Like many buildings in Northern Virginia, Fairfax County’s Herrity Building is surrounded by traffic and occupied by government workers. But Herrity also sports a landscaped pond that’s not just a parking lot decoration. It’s the headwaters of Difficult Run, a Potomac River tributary that winds through development-burdened Fairfax County before ending near Great Falls Park, where it’s enveloped in lush vegetation, dotted with boulders and surrounded by scenery that seems straight out of a time period from long ago.
(Image courtesy gawnesco/Flickr)
Difficult Run’s health fluctuates dramatically throughout its 15-mile run. In cities like Reston and Vienna, unsustainable land use practices have led to eroding stream banks and poor water quality. At 58 square miles wide, Difficult Run’s watershed is the largest in Fairfax County, which means the waterway is affected by development and pollution that happens very far away from its banks.
Luckily, in other places, forest buffers hug the stream’s edges, helping to keep soil in place, provide wildlife habitat, and shade and cool the water. These forested areas have become a favorite of locals who enjoy walking through the woods.
For an excellent weekend hike or bike ride, follow Difficult Run on a secluded 12-mile trail from Glade Drive in Reston to Great Falls Park. Will Difficult Run be difficult? Rumor has it that the trail is perfect for intermediate bikers and beginner hikers.
Perhaps the “difficulty” of Difficult Run lies in reversing the effects of development that has led to pollution in many parts of the stream. Fortunately, Fairfax County and others have begun work to restore this important local waterway. In 2008, the Herrity Building installed a green roof atop its parking garage. This colorful garden of native plants prevents stormwater runoff from carrying oil, trash, auto exhaust and other pollutants from the parking lot into Difficult Run.
Image courtesy Capitol Green Roofs
Along Difficult Run’s banks, the Virginia Department of Forestry has conducted streamside restoration projects and an outreach effort that now serves as a model for other local stream restoration initiatives in the state.