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November 20, 2011 - Four recreational divers went looking for known wreckages at the bottom of De Nieuwe Meer in Amsterdam, Netherlands, a ~30 m deep lake with strong bottom currents.
The group split into two pairs and set out on their adventure. Around 11:30 AM the only woman diver reported looking back for her partner, a 55 year old man from Amstelveen, but all she could see was a cloud of sediment. He never surfaced.
Rescuers operating the sidescan SONAR. Picture from AT5.
The fire department was called and they immediately sent out divers to locate the man. Because of dense fog, the search was called off for the day. The next day, National Police Agency divers and specially trained cadaver dogs along with AT (equivalent of American SWAT) with sidescan SONAR joined the retrieval mission. The water was cold enough and the diver had been down there long enough that he was assumed dead. On the third day of the search, the Dutch Navy brought in autonomous underwater vehicles (AUV’s), but they still couldn’t locate the body. On November 25 the site was opened to anyone from the public wishing to participate in the investigation.
It was at this point in the story that Henk de Vries and Metaldec Survey BV enter the picture. Metaldec uses Golden Software products Didger, Voxler, and Surfer, for a wide variety of projects, including pro-bono work with off-duty members of the Amsterdam police department. They had previously helped the department set protocols for forensic drowning scenes, and they were known to volunteer frequently to help the police.
So, on December 10th Mr. de Vries and his team, at the request of off-duty National Police Agency members, got to work. The divers had taken depth recordings every 30 seconds, so Mr. de Vries used Surfer to create a 3D depth map of the lake, from which the divers identified the approximate location where they’d lost track of their comrade. In this refined area, Metaldec set up their sidescan SONAR equipment and collected their own bathymetry data.
3D Surface Map of De Nieuwe Meer created with Surfer
As Mr. de Vries overlaid his bathymetry data on a Google Earth image of the lake, he made a surprising and concerning discovery. The pipeline running through the middle of the lake, which sucked up water to cool servers in a local hospital, did not cross the entire lake as everyone had assumed, but stopped at an inlet near the center of the lake. No previous divers had ever mentioned this, but they were all in danger of being sucked into the pipe, so all diving was immediately halted. Interestingly, this inlet area was near where the dogs and the other divers believed the man disappeared. The lake was dredged to no avail. On January 6, 2012 the search was called off permanently, as no body had been found.
Metaldec’s SONAR images overlain on Google Earth image of De Nieuwe Meer
Now, more than 5 months later, the body is still missing. Some think the body was sucked into the pipe, though it’s more likely the diver got stuck under the pipe or inside of one of the ship wreckages nearby. Regardless, through the selfless acts of Metaldec and Henk de Vries, the lives of numerous divers were saved with the discovery of the dangerous inlet pipe. As for the missing diver, Mr. de Vries holds out hope that he will be recovered one day.
For more information, visit:
AT5, 23 Nov 2011, “Duiker Nieuwe Meer nog steeds spoorloos.”
Franke, Ronald, Hulpdiensten Online, 21 Nov 2011, “Zoekactie naar vermiste duiker in Nieuwe Meer gestaakt.”
RTV-NH: Radio+TV Noord-Holland, 6 Jan 2012, “Zoekactie duiker Nieuwe Meer gestaakt.”
AT5, 21 Nov 2011, “Politie zoekt naar lichaam duiker."
Read an updated publication in Geoconnexion International Magazine: http://www.geoconnexion.com/uploads/publication_pdfs/int_v15i14-030-Gold16211EB.pdf