THE CHALLENGES OF CHARTING CANADA’S ARCTIC WATERS
Surrounded by three oceans, Canada has the longest coastline of any country in the world. The marine area of the Arctic alone totals 4.2 million square km and, as its waters become more accessible , the challenge of charting Canada's navigable waters grows.
Since 1883, it has been the Canadian Hydrographic Service (CHS)'s role to study Canada’s waters and ensure their safe, sustainable and navigable use, while providing mariners with road maps that guide them 'from port to port'.
"We produce paper charts, electronic charts and related publications such as tide tables, current atlases and also sailing directions. All these documents are required under the Canada Shipping Act for vessels of all kinds - including cargo ships, ferries, cruise liners and fishing boats - to navigate safely in Canadian waters," says Denis Hains - Director General, Canadian Hydrographic Service, a division of the Department of Fisheries and Oceans.
Canada's small icebreaker fleet combined with a short, unpredictable surveying window, the depth of the water and the vastness of the territory make charting Arctic waterways particularly daunting. Yet, with the increased traffic and a deadline to submit Canada's claim to the UN Law of the Sea - for which the Canadian Hydrographic Service is also responsible - it has become a priority.
"The Arctic is huge, and if you look at a map of the Arctic north of Canada you will notice the complexity of its geography with diverse islands, and a coastline dotted with inlets, channels, fjords and bays. While we have charts for all the Arctic, some of them are very poor in terms of their quality; because they have very old data, partial data, data that dates back to when a lead line was put to the bottom to have a punctual reading of the depth. Those charts are still valid but they’re certainly not the best information you can provide for navigation."
The challenges of mapping Canada's extended continental shelf are also very different from those related to the navigational charts.
"With the UN submission, we are dealing with very deep water but there is not that much shipping in the area. The challenge comes down to sending a ship in an area of multi-year ice where at times it is impossible to go even with the biggest icebreaker that we have,”says Hains. "The charting challenge is different, it’s more to the south and it is within the existing economic zone where there is already a lot of shipping. It has more to do with navigation safety "
In view of the monumental task it is faced with, the CHS is focussing its charting efforts on what Transport Canada, the Canadian Coast Guard and CHS refer to as corridors. These cover about 12 per cent of the Arctic and are classified as Primary or Shipping Corridors, Secondary or Supply Corridors and Tertiary Corridors which serve areas of refuge in case of difficulties.
According to Hains, about 32 per cent of these corridors have adequate or post-1979 surveys, where more accurate bathymetric data was acquired through the use of microwave positioning and echosounders.
"Over the last 15 to 20 years, we have also been using this technology called multibeam sonar which allows you to have full bottom coverage to about 5 times the depth you're in, so if you are in 100 m of water you would be able to cover 250 m on each side of your ship, which would give you a corridor of full-bottom coverage. The advantage being that you can see all the obstacles, including sometimes wrecks or other things that could be at the bottom and which we would include in our charts, “says Hains.
With limited icebreaker resources and a short surveying window, the CHS is also increasingly looking for technology other than ship-based data acquisition
UAVs - Unmanned Aerial Vehicle - are being used more and more in deep waters, especially for acquiring data to justify Canada's UN claim for an extended economic zone beyond the 200 nautical mile allowance. Satellite-derived bathymetry and LIDAR - a remote sensing technology that measures distance by illuminating a target with a laser and analyzing the reflected light- are also increasingly being explored. But this is all at the development stage as CHS searches for solutions to complement ship-based technology which is both expensive and seasonal.
Unfortunately, so far each new technology seems to come with its own drawbacks.
"The issue is always the same. For example LIDAR is not good everywhere, the water has be clear and ice-free. Same thing with satellite-derived bathymetry; whereas optical satellite technology does not see through clouds, Radarsat can see through clouds but its imagery is more difficult to interpret. So far, the multibeam onboard a ship still remains the most accurate surveying tool, but given the magnitude of the area we have to cover we have to use different technologies to help us,” he says.
Tom Zagon is a physical scientist with Environment Canada’s Marine and Ice Services, he has traveled extensively in the ice-covered waters on both Coast Guard and commercial vessels and has seen what it’s like firsthand .
“The Arctic is s one of those last frontiers,” he says. “ There are areas that have never seen a survey vessel because they remain ice-covered. They do open up during the summer months but they are not necessarily clear of ice every year and they might be clear for just a few weeks or days. Most captains try to avoid ice but invariably you have to travel through it. It’s a strange feeling because there is very little or no swell, what you're doing is breaking through the ice. And it's an exciting and challenging time on the bridge of a ship when you navigate through ice because you’re constantly making decisions as to which route to take through the ice.”
According to Zagon, ship captains are risk-averse unlikely to put their vessel or crew in danger. If it comes down to a choice between a clear area that has no soundings and an ice-covered area with soundings, they will choose to go through the ice because they know there is enough water depth through there.
A geographer by training and an expert in remote-sensing imagery, Zagon works a lot with Radarsat; he worked alongside CHS on the Franklin expedition's lost ships and was part of the team that found the Erebus.
“Right now we have a satellite image record that goes back to the mid-1990s with the launch of Radarsat 1; those detailed ice conditions give us understanding of exactly what happened in terms of freeze-up, break-up, patterns of movement and the movement of multi-year ice. You can see the importance of historical information of ice conditions to understand how things change, how ice moves and realize that it’s really not a random thing or a steady decline.”
In spite of his knowledge and appreciation for satellite technology, Zagon is convinced that icebreakers are an integral part of Arctic navigation.
“From my point of view icebreakers do an incredibly important job, if only in search and rescue operations.They are an absolutely crucial part of operating in Arctic waters,” he says. “Icebreakers are absolutely essential for Arctic operations”.
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