Project reports
04 May 2016 |   ByHugh Parker
Fugro Author
Airborne lidar Bathymetry (ALB) technology has been used around the world and specifically across the pacific region by Australian, New Zealand and French authorities for coastal zone management and nautical charting since the early 1990’s.

Since then advances in technology have helped to improve the cost effectiveness, speed, depth, accuracy and flexibility of ALB systems. One of the projects that benefited from such advances was carried out in 2015 for the French Polynesian Government, where a record depth sounding was achieved using the Fugro designed and built Laser Airborne Depth Sounder or ‘LADS’ ALB system.

With large populations and infrastructure concentrated along the increasingly vulnerable coastal zone, ALB technology can provide data suitable for assessing risks and mitigating adverse impacts of natural disasters.
Mark Sinclair, Managing Director, Fugro LADS
LADS system
‘LADS’ ALB technology designed, built and operated by Fugro to survey coasts with water depths of up to 80 metres (subject to water clarity).

During this project, Fugro captured a continuous reference digital elevation model of land-sea interface along the coastal fringe of NW Tahiti, Moorea and Bora Bora islands to depths greater than 50 metres using a configuration of simultaneously operated Fugro LADS Mk3 and Riegl VQ-820-G sensors that were installed side by side in a Beechcraft King-Air A90 aircraft. 
The Riegl sensor is a shallow water system providing high density shallow water returns to the nominal 10 metre depth contour and topographic returns. The Fugro LADS Mk3 sensor is able to provide returns in deep water and difficult environmental conditions due to its 7MJ laser power and superior receiver technology.

In the ideal water and atmospheric conditions in summer in French Polynesia the systems performed exceptionally well. The contract requested soundings to the 40 metre nominal depth contour and the LADS systems were able to consistently achieve 50 metre depths. At one of the sections along the Moorea Island coastline the LADS system achieved a sounding return of 76.1 metres, a record depth from a bathymetry lidar system!

”With large populations and infrastructure concentrated along the increasingly vulnerable coastal zone, ALB technology can provide data suitable for assessing risks and mitigating adverse impacts of natural disasters,” says Mark Sinclair, Managing Director of Fugro LADS. ”The technology is particularly effective in the Pacific due to its operational versatility and cost effectiveness, despite the remoteness and hazardous nature of this area.”

ALB continues to be a cost-effective and reliable tool to capture the deep reef and coastal topography interface, whilst still achieving international hydrographic data standards. With much of the world’s oceans unsurveyed, ALB will continue to help governments, charting agencies and citizens to create more informed decisions.

ALB data applications

  • Supporting safety to navigation
  • Coastal zone management, including
    • managing severe weather events of storms and floods, 
    • impacts of earthquakes including landslides and tsunamis,
    • input to circulation and wave models,
    • modelling of cyclonic submersion risk 
  • Understanding ecological processes on shallow coral reef substrates.

Find out more about Laser Airborne Depth Sounder (LADS)

 

Most popular articles

Sign up for email updates