The Finnish section of the pipeline route is 374 kilometres long. Prior to pipelay, works will include preparatory activities of munitions clearance, rock placement and mattress installation.
Before construction can start, some preparatory activities need to be carried out. These activities include munitions clearance, rock placement and mattress installation. To ensure safe installation and operation of the pipeline, potential war-time munitions have been cleared from the lay corridor. Rock material needs to be placed at precisely defined locations along the route to support the pipeline before and after pipelay where the seabed is uneven, for example. Concrete mattresses will be installed to protect the existing infrastructure, such as power and telecommunications cables and existing pipelines.
The actual pipelaying construction works in the Finnish Exclusive Economic Zone will be performed with a dynamically positioned pipelay vessel. Some rock placement is required also after the pipeline has been laid on the seabed.
During rock placement and mattress installation operations, safety zones of 0.3 to 1 nautical miles (500 metres to 1.85 kilometres) will be required around the working vessels, causing temporary navigation restrictions in the Gulf of Finland. The safety zone around the pipelay vessel is one nautical mile. All the safety operations within the Finnish EEZ have been planned in cooperation with the Finnish Transport Agency.
The responsible national authorities will oversee the preparatory and construction activities to ensure that they are carried out according to the permit provisions. The contractors will report on their activities to the authorities on a regular basis. Independent contractors will monitor the potential environmental impacts of the activities in accordance with the national environmental monitoring programme.