Excavated earth and rock will be dumped at the deepest point of the fjord next to the tunnel being excavated reads the NTB release;

Joint project Arna-Stanghelle: Application for a marine landfill in the Sørfjord has been approved.

The new solution for road and rail between Arna and Stanghelle goes in a tunnel. Now we have an approved solution for the disposal of masses and that an important...

Løyve applies to the disposal of up to nine million cubic meters of tunnel mass distributed across three landfills. One marine landfill is planned for each tunnel section. The landfill will be located next to land where the fjord is very deep. The highest filling height is 50 meters below the surface of the fjord.

— The state administrator's license is an important milestone for the project. The new solution for road and rail between Arna and Stanghelle goes in a tunnel. Now we have an approved solution for the disposal of masses and that is an important step for the project, says project manager Katrine Sælensminde Erstad.

Cost-effective and lower greenhouse gas emissions

With such a large mass surplus, marine landfill is the only realistic alternative for large parts of the tunnel masses in the Joint Project. The solution results in significantly lower costs and greenhouse gas emissions than other alternatives, and the impact assessment shows that there will be no significant long-term environmental consequences. It is very important for the project that the marine landfill ensures efficient tunnel operation during the construction phase. Care for traffic safety, road users and local communities makes it virtually impossible to transport all the masses via the road network. Transport over longer distances is also not favorable when it comes to greenhouse gas emissions.

The project has worked for several years to investigate alternatives for handling the masses and thorough investigations have been carried out of the impact on the natural environment, plastic pollution, noise and traffic.

— Our analyzes show that disposal at sea is overall the best alternative. We work continuously to find a balance between impact on the environment, cost and consequence for the local environment along the stretch, says Sælensminde Erstad.

Salt dump must be seen in conjunction with alternatives

Sælensminde Erstad further says that the proposal for a sea landfill must be seen in connection with what would be an alternative. Any other disposal or use of the tunnel mass on land or in the sea also has environmental consequences.

"Sjødponia that is approved has a large volume potential, and can therefore replace two of the regulated land-based landfills that have little or no use for after-use, so that unnecessary interventions and environmental consequences on land can be avoided.

Have developed a new solution

The potential for negative environmental effects of marine landfills mainly applies in the construction phase. The most critical thing is to prevent the spread of fine matter (silt and clay) in the fjord.

The joint project has worked on optimizing the landfill solution and developed a new, closed system to bring rock masses and fines down to a safe depth via shafts in the mountains. Through cross-cutting in the tunnels, the masses will be transported to closed shafts and deposited directly in the Sørfjorden. The new solution will save costs, reduce risk and be positive for the environment.

The regulatory plan stipulates that the rock masses should be brought down via long steel pipes from temporary, floating quay facilities. With the shaft solution, there is no longer a need for the planned quay facilities. The fact that stone handling takes place inside mountain halls is a clear improvement compared to an outdoor quay solution where trucks tip tunnel stone into steel pipes.

The shaft solution requires a regulatory change

The new shaft solution requires a regulatory change. In the main, this applies to changes in mountains with mountain halls and changing routes for access and transport tunnels. There will also be a need for some regulatory changes in the daytime zones. The biggest change will be that the marine landfill at Romslo will be moved to the Naustvika location somewhat further east.

In consultation with the municipalities of Bergen, Vaksdal and Samnanger, the Norwegian Public Roads Administration / Bane NOR will announce the start of the regulation change before the summer of 2023. This will be announced with advertisements and notified by letter to the landowners who will be affected. The joint project aims to submit a planning proposal to a public consultation in the autumn of 2023. The work on the planning proposal will take place in close dialogue with the municipalities, which are planning authorities and which must adopt the plan changes.

https://kommunikasjon.ntb.no/pressemelding/fellesprosjektet-arna-stanghelle-soknad-om-sjodeponi-i-sorfjorden-er-godkjend?publisherId=17847490&releaseId=17976288