Discussion of Results
To address our question of how the function of Bonneville Dam might be altered in the event of a Cascadia earthquake, we will first explain the possible effects of the various earthquake hazards on hydropower operations, salmon rehabilitation, and recreation opportunities. Because of inherent uncertainties about the location and strength of any future earthquake and a lack of seismic research regarding the site of the Bonneville Dam, it is nearly impossible to predict which specific structures will be affected. However, using our maps and background research about the layout of the Bonneville Dam, we speculate how earthquake geology might alter the functions of the dam.
For the hydropower operations of the dam, energy is generated within the infrastructure of the dam through turbines and is transported elsewhere by a system of power lines. While the internal infrastructure has a low risk of damage because it is protected by the sturdy concrete dam, these external infrastructure of energy transport which traverses the steep hillsides and banks of the river is at a far greater risk of serious damage. If indeed these pieces of infrastructure are compromised by liquefaction or landsliding caused by shaking, the Bonneville Dam’s ability to provide hydropower to the northwest region will be hindered regardless of the integrity of the turbines and other internal energy infrastructure. Our conversation with Army Corp employee, Amy Echols, indicated that the repairs to the dam in the case of an emergency would be granted by the federal government only if approved. In this case, the hydropower function of the dam could be stalled or inhibited for an extended period of time. Another possibility would be that any small cracks or damages to the internal infrastructure would experience a delay in being addressed and could potentially get worse during the aftershocks of the earthquake or during the waiting period for funds. Another possibility, of course, is that the dam continues to provide hydropower to assist in the recovery of the post-quake northwest and the hydropower function of the dam is enhanced by loss of other types of energy and infrastructure needed to rebuild affected communities.
Regarding the fish rehabilitation infrastructure, similar barriers to specific risk prediction apply. Similar to the hydropower, elements of the fish rehabilitation infrastructure such as the fish ladder are situated within the dam structure. These pieces of the fish program are likely as little risk of severe damage. Contrarily, the hatchery located off of Interstate 5 at Cascade Locks exists within the zones of severe shaking, landsliding, and liquefaction risk. Similarly, the avian attack prevention infrastructure exists on the Washington side of the river in a zone of severe liquefaction. While the infrastructure of fish rehabilitation itself may not be at extreme risk of complete failure, damages to small aspects of the program such as the avian prevention sprinkler or access to the hatchery could prohibit the program from fulfilling its full potential after a large earthquake. Another possibility for the scenario of a large landslide to move into the reservoir above Bonneville would be to block or partially block the river as happened historically with Bridge of the Gods. Any mass wasting into the reservoir might also increase the buildup of sediment on the pool and harm the migration of juvenile fish. What also would matter is the timing of the earthquake. If the earthquake occurs during peak upstream migration, any barriers to their migration caused by the earthquake or damage to the fish infrastructure would have a more severe impact, perhaps, than if the earthquake occurred during a time that fewer fish pass through the Bonneville Dam.
While Amy Echols explained that it’s difficult to prioritize different functions of the dam because each management office would argue that theirs is most important, with federal dollars likely being spent to rebuild cities like Portland and alleviate suffering for affected human populations, repairs to the fish infrastructure are not likely to be at the top of list for fund allocation. In these hierarchies, it is probably ideal for human lives to take precedent over fish lives. However, this highlights how crisis response and emergency procedures are generally anthropocentric. However, judging by the recovery from severe population collapse, it’s fair to say that the earthquake does not pose a huge threat to salmon species via the Bonneville Dam. What is more likely is that funding for any damages incurred by the fish hatchery, infrastructure, or other aspects might be delayed until immediate needs of those affected by the earthquake are adequately met.
While effects of the earthquake to hydropower and fish infrastructure is grounded in existing infrastructure, the possible effects on recreational opportunities at Bonneville Dam is less tangible. The three recreational activities focused on here are access to the visitor center on Bradford Island and use of the river for boating, swimming, and fishing recreation. First, the earthquake effects of liquefaction, shaking, and landsliding are all possible on Bradford Island, creating a risk for visitors to be frightened by the earthquakes effects. Falling objects and unstable structures within the complex of the visitor center could also cause damage to both the facilities and visitors. The dam visitor center and surrounding recreation sites are accessible by highways on either side of the river. Between the landslide hazard and the liquefaction, it
seems likely that these arteries of transportation will be disrupted, thus cutting off access to the dam by visitors and rescue and repair crews until the roads are repaired. Access would be the main immediate and short-term effect of an earthquake on recreation at Bonneville Dam. Long term effects might include altered layout of recreation facilities due to geomorphology. Since the dam is a national monument, it’s possible that new plaques or areas of interest will be developed in remembrance or interpretation of the events of the earthquake.
After speaking with Amy Echols from the US Army Corps of Engineers we learned is that although there is new advanced research and knowledge of earthquake risk at the dam and surrounding area, the funding can’t keep up with it. In order to get sufficient funding to make updates to the dam to ensure earthquake safety, a disaster must occur first. If a natural disaster like an earthquake did compromise the dam, there is emergency funding available. However, if an event like this took place and other areas were compromised, the area with greatest risk would get the most money. Not only would Bonneville Dam be competing with about 600 other dams, but Bonneville would also have to compete for funding against hospitals, highways, water filtration, etc. in the case of an emergency. While small repairs and low-cost updates can be made for the short term, funding for long-term changes seems to be a waiting game.
Broader Implications
In terms of symbolic implication, human-made dams are inherently fragile if they can be tested by natural forces. Since dams are given a “lifespan” when they are created, they become systems that need substantial care, especially when that lifespan has expired. Nearing the end of its functional life, the Bonneville Dam has always been a symbol of development in the Pacific Northwest. At the same time the dam’s primary function is to provide renewable clean hydroelectric energy. Through our study, we predict that if little damage is made to the dam, then the dam will remain a powerful symbol of expansion and development. The conclusions of our research are concerning, however, because dams like Bonneville do not have the resources to make the necessary precautions in case of an earthquake. This begs the notion that something needs to change to allow funding to be precautionary rather than reactionary. Instead, infrastructure waits for the disaster to happen and then surrounding communities start rebuilding and picking up the pieces. In the rare chance the Bonneville Dam completely fails, meaning the dam failure cause excessive damage to its communities, what will the impact be on the cultural significance of this structure? If the dam fails, a dam symbolizing the power of humans over nature, we can only imagine the backlash that will have on federally-funded infrastructure.
Looking into the future of predicting the outcome of the Bonneville Dam, it would be interesting to create an action plan for the dam for every scenario of the earthquake and calculating its chance of failure. This would constitute a more quantitative analysis. Each action plan would be a different rhetoric and the term “failure” would have to be defined, but it would be helpful for Bonneville to create at least an evacuation plan for the impending earthquake. Along those lines, another research alternative would be understanding the range of possible
damage to hydroelectric power is important for broader resilience and merits further research. It would also be interesting to interview people regarding their perceptions of the dam and how their image of the dam could change in the face of the 9.0 Cascadia earthquake.
Our project is largely hypothetical and covers a range of possible futures. While this certainly inhibits our ability to speculate from real occurrences, it does provide important lessons. When planning for the future, whether it be building a long-lasting structure or created an emergency action plan for one that already exists, there are so many possibilities and unforeseen circumstances that might alter the course of action. Planning for change, particularly change by disaster, can never be guaranteed to be correct. Furthermore, the building and maintenance of structures is an investment in some belief in the future. If that belief in is a resilient structure that can overpower the earth, as dams classically are seen, then perhaps challenges to this mindset are less likely to be taken seriously. These beliefs, which inspire and sustain the structures of our civilizations, are bound to change over time. Here we see the shift from wonder of the world, to ecological misstep, to responsible and functional historic monument. What’s next for the Bonneville Dam? How will the structures of our civilization be remembered and how do geologic events influence that perspective? Perhaps sometime in the next fifty years, the Cascadia earthquake will contribute to the many answers to this question.