snap shot
Value: > £50k
Distance: 75m
Duration: 5 days

Subduct installation in a culvert

The client commissioned JSM to increase fibre capacity beneath a dock by installing additional subducts within an existing Canal & River Trust (CRT) service culvert. The culvert naturally filled to dock water level and was subject to tidal influence from the River Thames.

Access was via 15.5‑metre‑deep shafts, requiring detailed planning to manage dewatering, tidal conditions and environmental constraints.

 

CHALLENGE

The service culvert filled to the same level as the Dock, with tidal influence from the River Thames. Deep access shafts (15.5m) and prolonged pumping were required to maintain safe working conditions.

WHAT WE DELIVERED

  • Installation of 14 no. 32/27mm sub ducts through the existing CRT service culvert
  • Continuous dewatering using high‑head pumps, coordinated with tidal cycles
  • Close coordination with Canal & River Trust, including water level management and environmental controls
  • Completion within a five‑day programme and within budget

14

no. 32/27MM

sub duct installation

15.5m

deep shafts

75m

in length

SPECIALISMS USED

  • Subduct installation
  • 32/27mm ducts
  • CRT service culvert
  • Fibre capacity increase
  • Culvert dewatering
  • High head pumping
  • Continuous pumping
  • Deep shaft access
  • Water quality testing
  • Tidal programming
“The project required a considered approach to planning and execution to manage access, environmental factors and site conditions. Maintaining that level of control was key to delivering the works safely and on programme.“
Steve Witt
Planning Manager