Deschutes Estuary Restoration: Lessons Learned from the Elwha River Complex
For almost 70 years, Capitol Lake in Olympia, WA has been sitting under the nose of our state government, quietly engaged in the processes of eutrophication and reduced habitability. The creation of this lake by means of the 1951 construction of the 5th Avenue Dam destroyed a once thriving estuary and partially cut off the Deschutes river from access to the Sound. A similar story can be observed just 80 miles north along the Elwha River of the Olympic National Forest near Port Angeles. For over 100 years, two dams cut off the river’s flow and made it impossible for the Elwha’s native salmon species to return to their ancestral home in order to complete their life cycle. This disruption of the salmon run resulted in a near complete decimation of the species populations in the region. The dams also had a negative impact on the estuary at the mouth of the Elwha, damaging a crucial system that young salmon depend on for development.
In 2014, both dams were removed from the Elwha River in the largest dam removal project ever completed in our country (Kim). As the river adapts to the dam removal, scientists have been able to observe and record the changes that have occured over the past four years. In support of the estuary as a habitat for salmon, the people of Olympia can use information about the Elwha dam removals to help better inform the process and have insight into deciding and planning an effective removal of the 5th Ave dam. Overall, the benefits of removing this dam outweigh the costs. While the results of restoration would not lead to a complete return of the estuary to pre-dam conditions, it would be a step in the right direction for the conservation of the estuary and salmon population.
Firstly, we can understand that removing the 5th Ave dam and thus Capitol Lake would lead to active ecological recovery and the promotion of a more healthy system in the waterway. According to the Deschutes Estuary Restoration Team, Capitol Lake is “…a stagnant and degraded lake that is steadily filling with sediment…and that suffers from algae blooms, and low levels of dissolved oxygen” (“Just Say Yes”). As young salmon mature, they must travel through the lake on their life cycle path away from their fresh water home into the ocean. This environment is very unhealthy for the salmon traveling through the lake because it exposes young fish to harsh conditions and pollution. Meanwhile, without the lake, DERT states that “you would see a healthy, vibrant and dynamic estuary that… support[s] a vast range of local wildlife” (“Just Say Yes”). By restoring the estuary, we could reduce pollution and improve conditions to support the young salmon. If the dam was removed, the lake water would be replaced with an estuary that facilitates continuous flow of water into the sound. This change will help deter the algae blooms and foster an increase in dissolved oxygen levels. Thus, the water will be healthier and able to support photosynthesis and aquatic plant growth that naturally filters the water. A healthy, natural system will provide a much safer passage for young salmon as they mature.
Although DERT’s argument sounds clear and attainable, when we look at the outcomes of the dam removal on the Elwha, we can understand that attaining the goal of a thriving estuarine ecosystem at the mouth of the Deschutes may be somewhat more complicated. According to a study exploring the effects of dam removal on the Elwha’s estuary, the redeposition of the sediment released by the removal led to high turbidity that decreased food availability for salmon fry. The sediment movement also impedes the “growth rates…community structure and juvenile salmonid diets” due to the “suboptimal environmental conditions” (Foley et al, 11). In other words, the rapid ecosystem change that occurred when the dams were removed was initially a detriment to the estuary and salmon fry that depend on it. With that said, however, the study goes on to note that “the potential for new estuary habitat to develop is high”, though it may take decades, and it is not clear how it will impact salmon (Foley et al, 12).
In the case of the Deschutes, we can understand that the dam removal would free tons of sediment backed up behind it. According to a state report, to mitigate effects, significant dredging would be necessary to help remove sediment in the lake before the dam is removed (52). This report emphasizes the dredging as the best option economically, though fails to closely consider the estuarine ecosystem and lacks clarity on the amount of sediment, if any, that will be left over and could disperse into the estuary. This lack of consideration could prove dangerous, because “studies have shown that deposition of as little as 3mm of sediment is enough to alter benthic invertebrate communities and 9cm of sediment can result in complete mortality and slow recovery” (Foley et al,12). Even a small amount of sediment can alter the estuary productivity, which can reverberate through the food chain and negatively impact young salmon. Moving forward, if it is decided that the 5th Ave dam should be removed, it is necessary to develop a plan that addresses all possible issues and avoids a mainly anthropocentric focus.
If this information seems disappointing, it may be favorable to hear that scientists visiting the Elwha’s estuary more recently have seen an influx of fish species returning to the estuary “such as bull trout, redside shiner, and slender eulachon” (Kim). By late 2016, some of the native salmon returning populations were growing slightly. Even after 100 years, it was still in the salmons’ genes to try to get past the dams to go home. Now that they finally can, their numbers are starting to climb. For all of the work and resources needed to remove the Elwha’s dams, the results are finally starting to grow apparent. Similarly to the Deschutes, a goal of the Elwha’s dam removal project was to revitalize the estuary as a healthy habitat for salmon. Scientists are already observing positive changes, though slightly, only two years later. This progress reminds us of the possibilities for success that are created when humans give back control to our land and waters, allowing them the freedom to return to a naturally controlled state.
If we can slowly see the improvements that we have hoped for in the Elwha, then we can have hope for the success of dam removal on the Deschutes as well. It is true that taking out the 5th avenue dam will not immediately open up a new, thriving, biodiverse estuary, as we may like to imagine. Instead, the ecosystem will need a lot of time to recover, and still may never return to the same state that it was in before humans ever altered it. Because of the damage done over decades to the Deschutes, it is important for our community to remember our responsibility to Earth as humans. According to Aldo Leopold in his chapter “The Land Ethic” from “A Sand County Almanac”, he writes that “A land ethic… reflects the existence of an ecological conscience, and this in turn reflects a conviction of individual responsibility for the health of the land. Health is the capacity of the land for self renewal. Conservation is our effort to understand and preserve this capacity” (236). According to Leopold’s ethical argument, it is worth the effort to remove the dam because it will open up the possibility for the “self renewal” of the estuary, as opposed to maintaining the current state and “giving no opportunity for the land to improve.”
When humans set the Elwha free, the river and estuary responded with signs of positive change and growth. To achieve a future for the people of Olympia to have a positive, mutual relationship with the land, the people have to foster the conditions necessary for the Deschutes estuary to recover.
Overall, the 5th Ave dam should be removed to drain the Capitol Lake, free the Deschutes river, allow the estuary to rebuild, and make a better habitat for salmon. When we focus on the impact of restoration on the ecosystem and especially salmon fry, we must realize that the only possibility to increase the local salmon population and survivability is to take down the dam. To build a healthy relationship with land, we must try to undo the anthropocentric changes that humans in the past have brought upon the land. We can also learn from the successes and failures of the Elwha dam removal project to better prepare and strategize methods to allow for the greatest possible outcome of removing the 5th Ave Dam. The citizens of Olympia need to free the Deschutes to work towards estuary restoration and supporting salmon populations through habitat and food access.
“Capitol Lake Alternatives Analysis – Final Report.” Wa.gov, Herrera Environmental Consultants, 30 July 2009, des.wa.gov/sites/default/files/public/documents/About/CapitolLake/21-CapitolLakeAlternativesAnalysisFinalReport(July2009).pdf.
Foley, Melissa M. “Rapid Water Quality Change in the Elwha River Estuary Complex during Dam Removal.” ResearchGate, 2015, www.researchgate.net/publication/280916943_Rapid_water_quality_change_in_the_Elwha_River_estuary_complex_during_dam_removal.
“Just Say Yes to Restoring the Deschutes Estuary. Just Say Yestuary!” Deschutes Estuary Restoration Team RSS, www.deschutesestuary.org/dert/restoring-the-estuary/.
Kim, E. Tammy. “New Life Along Washington State’s Elwha River.” The New Yorker, The New Yorker, 10 July 2017, www.newyorker.com/tech/annals-of-technology/new-life-along-washington-states-elwha-river.