August 2, 2002
The Ashburn Farm Association has reason for turning a storm water management pond into a small park site while the county builds the new Ashburn Library next door.
“There is the pond in the middle that really needed improvement to make the site cohesive,” said Susan Bell, community manager for the Ashburn Farm Association Homeowners Association (HOA).
The Breezyhill Storm Water Management Pond sits between the future library site and the Breezyhill Recreation Center with the park located northeast of the shoreline. The two properties are located near Hay Road and Claiborne Parkway.
As proposed, the vest pocket park will consist of an outdoor amphitheater-style reading area to serve Ashburn Farm and the library, which is scheduled to open in 2003. The park will include a pond observation platform with curved seating walls nearby and a prefabricated footbridge that crosses the stream channel, all in an area planted with native trees and plants.
“The whole interest of Ashburn Farm is not only to have an urban setting, but to use natural resources as an amenity to the community,” said Patrick Wegeng, environmental planner and landscape designer for Wegeng Environmental Design in the Ridges of Ashburn. “We see a strong interest in making these ponds into true amenities where people can fish, walk around and observe native wildlife.”
ASHBURN FARM has five storm water management ponds, including the Breezyhill Pond in the northern section of the 4,000-home, 1,300-acre development. The pond currently is fed by several storm drain outfall structures and incorporates a large watershed. The park is proposed in an area with a rip-rap-lined drainage swell, a drainage channel that has rock within its channel bed to slow down storm flow velocities before reaching the pond.
The original library site plan proposed adding pipes near the rip rap and building a pathway over the two pipes that ended at a fence surrounding the recreation center’s swimming pool.
The HOA, as recommended by the Open Space Committee, wanted to relocate the pathway to behind the swimming pool and extend it to the recreation center’s parking lot, which the library then could use for overflow parking. The Board of Trustees approved the HOA’s proposal, allocated $120,000 for the project and selected Williamsburg Environmental Group to draft a master plan for the Breezyhill Pond Improvement Project. Wegeng was the chief designer for the master plan, which was completed in August 2001 at a cost of $15,000. He then took over as construction manager of the project.
THE COUNTY'S Department of General Services agreed to work with the HOA on the section of the plan located on library property.
"It's an excellent opportunity for the kids to see a natural stream environment, instead of an ugly old covert coming into the pond," said Sharon Hodges, principal engineer for the Department of General Services. "I think it's going to be a nice enhancement for the facility."
The county requested Alpha Corporation in Sterling redraft the library's site plan without the piping and asked Ashburn Farm, owner of the piece of property, to grade it instead.
“Let’s get rid of all this rip rap and let’s make a nice sediment forebay,” Wegeng said.
As designed, a bowl-shaped grassy basin that is similar to a forebay will be used to capture water before it reaches the pond. From the pond, the water travels to Broad Run and from there the Potomac River and the Chesapeake Bay. The grassy basin will slow the water flow velocities, while removing sediment, nutrients and trash that can come from homeowners’ yards, storm drains and other sources.
"Instead of channeling, meaning a narrow channel, we broadened the swale to make it more of a grassy basin," Wegeng said. "This is to let water spread out, and trash coming through the storm drains will settle out."
TWO ROWS of indigenous rocks from the grassy basin to the pond will continue slowing the water to prevent erosion of the pond’s embankment and channel floor. A pump in the pond will circulate the water to the top of the stream channel. From there, the water will cascade back down the slope over rocks and under the platform before entering the pond, a movement that will increase water flow in what is now a stationary water area. The rocks and an erosion control blanket, which is a fabric placed on the ground surface and underneath the rocks, will replace the rip rap.
“The whole purpose of the park is to stop that erosion and to slow down velocity to create … a stream system with indigenous rocks and native plant material,” Wegeng said. “We’re going to make this look like a stream coming down a hill.”
Wegeng said the stream is intended to replicate a Northern Virginia stream that could be found in a pasture.
ASHBURN FARM Association began work on the pond site on May 1 and has completed the first phase of plantings, including nearly 25 native trees, 2,000 square feet of wildflowers and several large beds of ornamental grasses. The stream system is scheduled to be completed by the end of summer, with the rest of the plantings, including 25 additional trees, finished by late fall. The landscaping is estimated to cost the HOA $20,000 to $25,000.
“It really is an outdoor classroom,” Wegeng said. “We are looking at it as an environmental, educational tool.”
Some of the native plantings will be labeled and will include large dawn redwoods, weeping willows, bald cypress and black gum, along with several plants and flowers such as iris, pickerel weed, Joe-pie weed and bee balm. Some of the plantings will coordinate with plantings proposed for the library site, including native plants and grasses.
“While we have a nice library, we want to create a whole setting around the park,” Bell said. “The whole area seems like a park.”
The county agreed to grade the library’s section of property including the grassy basin. The HOA will fund the rest of the grading, purchase the bridge and platform and provide native plantings on the Ashburn Farm property.