Ramboll has been commissioned to support the Norwegian Coastal Administration (NCA) in the environmental monitoring of the installation of a supporting counter-fill for the sunken German WWII submarine U-864.
The rediscovery of German WWII submarine U-864 off the Norwegian west coast in 2003 prompted concerns that the vessel’s cargo of mercury could severely pollute surrounding Arctic waters, which led to the decision to cap the wreckage and install a supporting counter-fill.
German submarine U-864 was torpedoed by its British counterpart, HMS Venturer, off the island of Fedje on the Norwegian west coast in February 1945 while on route from Germany to Japan. Historical documents indicate that its cargo included 65-70 tonnes of mercury stored in steel flasks. The wreckage was rediscovered by the Norwegian Navy in 2003, resting on the seabed at a depth of 150 metres.
Geotechnical analyses conducted in 2013 revealed that the seabed in the area around U-864 is unstable leading to the recommendation that counter-filling should begin as soon as possible.
The counter-filling operation, which is scheduled begin in late May 2016, involves laying some 100,000 cubic meters of sand and rock in a controlled and precise manner from a specially designed ship owned by Van Oord in order to stabilise the seabed.
Stringent requirements have been set for environmental monitoring of the work. Tom Øyvind Jahren, Ramboll Head of Department for marine environment, ecology and sediment explains:
“The Norweigan Coastal Administration has commissioned us to perform the third-party control of the monitoring of the counterfill implementation. This will ensure that the project meets all relevant environmental requirements and procedures and will draw on the expertise of Ramboll ecology specialists from Norway and USA.”