The Oroville Dam is not only the tallest dam in the US, but also one of the most important ones. 770 feet tall, the dam provides clean water, electricity and security against floods for many cities. Now, the dam is in danger and the population does not know much about this.
From the beginning, the constructors of the dam had to face many challenges in order to build the way they planned, starting from a number of floods to human errors. However, this did not stop them and after 7 years of work the dam was finally ready to be used in 1968. In order to prevent the dam from affecting the habitat of the fish, a salmon incubator was built right next to the dam. Everything seemed perfect, at least until 2005.
In 2005 three environmental groups made a request for the government to improve the structure of the dam and to add concrete on the emergency spillway where necessary; according to them, extreme rain could cause damage to the dam. Their concerns were considered superficial and no action was taken. One year later, a civil engineer decided that the emergency spillway of the dam, the weakest part of it, meets FERC’s guidelines, therefore there is no need to reinforce it. In 2013, after years of pressure from an enormous volume of water, the main spillway cracked. This was the first time the officials saw that something is wrong with the dam, however they did not make any change until this year, except for a brief inspection in 2015.
On February 7 this year, the first crack appeared in the dam’s spillway while releasing the water. This happened after a period of heavy rain which put a lot of pressure on the weakened dam. Due to the high inflow of water, the engineers did not stop using the damaged spillway as they should; in 3 days, the hole was already too large to be fixed, measuring 300 feet in width, 500 feet in length and 45 feet in depth. Pieces of concrete from the dam were carried away by the water stream into the fish hatchery near by, creating damage and forcing the workers to move the fish and the eggs in a safe place.
Even after days of draining the water, the lake was still at a dangerous level, so the engineers decided that the emergency spillway had to be used for the first time since the construction of the dam. They opened it on 11 of February and the effect was not as they expected; an uncontrolled overflow and everything was compromised.
On February 12 the government proceeded with the evacuation of the population living in the low-lying areas surrounding the Dam. A potential failure of the emergency spillway would cause a disaster. Because the level of the water in the emergency spillway was lowered by the increased flow from the past day, on February 13 the engineers tried to stabilize the erosion, but they did not know for how long this was going to last. Even though the level of the water was going down, the evacuation order is still standing and more than 180.000 people were forced to leave their homes.
Now the situation is not as critical as it was, but it does not look like it will get improved any time soon. While the main and the emergency spillways are damaged, there is no guarantee that the dam will be fixed in time before it will give up under this huge pressure. The consequences of such an event would be a disaster: thousands of victims, flooded cities, many more without electricity and water not to mention destroyed railways that would make transportation in the area almost impossible.
While the authorities want to make everything look fine, the reality is far from this. The population from the area is still not allowed to go back to their homes, and the engineers are working day and night to fix the damage of the dam and to lower the level of the water.
The question is: for how long their fixing is going to last? What will happen if they have to face a few days of heavy rain? Will the dam be able to handle the pressure? Will the people be safe?