The Watery Wonderlands of Northern Virginia

A great egret forages in Dyke Marsh.

By Glenda C. Booth

ALEXANDRIA,VA- In the woods at the bottom of a hill, a few blocks from clusters of apartments and townhouses on North Beauregard Street, a lush wetland is alive with bullfrogs, green frogs, red slider turtles, spotted salamanders, and whitetail dragonflies amid marsh plants like pickerelweed and jewelweed. It is a watery green respite within Alexandria’s 50-acre Dora Kelly Nature Park.

There’s a lot going on in Northern Virginia’s wetlands. Snakes slither, fish forage, cattails nod in the breeze, beavers build, birds migrate through, and dragonflies zip around. Wetlands are dynamic ecosystems so rich in biodiversity that Kirk Havens, Virginia Institute of Marine Science biologist, calls them biological supermarkets. “In an area the size of an average desktop,” he says, “there can be as many as 8,300 animals.”

People, too, have often found wetlands inviting. A September 15, 1931 Washington Post article recounts that police raided Gus Quayle’s place in Dyke Marsh, just south of Alexandria on the Potomac River’s Virginia shoreline, after watching Quayle pull liquor out of the river bottom and make a sale. They found 138 bottles in gunny sacks of supposed homebrew.

The wetlands that lined the Potomac River often were jungley hideaways for many vice trades and law-dodging miscreants. In the first half of the 20th century, a squatter and trapper known as Cig Dodson had several mysterious enterprises going on in Dyke Marsh. The dense vegetation, where state and local jurisdictional lines blurred, provided perfect cover for nefarious and clandestine adventures.

The Old Town waterfront also had wetlands. As a surveyor’s aide, young George Washington mapped marshes and flats in areas that became Alexandria City. In 1762, Alexandria got the Virginia General Assembly’s approval to fill some two acres of shoreline wetlands to accommodate growing commerce. Late in the 18th century, the City reclaimed land to create Union Street by filling in the shoreline. There were once extensive marshes in parts of Cameron Run and Hunting Creek too.

This red-eared slider turtle in the Dora Kelly Nature Park’s wetland is an introduced species.

What is a wetland?

Wetlands are transition zones between water and land: wet land. They can be wet seasonally or all year. Water is the dominant factor in determining the type of soil, plants, and animals. Wetlands exist from the tundra to the tropics, on every continent except Antarctica. They are also called marshes, swamps, fens, or bogs.

In contrast to uplands or fast land, wetlands are primary habitat for animals like beavers, muskrats, and wood ducks and plants like cattails, wild rice, arrowhead, and swamp rose. Long-legged wading birds such as herons and egrets forage in wetlands. They are fish nurseries.

Potomac River wetlands are stopover sites for birds migrating in the fall, including black-and-white, magnolia, and yellow-rumped warblers; blue-winged teals and sharp-shinned hawks; scarlet tanagers and yellow-billed cuckoos. In autumn, many wetlands plants die back or go dormant, but some birds stay for the winter, like winter wrens, American black ducks, and swamp sparrows. Bald eagles that nested north of Virginia winter here.

Trees falling into the river signal the severe erosion of Dyke Marsh.

What is their value?

Why should we care about these murky, wild places? Often called “nature’s kidneys,” wetlands improve water quality by filtering out pollutants, they absorb floodwaters like sponges, and they attenuate tidal energy and stem erosion.

For centuries, people viewed wetlands as stagnant muck holes exuding foul odors, breeding mosquitoes, and harboring mysterious creatures. The “dark quivering mire” set the scene for Sir Arthur Conan Doyle’s 1902 book, The Hound of the Baskervilles. People drained wetlands and filled them, or used them as dumps.

But in Northern Virginia, some wetlands have endured despite the draining and filling; the digging, dumping, and poaching; the pollution, invasive species, and endless trash. We know now that they must be protected.

The City of Alexandria is planning to build the Potomac Yards Metro Station in a wetland within the Potomac Greens Scenic Easement. Although the permitting process is well advanced, this plan continues to be opposed by the Environmental Council of Alexandria, among others, and needs further permitting, for which people can still submit comments.

The Dyke Marsh boardwalk extends to the Potomac River.

Following are five important wetlands areas to visit in our region:

Dyke Marsh

Dyke Marsh, just south of Alexandria, was called Hell Hole in the 1800s. It has tidal and freshwater marsh, swamp forest, and floodplain habitats. “Hell Hole is a grand wild place,” opined the Alexandria Gazette in 1858. In 1947, Louis J. Halle biked from Washington, D.C., at dawn to watch Dyke Marsh awaken and wrote that it was the “nearest thing to primeval wilderness” in the area.

In 1959, Congress added the 485-acre Dyke Marsh Wildlife Preserve to the national park system “so that fish and wildlife development and their preservation as wetland wildlife habitat shall be paramount.” Dyke Marsh has 300 known species of plants, 6,000 arthropods, 38 fish, 16 reptiles, 14 amphibians, and more than 230 birds. We know that parts of it are 2,000 years old.

It was once one of largest tidal and freshwater marshes in the Washington area, but its marsh habitat has shrunk to a fragile remnant of less than 60 acres. Smoot Sand & Gravel Corporation dredged and hauled away around 270 acres of the marsh from 1940 to 1972, destabilizing the system and changing it “from a semi-stable net depositional environment into a strongly erosional one,” concluded the U.S. Geological Survey (USGS). Erosion eats away almost two acres a year, at an accelerating rate which means it will be gone by 2035. At last, the National Park Service has started stabilizing and restoring the marsh.

Huntley Meadows

Unlike Dyke Marsh, Fairfax County’s Huntley Meadows Park wetland is not tidal. In Virginia, around 75 percent of wetlands are nontidal. The centerpiece of the 1,500-acre park is the 50-acre, freshwater wetland in a lowland carved out by an ancient Potomac River meander. Over years, the land was ditched, farmed, and used by the federal government until 1975 when President Gerald Ford authorized the donation of 1,261 acres “exclusively for public park or public recreation purposes in perpetuity.” Fairfax County paid $1.00 for it.

In the late 1970s, beavers built a dam across Barnyard Run. This created a swamp and flooded forest that changed the shallow wet lowland into what is called a hemi-marsh. Because of several factors, the wetland lost some water depth, plants, and animals. Park managers decided to return it to a hemi-marsh to support species like Virginia rails, spotted turtles, green tree frogs, muskrats, American eels, and crayfish and more plants like bladderwort, bur reed, blue flag iris, and duck potato. Contractors built an earthen dam with controls to raise and lower the water.

Every year, more than 200,000 people visit this wetland, the largest of its kind and a rarity in urbanizing Northern Virginia. Ambling along the boardwalk that winds over the water, visitors delight in seeing diving and dabbling waterfowl, herons, snakes, turtles, beaver lodges, raptors, and other birds, and wetland plants like cattails and button bush.

Volunteers struggle to move a sofa out of Dyke Marsh.

The Great Marsh

Mason Neck’s 250-acre Great Marsh abuts the Potomac River in southern Fairfax County, part of the Elizabeth Hartwell Mason Neck National Wildlife Refuge. The refuge was established specifically to protect the bald eagle in 1969, a time when the number of eagle pairs had plummeted nationally to fewer than 500. Bald eagles, beavers, and muskrats thrive in the marsh. Ducks, raptors, and songbirds stop during fall and spring migrations. In winter, ducks like hooded mergansers and northern pintails, tundra swans, and geese lure visitors.

Occoquan Bay National Wildlife Refuge

In the Occoquan Bay National Wildlife Refuge, where the Occoquan River meets the Potomac, there are wet meadows, bottomland hardwoods, tidal marsh, and streams. Wetlands comprise half of the refuge’s 642 acres.

Alexandrian Jim Waggener led efforts to transform the former Harry Diamond Laboratory, a U.S. Army electromagnetic pulse testing site, into a refuge, and succeeded in 1998. He has conducted plant and wildlife surveys on the refuge for more than 30 years.

The Julie J. Metz Wetlands Neabsco Creek Preserve

From nature trails and a 3,000-foot boardwalk at the 230-acre Metz Wetlands in Prince William County on Neabsco Creek, visitors can see beaver lodges, egrets, wood ducks, red-tailed hawks, and wetland plants like spatterdock and marsh mallow. This wetland is both a preserved and constructed wetland: a wetlands bank. The county’s website explains: “Wetlands mitigation banks are areas of constructed, restored, or preserved wetlands consisting of quantified value units termed ‘credits’ that can be purchased by developers in advance of anticipated wetlands losses due to construction activities.”

While many of Northern Virginia’s wetlands are long gone, fortunately some remain and are even being restored and constructed. People no longer see a wetland as

’s mire of “miasmatic vapor” and “slimy water plants.” Now we know how these dynamic ecosystems contribute to the quality of our present, and future, environment.