We restrained ourselves from making a dam pun, it was really hard.
On Saturday, Feburary 7th, water from Lake Oroville breached an emergency spillway of the Oroville dam, potentially threatening the cities residing in the Feather River Basin and leading to a rush evacuation of 180,000 people. The increased rain and snow that California has been receiving this winter at first seems like a blessing, considering the major drought the state has been in for the past five years. Unfortunately these increased water levels have revealed major issues in the Oroville dam, particularly in the main and emergency spillways.
A spillway is meant to provide controlled releases from flooded dams, however the main spillway at the Oroville Dam was discovered to have a 45 ft deep crater in a section of the spillway’s concrete lane, making it unsafe for use. Without the main spillway being operable, the water began to overflow into one of the emergency spillways, which, unlike the fully concrete main one, is mostly just a clear dirt path with a concrete lip. However the flow of water over the emergency spillway was beginning to erode the concrete lip and the dirt path, posing a major threat to the people in the Feather River Basin. It was the emergency spillway’s erosion that led officials to call a mandatory evacuation on Sunday. Because the emergency spillway’s erosion problem was more likely to flood, the dam operators chose to release the excess water through the main spillway instead. After releasing 100,000 cubic feet per seconds worth of water for two days, officials were confident that the immediate threat was gone and on Tuesday turned the mandatory evacuation into a warning.
Unfortunately, more rain has been predicted for this week, and while originally the amount of rain was predicted to be low, new forecasts predict a whopping 10 inches of rain. In an effort to make the emergency spillway usable again, workers and helicopters have been placing tons of boulders along its path to reduce the risk of erosion, and recently the state has been bringing in concrete trucks in order to beat the upcoming storms. Officials hope that the main spillway will be able to hold up through California’s rain season without needing to rely on the emergency dam, however that’s easier said than done considering the massive 45 ft deep, 300 ft wide gap that’s still taking up a large part of the spillway. Another issue comes in the form of the Hyatt Power Plant, found at the base of the dam. If damaged, not only would locals lose their drinking water, but it could also damage the surrounding environment. Residents have been returning to their homes under the assurance that the risk of flooding is very low, and hopefully with the amount of work the state is doing the dam will be as fit as it can be for the incoming rains.
The Oroville Dam crisis is representative of the greater problem the United States has with its infrastructure. Three different environmental groups evaluated the emergency spillway in 2005 and requested that it be renovated with concrete in order to avoid, you guessed it, erosion. However the government was unable to look this far into the future and decided taxpayer money could be used in other places. The Oroville Dam is not alone in its unfortunate state of decay; the American Society of Civil Engineers gave the U.S. a D for our maintenance of our dams. Hopefully this event will be a wakeup call for our government to start fixing our dams, but, considering how massive this issue is, it isn’t likely we’ll wake up to brand new dams anytime soon.