Heavy rainfall Wednesday led to flooded streets, stranded cars and emergency rescues in the D.C. area, with one woman even trapped in 5 feet of water in her own home.
DC Water says the recurring flood problem is caused in part by the District’s aging infrastructure, and that its Northeast Boundary Tunnel Project may be a key to fixing it.
How Aging DC Infrastructure Contributes to Flooding
The severe flooding Wednesday night was far from a one-time occurrence for the District. According to the Department of Energy and Environment, D.C. has faced a long history of flooding, dating back to the 19th century.
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A large contributor to these flooding issues is the area’s outdated and aging infrastructure. According to DC Water, the District’s sewage system is over 200 years old, with some of the first major structures, such as storm drains, constructed as early as 1810.
DC Water said that although additions and renovations have been made to the District’s system over time, ultimately poorly planned constructions have transferred drainage problems to the marshes along the Potomac and Anacostia rivers, which is still apparent today.
“The century-old combined sewer system in the District of Columbia is not equipped to handle the population growth experienced during the last 100 years,” said DC Water.
DC Water said the sewer system is undersized, causing decades of chronic flooding in the Bloomingdale and LeDroit Park neighborhoods, in the Rhode Island Metro station area and on Mount Olivet Road NE.
What DC Water Says They're Doing to Respond to Flooding
DC Water said the Northeast Boundary Tunnel (NEBT) will address the District’s flooding problem.
The project features a 27,000-foot sewage tunnel that will have a diameter of 23 feet and a depth of 100 feet.
The tunnel will start slightly south of RFK Stadium and extend north to Rhode Island Avenue and west to R Street NW, targeting areas prone to flooding due to weak infrastructure.
The goal of the plan is to construct this sewage tunnel and connect it with the existing sewer system. DC Water said this will significantly mitigate sewer flooding, while improving the Anacostia River’s water quality.
DC Water said once the tunnel is connected, combined sewer overflows to the Anacostia River will be reduced by 98%. Construction of the NEBT is also said to “reduce the chance of flooding in the areas it serves from approximately 50 to 7 percent in any given year.”
The project will take about five years and cost $583 million to construct, according to DC Water.
Aside from the tunnel’s construction, DC Water has responded to the extreme flooding in recent years through other outreach efforts such as last year’s Flooding Awareness Week, which featured a number of activities to help residents and businesses stay informed on what to do in order to prepare for the impact of floods.
“We want to empower our customers to protect themselves,” DC Water Chief Executive Officer and General Manager David L. Gadis said in a statement. “The more our customers know about flooding, the less likely they are to be impacted when the District is subject to heavy rain events."
What We Know About the Timeline of the Northeast Boundary Tunnel Project
DC Water projects the NEBT will be completed in 2023.
The project began in July 2017, when the DC Water Board of Directors approved a $580 million contract to begin designing the NEBT, the largest project of the DC Clean Rivers Project. Construction began in September 2017 and has been moving along since.
According to DC Water, its latest construction efforts have been focused on the R Street NW construction site, where a large crane was replaced by a smaller one in April 2022.
The NEBT’s construction status is ongoing and on track. DC Water continues to offer community outreach meetings to answer the public’s questions on the construction process, traffic advisories and upcoming work.
