Maintaining old, aging infrastructure is difficult. This was shown to be true recently in the Oroville dam incident this past week.
The Dam Emergency
The dam, located near Sacramento, California is the tallest in the nation. With the influx of heavy rains, dam operators decided to use the concrete main spillway to avoid an overflow of the dam on February 7th. However, while the water was rushing over the spillway, a crater suddenly developed below the spillway. The Oroville Dam water began eroding the earth. Initially, operators decided to lessen the water to a slower rate in hopes that it would sustain or lower the dam levels enough. But by February 11, it was apparent the release of water simply wasn’t enough. So, dam operators made the decision to utilize the emergency spillway. Workers were unable to control the flow, and water began to reach the emergency spillway top. The water, no longer controlled, rushed out at a rate of 12,600 cubit feet per second – or roughly 94,000 gallons per second,
The emergency spillway, created for exactly this type of scenario, is old. Built in 1968 (with now antiquted technology), the emergency spillway had never been used prior to February 11, 2017. Ever. In 2005, 3 environmental groups proposed reinforcing the earthen spillway with concrete. It was argued that with extreme flooding the fast-rising water would overwhelm the main concrete spillway and create flooding for downstream communities. Water agencies in charge of of upgrades argued that such concerns were blown out of proportion, and this was unlikely to ever occur.
12 years later it happened.
By February 12, over 200,000 residents near Oroville were evacuated when rising water threatened downstream communities and the emergency spillway eroded.
After the Emergency
It’s easy to be reactive with maintenance, especially when something has never been an issue before. However, the cost of repairing the dam is exponentially more expensive than proactive measures. It’s also not as safe. By the evening of the 12th, the dam’s uncontrolled water flow had ended. Boulders were brought in as a makeshift stabilization. By the next morning helicopters began to drop large rocks and sandbags in the spillway in order to protect further erosion of the base.
An emergency spillway isn’t very useful if it doesn’t lessen the emergency. Moving forward, the Oroville Dam and the spillways need to be further inspected, repaired, and maintained. Dam infrastructure needs to stand the weather extremes – not just the average year.
This isn’t the only time the water industry has been reactive. It’s an industry that is slow to change. With the recent backflow incident in Corpus Christi, the continuing lead-laden water in Flint Michigan, and the Oroville Dam, maybe the industry can admit it’s time to be proactive. It’s will be interesting to see what happens next, and how the State of California proceeds to reduce water emergencies in the future. The five-year drought isn’t the only water emergency California has faced recently.