Responses to crises often advance the cutting edge in dam safety
By Zachary Matson
During heavy rain in February 2017, concrete collapsed at California’s Oroville Dam, the tallest in the nation. Water pushed through the 3,000-foot-long spillway and drowned the adjacent hillside, eventually overtopping the emergency spillway.
Erosion undermined the dam and officials ordered the evacuation of more than 150,000 downstream residents amid fears of a catastrophic failure.
The worst-case scenario didn’t materialize. But the structure suffered over a billion dollars in damage, and California lawmakers within six months passed laws strengthening oversight and requiring owners of risky dams to post inundation maps showing the extent of potential flooding if a dam failed.
In state after state, the gears of policy start grinding after a crisis.
“That’s what happens when you have a significant dam event,” said Lori Spragens, executive director of the Association of State Dam Safety Officers.
The responses that follow major incidents often advance the cutting edge of dam safety practices, paving the way for other state programs. Now, the California dam safety website offers downloads of inundation maps by the dozen.
In New York, the state’s dam inventory is inaccessible online. The state Department of Environmental Conservation requires formal records requests for the list of dams. The dam listing is also embedded in an online mapping program.
Adirondack dam database
After a pair of Michigan dams failed in 2020, forcing the evacuation of 10,000 residents and causing $200 million in damage, a dam safety task force proposed reforms to bolster funding, strengthen safety compliance and improve oversight. Michigan lawmakers still have not adopted many of the reforms.
Dam safety officials for years have highlighted the deteriorating condition of the nation’s dams and called for more money to repair, replace and remove them. Understaffed state dam safety divisions struggle to keep up.
With funds from a federal infrastructure law and New York’s state environmental bond act set to flow over the coming years, dam owners should see financing for repairs, but it’s not clear how far the money will go in addressing needs.
New York, which last updated its dam safety regulations in 2009, uses many of the field’s best practices—and required inundation maps years before California—but safety practices have continued to evolve in the past decade.
Other state dam safety programs and the Federal Emergency Management Agency’s “Model Dam Safety Program” suggests:
- Greater transparency with inundation maps, dam inventories and safety information on an accessible website.
- Risk-informed decision making based on more detailed analysis of failure scenarios.
- Alternative funding for inspections and repairs from annual owner fees based on dam size and hazard, and penalties for noncompliance.
- Inspections conducted in a routine and comprehensive cycle so that dams receive an in-depth review every few years.
- Reviews by outside dam safety experts to evaluate safety programs every 10 years and propose areas of improvement.
“I want inspectors to focus on meeting with owners, talking through what they’re doing, why they’re there,” he said. “We’re not just pointing things out to be picky, we have a reason, and the more the owner understands that, it moves us to the point of where we both want to be. We all want a safe dam.”
The average dam in New York is 86 years old, compared to the national average of 57 years, according to the 2022 Report Card for America’s Infrastructure produced by the American Society of Civil Engineers. “New York’s dams are significantly older than those across the rest of the United States and many of them were built before modern design standards,” the organization wrote. Adirondack dams are even older, nearly 90 years old on average.
In September FEMA updated its Model State Dam Safety Program guide, the first update in 15 years, outlining best practices.
The update included a stronger emphasis on overseeing, assessing and classifying the needs of existing dams and the continued development of risk analysis approaches. The model program highlights the value of publishing inundation maps, something Canestrari said he was open to if the purpose of the maps was well explained.
“Dam safety programs are determining there are more benefits to having a knowledgeable public during an emergency event than there are risks resulting from the release of this information,” according to the model program.
Officials should develop “an outreach and awareness mindset” among staff and set up workshops for owners and simulations for first responders. The guide promotes a “well designed web page that is kept current” to share information and “raise public awareness.”
FEMA recommends directing penalties assessed against dam owners into an emergency repair fund. Other possible measures include requiring dam owners to demonstrate the financial wherewithal to maintain a dam and charging annual owners fees based on dam size and hazard.
Keith Mills, a longtime Oregon dam safety official who chaired development of the new FEMA model program, said state agencies can do more to differentiate the risks of specific dams.
“For your risk analysis, you do a frequency analysis of how likely that flood would occur, what (storm) return interval would cause overtopping and what amount of overtopping would cause it to fail,” Mills said. “You are also looking at the number of people that would be affected.”
After a pair of neglected dams failed in 2020, Michigan created a task force of experts that in six months made dozens of recommendations. The experts found that, like in New York, many of Michigan’s dams “are aging, poorly maintained, and/or inadequately engineered for changing environmental conditions.”
The task force proposed a revolving loan program to finance dam repairs, while simplifying the process and offering grants to remove dams. Recommendations also included licensing dam owners for a finite period and requiring owners set aside funds for maintenance and removal if a license is not extended.
Explore more: Dam series
See all the articles in our Adirondack dams series
The Golden State approach
California dam inspectors face a risk landscape that includes the threat of earthquakes and populations of hundreds of thousands of residents living within the flood zones of high hazard dams, some of the largest in the country. With around 80 employees, mostly civil engineers and engineering geologists, California’s dam safety division is larger than the Adirondack Park Agency.
California attempts to inspect nearly 1,000 dams on an annual basis, deploying engineers by region.
“We see an advantage to getting out there every year,” said Sharon Tapia, head of California’s dam safety program.
The state charges dam owners an annual fee based on the size of the structure, generating around 90% of the dam safety program’s $23 million budget. They also raise funds through permit application fees. After the Oroville incident, California lawmakers strengthened the dam safety program and created an “extremely high hazard” classification.
“We felt it was important to separate those high hazard dams,” Tapia said. “You can’t really compare a dam with 50,000 people downstream to one with two, so we needed to define that.”
The new inundation mapping requirement took effect in June 2017, and owners were expected to submit them six months later. Tapia said the department shifted resources to process the maps and ensure the public could access them online.
“That information wasn’t readily available,” Tapia said. “Because of what happened at Oroville, there was so much discussion about inundation areas, it was really an educational moment for people.”
State lawmakers also required an independent peer review of its dam safety program every 10 years. Tapia said the first review encouraged the department to develop more internal methods to use risk-informed analysis.
“It’s a real in-depth look, a comprehensive review of the dam as a whole and looking at all potential failure modes,” Tapia said.
Federal and state dam money
Funding to repair and remove dams will see dramatic increases over the next few years as federal infrastructure dollars and the state’s environmental bond act money begin to flow –even as repair needs stretch indefinitely into the future.
The state bond act itemized $650 million for flood risk reduction projects, including moving, lifting or raising flood-prone infrastructure and buildings; relocation of roads; and removal, alteration or right-sizing of dams, bridges and culverts.
It’s not clear how much of that will be allocated to dams or how much of that will make its way to the Adirondack Park.
Separately, the federal Bipartisan Infrastructure Law approved in 2021 set $2.7 billion nationwide for dam rehabilitation, removal and retrofitting for hydropower. The bulk of the funds that can be used to repair high hazard dams will flow through FEMA’s high hazard grant program.
Spragens, head of the national dam safety association, said the FEMA funding process has been “slogging along and we don’t know why.”
For its part, FEMA in October released the first of $15 million in dam repair funds from the infrastructure law and promised $733 million over the next five years. The program had been funded at around $12 million per year.
“That was a substantial investment,” Spragens said.
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