Silver Line Phase 2 crews have been working hard to build a series of stormwater ponds to collect and treat water runoff along the alignment.
There are 15 stormwater management facilities positioned all along the rail alignment –which runs in the median of the Dulles Toll Road/Dulles International Airport Access Highway and the Dulles Greenway as well as through Dulles Airport – from Reston Parkway to Old Ox Road (Route 606). Thirteen facilities are under construction; of those, four are complete except for final paving and planting.
Stormwater management facilities serve an important purpose.
They have varying features from dry swales with specialized filters to manmade wetlands that contain multiple bioretention pools to treat stormwater flow.
While the stormwater management facilities in Phase 1 were designed primarily to prevent flooding, the ones that were built in Phase 2 were designed to also remove pollutants while retaining runoff.
Special grasses and plants are planted within the Phase 2 ponds, while locally appropriate trees and shrubs are planted around them to protect and screen them.
“During the design stage of Phase 2, the Commonwealth of Virginia adopted new stormwater management standards to treat stormwater runoff to remove pollutants,” said Stephen Barna, the project’s director of engineering.“The Project elected to adopt the new standards for the benefit of the public.”
The stormwater management facilities for Phase 2 vary in size from approximately 4,000 square feet to several acres. The largest facility is the constructed wetland just west of the Fairfax County Garage south of Herndon Station, while the smallest facility is located just east of that garage.
Pictured at top:
A stormwater management pond nearing completion along Sunset Hills Road near the Reston Town Center Station.
Photo courtesy of Dulles Corridor Metrorail Project