Dulles Corridor Rapid Transit Project
Reference
John Dittmeier, Environmental Manager, WMATA (703) 274-6578
Sina Raouf, Deputy Project Manager, CTC (703) 247-6579
Project Highlights
- Natural Resource Inventory
- Wetland Delineation and Functional Assessment
- Natural Resources Technical Report
- Environmental Impact Statement
Project Details
The Dulles Corridor Rapid Transit Project is a 24-mile corridor along the Dulles Airport Access Road from the Metrorail Orange Line near West Falls Church in Fairfax County to Route 772 in Loudoun County, Virginia, in which alternative transit system improvements will be implemented by the Virginia Department of Rail and Public Transportation and the Washington Metropolitan Area Transit Authority. CRI was responsible for assessment of natural resources in support of the NEPA process for the project.
CRI prepared a Natural Environmental Technical Report (NETR) and Draft Environmental Impact Statement (DEIS) to document the existing conditions and the environmental effects to the following resources: surface waters, wetland systems, floodplains, critical areas, aquatic biota and habitat, terrestrial biota and habitat, and rare, threatened, and endangered species. CRI gathered information pertaining to these natural resources from several state and county agencies such as the Virginia Department of Environmental Quality, Virginia Department of Conservation and Recreation, Virginia Department of Health, Fairfax County Department of Public Works and Environmental Services, Virginia Department of Game and Inland Fisheries, Fairfax County’s Department of Environmental Management, Loudoun County Department of Building and Development, and Virginia Department Agriculture and Consumer Services.
To prepare the NETR and DEIS, CRI identified and delineated thirty-nine wetland systems along the Dulles Corridor using the methodology adopted from the 1987 Corps of Engineers Wetland Delineation Manual- (Environmental Laboratory, 1987). Each wetland flag point and test plot was surveyed using a Trimble backpack GPS unit and the located boundaries were plotted on aerial photography in AutoCAD. Before the field investigation, CRI located possible wetland and waterway areas using maps generated by the Natural Resources Conservation Service (NRCS), United States Geologic Survey (USGS), and United States Fish and Wildlife Service. We then classified all identified waters of the U.S., including wetlands, according to established and accepted methodology. In our field work, we identified the wetland indicator status of the observed vegetation using the National List of Plant Species That Occur in Wetlands: Region 1 - Northeast (Reed 1988). We identified soil color using a Munsell Color chart. We assessed wetland functions for each wetland system using the New England Method. CRI conducted a jurisdictional determination with US Army Corps of Engineers of the thirty-nine wetlands identified within the corridor.
In addition, CRI conducted a biological assessment approved by the Virginia Department of Conservation and Recreation to review the presence of state and globally rare plant species associated with diabase glade communities in the Dulles Corridor. CRI conducted a field investigation for the following species: earleaf foxglove (Agalinis auriculata), white heath aster (Aster ericoides), blue-hearts (Buchnera americana), hairy beardtongue (Penstemon hirsutus), downy phlox (Phlox pilosa), stiff goldenrod (Oligoneuron rigidum), and marsh hedgenettle (Stachys pilosa var. arenicola).
CRI analyzed four project alternatives to determine the potential effects of each alternative upon the natural resources within the corridor. CRI assessed short and long term effects for each resource and analyzed mitigation options which were discussed in the NETR and DEIS. Following DEIS, CRI assisted the project management team in completing the FEIS for the project. CRI responded to agency and public comments, revised natural resource sections of the document and conducted follow-up wetland delineations to support engineering changes for stormwater management.