At least 188,000 residents in the areas surrounding the Oroville Dam in Northern California have had to evacuate their homes as workers scramble to prevent a potentially catastrophic breach. Now, reports are surfacing indicating local officials were warned about safety issues with the Oroville Dam 12 years ago, and did little to mitigate them.
Besides serving as a scary dose of hindsight, these reports are a grim reminder that experts have been sounding the alarm about America’s ageing infrastructure for a long time. In most cases, they haven’t gained much traction.
Aside from the fact that the average age of US dams nationwide is 56 years old, environmental changes, from changing river flow patterns to shifting weather patterns, are a major factor fuelling the growing infrastructure crisis. At the Oroville Dam, environmental change came in the form of heavier-than-average rains, something authorities were warned about over a decade ago.
Mercury News reports:
Three environmental groups — the Friends of the River, the Sierra Club and the South Yuba Citizens League — filed a motion with the federal government on Oct. 17, 2005, as part of Oroville Dam’s relicensing process, urging federal officials to require that the dam’s emergency spillway be armoured with concrete, rather than remain as an earthen hillside.
The groups filed the motion with FERC, the Federal Energy Regulatory Commission. They said that the dam, built and owned by the state of California, and finished in 1968, did not meet modern safety standards because in the event of extreme rain and flooding, fast-rising water would overwhelm the main concrete spillway, then flow down the emergency spillway, and that could cause heavy erosion that would create flooding for communities downstream, but also could cause a failure, known as “loss of crest control.”
Currently, the primary and emergency spillways that prevent overflow at the dam have been damaged by erosion. If erosion undercuts the 530m-long concrete lip running along the top of the emergency spillway, a 9m wall of water could come crashing down on the residents of nearby towns. Emergency workers are attempting to make repairs, and water levels appear to be falling. But forecasts for Wednesday show a foreboding new wave of rain headed in the Oroville Dam’s direction, and the problems could start anew.
According to the Association of State Dam Safety Officials (ASDSO), the US had 173 dam failures and 587 incidents between 1 January 2005 and June 2013. (“Incidents” are defined as “episodes that, without intervention, would likely have resulted in dam failure”.) A majority of those failures were attributed to extreme weather.
Lori Spragens, executive director of the ASDSO, told Gizmodo that it’s possible there are more incidents that have gone unnoticed or unreported. There’s no across the board rule about reporting incidents, she said. “It just depends on the state. Some states only regulate high-hazard dams, some regulate all three levels of hazard,” low, significant and high, according to the ASDSO.
A 2013 report card by the American Society of Civil Engineers gave the United States’ overall infrastructure a letter grade of “D+”, meaning poor. The score was even lower for the 84,000 US dams, which received a “D”. (It’s also worth noting that the average age of the failed dams was 62 years old, just 10 years older than the national average.)
Out of all those dams, the most immediately worrisome are the 2000 that have been categorised as “deficient high-hazard” dams. High-hazard dams are anticipated to cause loss of human life if they fail. Many of these were initially built as low-hazard dams, but as populations grew and development proceeded, people have increasingly found themselves in the danger zone.
Downtown Kingstree, South Carolina after flooding caused dam breaches around the state. Photo: AP
One complication for monitoring dam integrity is ownership. The US federal government only controls four per cent of dams, and a full 69 per cent are privately held. The rest are run by local and state governments. Importantly, dams that aren’t controlled by the feds are only regulated on the state level, where neglect has festered. Alabama, for example, doesn’t currently have a dam safety regulatory program, but it does have 201 high-hazard dams.
In South Carolina, following a period of heavy rain in 2015, 36 dams collapsed in the state, and 19 people died in the subsequent flooding. A report by South Carolina’s Department of Health and Environmental control from last December recorded 51 confirmed breaches since the 2015 flood. And in Hawaii, James Pflueger, owner of the Kaloko Dam, was charged with manslaughter after the dam failed in March of 2006 and seven people died. The century-old dam had reportedly never been inspected, despite the fact that state law requires an inspection every five years.
As politicians campaign on rebuilding America’s crumbling infrastructure, the country has mostly been engaged in half-measures that require little sacrifice. As one of his final acts as president, Obama authorised the Water Infrastructure Improvements for the Nation Act, which allocated $US12 billion ($15.6 billion) to a range of projects related to the nation’s water supply. But only a portion of the money is intended to improve the federal government’s high-hazard dams. The Association of State Dam Safety Officials estimates it would take over $US57 billion ($74.4 billion) to rehabilitate all of the nation’s dams.
It’s yet to be seen what the new US president will do — the infrastructure plan he floated before the election would rely on tax incentives for private companies — but the clock is ticking.