In the aftermath of World War II, the Allies loaded decommissioned vehicles with chemical warfare agents and sunk them in various 'dump fields', one of which includes the area outside Arendal.
During this year's mapping expedition, 35 shipwrecks in total were found in the dump field. 20 of these wrecks had previously been detected in 2009, leaving 15 new wrecks.
Due to the size and age of some of the wrecks, it is believed that some of them did not originate from the dumping programme, and further analysis is being undertaken to confirm this theory. There is also reason to believe that this discovery confirms the previously estimated number of between 36 - 38 wrecks, although official confirmation will not be given before the final survey is completed in 2016.
Collaboration between FFI and NIVA
The project has been led by the Norwegian Defence Research Establishment (FFI) and its ship "HU Sverdrup". A sonar on board an autonomous underwater vehicle (HUGIN) was used to scan the entire delineated dumping zone except for a small part in an area to the West. This area will be covered during the next survey planned for spring 2016, during which time zones outside the dump field will also be sampled.
In addition, NIVA have completed a project to collect samples from the seabed in the dump zone containing scavenging organisms, hagfish and amphipods. These samples will be analysed further in order to give an insight in to what extent organisms in the area may have been affected by the degradation of the chemical products on board the vessels. These results will be available later in the year.
The pictures give valuable insights
The Product Leader for the NCA, Hans Petter Mortensholm, is satisfied with the first phase of the survey. "We have now found further wrecks, and the upcoming survey in 2016 will provide the full scope of the Allied dumping after WWII. In addition, we can produce superior sonar images of the wrecks than previously, giving valuable insight about the state and distribution of the debris". observes Mortensholm.