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Dive brief:
- Construction crews broke the last two dams on a California section of the Klamath River on Aug. 28, The Associated Press reported, allowing water to flow and bring the the largest dam removal project in US history near completion.
- The $450 million effort involves building four hydroelectric dams on the Klamath River in Oregon and California in order to restore habitat and passage for migratory fish. Omaha, Neb.-based Kiewit is the prime contractor, while South Africa-based Knight Piésold is the lead civil design partner on the project.
- The removal clears the way for salmon to swim freely through a major watershed near the California-Oregon border for the first time in more than a century and allows Chinook salmon to access key habitat just in time to in the fall spawning season, according to The Associated Press. Deconstruction work is expected to be completed this fall.
Diving knowledge:
Dam removal has gained momentum in the United States over the past 50 years, as the country increasingly recognizes its negative environmental impact and general state of disrepair.
The Jobs and Infrastructure Investment Act adds $585 million to the High-Risk Potential Dam Grant Program, more than 18 times what the federal government gave between 2019 and 2021, according to The Associated Press, with $75 million designated for dam removal. Last year, at least 18 dam removal projects used IIJA funds, according to the environmental nonprofit American Rivers, with 80 removed in total.
Many dams in the United States are aging, unsafe, no longer serving their original purpose, or in need of costly repairs, and the number of dams with high hazard potential it has more than doubled in the past 20 years, according to the American Society of Civil Engineers.
For example, the dramatic Edenville and Sanford Dam faults in 2020, which forced the evacuation of 10,000 people and caused $175 million in damage to homes downstream, also underscored the danger of aging dams. In the wake of Edenville, Michigan earmarked about $28 million in new money for the removal and repair of damsaccording to Bridge Michigan.
A broader trend
In this context, the removal of the Klamath Dam illustrates a broader trend. Kiewit demolished the smallest of the four dams, Copco no. 2, in 2023 and withdrew JC Boyle’s dam in July of this year
The contractor is now finishing removal work on the last two California dams: Iron Gate and Copco No. 1.
The Klamath River Renewal Corp. took over ownership of the dams from Pacific Power in 2021. Removing the dams won’t have a big impact on power supply, according to The Associated Press: At full capacity, they produced less than 2 percent of the power of the old utility.
Although dam removal on the Klamath River is a key step in restoration, the work is far from over. After the dams are completely out and the reservoirs have been drained, restoration contractor Resource Environmental Solutions and local tribes will plant around 19 billion native seeds to restore the health of surrounding ecosystems, including culturally significant plants such as yampah and lomatium, important pollinator species such as oak and tens of thousands of oaks.
Klamath River Renewal Corp. will work with experts to monitor the impact of dam removal on the river in the coming years. Area tribes, fishery owners and environmental groups hope salmon will return to what was once the West Coast’s third-largest salmon-producing river.
