Hydroelectric Power in The Snake River


Samantha Bruha: Animal Science

Shane Murphy: Horticulture

Jake Schick: Building Construction Technology

Ashley Artwork: Building Construction Technology

The Nez Perce people reside on the Snake River in North Central Idaho and still practice a hunter-gatherer way of life (Smith, 2018).  In 1855, The United States Government and five Native American tribes residing in Washington, Oregon, and Idaho signed the Treaty of Walla Walla (Smith, 2018)  Since the the original treaty, the Nez Perce Tribe has retained the right to fish, to hunt, and to graze livestock on unclaimed lands outside of the reservation (Smith, 2018).  Due to the addition of hydroelectric dams, beginning in the 1950’s on the Columbia and Snake Rivers, the Nez Perce Tribe has suffered a great loss of fishing resources from the effects of dams on the Salmon populations (Quirke, 2017).  Elliott Moffett, a 65 year old member of the Nez Perce Tribe, fights for Salmon in the lower Snake River (Quirke, 2017). “‘I like to say we are like the Salmon, we need clean, cold, swift running water. And they don’t have that because the dams have impounded their river,’” Moffett states (Quirke, 2017).  Moffett and his fellow activists at the Nimiipuu Protecting the Environment organization, have dedicated their lives to defending the environment and the Nez Perce rights (Support|Nimiipuu Protecting the Environment, 2018).  Every decision the tribe makes has “seven generations ahead” in mind and the scarcity of resources is making it harder and harder to teach future generations how to live off of the land (Support|Nimiipuu Protecting the Environment, 2018).


In the 1950’s the salmon population of the Columbia-Snake River reached almost 300,000 fish, as of 2017, 10,000 fish return to the Snake River in the spring and summer to spawn (Helmer, 2018).  The Northeast Power and Conservation council states we need return rates of 2-4% for the survival of the salmon population and 4-6% return rates to begin to recover these populations (NW Energy Coalition, 2018). The return-rates of the past 20 years of Snake River Salmon is between .5 and 1%. (NW Energy Coalition, 2018).  In order for the Nez Perce people to continue their fisherman culture, they have began conservation efforts of their own with nonprofits such as the Nimiipuu Protecting the Environment organization. Despite efforts, the number of fish still continues to decline (Smith, 2018). It is evident that the salmon population needs protection and cannot withstand continual life loss due to dam intervention.

The United States government, specifically the Army Corp of Engineers, owns and operates four dams on the Lower Snake River. These four dams are the Ice Harbor, Lower Monumental, Little Goose and Lower Granite, spanning from west to east respectively (Wegner, 2003).   From east to west, the Snake River flows into the larger Columbia River, which ultimately leads to the Pacific Ocean (Bonneville Power Administration, 2016). The four dams are located in the Southeast corner of Washington State with the Ice Harbor Dam closests to the Columbia River and the Lower Granite closest to the Idaho border (Bonneville Power Administration, 2016).  The Lower Granite Dam was the last dam built of the four and is located just west of the Nez Perce reservation (Smith, 2018). Dam construction of the four lower Snake River dams began between 1961 and 1975 as a means of providing clean energy, flood control, recreation, and navigation (Wegner, 2003). Each dam stands approximately 100 feet tall and 3000 feet in length (Bonneville Power Administration, 2016).  All together the four dams average about 1,200 megawatts per year and provide approximately 5% of the energy in the Pacific Northwest (Wegner, 2003). These dams, and others alike, provide a physical barrier and harm the quality of river with regard to health indicators such as flow regime, dissolved oxygen, and temperature and in doing so significantly threaten fish populations.

Dams span the entire width of a river and result in a physical obstacle salmon must cross to get to and from the ocean.  Dams in a river can be thought of as traffic on a highway. The cars driving on the road are similar to the flow of the water within the river.  When an accident occurs on the highway, traffic backs up similar to the reservoir behind the dam. The Salmon within the river are anadromous meaning they are born in freshwater, mature in ocean water,  and return again to fresh water in order to spawn (USFWS, 2017) Dams, or an accident on the highway, greatly impact the natural traveling patterns of salmon. Spawning (salmon reproduction mechanism) habitats can be completely blocked by dams if adequate passage is not provided (Northwest Power and Conservation Council, 2018).  In the Columbia River Basin specifically, 55% of spawning habitats have been completely blocked by dams (Northwest Power and Conservation Council, 2018).  The natural flow of the water is affected by these physical barriers because dams only allow small amounts of water to pass through at one time.

Hydroelectric dams alter the natural flow regime of rivers and impact salmon populations.   The flow regime of rivers refers to the natural pattern of water quantity and timing throughout days, months, and seasons (Poff et al. 2017).  The ecosystem within a river depends greatly on the timing of flow especially as seasons vary (Poff et al., 2017). Since the flow of a particular river is largely dependent on geographical climate, the flow regime decides how habitats develop based on which species survive best within the annual or daily fluctuations of flow (Poff et al., 2017).  Dams create areas of constant low flow and high flow. In the low flow areas a large number of fish compete for a small number of resources (Poff et al., 2017). Fish also prefer to spawn during times where water flow is at a high level; an unusually low flow results in a habitat that lacks the necessary nutrients and room for spawning activities (Wang et al., 2018). For Example, dam intervention in the Yangtze River, China, directly affects the Chinese anadromous fish population.  Naturally, these fish prefer to spawn in October, with peak travel times in September, October, and November (Wang et al., 2018). Since the implementation of Dams along the Yangtze River in 1980, activities of spawning have decreased (Wang et al., 2018). Rivers with dams have failed to meet the natural flow by 24% (Wang et al., 2018). This alteration of flow has caused a sharp 70% decrease in number of fish since 2005 (Wang et al., 2018). Without a constant flow in rivers, the temperature of the water rises.  

Stagnant water created by dams forces rivers to trap heat which directly affects salmon.  In the summer of 2015 dead salmon were found up and down the Willamette and Clackamas rivers in Portland, Oregon (Quirke, 2017).  In the Columbia and Snake Rivers, summer water temperatures rarely exceed 64 degrees fahrenheit (Environmental Protection Agency, 2018)  Salmon are sensitive to temperature changes of even a few degrees within the normal range; when summer temperatures exceed 64 degrees salmon can suffer from increased disease, increased competition, migration delay, and increased lethality (Environmental Protection Agency, 2018). Water temperatures in the Columbia River had risen well above the safety limit of 64 degrees fahrenheit and even reached numbers as high as 79 degrees (Quirke, 2017).  A total of 250,000 sockeye Salmon died along the Columbia-Snake River (Quirke, 2017). Dissolved oxygen, another health indicator of a river, is directly affected by this increased water temperature.

Sinking dissolved oxygen levels in rivers due to hydroelectric dams significantly decrease fish survival rates (Cada et al.,1987). Dams slow the rate of river water, which forces the water temperature to rise and oxygen levels to drop.  Dissolved oxygen is how aquatic species “breathe” underwater, and is a direct indicator of water quality (Perlman, 2017). A healthy river ecosystem will have 100% air saturation, which means that the river is holding 100% of the dissolved oxygen possible, thus this number varies between rivers based on salinity and temperature of a sample (Perlman, 2017).   Rivers with dams have on average, a 92.1% dissolved oxygen concentration level (Jumani et al., 2018). The most common means of measuring dissolved oxygen levels is in mg/L of oxygen; in order to convert directly from % air saturation to mg/L, the air saturation, salinity, and temperature are put into the Henry’s Law equation (O2 mg/L = (Measured % DO)*(DO value from chart at temperature and salinity) (Fondriest Environmental, 2013).  Salmon are coldwater fish and prefer dissolved oxygen levels of 6.5 mg/L as adults and will die if levels drop below 3 mg/L (Fondriest Environmental, 2013). Dissolved oxygen levels of less than 11 mg/L will delay egg hatching and at levels below 8 mg/L survival rates significantly decline (Fondriest Environmental, 2013). In August of 2018, the dissolved oxygen levels in the Middle Snake River, located along the southern border of Idaho, dropped from 5mg/L to 0 mg/L in a fourteen hour time span just below the dam (O’Connell, 2018).  The sensors present in the water could not react quickly enough to the sudden drop in dissolved oxygen and hundreds of fish were observed dead along the banks of the river (O’Connell, 2018). The Idaho department of environmental quality speculates that the strong winds in the area likely blew oxygenated water away from the dam, therefore only deoxygenated waters entered the dams turbines (O’Connell, 2018). The combined effects of hydroelectric dams as a physical barrier and its impacts on river health on Salmon is universal to all areas of the Columbia/Snake River basin.  

The Lower Snake River is particularly important geographically to the Nez perce people, specifically the Lower Granite Dam within the river.  The sequencing of dams significantly limit their ability to hunt salmon and utilize the resources. The completion of the Lower Granite Dam in 1975 marked first of eight dams in a row Salmon must clear in order to get to the Ocean, before returning back once again later in life to spawn (Quirke, 2017). The dam stands approximately 100 feet tall and 3,200 feet in length (Bonneville Power Administration, 2018).  The Lower Granite Dam has an installed capacity (maximum potential output) of 810 MW of power; 1 MW of power equates to the instantaneous demand of about 700 homes (Bonneville Power Administration, 2016; Idaho Power, 2018). The dam provides a large amount of power but simultaneously harms salmon. The Columbia and Snake River Dams collectively drove all four salmon populations within the river to be at risk for extinction (Helmer, 2018).  In order to reduce damage to Salmon species caused by hydroelectric dams, the United States government should implement legislation to remove the Lower Granite Dam on the Snake River due to its proximity to the Nez Perce Tribe.

The environmental protection agency fears that removing dams will overwhelm the ecosystem and cause more harm than good.  

The Lower Granite Dam could be removed using the same Notch/Release Method used remove the Elwha River Dam which would slowly allow the ecosystem to adapt gradually.   Simply, the Notch and Release process uses hydraulic hammers to create spillways which allow the reservoir and built up sediment to be released slowly (Stroud, 2012). The removal of the Elwha Dam in Washington State was completed as a result of the Elwha River Ecosystem and Fisheries Restoration act of 1992 which mandated the Secretary of the Interior to implement action to totally restore the Elwha River ecosystem and its fisheries (The Elwha Act, 2015).  The Dam was removed in stages beginning with lowering the reservoir water level through existing spillways in the dam (Cho, 2014) In order for the rivers original channel to be cleared, the water was then diverted using cofferdams or temporary enclosures for the water (Cho, 2014) The powerhouse, turbine that is turned to generate electricity, and other existing structures were removed and the natural flow of the river was restored (Cho, 2014). Along with water flow, sediment must be carefully managed during the Lower Granite Dam removal. Due to the large amounts of sediment-sometimes millions of cubic yards- without careful preventative measures the sediment release can bury habitats and pose water quality concerns (Stroud, 2012).  The same notch and release method of removal could be used for the Lower Granite Dam would allow for the sediment to be released gradually, minimizing the harm to the ecosystem (Stroud, 2012).

Removal of the Lower Granite Dam would decrease the harmful effects of dam intervention on the ecosystem and jumpstart the restoration of Salmon populations.  The removal of the Elwha River Dams restored the free range of all five species of North Pacific salmon (Susewind, 2018). The Washington department of fish and wildlife predicts that the restoration of a significant number of fish species within the Elwha River will take decades, however the department is hopeful that now that the fish have been given the opportunity, in time, the fish species with thrive again (Susewind, 2018).   Based on estimations the number of fish are expected to climb from 3,000 to 300,000 over the course of many years (Susewind, 2018). The department monitors fish abundance within the river with SONAR and hatchery marking methods (Susewind, 2018). Both the Washington Department of Fish and Wildlife and the Kllalan Tribe that resides along the Lower Elwha River have agreed to ban fishing within the Elwha until a surplus of fish is present (Susewind, 2018).  The same precaution should be applied to the Snake River which would depend on an agreement between the Nez Perce Tribe and the Washington Department of Fish and Wildlife. This fishing ban would allow endangered species such as the Sockeye Salmon to return to the Snake River (National Oceanic and Atmospheric Administration, 2018)

The Bonneville Power Administration (BPA) are resistant to the removal of any and all of the dams in the Lower Snake River. They state that the removal of the Lower Snake River Dams would increase public utility costs to consumers. (Helmer, 2018).  The BPA argues that the the cost to take down the Lower Granite Dam would be far more than maintaining it. They estimate that removing all four of the lower snake dams and replacing their energy would cost between 1.3 and 3.8 billion dollars over a 10 year period (Bonneville Power Administration, 2007).  The BPA recognized that the current state of Salmon and other native fish populations must be improved and suggests that rather than dam removal, aggressive measures of intervention and restoration should continue to take place. This would include “structural improvements and hydro operations to help fish get safely past the dams and effective habitat and hatchery programs.” (Bonneville Power Administration, 2007).  

The BPA insists that salmon have a safe path through the Lower Granite Dam but these pathways are harmful to fish and ineffective.  The dams in the lower Snake River are equipped with fish ladders in attempt to allow salmon a path to and from the ocean (Bonneville Power Administration, 2016)  Fish ladders, are meant for adult fish and provide a path that requires them to leap into the ladder, rest in a pool, and leap again until they have crossed the dam (National Oceanic and Atmospheric Administration, 2018).  This process is tiring and often fish will simply die of exhaustion. On the Snake River, Salmon must pass through 8 dams before reaching the ocean. Additionally, Juvenile fish cannot utilize the fish ladders and rather are drawn to the turbines on the dam.  Salmon die due to substantial injuries caused by the turbines at a rate of 15% (Northwest Power and Conservation Council, 2018).  Removing just the lower Granite Dam would decrease the stress that salmon endure passing through dams and increase their chance of surviving their passage to the ocean.  

Dam removal would require significant funding but would also produce jobs and commerce from agriculture.  The total cost of the Elwha Dam restoration project which included, the removal of the two dams within the river, construction of flood protection facilities, fish hatcheries and green houses, totaled approximately 325 million dollars (U.S. National Park Service, 2018) This cost would be similar to the cost of removing just the Lower Granite Dam; as opposed to removing all four of the lower Snake River Dams.  A cost-benefit analysis conducted by the National Park Service concluded that the Elwha dam removal project provides approximately 50 million in business activity in Clallam county and the dam removal specifically created between 760 and 1,000 jobs (Meyer et al., 1995). Recreation and tourist attractions are predicted to generate 28.5 million dollars to the Clallam County per year and create approximately 500 additional jobs within 10 year (Meyer et al., 1995). As these removal project run on for years, this creates an economy for project managers, risk advisors and blue collar workers in the area for years to come.  The Kllalan Tribe with again have fishing rights and a healthy recreational fishing business will return to the area and the after the Elwha restoration project is complete. Along with other funds from state natural resource agencies, the cost could be cut significantly. (Otto, 2000) The Removal of the Lower Granite Dam could generate the same income and jobs for Southeastern Washington .

The dams along the Columbia River Basins amount for 40% of the U.S. Hydroelectric electricity generation. (Energy Information Agency 2016) Despite the overwhelming evidence that dam removal will improve the environment and ecosystem, the BPA argues that removing any or all of the the lower Snake River dams will require the burning of fossil fuels.  They state that if all four of the dams were removed, and the area switched purely to fossil fuels, the regions carbon emission would increase by up to 2.6 million metric tons annually (Bonneville Power Administration, 2007). With the rise of renewable energy technology in the United States, burning of fossil fuels or harmful natural gases is not the only reasonable option available.

The energy generated by the Lower Granite Dam can be replaced by renewable energy such as wind power in the state of Washington. Washington is currently ranked among the top 10 states in the nation for electricity generated from wind production (U.S Energy Information Administration, 2017)  The state currently has $6.1 billion of capital investment on wind projects (American Wind Energy Association, 2018). Wind energy creates high quality jobs across the state and accounts for 7.1% of the electricity provided for the state of Washington. As of 2017, Washington has an installed capacity  of 3,075 MW of wind power (American Wind Energy Association, 2018). This power can be replaced partially by windmills producing anywhere from 2-10 MW a year, along with other forms of energy (American Wind Energy Association, 2018). The environmental impact wind energy has is very minimal because wind power requires no water and creates no greenhouse gas emissions. The state currently saves 220,000 million metric tons of CO2, and 1 billion gallons of water per year due to the use of windmills (American Wind Energy Association, 2018). That is the equivalent, in carbon emissions, of taking 474,000 cars off the road (American Wind Energy Association, 2018). With wind and solar energy quickly becoming the affordable forms of new energy, replacing the deficit from the dams will be feasible.  

Hydroelectric dams not only cause a significant risk to river ecosystems as a whole but have pushed salmon species to endangerment which directly impacts those who rely on the fish as a source of food (Helmer, 2018).  The salmon of the lower Snake River provide a source of food, income and culture for the Nez Perce Tribe (Quirke, 2017). The removal of the Lower Granite Dam would certainly not single handedly regrow the salmon population; rather it would jump decades of improving river health and rebuilding the fishing culture of those that call the river home.  Like the Elwha river restoration project, a multitude of steps must be taken to slowly allow the lower Snake river to run freely and the salmon population to flourish once again.


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