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Corbalis to Fox Mill Water Main. Fairfax, Virginia.

The Corbalis to Fox Mill Water Main will complete the connection of the Corbalis Water Treatment Plant to the Fox Mill Water Storage and Pumping Facility.

The project consists of the design of over 12,000 linear feet of new 54-inch water transmission main. The Corbalis-Fox Mill Water Main will be constructed on the east side of the Fairfax County Parkway in a highly urbanized area in Fairfax County. The pipeline will be constructed parallel to an existing 48-inch diameter Fairfax Water transmission main within an existing County utility easement. Roadways along the alignment will be crossed by tunneling. Maintaining access to roadways and park areas for automobiles and pedestrians is of particular concern during this project. Another key project element will be coordination of the alignment with the many utilities that parallel the pipeline such as natural gas, petroleum and telecommunication utilities.

Corbalis to Fox Mill Water Main
Project Highlights


For the Corbalis Water Main tunnel, WRA assessed subsurface conditions at two TBM sites and four shaft sites. WRA prepared geotechnical profiles and a report for Fairfax Water. Analysis was based on the results of approximately 40 borings in soil and rock.


WRA provided wetland delineation, permitting, and regulatory coordination in order to install approximately 12,000 feet of 54-inch water main along Fairfax County Parkway. Groundwater levels were periodically measured to determine groundwater conditions for construction of the tunnel and pipeline access shafts.