Changing climate increases risk for 91,000 US dams, research warns
Studies find potential for ‘significant destruction’ near fire-scarred areas due to increased, uncertain streamflows.
Updated: 3:06 PM CDT Oct 5, 2022
Jordan Crossing Ministries in California’s upper Sacramento Valley is a congregation of survivors. Some members have lived through homelessness, struggled in recovery programs, or battled the court system. Their resilience has brought them together. Five years ago, the parish also survived an almost biblical event, when the spillways at nearby Oroville Dam, the country’s tallest, began deteriorating under unceasing rainfall, forcing more than 180,000 people – including the congregation – to frantically evacuate. “Everybody was saying, we need to go home, pack a bag and leave immediately,” Kayley Reni, a church member, recalled.Rapidly rising water damaged the dam’s main spillway and overran its emergency spillway, leading to several chaotic and tense days in February 2017. Billy Speer, Jordan Crossing’s pastor, shepherded his flock to safety during that time, helping them evacuate and leading them in prayer at shelters in Chico, about a half-hour’s drive away.”We’ve never had to worry (before) about if the dam was going to break or the spillway,” Speer said in an interview.New research points to climate riskBut more communities across the country may now need to worry about previously-unforeseen damage to the nation’s critical infrastructure – including dams, bridges, highways, and cities – due to increasingly severe storms, supercharged by a warming atmosphere, according to two climate studies released in recent months.One study, led by researcher A. Park Williams at UCLA, warns that as increasingly ferocious fires decimate larger forest area – especially once a threshold of 20% of a particular forest is crossed – then those forests will have less ability to hold back or slow stormwater, snow melt, and debris, potentially putting more pressure on dams and other infrastructure caught off guard by stronger streamflow.The second study, from scientists affiliated with the National Center for Atmospheric Research in Boulder, Colo., amplifies the climate warning, projecting the number of times an extreme fire event leads to extreme rainfall within just one year could soar up to 800%, also increasing pressure on dams. “When you have had an extreme wildfire and then you follow it with an extreme precipitation event,” he explained in an interview within sight of burned hillsides by NCAR’s main facility, “that can greatly amplify the flood and debris flow and debris flow hazards because you’ve removed so much of the vegetation from the landscape. If the fire has burned at a high intensity, you’ve transformed the soil into hydrophobic soil, meaning that it repels water.””These kinds of events can be potentially deadly and destructive to property, but they can also be really disruptive to society,” Swain said. Video below: Watch climate researcher Daniel Swain and Chief National Investigative Correspondent Mark Albert use sponges to demonstrate how a changing climate is affecting our atmosphere, leading to more severe droughts and, in some cases, more precipitation Climate change has ‘changed the industry’ Trying to avoid that type of disruption is the focus of David Sarkisian, who leads the California State Water Project’s dam safety program. In a recent interview on top of the Oroville Dam spillways now rebuilt to withstand more intense rainfall events, Sarkisian said that 2017 near-catastrophe “certainly changed the industry across the nation.”Sarkisian described it as “a turning point” in “how we look at spillways, how we look at risk in terms of dam safety and how we’re utilizing risk to really focus our efforts and resources.”In August, scarred hillsides surrounded Oroville Dam on two sides, recent remnants of the Potters and Dixie fires. The land’s newly-burnt, flat surface could impact how fast future precipitation pours downhill into the reservoir. “I see a lot of work ahead of us. I see a need for lots of investment across the nation,” Sarkisian said.America’s dams get ‘D’ grade The danger to the nation’s 91,000 dams – and their nearby communities – has been building. The American Society of Civil Engineers, in its quadrennial infrastructure report card last year, gave America’s dams a ‘D’ grade, citing, in part, a “lack of investment” in maintenance and upgrades. During the past two decades, the report says, the number of high-hazard-potential dams – those that would likely cause a direct loss of human life and extensive property damage in a structure failure – has more than doubled “as development steadily encroaches on once-rural dams and reservoirs.”SEARCH FOR ‘HIGH-HAZARD’ DAMS IN YOUR COMMUNITY HERE The eight-page ASCE report cites the Oroville Dam spillway failure, as well as the failure of dams in Edenville and Sanford, Michigan, in 2020, as “recent crises following heavy seasonal rains… highlighting the poor condition of many of the nation’s dams.”Angelique Fabbiani-Leon, state hydrometeorologist at the California Department of Water Resources, said in an interview that some dam managers are now changing the decades-old models they’ve previously used to project how much water will be accumulating, in order to adapt to a changing reality.”Of course, yes,” a changing climate is affecting Oroville Dam, she said.”We’re not seeing normal conditions anymore,” said Fabbiani-Leon. “We’re seeing the more extreme precipitation.”Climate resiliency buildsFor the resilient church community just downstream from Oroville Dam at Jordan Crossing Ministries – which first fled from a climate crisis five years ago – the extremes have not stopped coming since.Drought, severe storms, possible flooding, and ferocious wildfires have all put the congregation on edge through multiple evacuations – but the parishioners always return.”It’s made us stronger,” said Pastor Billy Speer. “I seen the community come together like never before.”A community – and a congregation – of climate survivors. Mark Albert is the chief national investigative correspondent for the Hearst Television National Investigative Unit, based in Washington D.C. April Chunko, Tamika Cody, John Breedlove, Mason Silva, Sarah Venti, and Greg Compton contributed to this report. Help us cover a changing climate for our ‘Forecasting Our Future’ series. If you know of innovative projects or controversial issues in your community, send confidential information and documents to the National Investigative Unit at investigate@hearst.com.’Forecasting Our Future’ Full National Investigative Unit Coverage:Survey: Most concerned about future extreme weather, only half taking steps Why a 1-foot rise in sea level has a bigger impact than you think Man loses home to Hurricane Ida, 16 years after grandmother lost hers to Hurricane KatrinaInside America’s ‘Forest Census’ Spurred by Climate Urgency, Communities Begin Searching for Water Taming the Surge: Communities Race to Contain Climate-Fueled Floodwaters Communities create ‘green jobs’ now to forestall climate impacts Changing climate increases risk for 91,000 US dams, research warns Virtual reality increasingly used to convey climate urgency All ‘Forecasting Our Future’ special reports
Jordan Crossing Ministries in California’s upper Sacramento Valley is a congregation of survivors. Some members have lived through homelessness, struggled in recovery programs, or battled the court system. Their resilience has brought them together.
Five years ago, the parish also survived an almost biblical event, when the spillways at nearby Oroville Dam, the country’s tallest, began deteriorating under unceasing rainfall, forcing more than 180,000 people – including the congregation – to frantically evacuate.
“Everybody was saying, we need to go home, pack a bag and leave immediately,” Kayley Reni, a church member, recalled.
Rapidly rising water damaged the dam’s main spillway and overran its emergency spillway, leading to several chaotic and tense days in February 2017. Billy Speer, Jordan Crossing’s pastor, shepherded his flock to safety during that time, helping them evacuate and leading them in prayer at shelters in Chico, about a half-hour’s drive away.
“We’ve never had to worry (before) about if the dam was going to break or the spillway,” Speer said in an interview.
New research points to climate risk
But more communities across the country may now need to worry about previously-unforeseen damage to the nation’s critical infrastructure – including dams, bridges, highways, and cities – due to increasingly severe storms, supercharged by a warming atmosphere, according to two climate studies released in recent months.
One study, led by researcher A. Park Williams at UCLA, warns that as increasingly ferocious fires decimate larger forest area – especially once a threshold of 20% of a particular forest is crossed – then those forests will have less ability to hold back or slow stormwater, snow melt, and debris, potentially putting more pressure on dams and other infrastructure caught off guard by stronger streamflow.
The second study, from scientists affiliated with the National Center for Atmospheric Research in Boulder, Colo., amplifies the climate warning, projecting the number of times an extreme fire event leads to extreme rainfall within just one year could soar up to 800%, also increasing pressure on dams.
“When you have had an extreme wildfire and then you follow it with an extreme precipitation event,” he explained in an interview within sight of burned hillsides by NCAR’s main facility, “that can greatly amplify the flood and debris flow and debris flow hazards because you’ve removed so much of the vegetation from the landscape. If the fire has burned at a high intensity, you’ve transformed the soil into hydrophobic soil, meaning that it repels water.”
“These kinds of events can be potentially deadly and destructive to property, but they can also be really disruptive to society,” Swain said.
Video below: Watch climate researcher Daniel Swain and Chief National Investigative Correspondent Mark Albert use sponges to demonstrate how a changing climate is affecting our atmosphere, leading to more severe droughts and, in some cases, more precipitation
Climate change has ‘changed the industry’
Trying to avoid that type of disruption is the focus of David Sarkisian, who leads the California State Water Project’s dam safety program.
In a recent interview on top of the Oroville Dam spillways now rebuilt to withstand more intense rainfall events, Sarkisian said that 2017 near-catastrophe “certainly changed the industry across the nation.”
Sarkisian described it as “a turning point” in “how we look at spillways, how we look at risk in terms of dam safety and how we’re utilizing risk to really focus our efforts and resources.”
In August, scarred hillsides surrounded Oroville Dam on two sides, recent remnants of the Potters and Dixie fires. The land’s newly-burnt, flat surface could impact how fast future precipitation pours downhill into the reservoir.
“I see a lot of work ahead of us. I see a need for lots of investment across the nation,” Sarkisian said.
America’s dams get ‘D’ grade
The danger to the nation’s 91,000 dams – and their nearby communities – has been building.
The American Society of Civil Engineers, in its quadrennial infrastructure report card last year, gave America’s dams a ‘D’ grade, citing, in part, a “lack of investment” in maintenance and upgrades. During the past two decades, the report says, the number of high-hazard-potential dams – those that would likely cause a direct loss of human life and extensive property damage in a structure failure – has more than doubled “as development steadily encroaches on once-rural dams and reservoirs.”
SEARCH FOR ‘HIGH-HAZARD’ DAMS IN YOUR COMMUNITY HERE
The eight-page ASCE report cites the Oroville Dam spillway failure, as well as the failure of dams in Edenville and Sanford, Michigan, in 2020, as “recent crises following heavy seasonal rains… highlighting the poor condition of many of the nation’s dams.”
Angelique Fabbiani-Leon, state hydrometeorologist at the California Department of Water Resources, said in an interview that some dam managers are now changing the decades-old models they’ve previously used to project how much water will be accumulating, in order to adapt to a changing reality.
“Of course, yes,” a changing climate is affecting Oroville Dam, she said.
“We’re not seeing normal conditions anymore,” said Fabbiani-Leon. “We’re seeing the more extreme precipitation.”
Climate resiliency builds
For the resilient church community just downstream from Oroville Dam at Jordan Crossing Ministries – which first fled from a climate crisis five years ago – the extremes have not stopped coming since.
Drought, severe storms, possible flooding, and ferocious wildfires have all put the congregation on edge through multiple evacuations – but the parishioners always return.
“It’s made us stronger,” said Pastor Billy Speer. “I seen the community come together like never before.”
A community – and a congregation – of climate survivors.
Mark Albert is the chief national investigative correspondent for the Hearst Television National Investigative Unit, based in Washington D.C. April Chunko, Tamika Cody, John Breedlove, Mason Silva, Sarah Venti, and Greg Compton contributed to this report.
Help us cover a changing climate for our ‘Forecasting Our Future’ series. If you know of innovative projects or controversial issues in your community, send confidential information and documents to the National Investigative Unit at investigate@hearst.com.
‘Forecasting Our Future’ Full National Investigative Unit Coverage:
