I can’t claim to be an expert in roadway engineering. But when an urban roadway literally washes into the stream below, that strikes me as problematic design.
That is exactly what happened in the early 1990s on a section of Klingle Road in Washington, D.C. The roadway and its stormwater management system dated back to the early 20th century, when the area drained by Klingle Creek—which the roadway parallels—was far less developed and more able to handle the water runoff that ran into the creek naturally.
But recent developments with the Klingle corridor—as I’ve outlined below—show how sustainably designed trail systems can work to solve transportation and environmental issues while benefiting the environment and surrounding community.
Why the Road Washed Away in 1991
The Klingle Creek watershed was far less developed through the turn of the century and, therefore, had far more permeable surface area that allowed water to infiltrate the ground rather than run across impervious surfaces into the creek. But over the next decades, neighborhood development brought more impervious surfaces to the 320-acre area drained by the creek. More impervious surfaces in the creek’s watershed meant less rainwater seeping harmlessly into the ground and more polluted, fast-flowing water washing into the creek during storms. Over time, this eroded the creek’s banks.
By 1991, the erosion had progressed to the point that much of the earth supporting the roadway washed away, and the road could no longer support traffic. Klingle Road was closed, and the District of Columbia had a debate on its hands.
Debating the Future: Road or Trail?
Many residents wanted the road rebuilt. But others argued that a full-width roadway was simply unsustainable along the banks of Klingle Creek and that reconstruction would invite a costly repeat of the collapse. For nearly three decades, the District Department of Transportation grappled with the issue, conducting environmental assessments and engineering studies while the roadway remained closed and continued to deteriorate. All the while, commuters learned new ways to get where they were going. Drivers adapted to not having this crosstown option.
But eventually—a solution was reached, and it’s one that is likely to have an impact on the walking and biking mobility of the area—and contribute positively to stormwater management in the watershed.
Connectivity + Sustainability
On Saturday, D.C.’s mayor and its director of transportation cut the ribbon on a beautiful replacement for Klingle Road. But the replacement is not a roadway. Instead, it is a sustainably designed trail that allows walkers and bicyclists to traverse Rock Creek park in a tree-filled, natural setting.
Here’s a snapshot of its potential impact:
- Stormwater design for cleaner waterways: The trail itself is made of permeable pavement so that it allows water to infiltrate rather than run into the creek, and the additional right-of-way that once carried a lane of auto traffic and flowed pollutants into the adjacent creek now contains a series of bioswales—a form of green infrastructure that uses sloping and vegetation to naturally capture stormwater and remove pollutants.
- Increased off-road access between the east and west: The trail now provides a safe, non-motorized option for people to reach eastern or western destinations across busy Connecticut Avenue in an area that, otherwise, only provides indirect on-road routes.
Retrofitting for Human-Scale Connectivity and Environmental Sustainability
While the trail is only 0.7 mile in length, this achievement is about more than the distance. The opening of the Klingle Trail shows that we have the opportunity to learn from our past mistakes, to build trails in ways that repair the environmental harms of our unsustainable engineering past, and to repurpose linear corridors that once carried cars to instead provide sustainable corridors for active transportation and recreation.
Klingle Trail is an excellent case study in how environmental degradation resulting from unsustainable design can provide an opportunity to rethink and repurpose a corridor in a sustainable, connective manner. Hopefully, we will see an increase in these sorts of sustainable projects in years to come.
And perhaps we shouldn’t wait for a road to fall in a creek before we ask if it could be put to better use.