She is smooth, round, and has teeth so hard they can chew through rock. She hangs out down by the river, waiting for when she gets the thumbs up signal. Her name is Nannie. Standing 26 feet tall, she’s a tunnel-boring machine that is waiting to drill a tunnel from RFK stadium, along and under the Anacostia River, where she will meet up with another part of the tunnel currently under construction.


Nannie sits ready and waiting near the parking lot of RFK Stadium, next to the Anacostia River. Image from the author.

Nannie’s 96 cerulean blue grinding teeth glisten in the sun. Resting only feet away is a 109-foot deep shaft, where she will begin her descent into the underworld to dig through the compacted layers of clay and sediment material.

Named after Nannie Helen Burroughs, a prominent early 20th century African-American educator and civil rights activist in DC, Nannie is an essential component of the Clean Rivers Project, a massive engineering endeavor in the District that will fix the city’s sewer system’s overflow problems.

Nannie’s task is to create a new tunnel large enough that the combined sewer system, which makes up a third of the District’s sewer, will not overflow during heavy rainfall or snowmelt events.

Currently, heavy rains result in sewage, stormwater, and other runoff flowing into the Anacostia. For example, between October and December of 2014, the Anacostia River experienced multiple overflows at stations along its shore. There were 12 overflows on the south side of the river by Anacostia Park, which is the most of any site. Eight happened directly across, at the Navy Yard.

The Anacostia River is at the backdoor of the Nation’s capitol, but is often referred to as “The Forgotten River.” Once complete, the Clean Rivers Project will cut sewage and stormwater overflow by 98% in the Anacostia River and provide similar reductions for the Potomac River and Rock Creek, paving the way for a cleaner, healthier ecosystem.

Beyond runoff, the Anacostia is also polluted with chemicals and trash

Stormwater and sewage overflow is just one of many problems the river is experiencing. Years of neglect have led to a river so polluted that it’s dangerous to get into the water or eat the fish.

According to a 2012 study commissioned by local, District, and federal groups, approximately 17,000 residents might be eating these fish. Some, like the brown bullhead catfish, have red fleshy tumors on their lips, which is a visible sign something is wrong. But not all of them have visible deformities, and what’s going on under the skin can be just as alarming.

The same can be said for the river. After a heavy rain storm the river is visually polluted. Trash floats all along the river and collects along its shores, and the stench of waste is too hard to ignore.

Nannie should help with those problems

The Clean Rivers Project will reduce overflows, which will also help with part of the trash problem. But the river will still be polluted by heavy metals in sediment, upstream sources of pollution, and runoff that doesn’t get captured by the sewage system.

Jim Foster, the president of the Anacostia Watershed Society, wants to get back to the root cause of all these problems. He argues that more needs to be done if we want to make the river “swimmable and fishable by 2025” - a motto he and others are using as a goal post.

Combined sewer systems are found in many other US cities, including the District. These types of sewers consist of a central pipe that serves as a catchall for storm runoff and household and industrial sewage. During heavy rain events, the untreated sewage runs into local waterways. Combined sewer systems are found in the older parts of the city, flowing from the northern boundary through the heart of the District.

Nannie’s tunnel and the Clean Rivers Project are expected to fix this problem by creating a larger sewer drain to capture all of the waste. Nannie will “drive the most important, ground — or better yet - water-breaking improvements to the Anacostia in the last century. And we will do it in the next 10 years,” said George Hawkins the chief of DC Water and Sewer Authority at a public event in February.

Here’s how Nannie will work

Nannie is a beast, her cutting head spinning one to two rotations per minute. Nate Wageley, an inspector with DC Water, described the process. Nannie “will basically rip the soil into shreds, or cuttings. And if you hit a boulder, there are discs that will cut them up into little fragments.”

The excavated material is then softened with a foam, producing a taffy-like substance that gets transported on railway carts out of the tunnel and offsite. Nannie will travel at approximately 500 feet a week, eventually excavating a 12,500-foot tunnel. When she gets the green light, the engineers expect her to finish the tunnel in less than a year. Once complete, the foot thick concrete tunnel will have a lifespan of 100 years.

Nannie is expected to begin tunneling this summer and her portion of the Clean Rivers Project will be completed by 2018. The longer-term plan for the District, including projects along the Potomac River and Rock Creek, is currently scheduled for completion in 2025 unless it gets amended to accommodate proposed green infrastructure.

Community advocates have concerns

Some environmental advocates are concerned that the Anacostia portion of the Clean Rivers Project is solely focused on a hard engineering solution. The tunnel will improve water quality, but it does not include other softer, aboveground, measures, like green infrastructure, which would benefit residents by increasing property values. Foster worries that the communities around the Anacostia River are not seeing similar investments in green infrastructure like those planned for the Potomac River and Rock Creek areas.

In May, DC Water proposed green infrastructure on 498 acres for the Potomac River and Rock Creek neighborhoods under the Clean Rivers Project. But improvements of similar proportion have not been proposed for the communities around the Anacostia River.

“The [engineering] benefits don’t accrue to the community. Planting trees and doing rain gardens and landscapes improves the assessed value of a community, it raises the aesthetics and helps improve the infrastructure that people use every day,” Foster says. “They get the gold mine, and we get the shaft.”

Despite concerns about equity of the project, the District is taking serious steps to clean up its waterways. “Everybody has to do a little bit. Everyone has some skin in the game. In the end of the day, it’s not about the river. The river represents what’s happening in the community,” says Foster.

Kristan Uhlenbrock is a science writer and outdoor adventurer. She lives in southeast DC and can often be spotted on a paddle board cruising the Anacostia River. An ocean scientist by training, she moved to DC in 2010 to work on at the intersection of policy, science, and communication.