The DC Department of Energy and Environment has undertaken, with the cooperation and support of the National Arboretum and the Friends of the National Arboretum, a series of projects that use nature to substantially reduce pollution to the Anacostia River. These projects are so innovative and promising that they have drawn attention worldwide to how natural areas can be re-established or improved to absorb and reduce pollution levels from storm sewers and ditches that otherwise would empty directly into rivers like the Anacostia. We should all be aware and proud of what is going on here in our watershed.
Rebuilding Springhouse Run
The first of three current projects was to rebuild Springhouse Run. It had over the years lost much of its natural function and was a ditch that took the content of storm sewers from about 100 acres above New York Avenue. The water entered the Arboretum from a large sewer pipe under the Avenue, ran around a manmade pond and carried it for about a quarter mile to enter Hickey Run. Since it was a storm sewer and was not supposed to carry sewage, it would be best to let it flow naturally to the Anacostia in Hickey Run. The project was completed in 2017 for a bit over $1.5 million, not counting the large number of plants donated by the Arboretum. Near the place where the sewer entered the Arboretum there are two springhouses, marking the place in the late 19th and early 20th centuries where groundwater was bottled and sold in the City—long before the highway and sewer line went in, but indicative of historically good quality groundwater in the area.
The restoration project reconnected the man-made pond right below the springhouses to the newly widened stream around it, with the entering waters able to drop sediments and to exit over a dam at the other end. The connecting of the flowing water also attracted to the pond to an array of fish, birds, turtles and other animals. Past the dam, the stream opens up to a wide natural habitat with mini-ponds and native plants all along it. Soils in this area were replaced by a combination of stone, soil and wood chips to attract a range of species at the bottom of the food chain. Most recently, in an expression of how much of nature has been restored, the effort was greatly complimented by the arrival of beavers, who took advantage of the new broad land and water areas along the stream to build their own dam from one side to the other, creating a new pond!
And people are drawn to this new expression of nature in land and water. Children love to see the fish and other critters. Adults are drawn by the beautiful natural plants and flowers that grow high along the unpaved paths throughout the new valley. It has been designed and placed to deliver cleaner water to the Anacostia. But by building with nature, it has brought so much more to all of us!
Hickey Run Wetlands
The second stormwater improvement that is nearly complete is a much more modest project, but the first of its kind in DC. It is on Hickey Lane right below the R Street entrance to the Arboretum. It is called a “submerged gravel wetland.” The idea is to capture runoff and hold it and treat it, with some eventually slowly making its way down alongside the road to Hickey Run.
The wetland is only about 100 feet long and a third that wide, but it can handle a drainage area of 8.1 acres, 2.2 of which are impervious runoff from R Street and the Arboretum entrance area. The dug out area is filled two feet deep with ¾ inch crushed stone and tall plantings of species with the ability to grow in such a submerged area. In addition to holding back the runoff, there is biological uptake by algae and bacteria in the filter media and wetland plants. Physical and chemical treatments can also increase the absorption of organic matter, so less runs down the hill to Hickey Run and what does brings little pollution.
Restoration of Hickey Run
The final project in this group is the restoration of Hickey Run. With progress upstream to handle pollutants and the lessons and positive effects of restoring Springhouse Run, there is much excitement over what we can do with its big sister, which goes all the way to the Anacostia after Springhouse joins it.
Because it drains a substantially larger area than Springhouse, and because of years of wrong connections of sanitary sewage lines to what is supposed to be another storm sewer, this is a substantially bigger and more challenging project. After coming out of a sewer as it comes under New York Avenue, this larger stream currently moves through the Arboretum in a ditch built of concrete blocks about 10 feet wide and 10 feet deep. It is not clear after all these years how contaminated the soils are under this large strip through the Arboretum to the Anacostia, although upstream clean-up is about completed. Still, it may be difficult to replicate the recreated watershed of Springhouse Run in the Arboretum. On the other hand, there is room to spread out Hickey and make the waters wider and more shallow. Much of it also runs through mature woods, so curves and spreading out will require removal of a number of trees. But there is sizable pond part way down the stream that could be readily connected as was done in Springhouse and provided many benefits to water quality and natural recovery of the stream. It will be very interesting to see what the City and the Arboretum and their contractors come up with to restore Hickey Run from New York Avenue to the Anacostia.
And we should all be anxious to see what these folks come up with next to show the world how to restore the rivers, their streams and the lands along them.
Bill Matuszeski is a member of the Mayor’s Leadership Council for a Cleaner Anacostia River, and the retired Director of the Chesapeake Bay Program. He also serves on the board of Friends of the National Arboretum and on Citizen Advisory Committees for the Chesapeake and the Anacostia.