Two weeks ago, the risks posed by the Oroville dam occupied relatively few minds. But in the days since its near-failure and the evacuation of 200,000 people downstream, it’s become a household word. The news media have devoted much ink and uncountable electrons to the discussion.
The Atlantic provides a particularly well-balanced article, beginning with some background:
…In December 1964, three years into the massive barrier’s construction, a huge flood struck the northwest, killing dozens. The dam was nearly overtopped, which could have led to its failure even before it was completed. Instead, the partially completed dam helped prevent a larger disaster by reducing the flow of the Feather River…
The dam, which sits south of Chico and north of Sacramento, was eventually completed in 1968, creating the nation’s tallest dam. It forms the head of California’s massive, byzantine State Water Project (SWP). The SWP moves water from Northern California south toward Los Angeles, an average of 3 million acre-feet per year. A drop of water that starts at Lake Oroville, above the dam, takes 10 days to move all the way to the end of the system, south of Los Angeles…
…There’s some bitter irony to the problem of too much water menacing the Golden State. California has suffered through a long and severe drought, at times driving Governor Jerry Brown to institute stringent—critics say draconian—water controls. This winter has seen much more snow and rain, which is good news for the parched state, but bad news for the Oroville Dam, where huge amounts of water are collecting. The lake rose 50 feet in a matter of days. Earlier in February, as operators let water over a concrete spillway to reduce the pressure, a crater appeared in the spillway. Faced with too much water in the lake, they continued to use the spillway anyway, and the damage got worse. On Friday, the crater was 45 feet deep, 300 feet wide, and 500 feet long.
The full article provides more particulars, and explores three contributing causes to the emergency: drought, climate change, and infrastructure maintenance.
Stanford’s School of Earth, Energy, and Environmental Sciences this morning posted a discussion with in-house experts Noah Diffenbaugh and Newsha Ajami on what happened at Oroville Dam and what Californians might see. Some excerpts:
Noah Diffenbaugh is a professor of Earth System Science in the Stanford School of Earth, Energy & Environmental Sciences and the Kimmelman Family Senior Fellow at the Stanford Woods Institute for the Environment. He focused on the climate change aspects. A sample, to whet your appetite for the fuller discussion:
What’s happening now is very much in line with our recent research analyzing the historical climate record and projections of future climate change. It’s really an issue of extremes. Right now, we’re having an extremely wet year, on top of a record-breaking five-year drought. The basin upstream of Oroville Dam is at a record 224 percent of normal precipitation, and we are witnessing what happens when so much precipitation falls in such a short amount of time. Our research has shown that global warming doubles the odds of the warm, dry conditions that intensified and extended our recent drought. At the same time, that warming atmosphere carries more water vapor, so you have the potential for more extreme wet periods like this winter.
Dr. Newsha Ajami is director of urban water policy at Stanford’s Water in the West Program[1]. She focused on the infrastructure:
[The Oroville event] …demonstrates that our aging infrastructure requires better maintenance and upkeep, otherwise it can fail, especially under new climatic realities that are quite different from the historical knowledge used to design and build it. We have to become smarter in the way we manage our water infrastructure system. Using 20th-century tools and governance strategies to manage our existing infrastructure will not meet our 21st-century challenges and needs. We also have to update our water governance tools and strategies at every scale to incorporate today’s climatic realities in our decision-making process and consider innovative solutions that can enable more effective management of our system without any social or economic consequences…
… my colleagues in the transportation and energy sectors might not fully agree, [but] people are much more willing to pay for the upkeep and maintenance of roads, bridges or energy transmission lines than our water system. This is partly because water is a hidden system and people are disconnected from our complex and sophisticated water network. Most people hardly know where their water comes from or where it goes after use. To change the public’s attitude toward water, we have to do a better job educating the public and demonstrating that reactive responses to our water challenges will end up being costlier than proactive ones. Authorities need a steady fund to maintain the water system and that may mean a change in water rates.
Well said!
Returning to The Atlantic narrative, we find:
In 2005, a trio of environmental groups filed a complaint with the Federal Energy Regulatory Commission, saying the emergency spillway was unsafe, The Mercury News reports. Their worry proved prophetic: The groups said in the event of heavy rain and flooding, the hillside would wash out and produce flooding downstream. They asked that the auxiliary spillway be paved with concrete, like the primary one. But the federal government rejected the request after consulting with the state and local agencies involved in the water system, which said they did not believe the upgrades were needed.
As for the primary spillway, the state did some repair work around the area of the collapse in 2013, CBS Sacramento reports. The last state inspection was in July 2015, but workers did not closely inspect the concrete, the Redding Record Searchlight notes, instead eyeing it from a distance and concluding it was safe. Officials say repairs should cost $100 million to $200 million, once it’s dry enough to begin them.
For comparison, let’s estimate that the cost of the emergency evacuation and housing for 200,000 people for five days is of the order of $1000/person. That comes the order of $200M. Failure to perform routine maintenance on the dam essentially doubled the cost to the Nation. And that was without actual dam failure, and the resulting property damage that would have raised losses by an order of magnitude.
This calls to mind the periodic assessments by the American Society of Civil Engineers on the need for infrastructure maintenance of all types. Focusing on the dams alone, we learn from their 2013 report that
Dams again earned a grade of D. The average age of the 84,000 dams in the country is 52 years old. The nation’s dams are aging and the number of high-hazard dams is on the rise. Many of these dams were built as low-hazard dams protecting undeveloped agricultural land. However, with an increasing population and greater development below dams, the overall number of high-hazard dams continues to increase, to nearly 14,000 in 2012. The number of deficient dams is currently more than 4,000. The Association of State Dam Safety Officials estimates that it will require an investment of $21 billion to repair these aging, yet critical, high-hazard dams[2].
As of 2012, there are 13,991 dams in the United States that are classified as high-hazard, showing a continued increase in the overall number of dams with that classification. The number has increased from 10,118 high-hazard dams just ten years ago. Another 12,662 dams are currently labeled as significant hazard, meaning a failure would not necessarily cause a loss of life, but could result in significant economic losses.
The average age of our nation’s dams is 52 years. By 2020, 70% of the total dams in the United States will be over 50 years old. Fifty years ago dams were built with the best engineering and construction standards of the time. However, as the scientific and engineering data have improved, many dams are not expected to safely withstand current predictions regarding large floods and earthquakes. In addition, many of these dams were initially constructed using less-stringent design criteria for low-hazard dams due to the lack of development below the dam…
…Dam failures can not only risk public safety, but they can cost our economy millions of dollars in damages… Since dam failures can cause severe consequences to public safety and the economy, emergency action plans (EAPs) for use in the event of an impending dam failure or other uncontrolled release of water remain vital. While the number of high-hazard dams with an EAP has increased, only 66% of dams have EAPs, far below the national goal of 100%.
The complexity of monitoring the conditions of our nation’s dams is partly because they are owned and operated by many different entities. While some of the nation’s dams are owned and operated by federal, state, and local governments, the majority, 69%, are owned by a private entity. The federal government owns 3,225 dams, or approximately 4% of the nation’s dams. It may be surprising to some that the U.S. Army Corps of Engineers owns only 694 dams.
Other than 2,600 dams regulated by the Federal Energy Regulatory Commission, the remaining dams in the nation are not regulated by the federal government, but instead rely on state dam safety programs for inspection. State dam safety programs have primary responsibility and permitting, inspection, and enforcement authority for 80% of the nation’s dams. Therefore, state dam safety programs bear a large responsibility for public safety, but unfortunately, many state programs lack sufficient resources, and in some cases enough regulatory authority, to be effective…
Putting Americans to work to maintain dams and avert catastrophe seems an attractive alternative to paying comparable amounts to evacuate and house those threatened by dam failure.
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[1] Full disclosure: Dr. Ajami, when a graduate student at UC Irvine, participated in the 2005 AMS Summer Policy Colloquium (can’t understand how the Stanford News Service failed to catch and highlight this… ).
[2] A small fraction of the $3.6T the ASCE estimates is required to renovate all U.S. infrastructure, including levees and drinking water supply, energy, waste disposal, transportation, etc. For comparison, Americans spend $20B annually on pet food.