The Potomac River is the nation's river. George Washington had his home here and lobbied to have the capital city on its shores. The river flows through four East Coast states and Washington, DC on its way into the Chesapeake Bay, the largest estuary in North America.

VOA's Rosanne Skirble takes us on a journey on the Potomac River, a waterway in the eastern United States that flows through four states and the nation's capital on its way into the Chesapeake Bay, the largest estuary in North America. Our trip takes us to the Potomac Gorge near Washington, one of the most biologically diverse areas of any urban landscape in the world.

The Potomac has been called the wildest urban landscape in the world. In some places it is flat and broad and so clear that you can see all the way down to the rocks and sand on the bottom. In others it is thick with gardens of aquatic vegetation with native species like wild celery, curly pondweed and stargrass, and exotic plants like hydrilla.

In one stretch 24 kilometers from Washington, the river changes dramatically, picking up speed and cascading over jagged rocks and waterfalls into a narrow gorge thirty meters below.

This is the Potomac Gorge

Stephanie Flack, a conservation planner with the Nature Conservancy, says the Gorge was carved from 600-million-year-old sedimentary rock that today is dotted with clusters of rare plants that she calls communities.

Flack: "So, you look to your left and your right as you paddle downstream, you see these exposed cliffs, these grand rocky exposed banks on the sides. And on these exposed rocky bedrock you find these really rare communities [of plants] things that are not common, that are considered globally rare and probably the best preserved examples of those exist in the Potomac Gorge because much of it is in Park Service ownership."
Skirble: "What are these things? What can we see?"
Flack: "You can see open communities that we would call savanna communities that you wouldn't think that you would find in the eastern seaboard [United States]. [The landscape is] more characteristic of the West and savanna prairie type systems. You can also find a ton of rare plants. There are more than 200 different rare plants and natural communities that occur here in the gorge."
Skirble: "And is this unusual in a urban community like where we live?"
Flack: "It's is very unusual. All along the eastern coast is the fall zone, where we have the hard rocky bedrock of the Piedmont reaching the soft sandy deposits of the coastal plain, and most of the East Coast cities have developed at this fall zone. But, even though the land is in public ownership and is not subject to development, a lot of potential effects threaten the rare species and communities and the important ecological diversity of the area, despite not being in direct development."

Stephanie Flack is working with the National Park Service, the principal landowner, on a conservation plan to protect the Gorge from the more than four million people who live nearby. She says invasive species, a growing deer population, and adjacent land use are the major problems.

She says while the Gorge has become a recreational magnet, most users, including landowners and municipalities upstream, are unaware that their actions put the biological diversity of its ecosystem at risk. "I think people realize that it is a fun place to come to but I don't think they really recognize the exceptional global bio-diversity value that due to the dynamic hydrology and geology that we have things that are not found anywhere else," she says. "And I think that it is not as well known and recognized and I think there are a lot of opportunities to really instill a sense of pride of place in this area here. It is a wonderful living laboratory to teach people about ecological processes, about ecosystem health. Because you have got such a concentration of people near this area it's a great, great place to raise awareness, not only locally here in the back yard of the whole metro [Washington, DC] area, but globally."

Stephanie Flack says the conservation plan she is developing with the National Park Service is an attempt to focus attention on the management of this urban oasis and to protect its bio-diversity from both recreational overuse and pollution from upstream development.

This is the fourth piece in a five-part series on the Potomac River, the waterway in the eastern United States that flows through four U.S. States and metropolitan Washington DC into the Chesapeake Bay, the largest estuary in North America. In a canoe trip down the river VOA's Rosanne Skirble explores the natural riches of the Potomac and the struggle to protect the land and water resources of the river in the face of population growth, sprawling development and pollution.