Category A Hydrographic Surveying

What is Hydrographic Surveying?

In general terms, hydrographic surveying is the measurement of the physical characteristics of the marine environment. Traditionally, this has been focussed on measuring the depth of water (known as the bathymetry) for the safety of navigation of ships. Most marine explorers through history, including Abel Tasman, James Cook and Jean-Francois Laperouse, were hydrographic surveyors, making charts of the waters and lands they explored. Their work was conducted with sextants and leadlines, and they would be impressed with the leaps in technology that the modern surveyor has at his or her fingertips, from GNSS positioning equipment, precision motion sensors and multibeam echosounders to airborne lasers and even satellite based radar!

Today surveys for nautical charting are of high importance for all maritime nations, with well over 90% of their trade travelling by sea, for which safety of navigation is paramount. But the story doesn't end there. Surveys are now conducted with highly specialised equipment: to support the oil and gas industry; for port management, dredging and coastal engineering; for marine environmental monitoring; for marine archaeology; and for other marine scientific purposes.

The information gathered by hydrographic surveyors goes well beyond just bathymetry. Seabed composition (both surface and subsurface), tidal heights, tidal streams and current measurements, water clarity, salinity and temperature, are all collected and analysed, depending on the project requirements. Work is conducted in small inflatable boats on lakes, rivers and in ports, and a range of sea-going vessels up to seismic survey vessels weighing thousands of tonnes. Hydrographic surveyors often have to work surveying on the adjoining land as well as the water - they get to experience the best of both worlds!