Four Things To Know About the Impacts of Dam Removal on the Klamath River — (2024)

The world’s largest dam removal on the Klamath River continues to push forward, with one dam completely removed, and the remaining three in progress. During the removal process, sediment impounded in the dam’s reservoirs will keep moving downstream. What do these processes mean for fish and wildlife in the river and the communities who depend on the Klamath?

To make things easy, we put together four key things you need to know about the impacts of dam removal on the Klamath River.

1. Muddier in the short-term, healthier in the long-term 

Since the drawdown behind three remaining Klamath dams began in January, the river has been looking muddy, and residents of the Klamath watershed are understandably concerned. Sediment is a natural part of river systems. Healthy rivers move sediment downstream and out to the ocean as part of their regular flows. Sediment has built up behind these dams since they were built, starting in the beginning of the 20^th century. The Klamath dams impounded millions of tons of sediment over nearly 100 years. Before a single dam was breached, multiple scientific studies were conducted to predict how their stored sediment could affect the river. To minimize the harm to the river, including state and federally protected species, and harness the power of the river to mobilize the stored sediment, dam breaching, and the subsequent sediment release was scheduled for the winter months. Now that the three remaining dams have been breached, a century’s worth of sediment is flowing downstream and will temporarily affect the river’s water quality. The worst water quality conditions have likely passed as the initial slug of sediment has been flushed downstream. Water quality is seeing steady improvements; as the river begins to heal the removal of the dams will improve water quality, from nutrients to dissolved oxygen and stream temperature, and reduce the likelihood of toxic algae blooms, creating healthier habitat for salmon, other fish and wildlife, and people.

2. Is the Klamath safe to drink and play in?  

No one should ever drink untreated surface water. This is true on major waterways across the U.S., including the Klamath River. Since there are no drinking water sources that draw directly from the Klamath River, and groundwater wells will be unaffected by sediment from the dam removals, the dam removals are not impacting the availability of clean drinking water. While the turbid river may look unappealing, recreating in the Klamath is also possible. According to the California Water Quality Board, data collected by Siskiyou County and the Klamath River Renewal Corporation indicate it is “unlikely that recreational activities in the Klamath will lead to adverse health effects from dam removal related sediment in the water.”  

3. Are fish dying because of the dam removals? 

Yes: while reports and images of dead fish following dam breaches are unfortunate, this outcome was expected. Fish stranded in the drained reservoir were invasive non-natives, including bluegill, yellow perch, and small- and largemouth bass.  

Reports of a fishkill of juvenile salmon are related to the California Department of Fish and Wildlife’s release of non-listed fall-run Chinook salmon. These fish were released from the new hatchery facility upstream of the Iron Gate Dam because the hatchery had already exceeded its quota for producing these fish for the year, and the hatchery conditions were becoming too crowded. Although the loss of these fish is unfortunate, it will not affect the hatchery’s ability to reach its production goals. Mortality was caused when juvenile fish swam through part of the Iron Gate Dam facility that resulted in a gas-bubble disease, similar to the “bends” that scuba divers can experience.

CDFW will release all hatchery fish below Iron Gate Dam until the facility is removed. This past week, CDFW successfully released about 90,000 coho salmon, a threatened species, as well as more than 400,000 fall-run Chinook salmon that were raised in the Fall Creek Fish Hatchery. The problem associated with the Iron Gate Dam tunnel is temporary, as is the dam itself; following the dam’s removal, future hatchery releases will not need to take this into consideration. The good news is that we’re seeing healthy fish in downstream monitoring programs from partner agencies, the U.S. Fish and Wildlife Service, and the Karuk Tribe. 

4. What is the timeline for recovery? 

Other dam removal examples indicate that healing on the Klamath will take time… but not as much as you might think. When the Condit Dam on the White Salmon River was removed, 60% of the sediment was eroded through natural processes within 15 weeks, and native fish were found above the former dam locations within a year of the removal. When Bloede Dam was removed in 2018, 50% of the sediment eroded away within 6 months of removal, with native fish populations making a similar rebound. These case studies show us the immense ecological value of dam removal, in addition to providing some context around what’s happening on the Klamath River. However, since the scale of the Klamath River dam removal is unprecedented, it’s difficult to predict exactly when the negative short-term effects will subside. What is certain is that dam removal is the first vital step to restoring the Klamath River and will jump-start its path to recovery.