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Subsea EngineeringDredging Support

Diver Survey and Obstruction Identification Before Dredging

What is Pre-Dredge Obstruction Survey?

KCC provides pre-dredge obstruction surveys to identify and record seabed obstructions, buried utilities, and other hazards before dredging plant is mobilised. Commercial divers systematically survey the dredge footprint, probing the seabed and recording the position, size, and nature of any obstructions — concrete debris, rock outcrops, old piles, cables, pipelines, and unexploded ordnance (UXO) indicators.

Survey findings are compiled into a pre-dredge obstruction register with diver sketches and photographs, allowing the dredging contractor to plan obstruction clearance or route avoidance before committing plant to the area. KCC also provides magnetometer survey support and liaises with the Hong Kong Police Explosive Ordnance Disposal (EOD) Bureau where UXO indicators are identified.

Compliance: Pre-dredge surveys are conducted in accordance with Hong Kong Civil Engineering and Development Department (CEDD) dredging guidelines and IMCA D 045. All diving operations comply with HSE Diving at Work Regulations 1997.

What's Included

  • Systematic seabed probing and visual inspection of the dredge footprint
  • Obstruction identification — concrete, rock, piles, cables, pipelines
  • UXO indicator identification and EOD liaison
  • Magnetometer survey support
  • Obstruction register compilation with photographs and sketches
  • Obstruction position marking and buoying
  • Briefing of dredging contractor on obstruction locations
  • CEDD-compliant survey reporting

Why This Matters

Unidentified seabed obstructions are a leading cause of dredging plant damage, programme delays, and utility strikes. A thorough pre-dredge survey by commercial divers is the most reliable method of characterising the seabed before plant is committed.

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IMCA ADCI HSE HKCP

IMCA · ADCI · HSE · HKCP Compliant

All diving operations conducted to IMCA, ADCI, HSE & HKCP standards

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