interior, Bureau of Land Management. The project consists of four developments: J.C. Boyle Dam, a 98 MW project with an earthfill dam built in 1958; Copco No. 1 Dam, a 20 MW project with a concrete dam built in 1918; Copco No. 2 Dam, a 27 MW project with a concrete dam built in 1925; and, Iron Gate Dam, an 18 MW project with an earthfill dam built in 1962.

Removal of the Copco No. 2 dam structure was completed in September, and crews spent the past month removing the remaining diversion infrastructure, grading the river channel and performing erosion control. This work prepares the river canyon for consistent river flows, likely commencing within 30 days. Currently, flows in the canyon are fluctuating due to work being done to prepare Copco No. 1 for drawdown.

“Copco No 2 is the first dam to be removed due to its small stature, location, and lack of reservoir,” noted Mark Bransom, chief executive officer of the Klamath River Renewal Corporation (KRRC), the entity tasked with the safe and efficient removal of the four lower Klamath hydroelectric dams. “However, while Copco No. 2 was significantly smaller than the other dams slated for removal, it still had a significant impact on the river.”

Copco No. 2 was located right below Copco No. 1 in a steep river canyon, commonly known as Ward’s Canyon. Completed in 1925, Copco No. 2 was a diversion dam that funneled the river’s flows out of the canyon and into a tunnel system that sent the water to the Copco No. 2 powerhouse, essentially dewatering the 1.7-mile-long canyon. Without the river’s presence, trees grew in the riverbed that, when exposed to consistent river flows, would have died off, creating a hazard for future recreationists. These trees were removed in September in collaboration with area tribes.

The remaining three dams — Copco No. 1, Iron Gate, and JC Boyle — are slated for removal next year. In January, KRRC will implement drawdown of the reservoirs, which is expected to take three to five months, depending on the amount of water entering the system as a result of spring runoff. Once drawdown is complete, restoration and deconstruction activities will begin. All three dams are expected to be completely removed by November 2024, while restoration activities will continue for years to come.