Final Step in Klamath River Dam Removal Opens Path for Returning Salmon

The removal of four large dams from the Klamath River allows salmon to again reach about 400 miles of their original habitat that had been blocked for many decades. Photo: Jason Hartwick/Swiftwater Films

NOAA Fisheries led coordination efforts to protect water quality.

Heavy equipment removed the final obstacle separating the Klamath River from the Pacific Ocean on Oct. 1. The reconnected river was turbid but remained safe for fish after crews took steps to avoid erosion and impacts to water quality.

“These final dam removal steps set the stage for salmon to return to reclaimed habitat and expand their population recovery,” NOAA Fisheries West Coast Region Klamath Branch Supervisor Jim Simondet said.

NOAA Fisheries analyzed the impacts of dam removal on Endangered Species Act-listed species in a biological opinion. That analysis found that short-term impacts, such as the potential effects of sediment in the water on salmon, would be outweighed by much greater long-term benefits as river ecosystem processes return at a landscape scale.

The project looks to reopen more than 400 miles of habitat to salmon, steelhead and lamprey.

The final step in removing the Klamath dams involved dismantling a final cofferdam (a temporary watertight enclosure within the body of water) that temporarily diverted the river to allow for deconstruction.

In advance of that step, NOAA Fisheries convened a group called the Fisheries Coordination Team to discuss how to best protect fish and water quality. It included experts from tribes, states and other federal agencies.

The team provided technical recommendations to manage water quality impacts, such as those observed earlier in the year when the reservoirs were initially drained. Crews used a strategy of releasing sediment and organic material that muddied the river but avoided a decline in dissolved oxygen that could have otherwise harmed fish.

The Coordination Team developed recommendations for the Klamath River Renewal Corporation, which is responsible for completing the dam removal project. The team advised the Renewal Corporation to consider using methods that would release the material in a controlled way prior to the complete removal of the cofferdam.

“The network of water quality monitoring sites managed by the tribes are providing real-time data to the Fisheries Coordination Team, allowing them to manage sediment inputs and adaptively manage fisheries needs during the final removal process,” Toz Soto, Fisheries Program Manager for the Karuk Tribe, explained.

The Renewal Corporation followed the recommendation to remove sediment and organic material from behind the cofferdam before the dam was fully removed. That resulted in a slower release of the material. The Fisheries Coordination Team plans to hold weekly check-ins to track extensive water quality monitoring up and down the river.

“Our goal was to provide a forum that allowed for transparent sharing of information, collection of observations and recommendations from experts who live and work on the river,” said Shari Witmore, a fisheries biologist in the Klamath Branch of NOAA Fisheries West Coast Region.

“Leaning on the advice of our partners, we were able to minimize impacts to fish in the Klamath River during the final step of dam removal,” she added.

“Given all the complexities and details necessary to remove the four dams, the work has gone pretty smoothly and commensurate with our expectations,” Simondet said. “That is a testament to the hard work and expertise of the KRRC and its contractors and the planning we all contributed to ahead of time to get this right.”