For our independent project my group is focusing in on the Bonneville Dam. The dam is a recreational area, connected to a salmon hatchery, and provides a large portion of electricity via hydroelectric power to the city of Portland. It is geologically interesting because it is situated right next to two historic landslides. Also, if the Cascadian 9.0 earthquake hits the Bonneville Dam is in a high danger zone. On top of all of this the Bonneville Dam has a high hazard rating. To better understand the broader implications of the possible dam failure I am looking at three different case studies and relating them back to the Bonneville Dam.
Dam 1: Japan
The Fujinuma Dam located in Sukagawa City, Japan on the Ebana River, failed in March of 2011 directly after the Tōhoku earthquake. About 20 minutes after the earthquake the Fujinuma Dam began to overflow and flood. The breach that caused the failure was locate at the tallest section of the dam. While the Fujinuma dam was a different type of dam it still provides insight into what could happen at Bonneville in the case of a large earthquake.
Dam 2: Brazil (dam failure, no quake)
The Bento Rodrigues dam provides an example of what could happen if a leak damages the integrity of the structural aspects of a dam. While there was no earthquake even that caused the Bento Rodrigues dam to failure, it still provides insight into the fallout that can occur with dam failure. A large flooding event followed the failure of the dam which resulted in approximately 17 deaths and 16 injuries. The environmental damage fallout was extreme, it is called one of the worst environmental disasters in Brazil. Another portion of this event that relates to the Bonneville dam is the reaction of near by residents. Most people did not have an evacuation plan, this is similar to the situation in the Bonneville area. Because the Cascadian earthquake was just recently learned about, people are still very unaware of what the consequences could look like, especially is they live near a dam that has the potential to fail.
Dam 3: Dams in the Himalayas
Environmentalists against the building of the Tehri Dam in India took their concerns to court. But the court ruled in favor of the government and went forward with the construction of the dam. The dam is a concern because it is built in a very geologically active area, this relates to the Bonneville dam because it is also in a danger zone. Scientists voiced many concerns over the risks of the dam, while nothing has happened thus far the public is still not well informed about the impending danger.