The Norwegian Armed Forces' planned underwater explosive range in the Ofotfjord is assessed as being usable without significant impact on the surrounding marine environment, provided that the proposed protective measures are followed. This is set out in a new environmental assessment from the Norwegian Defence Research Establishment (FFI, Forsvarets forskningsinstitutt).
According to FFI, the explosive range at Ramsund (northern Norway) is intended for training personnel who handle and neutralise explosive objects underwater. The exercises require the use of live explosive charges under realistic conditions.
Petter Helgevold Kvadsheim, Chief Scientist at FFI, commented in the institute's news release: "This concerns a training area where relatively small charges will be detonated, but on multiple occasions."
According to FFI, exercises are planned using charges of up to 10 kg TNT on 50 to 70 occasions per year. In addition, one to three larger detonations per year are planned, equivalent to 140 kg TNT.
FFI assesses that a combination of an angled protective barrier and a so-called bubble curtain, where compressed air forms a wall of rising air bubbles, largely limits the impact of pressure waves on fish, marine mammals, and seabirds.
"We have therefore provided a list of concrete recommendations for how the area should be managed. Among other things, we recommend that the bubble curtain is always used during larger detonations and also during smaller charges in the sensitive spawning and nesting period. Detonations should also be postponed if seabirds or marine mammals are detected in the vicinity," said Helgevold Kvadsheim.