My name is Annie Biron, and I work for the Canadian Hydrographic Service in Mont Joli.
One of our mandates is to chart Canada's navigable waterways to make them safer.
We use two main technologies to update water depth data on nautical charts: sonar and topo-bathymetric LiDAR.
Sonar measures the water depth by emitting a sound wave and calculating the time it takes to be reflected back from the sea floor. Sonar is used at a variety of depths, and its range increases with depth.
These devices are installed and operated on both large ships and small craft, and can even be remote-controlled or autonomous. Topo-bathymetric LiDAR measures elevation or water depth by emitting light waves and calculating the time it takes for them to be reflected off the surface of the ground or the bottom of the water.
LiDAR will be used mainly to map coastlines and very shallow areas, because this technology depends entirely on clear water and therefore cannot be used everywhere, or at depths of over about 10 metres.
The combined use of these two technologies will improve knowledge of waterways in Canada and make them safer to navigate.