Removing Dams on Rivers to Ensure Climate Resilience for Salmon, with Regina Chichizola

The Benefits of Restoring Aquatic Ecosystems For over a century, native salmon populations in California have been adversely impacted by human activities such as mining, dam building, and overfishing practices, often leading to the loss of critical habitat and  decreased genetic diversity. With additional environmental stress from climate change, such as rising surface temperatures and changes in freshwater temperature and flow, salmon populations have been quickly declining. In addition, dams trap salmon into the warmest parts of the watershed, where they are more vulnerable to predators and have decreased breeding area necessary for their survival. Salmon are an incredibly important marine species, often referred to as a keystone species, as they play an essential role in the health and function of an ecosystem. Not only are salmon ecologically beneficial through their ability to disperse nutrients throughout streams and rivers, but they are also culturally significant to Indigenous people. Indigenous culture has historic ties to salmon, including reliance on the species for sustenance and livelihood. As a result, indigenous tribes have a particular attachment to and concern for salmon, and issues such as diminished water quality and the burdens brought about by climate change have a deep resonance. In order to restore salmon populations, Indigenous groups and environmental activists have advocated for increased restoration of watersheds, the reopening and improving of ecologically important areas, and the removal of dams that block natural salmon spawning habitats.   Dam Removal as Solution to Climate Change As climate change reduces water flows in California and increases temperatures beyond which salmon can tolerate, certain populations of salmon have become endangered species. Drastically reduced population levels have brought about a wave of concern, as their absence can disrupt nutrient cycling, reduce food availability, and negatively impact the livelihoods of people who depend on salmon for sustenance, income and cultural value. The “California Salmon Strategy” outlines actions for state agencies to stabilize and promote recovery of salmon populations. The plan envisions coordination among multiple state agencies, Tribal Nations, and federal agencies for implementation.  In the late 19th century, treaties between Pacific Northwest tribes and federal agencies gave tribes the right to hunt, gather, and fish in “accustomed grounds” in exchange for land. However, by the mid-20th century, these agreements had largely been abandoned by the federal government, with states outlawing traditional methods of subsistence fishing. Coupled with increased development and resultant large-scale habitat loss, salmon populations have been on a steady decline. Tribal governments have long opposed the construction of dams in California, raising concerns of the devastating effects such construction has had on their way of life and the biodiversity of river ecosystems. Therefore, one solution has been the removal of dams to allow for continual, unobstructed streams of water for salmon to move freely through. Large dams built in the early 1900s block salmon’s access to over 90% of historical spawning and rearing habitat in mountainous streams. The largest river restoration project is currently taking place on the Klamath River, located in Southern Oregon and Northern California, where dam removal is predicted to improve water quality and restore access to more than 420 miles of habitat. The lack of access to these cold waters for spawning was one of the primary reasons for the steady decline of California’s salmon population. Studies project that the removal of the Klamath Dam will reduce the river’s temperature by 2-4 degrees, which salmon prefer as cold water holds more oxygen, allowing for improved metabolism and the preservation of salmon quality, spurring new population growth. In addition to dam removal, the California Salmon Strategy proposes expanding habitat for spawning and protecting water flow and quality in key rivers. By fostering collaborative efforts, the State of California and Tribal Nations hope to successfully restore salmon spawning habitats and reintroduce salmon through traditional ecological knowledge. Benefits of Salmon Restoration Salmon restoration will help restore genetic diversity, improve habitat, and foster resilience. Beyond ecological benefits, restoring salmon habitats will benefit local communities and restore their cultural significance. The removal of dams like that on the Klamath River has already been a huge success in reopening former habitat that historically supported diverse salmon populations, with significant salmon spawning showing signs of a rejuvenation of this endangered species.  Challenges of Restoring Salmon  Unfortunately, salmon will continue to face the threat of climate change, particularly due to the lack of cold, readily available water. Salmon’s migratory lifestyle patterns are also under threat from climate change, as a lack of cold water prevents survival at different stages of the life cycle in order to reach their spawning habitats in time. One major concern of the dam removal process is the short-term increase in turbidity and water quality problems during the removal process. There also could be the potential for disrupted habitats and short-term fish mortality due to the changing water quality dynamics. However, water quality problems usually pass after the initial slug of sediment moves downstream, allowing for long-term benefits to take hold. About our guest Regina Chichizola, Executive Director of Save California Salmon is a long-term advocate for tribal water rights, clean water, wild salmon, and environmental justice. Chichizola is an advocate for the restoration of salmon populations through strategies like dam removal and wetland restoration. ResourcesCalifornia Trout: Klamath Dams RemovalUS Fish and Wildlife Service: Why are dams getting removed and how will this change our rivers?USGS: Simulating Water Temperature of the Klamath River under Dam Removal and Climate Change ScenariosFurther ReadingAmerican Rivers: The Ecology of Dam Removal: A Summary of Benefits and ImpactsCalifornia Salmon Strategy for a Hotter, Drier Future: Restoring Aquatic Ecosystems in the Age of Climate ChangeKatherine Abbott et al: Incorporating climate change into restoration decisions: perspectives from dam removal practitionersNOAA Fisheries: River Temperatures and Survival of Endangered California Winter-Run Chinook Salmon in the 2021 DroughtScientific American: Climate Change Complicates the Whole Dam DebateUSGS: Shifting Practices of Dam Management and Dam Removal in a Changing World For a transcript, please visit https://climatebreak.org/removing-dams-on-rivers-to-ensure-climate-resilience-for-salmon-with-regina-chichizola