Frederick Griffith, Jr. W.T.P. Raw Water Facility Occoquan


Fairfax County Water Authority


Lorton, Virginia

Key Challenges & Project Details

  • Consisted of 800′ of 84″ raw water intake and 2,300′ of 84″ raw water discharge from Occoquan Pump Station to the water treatment plant
  • 84″ steel intake constructed within a 10′ diameter rock tunnel across the Occoquan River
  • Two shafts, 35′ diameter and 14′ diameter, were constructed 80′ deep at either end of the tunnel
  • An 84″ connection was constructed into the existing water line on one end
  • 84″ PCCP discharge was constructed along a quarry wall in solid rock
  • Pipeline included extensive cathodic projection
  • 24″ overflow decant line was installed from the quarry to the river with excavation cuts of 30′ in solid rock
  • Also included yard piping for the pump station from 6″ to 36″ in diameter, including valves and fittings