Landsort Fairway, Landsort–Södertälje

Name of project: The Landsort Fairway.

Where: Public Fairway 511 between Landsort and Södertälje.

Planned implementation period: From 2024 to 2025, inclusive.

State of maturity: The Government is currently considering the establishment of two new fairways. The water activities will then be subject to review, and this is expected to take place in 2022–2023. The project is included in the Government’s infrastructure plan.

Planned depth: Dredging depth varies from 14.0 to 11.65 m.

Preliminary dredging volume: Approximately one million m3 in situ.

Approximate distribution of rock/dredgable material: The material consists of approximately 950,000 m3 in situ of loose material consisting of clay and cohesive matter and around 70,000 m3 in situ of rock.

Known contaminated material?/Management of contaminated material? Permit to sea disposal of the spoil will be applied for. The dredgable material is divided into two types, clean masses and a minor amount of contaminated dredging spoil.

The clean dredging masses are planned to be disposed of in the proposed disposal areas without specific restrictions. This consists of sand, gravel, blasted rock and clay without contaminants, but also mud and similar material with some degree of contamination.

The moderately contaminated soil requires specific management. The plan is to dredge this material, approximately 20,000 m3 in situ, early on in the implementation phase and dispose of this at the bottom of a suitable disposal site. The moderately contaminated spoil is planned to be dredged by using an environmental dredging bucket.

Potential distance to disposal site or landfill site: A plan for management of the spoil is not yet complete. Several disposal sites are being investigated.

Potential difficult traffic situation: Approximately 2,500 vessel movements take place each year. Traffic in the fairway will continue during the planned dredging works and measures will be put in place to ensure that traffic is disrupted as little as possible.

Skanssundet, the narrow between Södertörn and Mörkö, is crossed by a road ferry. At present, this normally sails once every half hour between 06:00 and 23:00 hours. Each crossing takes around three minutes.

Special conditions: The majority of the work areas are relatively protected and factors such as waves, wind and currents are thus not expected to have any impact on the implementation of the project, other than occasionally. However, the weather conditions may be problematic when dredging the outer areas.

Estimated production time: Probable period of works 15 August 2024–31 March 2025. In order to minimise the negative environmental impact, the works will be carried out in early autumn and winter.

In order to allow the dredging to be limited to one season, an early start is important in this project. It is especially important to complete operations in the southern area early, i.e. late summer or early autumn. Difficult weather conditions during late autumn and winter may lead to a delay. When procuring a contractor, requirements are set on the basis of the conditions in the environmental permit.

Type of contract: Not decided.

Questions received

Will there be any land-made constructions within the dredging contract?

No, foundations for lighthouses etc will be purchased separately. The only so far known man-made construction included in the Landsort project is the planned erosion protection at the sides of the narrow Brandalssund.

What about piloting for own equipment?

Pilot dispensations are normally given after a few trips. Exactly what will apply needs to be specified and clarified in the contract.