SeaTerra has completed UXO survey, investigation of targets and disposal of ordnance targets, at Trianel Windpark Borkum II offshore wind farm site.
SeaTerra examined and cleared in recent weeks and months numerous metal objects from the future OWF Trianel Borkum West II.
The project is going to establish 32 wind turbines with a capacity of 200 megawatt in an area of 33 square kilometers in the south‐western part of the German North Sea.
The distance to shore is 45 kilometers. The water depth is between 28 and 33 meters.
As part of the required UXO survey and target investigation, 11 major unexploded ordnance targets (7 buoyant mines, 2 ground mines, 1 depth charge and 1 bomb) were identified.
The ordnance targets were not transportable and therefore had to be demolished in situ by explosives specialists and ordnance divers of SeaTerra.
All demolitions were thoroughly prepared and designed in close cooperation with the responsible regulators. Marine mammals were protected by scaring devices and a “Big Bubble Curtain” to minimize noise.
The ordnance clearance operations were preceded by geophysical surveys. 427 hectares of the seabed (wind turbine locations, infield cable routes and anchor areas) were surveyed with high‐resolution magnetometers utilizing array systems (ROTV) or remote operated vehicles (ROV). Subsequent data interpretation led to the identification of hundreds of anomalies. SeaTerra
identified 288 potentially dangerous objects and investigated and cleared them with the help of remote‐controlled devices (ROV, airlift), cranes and ordnance divers.
The UXO campaign was carried out with the vessels Mimer (ROTV survey), Vos Star (ROV survey and target investigation) and Olympic Challenger (target investigation).
The project ended on the March 12, with the last detonation of a buoyant mine.