The nation’s capital, built on water, struggles to keep from drowning
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This is the shoreline George Washington would have seen in 1791, when he chose the site for the nation’s new capital. It was a land of wetlands, marshes and creeks.
Horse-drawn carts carried crushed rock from the construction site of the Capitol, nearby quarries and sediment dredged from the Potomac River. The fill was compacted to create the land where the National Mall sits today.
The African American museum was built on the lowest and last spot then available on the Mall. Engineers had expected to hit water, but the forces of nature they disturbed put the project in immediate peril.
Derek Ross, head of museum construction, despaired as he stared into the colossal 80-foot pit where workers were digging out the basement for the new African American history museum. The huge excavators had broken into a hard clay soil that encased much of Tiber Creek, which was buried 150 years ago. Over the decades, the soil had formed a pressurized cushion around the underground aquifer that held up other buildings on the Mall. But now, it seemed in danger of collapsing.
The water was rushing out of the aquifer more quickly than it was being replenished by the creek. It was the same aquifer that flowed under the Washington Monument, a mere 800 feet away. Ross worried that if the cushion collapsed, the monument would shift or, worse, topple over. When he closed his eyes, he saw a giant sinkhole.
“I had a recurring dream that I’d walk to work one day and the Washington Monument wouldn’t be there.”
The work had to stop. Water pumps around the monument normally used to pull extra water out of the ground during rainstorms were reconfigured to force water back underground to refill the cushion. Piezometers were installed to measure the pressure and level of groundwater.
What excavators unearthed at the site of the African American museum in 2012 was not only the long-forgotten topography of the nation’s capital, but a subterranean geology that, two centuries later, determines the city’s vulnerability to catastrophic flooding as climate change intensifies storms, rainfall and sea-level rise.
At risk are the national treasures housed inside the Federal Triangle, the low-lying area between the White House and the Capitol, home to 39 critical government facilities, $14 billion in property and irreplaceable artifacts of America’s history.
Personal treasures and the homes and businesses of Washingtonians living atop historical, buried streams across the city, are regularly inundated with raw sewage and filthy water. Urban floods can be fatal, as in August when 10 dogs drowned inside a kennel on Rhode Island Avenue NE, a location with a decades-old flood history.
While federal Washington is best known for its neoclassical buildings and white marble monuments, the District of Columbia is actually a low-lying delta city like New Orleans, but one constructed on top of settling rock and rubble fill.
The buildings that make up the Federal Triangle sit on land reclaimed from Tiber Creek. Once a few hundred feet wide, the creek ran along what is now Constitution Avenue, and drained much of Washington into the Potomac.
The plan for the new capital turned Tiber Creek into a canal. But that attempt to harness nature backfired because the waterway was often choked with sediment, pollution and sewage.
To improve sanitation, the city covered Tiber Creek and created a sewer.
Buried but not vanished, the underground streams and canals became part of a permanent high-water table in the downtown area known decades later as the Federal Triangle.
Then there’s the water that comes from the gigantic Potomac Watershed, where the rain falling on the 14,690 square-mile region travels from as far away as the Appalachian Mountains in West Virginia, down the streams of the Piedmont’s hard rock, past the Atlantic Fall Line onto the sandy Atlantic Coastal Plain. From there, it flows into the Potomac River and then Chesapeake Bay on its way to the wide-open Atlantic Ocean.
Before colonization, when Native American tribes lived here, rainfall was naturally absorbed along its journey to the ocean by marshes and streams. Once European settlers began clearing and grading the land for farming, though, the ground became less permeable. Erosion and runoff carried massive quantities of sediment downstream and deposited them into mud flats along the banks of the Potomac.
A few centuries later, the Army Corps of Engineers reshaped them into the Reflecting Pool, Tidal Basin and adjoining parkland.
Fast forward to the 21st century, a heavy downfall on top of a high-water table in an already low-lying area such as the Federal Triangle can even “cause the water to come back up from the ground,” said Karen Prestegaard, a geologist at the University of Maryland. A series of spectacular floods has resulted.
Derek Ross’s confrontation with the underground history of Washington turned into $20 million in unplanned changes to the National Museum of African American History and Culture. “I expected it to test us, but I didn’t expect it to test us as much as it did and in the way it did,” said Lonnie G. Bunch III, head of the museum at the time and now secretary of the Smithsonian Institution.
The result was the first museum on the National Mall to listen to what nature is telling us about coexisting on the planet in the era of climate change.
Builders hauled in loads of fill to lift the building’s ground level 15 feet above the rest of the Mall.
To protect the five stories underground, the African American museum’s basement has double walls eight feet apart from each other. The inner wall is coated with a waterproof skin. Between the two walls, gravel and light concrete absorb any water that might seep in. The two walls are capped with another waterproof barrier. The lawn surrounding the museum’s above-ground bronze crown is actually a grass roof installed to absorb rainwater.
Two buried tanks, one that holds 100,000 gallons,the other 15,000 gallons, capture rain and underground water that collects near the basement and uses it to flush toilets and water the landscaping. In a flood, the full cisterns can wait to release their loads until the District’s wastewater pipes have been drained of storm water elsewhere.
A state-of-the-art flood wall protects the museum’s “Achilles’ heel,” as Ross calls the entrance to the underground loading dock, the lowest part of the building. “It doesn’t require any human beings,” he said, because people make mistakes. Instead, the flood wall is automatically triggered when a flotation device underneath it senses the presence of water.
Other Smithsonian museums in or near the 100-year flood plain are being slowly retrofitted with flood protection: A new flood gate is up at the National Air and Space Museum; the chronically flooded Hirshhorn Museum and Sculpture Garden is getting its first storm water system; and the National Museum of American History, the most vulnerable of the Smithsonian museums, will get two cisterns and higher flood gates, and send its basement-level collection to Suitland, Md. for storage.
Under the worst-case climate scenario, the American History museum could find itself beyond protection of the 17th St. Levee and “under 16.3 feet of water,” according to the Army Corps and the D.C. Climate Projections & Scenario Development Report.
A sinking capital faces rising waters
After he began his new job, Matthew Morrison discovered the most important charges under his care were suffering from limb lacerations, solar radiation burns and a chronic lack of oxygen that had severely weakened and deformed them. “What can we do to stop the bleeding?” he asked himself.
It was 2019, and Morrison had just been named National Park Service chief arborist for the National Mall and Memorial Parks, which means he was in charge of the Mall’s 2,700 cherry trees. He quickly realized that a swift action plan to save the drowning cherry trees was unlikely with so many decision-makers above him.
So Morrison went rogue. At the end of one workday, he dispatched a dump truck filled with fresh wood chips to a grove of cherry trees at the Tidal Basin near the Jefferson Memorial. Packing a deep bed of nutritious chopped wood around their trunks, he believed, was like injecting a dying patient with a miracle drug and would help heal the most recognizable living icon in the nation’s capital from the wounds of climate change and soil as dense as a brick from foot traffic.
Morrison, 62, has the earthy hands of the Adirondack tree climber he once was before college turned him into an arborist. But for all his derring-do and skill, he was unable to save scores of twisted cherry trees starved of oxygen from standing in polluted high-tide waters twice a day.
In the Tidal Basin, completed in 1897, water has risen four feet over the past century — one foot from rising seas and three feet from its sinking foundation built on fill, according to the National Park Service. But in the next 30 years alone, sea levels will rise another foot, tripling the rate of the previous 100 years, according to National Oceanic Atmospheric Administration.
Morrison and his maintenance crew are preparing for an even larger and more painful rescue effort: To upgrade the Tidal Basin, 300 trees will be cut down so construction workers can raise the 90-year-old sea wall nearly five feet higher and widen it as well.
In the spring, after the trees bloom one last time, Cianbro Construction of Pittsfield, Maine, will begin a two-year, $112.7 million renovation along a 1.2-mile segment near the Jefferson Memorial and along West Potomac Park. After they are done, they will plant 400 new cherry trees.
The last time so many trees were removed from the Tidal Basin, during construction of the Jefferson Memorial, 150 Washington society ladies chained themselves to trees in protest. The 1938 Cherry Tree Rebellion won President Franklin D. Roosevelt’s promise to replant them — and more — nearby.
The first 2,000 trees were imported from Japan in 1910, after President William Howard Taft’s wife and the first female National Geographic board member teamed up to spruce up the mud flats behind the Washington Monument. Those trees, however, turned out to be diseased and were burned. The Japanese ambassador and Tokyo’s mayor arranged for a donation of 3,200 trees two years later.
By the time Japan offered another 3,800 trees to Lady Bird Johnson’s beautification of the nation’s capital in 1965, the trees had become a symbol of peace and friendship between the two nations and the annual Cherry Blossom Festival was drawing thousands of visitors.
Predicting the peak bloom is Morrison’s most stressful time of the year, he says. He taped a history of peak dates to his office wall as a reminder of the power of global warming. As the date moves wearisomely earlier each year, the urban forester has also noticed a lack of pollinating bees, a nearly imperceptible imbalance in the phenology of nature that may indicate a greater looming threat to the Tidal Basin’s ecosystem. “When the big, showy flowers open,” he said, “the insects aren’t there.”
The Tidal Basin channels water from the Potomac River and Chesapeake Bay through mechanical gates under the Inlet Bridge that open at high tide to let the water in, then route it to the Washington Channel on the opposite side. As the water moves, it also flushes out sediment and dirt, keeping the channel navigable.
The new sea wall will save the Tidal Basin for now but will not solve the larger troubles looming beyond the cherry trees. The Federal Triangle, a 25-minute walk away, is prone to flood during heavy rain because the ground can’t absorb much water. Instead, water pools on the streets before rushing chaotically to wherever gravity drags it.
The grave flood risks are well-known to federal city planners and employees who have been evacuated multiple times, as well as to the engineers who have designed multimillion-dollar fixes for individual agencies and museums in the floods’ path.
For decades, environmental experts, architects and local planners have studied comprehensive solutions to Federal Triangle flooding. They have considered restoring the underground Tiber Creek as a retention area, digging a giant tunnel or parking garage under the mall to act as a cistern during floods, and adding another pumping station to suck floodwaters away when needed.
It is the quintessential story of how Washington works that none of these proposals has reached senior decision-makers. That’s because more than a dozen federal agencies own land and buildings there, each with its own congressional appropriation committee to please.
“There is nobody with the power and authority to rise above the divisions among these entities, so everyone just throws up their hands,” said Judy Feldman, a medieval art historian who chairs the National Mall Coalition and is part of a multiagency flood mitigation group called the Silver Jackets that has studied and debated ways to keep the Federal Triangle safe. “This is the most urgent, existential threat to our museums, our government treasures and the symbolic place that represents who we are.”
For now, and the foreseeable future, the bulwark against national disaster in the Federal Triangle is a $3.8 million portable aluminum levee whose 35 disassembled parts each weigh about four tons and must be assembled by hand. They sit five miles away from the place they protect, in the open air all year round, atop a flatbed truck parked next to old trash cans and concrete culverts at the NPS’s maintenance yard on New York Avenue NE.
On a recent clear, still morning, NPS employees drove the levee through heavy traffic for their annual installation rehearsal at the intersection at 17th Street and Constitution Avenue NW. There, two dozen city and federal workers standing by wondered whether the operation would go as smoothly on a windy or rainy day.
Alex Baldowski, the local safety program manager for the Corps of Engineers, said that in high winds, up to six people “with rigging lines would be needed to keep it from swinging like crazy.”
The portable levee, built in 2014, can’t be used during a flash flood because NPS requires two to four days’ notice to get it in place.
When the levee parts arrived, workers on tall ladders helped guide each of eight H-beam posts from the crane into metal latches embedded in the pavement. They do the same for each of the 27 aluminum panels.
Assembly of the levee took two hours and went off without a hitch. But the Army Corps’ National Levee Database rates the levee “high risk,” noting that the panels are stored five miles away, that there’s “inadequate drainage within the Federal Triangle area” and that a hasty evacuation would be needed were floodwaters to break through.
“Evacuation effectiveness is poor due to many local and federal entities in the area with competing priorities in a flood emergency, and may lead to a disjointed effort,” it notes. “There are also large amounts of [tourists] and resident populations that have no idea they are within a leveed area or where the evacuation routes are.
“If an overtopping with breach event occurs, loss of life is likely expected,” it says, with flood depths “more than 15 feet in some places.”
But there’s another problem: Who, exactly, makes the call to assemble the levee as a weather disaster brews? The Park Service and the Army Corps pointed to each other.
When The Washington Post observed that neither agency was taking responsibility, the Army Corps doubled down. It emailed a copy of a typewritten 1937 Operation and Maintenance Manual that was, in fact, not clear on the matter. Asked again, a Park Service spokesman said the agencies’ top managers would no doubt consult one another and make a joint decision.
Zombie creeks come alive
On the morning of Sept. 10, 2020, the creeks and streams that President Ulysses S. Grant’s administration corralled into a civilized wastewater system trickled quietly, dormant but undead.
By 3:40 p.m., however, a fierce atmospheric river of moisture from the tropics had dumped six inches of rain in some neighborhoods in just 70 minutes. Like underground zombies, the historical waterways swelled under the Edgewood, Bloomingdale and East Corner neighborhoods, gathering power and speed until finally forcing themselves to the surface via manhole covers, catch basins, shower drains and toilets.
Water from the old Tiber Creek, the same one construction crews hit while digging the basement of the African American museum, picked up city runoff and seeped into the 801 Restaurant and Bar on Florida Avenue NW.
Atop a buried tributary of the Anacostia River, the rising waters flooded two dozen homes in the northeast neighborhood of Riggs Park. Some residents were prepared but defeated by the volume. “We have two sump pumps that were overpowered by this flood … nothing helped us,” a homeowner on Nicholson Street NE told a city worker.
In Edgewood, above the remnants of Tiber Creek and below a massive 13-acre concrete development, water belched up out of Jessica Sarstedt’s toilet and into 30 homes around Bryant and Third streets NE. Blocks away, on Rhode Island Avenue, high water pushed up against the windows of the building where, three years later, a similar flood broke through District Dogs, drowning 10 animals trapped inside.
The 2020 storm hit Edgewood, in Northeast D.C., hard.
First responders took to lifeboats to rescue motorists trapped in an underpass on Rhode Island Avenue NE.
Long-buried creeks across the city burst back to life during heavy rain that day.
The 2020 flood damaged more than 250 properties across the District, according to a city survey.
A flood risk map recently developed by the nonprofit First Street Foundation shows that internal flood risk often follows the path of the zombie streams.
“These storms aren’t going away,” said Sarstedt, who had to throw out her furniture and strip the basement walls down to the studs. “The city’s response was disappointing in what they offered us to repair. This is not our fault.”
Whose fault — or responsibility — is it when flooding occurs in the same places for the same reasons, year after year?
The federal government maps river and coastal flooding, funds projects to mitigate both and underwrites flood insurance for many homeowners and businesses affected by them. Other flooding is the responsibility of local governments, homeowners and businesses.
As warming temperatures have ushered in more intense and frequent storms like the one that happened in September 2020, many cities are grappling with whether they can afford to modernize underground wastewater infrastructure when so many other issues, like crime and homelessness, seem more urgent.
“This is the question facing all cities in the age of climate change. How big should we build our water infrastructure?” asked Nicholas Bonard, chief administrator of the DC Flood Task Force created after the flooding. “And if we go bigger and spend more, what does it mean for the city’s other priorities?”
Thousands of District homes and other buildings suffer costly and unhealthy damage from flash floods that the city’s underground highway of pipes can’t contain, and that more paving and development only worsen.
But like most cities, the District doesn’t have public maps of chronically flooded neighborhoods. Outdated maps involving either rivers or coastal water show about 1,100 homes, businesses and other buildings at serious risk of flooding because they’re in the federally designated 100-year flood plain.
A more accurate count of properties at risk is 16,000, according to a more robust model developed by First Street Foundation, a nonprofit environmental research group.
First Street’s model includes what government leaves out: climate change projections and data showing that internal flood risk often follows the path of the zombie streams. Flooding here occurs far from the Potomac and Anacostia rivers, where streams and creeks were buried but never dried up over two centuries of development.
“Having the understanding of where the hidden streams and creeks are gives you the ability to see where water is likely to pool,” said Jeremy Porter, a demographer at First Street Foundation. “It has been forgotten that there’s all this water running underneath a city.”
Andrew Elmore, a professor of landscape ecology at the University of Maryland’s Center for Environmental Science, has studied the correlation between internal flooding and buried streams and creeks. “Think like a drop of water,” he said. “Think about how the water is flowing and pooling to know if there’s a flooding issue.”
The District is a year or two away from having its own computer model that will include the first-ever look at the subterranean infrastructure for water and sewage. The Department of Energy and Environment (DOEE) declined The Post’s request to view any part of the $2.5 million model.
Unlike many cities, the District makes the danger of our changing climate clear. The DOEE spends $7.4 million annually to help homeowners assess and pay for rain gardens, green roofs, permeable pavers, rain barrels and other larger projects that reduce flooding. But the mayor this year cut a $2.5 million program that would have helped homeowners manage flooding.
One-third of the city’s drainage system, much of it built in the 1800s, combines wastewater and sewage into one pipe. The building boom continues to pave over raw earth that once soaked up the rainfall, another key driver of urban flooding. City officials often blame their problems on the decrepit state of the drainage system they inherited when Congress passed the Home Rule Act in 1973, during the Nixon administration, which turned control over to locally elected officials.
The 70 minutes of extreme rainfall on Sept. 10, 2020, maps the story of the city’s deeper vulnerability to climate change. Within 35 minutes, 8 million gallons of water filled one underground tunnel built to hold excess wastewater and overflowed into rivers and neighborhoods. About 135 calls for help, more than on any day in 10 years, came into D.C. Water, according to sewer complaints obtained through the Freedom of Information Act.
The city’s firefighters and emergency responders used inflatable boats to rescue drivers. Buses barreled through wheel-high water. Call centers were overwhelmed.
“I live in my basement and am afraid of black mold. I see it now in the basement bathroom,” a resident in the 5000 block of Ames Street NE told a survey-taker. “I just had knee surgery and had to temporarily move out of the home to make sure I am not affected by any mold spores.”
For the unemployed and working-class residents east of the Anacostia River, the lack of adequate storm drainage creates an extra burden because so many also face relentless crime, few grocery stores, understaffed schools and unreliable public transportation.
City officials are counting on the recently opened Northeast Boundary Tunnel, which is five miles long and can hold 90 million gallons of water, and the First Street Tunnel, which is 2,700 feet long and holds 8 million gallons, to alleviate flooding in parts of the city where sewer and storm water pipes are combined. Construction on another tunnel is slated to begin next year.
The nearly $3 billion project is the result of a consent decree between city and federal agencies to carry wastewater to the Blue Plains Advanced Wastewater Treatment Plant rather than dumping millions of gallons of raw sewage and other pollutants straight into Rock Creek and the Potomac and Anacostia rivers — as the city had done for decades.
On Sept. 20, 2020, the First Street Tunnel filled within 35 minutes, D.C. Water found. Once its 100-foot deep shaft also filled, the water forced the concrete lid off and burst into the surrounding northwest Bloomingdale neighborhood.
Christian Ferro and his husband, who suffered their first flood there in 2012, were headed home on Thomas and First streets NW. They were coming from the hospital with their two-day old daughter when a neighbor texted with a picture of Ferro’s submerged car. “Are you ok?”
Minutes later, they were met by rapids at the front door and a violent waterfall cascading down the basement stairs. Ferro’s husband rushed upstairs with the newborn and “I got my little pool pump out and my Clorox and gloves,” he said.
The damage cost Ferro and his husband $55,000. The couple has not dared to refurbish the basement as planned. Ferro filed a claim with the District’s insurance company, PMA Management Corp. It denied the claim, according to a letter to Ferro. “The sewer system operated as designed.”
No, Ferro insists. The tunnel shaft outside their home drew water toward the low-lying area, then flooded the neighborhood once it was filled.
City officials say everything in Bloomingdale, and in other parts of the city, worked as designed. In fact, according to officials and a 2020 D.C. Water slide presentation, “the system prevented a much more widespread and destructive flooding event.”
Residents told survey-takers in 2020 a different story: “This is the third time in three months we have had sewer water come into our basement, and by far the worst,” a resident in Columbia Heights said.
“There is currently a sinkhole in our front yard,” another in the H Street Corridor reported. “After Sept. 10, our front yard has dropped a foot below where it was before the flood.”
A Michigan Park homeowner said: “Can’t keep building all this density without upgrading infrastructure.”
Six months before the 2020 deluge, Deborah Wiggins bought a two-bedroom bungalow in the East Corner neighborhood knowing full well, she said, that she would be sharing the block with drug dealers, carjackers and nightly gunfire. But the public-school administrator figured if other employed people like her moved to this section of the city, property values and the quality of life would soar.
What she didn’t realize before her $280,000 purchase, was the other looming threat to the 5900 block of Clay St.: the watershed of Watts Branch, a tributary of the Anacostia River.
Wiggins was required to buy flood insurance because she sits in FEMA’s 100-year flood plain. But internal, urban flooding badgers her too because parts of the creek have been channeled underground and catch basins are chronically blocked with debris, forcing rain to pool on the streets and spill over the curbs even in a moderate rainfall, she and other neighbors said.
Still, flooding was an abstraction when she bought insurance for it, Wiggins said, until Sept. 10, 2020, when flood gauges along the Watts Branch tributary reached 11 feet.
By then, brackish water had burst through her back fence, gushed under the back, side and front doors and through the floor grates and air vents, stopping just below the electrical outlets and Wiggins’s knees.
“We walked around in a daze, not knowing what to do,” she said. “Everything was wet, smelly and humid. I was grabbing at my hair.”
Her flood insurance paid for the damage, but not the eight months she had to move out.
For decades, Watts Branch has flooded homes and the heavily traveled Nannie Helen Burroughs Avenue NE. Wiggins said it’s embarrassing to have to verbalize what she and other Ward 7 residents view as neglect by Zip code.
“It’s a working-class neighborhood of poor Black people, and they aren’t making enough noise,” she said. “It’s a shame to say in this day and time, but I’m not asking you to build an amusement park!”
Andrew Ba Tran contributed to this report. Bryan Gallion and Mel Madarang, former Masters students at the Merrill College of Journalism at the University of Maryland, conducted research for this article.
About this story
Sources: The 1791 shoreline is based on a 3D model created by the Imaging Research Center at The University of Maryland, Baltimore County. Historic streams data are from Straughan Environmental, Inc., David Ramos and D.C.’s Department of Energy and Environment. The Post used the D.C. Underground Atlas to understand the city’s sewer system.
Videos by Jorge Ribas. Photos by Bonnie Jo Mount. Design and development by Tyler Remmel. Additional 3D production by Aaron Steckelberg. Editing by Trish Wilson, Monica Ulmanu, Robert Miller, Joe Moore, John Farrell, Jessica Koscielniak and Phil Lueck.