State dam safety programs could get new look after summer storms

Supercharged summer storms unleashed a deluge of rain in many Midwestern states this year, pushing several aging dams past their capacity as floods tore away embankments, inundated subdivisions and carried sediment that had built up for decades downstream.

In the southern Illinois town of Nashville, six inches of rain fell in just a few hours in mid-July. The deluge pushed water from a city reservoir over the top of a 90-year-old dam, prompting evacuations of 200 nearby homes and businesses. Officials also ordered evacuations in the eastern Wisconsin town of Manawa in early July, after water started eroding the banks along the side of a dam.

But the most striking scenes came from southern Minnesota in early June, when the Blue Earth River tore a new path around the Rapidan Dam near Mankato. Trees and other debris blocked the gates where water was supposed to flow, so it diverted course to its western bank, which was made of topsoil. The river eventually caused the collapse of a house next to the dam. County officials bought a nearby store and tore it down, to prevent it from becoming dangerous debris flowing down the river.

There are more than 92,000 dams across the country, and most of them are regulated by states—not the federal government. More than half of them are owned by private entities, and a fifth are owned by local governments. At least 4,000 dams are in poor or unsatisfactory condition, according to the federal government, meaning they could kill people or do significant damage to the environment if they fail. But even with the growing threats from climate change and the rising age of dams—the average dam is 63 years old—getting attention and funding for their upkeep is still a challenge.

“Over the last 20 years, the number of high-hazard-potential dams has more than doubled [to more than 2,300] as development steadily encroaches on once rural dams and reservoirs,” warned the American Society of Civil Engineers in its 2020 infrastructure report card.

Unwanted Attention Gets Money Flowing

Often, attention only comes when disaster strikes.  

“Dam safety programs are usually hidden somewhere in the water resource program or somewhere else in government,” said John Moyle, the former head of New Jersey’s dam safety agency and a member of the American Society of Civil Engineers’ infrastructure committee. “It’s difficult to get the governor’s attention until we have an incident. … But it’s a very important program: It’s protecting lives by making sure these dams are safe.”

While he worked in New Jersey, the dam safety staff went from two entry-level engineers to 17 full-time employees, following repeated incidents of dams failing. The state now offers a $100 million revolving loan program that gives grants and low-interest loans to public and private owners of high-hazard dams that need rehabilitation.

Michigan ramped up staffing and increased funding for dam repair and removals in 2021, following the failure of the Edenville and Sanford dams the prior year.

In Vermont, Gov. Phil Scott has had little choice but to become an expert in dam safety, Moyle said. More than a third of dams in the state are more than a century old, a fact that the public is increasingly cognizant of because of recurring flooding. Last year, five dams were effectively destroyed, while 60 were overtopped. New York and Massachusetts sent engineers to help Vermont evaluate the safety of dams in the wake of the storms. Rising water at the Wrightsville Dam near Montpelier threatened to flood the capital city for a time. This year, the remnants of Hurricane Beryl inundated the state once again, but the damage turned out to be less severe.

Vermont lawmakers responded to the flooding last year by passing legislation that increased the number of staff positions for the state’s dam safety program from five to nine. They increased scrutiny of power-generating dams and added $4 million to a revolving loan fund that could help private landowners remove dangerous dams.

Scott, a Republican, allowed the package to become law without his signature, arguing that the law did not give landowners enough time to comply with other provisions of the measure.

Disasters Bring a New Approach

The 2017 failure of the Oroville Dam in California—the tallest in the country—resulted in big changes to safety preparations in the state.

The Oroville Dam north of Sacramento is a crucial piece of California’s water infrastructure. But after a wet winter, the dam’s concrete spillway became damaged. State operators shut the gates leading to the spillway, which filled the reservoir more quickly. Then water started spilling over a second opening. That threatened the integrity of the dam, so the operators opened up the damaged spillway, an act that destroyed it. Meanwhile, local officials evacuated 200,000 area residents in case the dam itself failed.

The dam held, but the incident caused $1.1 billion in damage.

Outside experts produced a 584-page report in 2018 outlining the many human and engineering factors that led to the near-disaster. They found pervasive problems that started with how the spillway was designed before the dam opened in 1968, and continuing up until the incident.

But some of the engineering team’s findings focused on gaps in the state’s regulation of dams and its enforcement of dam safety regulations.

Sharon Tapia, the chief of the dam safety division of the California Department of Water Resources, said having the report’s findings gave her leverage and helped bolster the case with lawmakers and other state officials to shore up California’s regulatory approach.

“The report listed the good parts about our program—the strengths—but then it listed the gaps where we weren't up to par, compared to other programs and the model program for the nation,” Tapia said. “After the Oroville incident, I was able to use that to [help lawmakers decide] what to focus on.”

In the incident’s wake, state officials began requiring flood inundation maps and emergency action plans for most dams. The state also stepped up assessments of dam spillways to look at their maintenance and inspection, how they performed historically and any repairs that had been made.

The state ramped up the size of the dam safety team, which was already the largest in the country before the Oroville incident. The staff grew from 61 full-time employees to 91, and the budget went from about $13 million a year to $28 million. (California’s program, unlike that of any other state, is funded through assessments of dam owners.)

“Our staff increased because we had a significant expansion of the program. We took on a lot more authority,” said Tapia, who is also the president of the Association of State Dam Safety Officials.

Dam Safety Makes (Small) Strides

But dam safety officials say there is a long way to go to fund the upgrades needed for the nation’s dams, whether that means shoring up critical structures or removing obsolete ones. State dam safety officials estimated last year that the total cost of rehabilitating non-federal dams would be nearly $158 billion. Just addressing the needs for the most critical dams would cost more than $34 billion.

The federal government has provided some support for safety efforts. The 2021 infrastructure law, for example, included more than $3 billion in various dam safety activities.

Tapia said advocates should take advantage of attention on dam safety when incidents occur, even if those incidents are in other states. Local advocates can keep their own lists of needed improvements, so when lawmakers raise concerns, they have potential changes ready to go, she said.

“We need continued investments to improve dams,” Tapia said. “They are a vital part of our nation’s infrastructure, and we have to keep our attention on them.”