In New Zealand, Land Information New Zealand is tasked with keeping our nautical charts current, to ensure safe ship navigation around New Zealand's busy coastline. Port authorities undertake regular hydrographic surveys to monitor and manage adequate under keel clearance within ports.
Delivering a hydrographic survey which meets the needs of nautical charting, as well as providing a base line coastal data set for marine science, is no mean feat! Depending on the complexity of a survey, it can involve between 50 - 80 days of vessel operations just to gather the data, working long days.
In addition to this, it can take upwards of 3-4 months to complete the analysis and reporting phase. During a hydrographic survey strong emphasis is placed on collecting precise depth measurements (bathymetry), seafloor backscatter, water column data, positioning of the shoreline, tides, currents, seabed and submerged obstructions - all features that may influence safe ship navigation and coastal zone coastal management.
The surveys may use a variety of sensors/techniques including Single Beam Echo Sounders (SBES), Side Scan Sonar, Multibeam Echo Sounders(MBES), Sound Velocity Profilers, temperature & salinity sensors, sediment sampling, Acoustic Doppler Current Profiler (ADCP), Mobile Laser Scanning (MLS), underwater photography/video, drone photography, motion senors and RTK/WAGNSS positioning. Discovery Marine undertakes hydrographic surveys using vessels ranging in size from 5m for inshore shallow-water surveys, to larger vessel for off-shore deployments.
There is considerable investment required in state-of-the-art technology and platforms. Our teams operate in challenging environments, where they encounter rocky coastlines, swell, changeable weather and remote locations with extended periods away from home.
DML is one of only two panel providers approved to undertake regular hydrographic surveys for nautical charting.
We are also the only New Zealand owned company, approved to provide these services to the Royal Australian Navy.
DML personnel hold IHO Cat A and CPHS Level 1 Certifications; mandatory for meeting Land Information New Zealand and Royal Australian Navy requirements. Our senior hydrographic surveyors have upwards of 15 years experience delivering complex projects and are extremely proficient mariners. This combined skill set is both scarce and highly-valued.