Standing in a forested wetland, you are surrounded by native sweetbay magnolia (Magnolia virginiana) trees. The sweet, lemony scent of magnolia blooms fills the summer air. You are lucky to bear witness to a rare plant community — the magnolia bog.
The National Park Service has determined that only 13 of these wetland areas, rich with clusters of native magnolia trees, remain in the Atlantic Coastal Plain. Four of these 13 exist within the boundaries of Oxon Run Parkway, a 126-acre forest in the District of Columbia that is managed by the National Park Service.
The survival of magnolia bogs, though, is threatened by habitat fragmentation and other stressors associated with increasing urbanization. Oxon Run, the stream for which the parkway is named, flows across the entire width of the urban park and is a tributary of the Potomac River. The run’s watershed is roughly 12 square miles, originating in Prince George’s County, MD, before flowing into the District via the parkway.
More than 50% of the Oxon Run watershed is developed. Residential use counts toward the majority of that development. This increase in development creates a larger footprint of impervious surfaces, which contribute to increased volumes of stormwater runoff as well as the degraded quality of that runoff. According to the Chesapeake Bay Program, stormwater runoff is the fastest-growing source of pollution impacting the Chesapeake.
In the Oxon Run watershed, the Asheford Court neighborhood is a successful model of residential stormwater mitigation. The overwhelming majority of homes in the loop-shaped neighborhood have at least one best management practice installed through the River-Smart Homes Program, a partnership between the Alliance for the Chesapeake Bay and DC’s Department of Energy and Environment. The program helps DC residents install numerous BMPs: rain barrels, rain gardens, BayScape gardens, shade trees, permeable pavement and impervious surface reduction.
Because the Oxon Run watershed is entirely within the District’s Municipal Separate Storm Sewer System, or MS4, everything that enters a storm drain — water, trash, sediment, pet waste or other pollutants — goes directly to the local waterway without treatment. These and other on-the-ground efforts from area residences are imperative to reduce the total volume of stormwater runoff.
There has not yet been the same level of involvement in Ward 8 outside of the Asheford Court neighborhood, but the increased participation in the River-Smart Homes Program there is indicative that there is opportunity for growth.
The Alliance and DOEE are leading a free walking tour of RiverSmart Homes at 10 a.m. Saturday, June 15. All are welcome to take the tour, which begins at Malcolm X Elementary School. Its goal is to educate local residents about stormwater and engage them in practices at their homes to make a difference in their watershed and community.
Attendees will get a close look at numerous best management practices that their neighbors have installed. They can also participate in a question and answer session with DOEE auditors and a tree identification and maintenance workshop with arborists from Casey Trees.
A limited number of DOEE Storm-water Audits will take place at homes in the neighborhood. In addition, participants will be able to mark storm drains to remind their neighbors that these drains go directly to their local stream. Activities for children will be available, too.
This event is made possible through a partnership with the Asheford Court Homeowners Association. While residential stormwater mitigation is gaining local traction in the Oxon Run watershed, additional planning is also in effect to restore the stream itself.
In the District, challenges to future restoration projects include roadway crossings and nearby sanitary sewer pipes. While formal restoration efforts have yet to take place, the planning process is under way. A few years ago, the DOEE and the U.S. Army Corps of Engineers completed a flood study to determine whether nearby properties would be negatively impacted by the removal of a concrete channel. The channel, in southern portion of Oxon Run, was constructed in the 1960s to alleviate nearby flooding issues. Ideally, all of the concrete will be removed in favor of restoring a more naturalized stream channel and surrounding landscape.
Josh Burch, a watershed protection specialist at the Department of Energy and Environment described a restored Oxon Run as having “a low, wide floodplain bench so that when storms come in and water levels rise, flood flows have room to spread out.” He said that while the site certainly has its design challenges — it is adjacent to an old firing range and has a flood control dam overcome with sediment — there are also plenty of design opportunities. When restored, Oxon Run should be a vibrant natural area with increased opportunities for recreation, including fishing.
Not everyone resides within a stone’s throw of a rare magnolia bog, but we all have a part to play in protecting our local waterways. Increased rainfall is exacerbating the harmful effects of stormwater runoff, and the streams and tributaries of the Chesapeake Bay are feeling the consequences. In the District, the Oxon Run watershed has long been subject to this and numerous other environmental challenges.
But for the magnolias and the communities near the stream, there is opportunity in Oxon Run.