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Hunting for shallows

Mapping authority hydrographer Tomas Albrigtsen maps conditions outside the old pier. On the screen at the right is a glimpse of the Tyr that is docked and making the measuring work a little more challenging. FOTO: Line Nagell Ylvisåker

Hunting for shallows

Two new measuring vessels this year have mapped what's below the surface in Svalbard's fjords. They found several new sinister shallows.



23.09.2014 kl 13:17

After a ten-week-long expedition to Svalbard, the Norwegian Mapping Authority vessel Hydrograf docked in Longyearbyen on the second Wednesday in September.

For the past five weeks, hydrographer Glenn Maan has been part of the crew.

"We have mostly been in Hinlopenstretet, Dicksonfjorden and Ekmanfjorden," he says.

Areas measured in Hinlopenstretet included, among others, Kinnvika and Sorgfjorden.

"The shift that was here before us measured in the area from Hornsund down to Sørkapp," Maan says.

He says areas the mapping authority were at this summer have mostly not been measured previously.

"It was only in Dicksonfjorden and Hornsund there were old measurements," Maan says.

Measuring the old pier

Before the mapping authority leaves Longyearbyen and Svalbard, there will be a final measurement.

"We have been informed that it should have been shallower at the old pier," Maan says.

Now he, hydrographer colleague Tomas Albrigtsen and Chief Officer Niklas Lund are on their way to find out if more sludge is at the pier.

The mapping authority's main vessel is the Hydrograf. On board, the mapping authority has the measuring vessels Guillemot and Havelle. The latter is now moving towards the old pier to measure the depths there.

"The new boats can measure seas at 12 knots instead of six and have a larger resolution in the echo sounders," Lund says.

Maan says they have had a measuring boat outside around the clock and, in addition, they have taken ​​measurements using the Hydrograf.

"Once we are here, it is about doing everything as effectively as possible," he says.

During the summer's charting voyage, the mapping authority discovered several hundred new shallows. A large proportion of these are so shallow they are critical to navigation.

Takes time

On the way towards the old pier they see the Governor of Svalbard's Tyr vessel is docked. They decide to attempt measuring under it and continuing the survey nevertheless.

A little bit out from the dock, Albrigtsen goes out to measure the speed of sound in the water. He lowers a small cylinder into the water and leaves it there for a few seconds before he lifts it back up.

"The rays of the sonar go differently in different temperatures," Maan says. "Therefore, the water must be examined."

The hydrographer then goes in again and begin to map the seabed. One screen shows the old wharf and the Tyr, another shows the contours of the seabed as drawn by the sonar.

The Havelle goes back and forth along the quay, and is also able to ascertain the bottom under the Tyr.

Albrigtsen picks up the map of the routes they measured earlier in the cruise. They cruise back and forth, back and forth to survey every inch of the seabed.

"We will not go into uncharted waters before they are measured," Maan says. "Up here it is shallow in many places. Then we're not going so far. Maybe we can only go ten meters at a time. When we are a kilometer from land it can take time."

"It's like mowing the lawn" Lund chimes in.

Large parts of Svalbard's waters are not yet surveyed and only 27 percent are mapped using modern methods. At the current mapping pace it will take several decades before Svalbard's coastline is adequately mapped.

Correcting for tidal waters

After the measurements are made​​, they are corrected for the tidal waters. In addition, the GPS data is corrected with satellites. As a result, they go from being accurate to the meter to being accurate to the centimeter

The Havelle sets a course back to the mother ship and Captain Hermod Stokmo. He is happy with the cruise, except that they did not do measurements in Franklinsundet.

"That is is an area many are asking for data from," the captain says.

The mapping authority was, in fact, plagued by ice and wind for a period in Hinlopenstretet.

"We had us a little storm," Stokmo says.

The captain hopes data from this year's surveying comes out quickly.

"If they are lying still for years they become meaningless," he says.

When the readings from this year's cruise will be available on the map is not clear.

"The measurements are standing in line to get onto the map," says Kjetil Wirak, an official in the map production section of the Norwegian Mapping Authority's sea division.

When Svalbardposten went to press Wednesday, it was not yet clear whether it has become shallower at the old pier.


Se bildet større

Tomas Albrigtsen lowers a cylinder into the water to measure, among other things, the temperature. FOTO: Line Nagell Ylvisåker

Se bildet større

Captain Hermod Stokmo hopes this year's measurements will quickly be entered on maps. FOTO: Line Nagell Ylvisåker

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