Work has begun on the largest hydroelectric dam removal project in U.S. history, with construction crews upgrading access roads for heavy equipment to reach the four Lower Klamath Project dams on the Klamath River in southern Oregon and northern California.
“The Federal Energy Regulatory Commission approved this project — the largest dam removal in American history — in November 2022, a project valued at $450 million,” according to Construction Equipment Guide.com.
That cost figure may be inflated. Oregon Public Broadcasting reported last fall when FERC approved the dam removal, “PacifiCorp spokesman Bob Gravely said removing the dams at a cost of $215 million to the utility’s ratepayers was actually the cheaper option, and the electricity they generate is easily replaced — it’s less than 2% of the utility’s supply.”
Existing bridges require reinforcement and new bridges must be built to handle the heavy equipment. Job trailers, offices, and housing for workers are also under construction. The preliminary work is expected to consume the rest of this year, with destruction of the four dams set to start in 2024.
The dam removal is the culmination of some 20 years of regulatory wrangling, which began early this century with the expiration of the FERC license for the project. The license expired in 2006 and the project has operated under an annual license since. In 2004, PacifiCorp, in a relicense request, proposed to trap fish downstream of the dams and transport them to above the dams. FERC rejected that plan, telling the utility it would have to install fish ladders at each of the dams to get the license renewed, which the company rejected as too expensive. That led to predictable regulatory, litigatory, and legislative back-and-forth until a settlement agreement in 2020 that FERC approved last fall to take down the dams.
According to the American Society of Civil Engineers, the four dams have a collective generating capacity of 163 MW. “Draining a watershed of nearly 16,000 sq mi, the Klamath is California’s second-largest river in terms of average discharge and provides critical habitat for anadromous fish species, which migrate from freshwater rivers to the ocean and back.” The dams have closed sections of the river to salmon and steelhead trout for up to a century.
The four dams are approximately 190 to 225 river miles upstream of where the Klamath River meets the Pacific Ocean. They are:
- J.C. Boyle, located farthest upstream, 68 feet tall, 693 feet long, a combination embankment and concrete structure completed in Oregon in 1958. It has the capacity to impound 3,495 acre feet of water.
- Copco No. 1, the next-farthest upstream facility, 126 feet tall, 415 feet long, a concrete gravity arch dam completed in California in 1918. It has the capacity to impound 46,900 acre feet of water.
- Copco No. 2, approximately a quarter-mile downstream of Copco No. 1, the smallest of the four dams, 33 feet high, 278 feet long, a concrete gravity dam completed in California in 1925. It has the capacity to impound 73 acre feet of water.
- Iron Gate, 8 miles downstream from Copco No. 2, 173 feet high, 740 feet long, an earthfill structure located 8 mi downstream, completed in California in 1962. It has the capacity to impound 58,800 acre feet of water.
Deconstruction work will start with Copco No. 2, followed by J.C. Boyle, Copco No. 1, and Iron Gate, in that order. Omaha-based Kiewit is the prime contractor on the Klamath dam removal.
The work around the dams will not end once they are gone, as Oregon Public Radio has noted. Habitat restoration will follow, led by Virginia-based Resource Environmental Solutions, which bills itself as “the nation’s largest ecological restoration company.” The radio account said, “The revegetation of the Klamath River has been called the largest river restoration project in American history. Collecting, propagating, and growing enough seeds and plants to populate the reservoir footprints — approximately 2,200 acres in all — is a staggering task. RES launched the effort in 2019, recruiting and training crews from area tribes to collect seed and prepare the ground, and partnering with commercial nurseries to propagate plants and seeds.”
–Kennedy Maize
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