Dulles Corridor Metrorail Project Phase 2

The Dulles Corridor Metrorail Project (DCMP) Phase 2 is an 11.5-mile corridor along the Dulles Airport Access Road from the terminus of Phase 1 at Wiehle Avenue through Dulles Airport to Route 772 in Loudoun County, Virginia.  The DCMP Phase 2 Preliminary Engineering (PE) study was conducted for the Metropolitan Washington Airports Authority, the agency responsible for constructing the project.  Coastal Resources, Inc. (CRI) was responsible for assessment of natural resources in support of the National Environmental Policy Act (NEPA) and environmental permitting process for the project.

CRI assisted with the preparation of an Environmental Summary Report that identified all environmental commitments from the Final Environmental Impact Statement (FEIS) and Record of Decision (ROD) that must be carried forward through final design.  CRI also assisted with preparation of the environmental section of the Basis of Design Report that identifies all design features, including environmental considerations, carried forward from the baseline PE.  CRI assisted with preparation of the natural resource sections of the Preliminary Engineering Design Refinements Environmental Assessment (EA), required for compliance with the NEPA.

To prepare the environmental documents described above, CRI identified and delineated nine new or revised wetland/waterway systems along the Dulles Corridor using the methodology adopted from the 1987 Corps of Engineers Wetland Delineation Manual (Environmental Laboratory, 1987).  CRI also reviewed the limits of wetlands/waters that were previously delineated and for which a valid Jurisdictional Determination (JD) already existed.  Each new wetland/stream flag point and test plot was surveyed using a GPS with sub-meter accuracy and the located boundaries were plotted on aerial photography in Geographical Information System (GIS) format.  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.  CRI then classified all identified waters of the U.S., including wetlands, according to established and accepted methodology.  In our field work, CRI 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). CRI identified soil color using a Munsell Color chart.  CRI assessed wetland functions for each wetland system using the New England Method.  CRI completed JD forms for all new wetlands that documented a significant nexus to navigable waterways.  CRI conducted a jurisdictional determination with US Army Corps of Engineers of the 9 wetlands/waterways identified within the corridor and obtained a revised JD for all wetlands within the Phase 2 project corridor.

Location:

Fairfax and Loudoun Counties, VA

Client:

Metropolitan Washington Airports Authority (MWAA)

Key Services:

• Natural Resource Inventory
• Wetland Delineation, Functional Assessment, and Significant Nexus Evaluation
• Preliminary Engineering Design Refinements EA
• Basis of Design Report
• Environmental Summary Report
• State and Federal Wetland Permits
• Wetland and Stream Mitigation Assessment and Unified Stream Methodology