Marine York River Treatment Plant Outfall/Diffuser Modifications

KEY CHALLENGES & PROJECT DETAILS

MARINE PORTION

  • Dredge 50,000+ CY and transport to 40% to Shirley Plantation for disposal and the other 60% to Portsmouth, VA for storage as backfill material
  • Drive 35 14 inch square concrete piles (up to 70鈥� length) in 40鈥� deep water. Used a custom-built pile follower.
  • Fuse 3,000 linear feet of 54鈥� HDPE into 600鈥� lengths and float into York River. Then, fuse all sections into 1,200鈥� lengths together and sink into position (center of trench and onto pile caps)
  • Install 54鈥� diffuser section, 380鈥� in length;
  • Place 361 articulated concrete mats over the pipe for protection
  • Backfill (clamshell and hydraulically) 30,000+ CY

LAND PORTION

  • Install 1150 feet of new 48鈥� DIP (ductile iron pipe) to tie into existing treatment plant outfall pipe
  • Build and set a pipe bridge in place over the Dominion Power Plant cooling channel to hold the pipe
PROJECT DETAILS:
  • Project Owner:
    Hampton Roads Sanitation District (HRSD)
  • Location:
    Yorktown, Virginia