Disturbing Deficiencies Seen in California’s Dam Safety Efforts

The dam burst on a warm afternoon, unleashing nearly 300 million gallons of muddy water on a Los Angeles neighborhood. Five people died and dozens of homes were swept off their foundations and destroyed.

In the aftermath of the 1963 Baldwin Hills Dam catastrophe, the state strengthened inspection regulations, helping establish California as a modern leader in dam safety.

That reputation was called into question last week, however, as two spillways at the towering Oroville Dam north of Sacramento began to crumble in the wake of heavy rains and snowmelt, forcing tens of thousands of people to evacuate. Though the dam — the tallest in the nation at about 770 feet — had been regularly inspected and cleared as safe, both spillways eroded when carrying relatively small amounts of water.

The 50-year-old structure’s apparent fragility took many by surprise, prompting calls for more robust inspections, maintenance and emergency planning at all of California’s 1,585 dams — aging facilities that likely will be tested more severely in the coming years by global warming and anticipated periods of intense rain.

Despite those concerns, a Chronicle review of federal data found disturbing deficiencies in California’s dam-safety efforts.

As of October 2015, about a dozen state-monitored dams where failure could result in death or property destruction had gone more than two years between inspections, though checks are supposed to be done once a year. Home to some of the country’s biggest dams, California also lags behind the national average in emergency preparedness for dam failure, with hundreds of high-risk sites lacking plans to handle a potential crisis.

“It is reason for alarm,” said Robert Bea, a professor emeritus and engineering expert at UC Berkeley. “If systems are in the very old, geriatric phase, inspections need to be annual.”

Officials with the Department of Water Resources, which inspects most dams in California, defended their safety program as well-funded and robust. In recent years, they said, they have worked with more than 100 dams to prepare emergency plans and currently have about $2 billion worth of repair projects under way.

“In California, detailed reviews of dams is based on highest priority and greatest need, with public safety as the first priority,” department officials wrote in an email.

A 2016 peer review conducted by the Association of State Dam Safety Officials at the request of the Department of Water Resources concluded that California had the leading dam safety program in the country, noting that most high-risk dams were monitored by a “very well-documented and rigorous” state inspection program.

One in 3 dams in California was built in the 1950s and 1960s, when the bulk of the state’s sprawling water system was put in place. Since then, entire towns have popped up downstream from the aging facilities, making inspections and maintenance increasingly important, experts say.

California routinely monitors most of its dams, including Oroville, which is designated as “high-hazard” — meaning failure or misoperation would likely result in people dying.

State-regulated dams that could pose safety risks to people or property are supposed to be inspected at least once a year, but can go essentially 24 months between reviews if inspected at the beginning of one year and the end of the next. Those examinations often include visual checks to see if anything obvious is amiss and measurements of issues like seepage and water pressure. Every five years, federal inspectors and independent consulting boards conduct more in-depth evaluations of the critical structures, which are used to prevent floods and store water.

More than half of California’s dams — 833 — are rated “high-hazard.” More than 80 percent of those are considered to be in relatively good condition, compared with only 40 percent nationally, according to 2015 National Inventory of Dams data.

California is one of only 16 states that strives to inspect high-hazard dams once a year, according to Mark Ogden, project manager with the Association of State Dam Safety Officials. Although the association recommends annual checks to ensure safety, most states go two or more years between inspections.

As of Oct. 20, 2015, at least 38 California facilities overseen by the state also had not been inspected within the recommended time frame, according to a Chronicle review of U.S. Army Corps of Engineers data. Of those dams, at least 13 would likely cause property damage or death if they failed.

The Bidwell Lake Dam, which was built in 1865 and stores drinking water for 660 homes in rural Plumas County, has not been inspected since June 2014, despite being considered a high-hazard facility.

The dam sits about 2 miles upstream from the small town of Greenville, and pales in size compared with Oroville. Still, the recent crisis has some residents worried about the man-made lake above them.

“I think whenever those things happen it raises concern,” said Chris Gallagher, general manager of the Indian Valley Community Services District, which owns the dam. “Because of its age, it would be nice if the Department of Water Resources came and took a look at it on a more regular basis.”

The Suttenfield Dam in Sonoma County near Glen Ellen, also considered high-hazard, went more than two years without inspection between 2013 and 2015. An examination last year revealed no safety concerns, said Brian Ferguson, a spokesman for the agency that operates the facility.

Sonoma County had 10 of the 13 high-risk dams that went multiple years without an official review by the state.

“If you don’t do (timely) inspections, you’re going to miss problems,” said Peter Gleick, co-founder of the Oakland environmental think tank the Pacific Institute. “There are unsafe, hazardous facilities, and I would suspect that deeper inspections will reveal deeper problems.”

Unlike some states, California does not require owners of high-hazard dams to create emergency action plans. Such plans include maps of areas expected to be inundated by flooding, procedures for warning downstream residents and other information crucial to reducing potential death and destruction following a breach.

The Rector Creek Dam, which is 3 miles from Yountville and supplies water to a nearby veterans home, does not have an emergency plan, according to the Department of Water Resources, which has regularly inspected the facility.

A spokesman for the state’s Department of Veterans Affairs, which owns the dam, said the dam does have an emergency plan, but he was unable to provide it before publication.

Of the 678 high-hazard dams regulated by state authorities, 216 did not have a formal emergency action plan in place, according to 2015 data provided by the Association of State Dam Safety Officials.

“It’s troubling,” said Ogden of the national association. “Emergency preparedness comes down to human life: If you can prevent failure from occurring, or at least get people out of the way, you can save lives.”

The review conducted last year by the association also found emergency response weaknesses in the state’s dam safety program, including that many staff members were unaware of their responsibilities during and after an event.

As of last month, Department of Water Resources officials said, there were 679 high-hazard dams and they had encouraged about a dozen more to implement emergency plans.

Oroville Dam, built in 1968 and owned, operated and inspected by the Department of Water Resources, has an emergency plan. But a 2011 letter from the agency to federal regulators revealed that local officials do not believe there would be enough time to evacuate nearby residents in the event of a dam failure, according to the Associated Press.

Lake Oroville is a key cog in California’s water system, second only to Lake Shasta in storage capacity. The massive reservoir sends water to Central Valley farms as well as several urban water agencies, including the Metropolitan Water District of Southern California and the Santa Clara Valley Water District.

The reservoir also provides flood control for downstream communities and helps regulate salinity in the Sacramento-San Joaquin River Delta.

On Feb. 7, a gaping crater formed in the primary spillway, and the dam’s emergency spillway later eroded to a point of near-failure under far less water flow than both were designed to withstand. Surrounding towns were evacuated on Feb. 12.

The problems appear to have been caused by defects that either had shown up in inspections or were flagged to state and federal officials going back more than a decade — prompting some experts to question the state’s monitoring of the dam.

The Department of Water Resources has defended its management of the main spillway and its handling of the situation, describing it as a unique event.

It is unclear what inspectors may or may not have found during the dam’s most recent, more detailed five-year inspection; those records were not immediately available.

“Did they miss something that they should have caught? Or did they catch it and ignore it?” said Martin McCann of Stanford’s National Performance of Dams Program, a research group dedicated to dam operations, safety and public policy. “Maybe they did everything right and it just wasn’t good enough to catch this particular problem.”

Still, McCann said, the deterioration of both spillways under relatively low water flows raised serious concerns about whether the inspections and engineering evaluations were thorough enough and whether they should be done more often.

In response to the crisis at Oroville, Assemblyman Marc Levine, a San Rafael Democrat, introduced legislation Friday that would require more extensive annual inspections of spillways on state-managed dams.

“It was announced that the state had engaged in visual rather than physical inspections of the Oroville Dam spillways,” Levine said. “I was alarmed and, quite frankly, angry to learn they had not applied a level of seriousness necessary to protect human life in California.”

Similarly strong reactions followed the breakdown of a huge gate at Folsom Dam in 1995. The breach spilled enough water each second to supply a family of five for a year and forced boaters, hikers and anglers to evacuate the American River, the Associated Press reported at the time.

Michael Macor, The Chronicle

Although the incident posed no danger to communities downstream, it prompted significant improvements in how dam gates are evaluated, inspected and maintained, McCann said, such as establishing regular replacements of mechanical components.

“All of this points to some level of concern about how we look at dams and how we capture evidence on issues that may be taking place that we are not uncovering and dealing with in a timely manner,” McCann said.

As of 2013, California budgeted nearly $12 million for its dam safety program, or more than $9,000 per regulated dam — compared to the national average of less than $1,000 per dam, according to National Inventory of Dams data. That funding does not include money for maintenance and repair, said Ogden of the Association of State Dam Safety Officials.

“They are really far and above any other state program,” he said. “They have a lot of resources and they use them.”

Still, critics argue that the investment is not enough for the nation’s largest and most complex water system, which was built with much different weather patterns in mind.

Due to ongoing climate change, experts say California’s expected snowfall will decrease, and the state will face longer stretches of drought followed by extreme rain and floods. Dams will likely be severely strained during wet years and should be upgraded to handle more punishing weather.

The 64-year-old Isabella Dam, on the Kern River near Bakersfield, is set to begin a sweeping $500 million reconstruction project this fall to address earthquake safety concerns, seepage problems and to prepare for more water flow than it was constructed to handle.

In the new design, the dam’s spillway capacity has been tripled to accommodate a “Noah-like event,” said Dana Munn, the Kern River Watermaster, who handles policy affecting the river.

“The crisis at Oroville tells us we need to be thinking more carefully about California’s overall water challenges,” said Gleick of the Pacific Institute. “We can’t take the old infrastructure’s safety for granted any longer.”

Nicholas Sitar, a UC Berkeley professor in civil and environmental engineering, said the situation at Oroville provides important lessons. Historically, the political climate in California has put dam maintenance and upgrades low on the state’s list of priorities — even as the risk of failure, and the potential for catastrophic damage, have steadily grown.

“The impact if something happens is so different than when these dams were built and designed,” Sitar said. “What was acceptable risk at the time is no longer acceptable.”

Residents of Oroville were confronted with that reality last week as their local dam turned from a scenic hill, often used for hiking and recreation, into a life-threatening hazard.

Joe Williams, a 27-year-old manager at a local coffee shop, said the evacuation was chaotic and surreal. Since his return last Tuesday, he said he has kept an emergency backpack full of clothes in his car just in case he must flee again.

“It has left us all with an uneasy feeling that hasn’t gone away yet,” Williams said.

Article by: Joaquin Palaomino and Cynthia Dizikes
Published: February 19, 2017 by The San Francisco Chronicle
Read original here.