The Lower Snake River Dams
How they impact salmon, and why removing them can move our region forward
Idaho’s rivers are home to the one of the most endangered salmon run in the world, as well as the best available salmon spawning habitat in the continental US. While our work also includes advocating for and protecting Idaho’s western cutthroat trout, lampreys, and bull trout, the unprecedented crises that Idaho-born salmon are facing has been at the forefront of our work for three decades. Since time immemorial, our salmon have been an ecological, economic, sociological, and cultural cornerstone for our region, and IRU has been the leading conservation organization in the campaign to ensure their recovery.
The organizational goals for our salmon and steelhead recovery program are removal of the Lower Snake River dams (LSRD), as well as max spill at the main-stem Columbia dams, to help migrating salmon and steelhead recovery. Science has shown this is the most important component of recovery of these species. Decades of the best available fisheries science has demonstrated that the four LSRD have created a lethal mix of river conditions for migrating salmon, drastically reducing the number of migrating fish that survive the 1,500 mile journey from Idaho’s mountain streams to the ocean, and causing tremendous losses of adult salmon returning to Idaho to spawn.
Removal of these dams is imperative to avoid the extinction of Idaho salmon, and one of the most direct avenues to breaching the LSRD is through federal action. The next two years will prove to be the most important in the history of this campaign, as we finally have Congressional and Administration engagement on these efforts, including removal of the LSRDs.
Of the 400 dams in the Columbia River Basin, none are more controversial than the Lower Four Snake River Dams (LSDRs). Despite comprising merely 1% of the river basin’s dams, they have been the source of decades of legal battles, cultural conflicts, and research. When discussed in the media, the benefits and role of the Columbia-Snake Hydrosystem is often referenced, encompassing both the mainstem Columbia River Dams and the Lower Snake River Dams. However, these dams need to be evaluated separately to truly understand the issues, costs, and benefits. When it comes to impact on salmon, energy production, uses, benefits, and costs, it becomes clear that the dams on the mainstem Columbia and the Lower Snake River are two separate systems.
We work closely with both the statewide Idaho Salmon Partnership, as well as regionally, as President of the Save our Wild Salmon Coalition. Key partners for this program include: Idaho Conservation League, Idaho Wildlife Federation, Advocates for the West, Save our Wild Salmon, and Trout Unlimited, among others. Key Tribal partners include the Nez-Perce Tribe, Shoshone-Bannock Tribes, the Columbia River Intertribal Fish Committee, and the Upper Snake River Tribes (and Foundation).
What do dams in Washington have to do with Idaho’s salmon?
Image created & published in The Oregonian (David Badders)
Salmon are an anadromous fish species, meaning that they spend part of their life cycle in freshwater, and part of their life cycle in saltwater. Salmon born in Idaho will spend the first few years of their lives maturing in high mountain, alpine streams, and later migrate to the ocean, only to return to Idaho to spawn.
When juvenile salmon grow to about four inches in length, they begin their migration. Their migration is a 1,800-mile downstream journey to the Pacific Ocean, beginning in the Salmon River, which feeds into the Snake River, which flows into the Columbia River. Salmon swim downstream tail first, carried by the current to the delta where the river meets the ocean. Along the way, they utilize scent markers to ‘imprint,’ allowing them to navigate home, when they’re ready to spawn. Prior to the dams built on the Columbia and Lower Snake Rivers, this journey would only take a few days. Now, it takes upwards of two weeks.
After spending a few years in the ocean – some swimming as far as the tip of Alaska in the Bering Sea and out to the coast of Japan and Russia – salmon begin their journey back home to spawn. Salmon return to their natal stream, swimming back to their birthplace to mate, once again navigating the Columbia, Snake, and Salmon rivers. Using the current and olfactory scent imprints to navigate, they slowly work their way upstream. This journey is also significantly delayed due to the slow moving current, warm temperatures, and pollutants of the reservoirs behind the dams making navigation much more difficult.
Navigating over 1,800 miles and a mile in elevation to their spawning groups, Idaho’s salmon travel the farthest and highest in elevation of any salmon runs in the world. Despite incredible recovery efforts and having some of the most pristine salmon spawning habitats in the world, salmon numbers have continued to decline and hover on the brink of extinction. Yet, other rivers in the larger Columbia River Basin that have four or less dams, such as the Yakima and John Day Rivers, maintain higher success rates despite having significantly degraded salmon habitat. Science has shown that the key difference between these salmon runs is the number of dams they must navigate, and that navigating more than four dams negatively impacts salmon runs beyond the ability of recovery efforts to counteract.
History of the dams
Between the 1920s and the 1980s, there was an era of dam construction and hydropower generations, resulting in over 50,000 dams being constructed. In the west, the federal government worked to harness our large rivers, constructing mega-dams throughout the region for power generation, barging, and irrigation.
Construction of the federally managed mainstem Columbia River Dams began in 1934 with Bonneville and Grand Dams, which were completed in 1938 and 1941. Later, the McNary Dam and the John Day Dam were completed in 1954 and 1971.
The Lower Snake River was also slated for dam construction, with dams constructed in the 1960s to 70s: Ice Harbor Dam, Lower Monumental, Little Goose Dam, and Lower Granite Dam.
Upon construction of the Columbia River Dams, salmon numbers had already declined by nearly 50%. While this was a major hit to the population, salmon populations still continued to reproduce and return at abundant and harvestable numbers. Although reduced, the runs continued to thrive.
However, there was growing concern among biologists as to whether salmon could continue to thrive with the construction of more dams. In a report from the U.S. Fish and Wildlife Service (FWS) to the Corps of Engineers on a study initiated in 1944, the FWS said: “The lower Snake River dams present, collectively, the greatest threat to the maintenance of the Columbia River salmon population of any project heretofore constructed or authorized in the Basin. Because of this, serious doubts have been raised as to the possibility of maintaining anadromous fish populations in the Snake River watershed.”
Despite concerns of the viability of salmon, other interests prevailed. The four Lower Snake River Dams were constructed, and salmon numbers quickly declined.
How the dams impact salmon
Warm Temperatures
The dams, and their slow moving, slackwater reservoirs, increase water temperatures. These fish need cold, clear waters and habitat to survive and thrive. Additionally, dams cause the water to stay warmer for longer periods and retain heat, rather than follow the natural cooling cycles of a fast, free-flowing river.
In a free-flowing river system, when surface temperatures become high, salmon will take refuge in deeper pools and wait for cooler temperatures in between the evening and morning hours to continue their migration. The heat retention of the slack water reservoirs and elevated temperatures from dam operations disrupt this pattern. They also raise water temperatures overall, and keep the water warmer for longer periods of time during the year.
As cold water fish, salmon begin to suffer from overheating at 68 degrees (F), and become susceptible to disease, organ stress, and predation as they slow down. Prolonged exposure to temperatures exceeding 70 degrees (F) becomes lethal for salmon. According to the U.S. Environmental Protection Agency, the main source of excessively high water temperatures in the Lower Snake River is the Lower Snake River Dams.
Slowing Currents
Salmon rely on fast moving currents to navigate, pushing against the flow of water to move upstream and relying on currents to carry them downstream. Slackwater reservoirs disrupt the flow of the river and significantly slow the current, causing navigation issues for salmon. These reservoirs are several miles long, leading to a lengthy and disorienting disruption filled with invasive species.
Juveniles navigate downstream tail first, relying on the current to carry them. As they move downstream, they ‘imprint’ on currents and scents that will serve as a map that guides them home when it comes time to spawn. The stagnant reservoirs result in loss of current, meaning that juveniles can no longer use it to carry them downstream. When salmon reach reservoirs they must swim, often becoming lost as they attempt to evade predators and find the current again. This disrupts their ability to imprint, significantly prolongs their migration, and expends tremendous energy.
Adults rely on swimming against a fast current to navigate back to their natal streams. When they reach the slow moving reservoirs, migrating salmon must attempt to figure out what is ‘upstream’ without a current to guide them.
Trauma to Juveniles
Passing through the massive turbines causes tremendous stress on juveniles, as does navigation of the massive slackwater reservoirs. Roughly 10% of juveniles are lost at each dam, making the dam turbines the greatest cause of juvenile salmon death during the migration.
Many of the juvenile salmon experience delayed mortality, meaning that while they may survive passage through the turbine, trauma sustained during the passage will kill them shortly after.
What has been done to recover salmon so far?
Roughly $18 billion dollars has been spent on salmon recovery efforts since the 1990’s, and salmon populations are still far from recovery goals. Over the last three decades, restoration efforts have included:
fish passage improvements for juveniles and adults
adjusting dam spill during critical migration times
attempts to cool water temperatures
fish hatcheries
fishing season closures, both voluntary and involuntary
predator management for birds, mammals, sea lions, etc.
habitat restoration
Restoration efforts have been led by the federal government, states, and Tribes. Private landowners, recreation users, and stakeholders throughout the region have all made efforts to help recover salmon. However, despite all of the best efforts employed, science has consistently shown that the critical action for salmon recovery is removal of the Lower Snake River Dams.
What services do the Lower Snake River Dams provide?
Crop Transportation
The key benefit of the Lower Snake River Dams is crop transport. The locks on the dams allow for barges to transport crops from the inland port of Lewiston, located at the border of Washington and Idaho, down the Snake and Columbia Rivers. However, barging has declined on the Lower Snake River by over 70% in the last few decades. Instead of using the Lower Snake River, many crops are being transported by other means to downstream locations on the Columbia River. Considerable expansion of rail has allowed for this to become a cost-effective and competitive means of crop transport, with some communities developing producer owned rail co-ops. Overall, barging is incredibly expensive, but has remained competitive due to considerable government subsidies, ranging from $30,000-$50,000 per barge.
Irrigation
Some producers utilize the Ice Harbor Dam for irrigation, which currently feeds 41 surface water diversions and 84 groundwater wells. Modification to these wells is a viable, albeit expensive, option for continuing irrigation, and should be federally supported by any action taken to breach the Lower Snake River dams.
Energy Production
While the Lower Snake River Dams do produce some power, it is a mere fraction of the power produced throughout the Columbia Basin region. On average, the Lower Snake River Dams only generate roughly 4% of the energy produced throughout the Columbia Basin, and produce mostly surplus power. Our region only taps into surplus power one or two days a year; surplus power is mostly sold to California energy suppliers, and typically at a loss.
Problems with the Lower Snake River Dams
As run-of-river dams, the Lower Snake River Dams do not provide any flood control, and they do not have the ability to “ramp up” and “ramp-down” at will; their ability to produce energy is directly linked to the current flow of the river. This means that the energy production capacity of these dams is contingent upon river flow. River flow is highest in spring, when energy production needs are low. In winter and summer, when energy production needs are high, the river is at its lowest flow points, meaning the dams cannot serve as high producers of energy.
