Questions and answers about the Mälaren Fairways

Here you can find questions and answers about the Mälaren Fairways Project.

What work has been carried out in the Mälaren fairways?

Through increased investment in navigational aids and dredging in Lake Mälaren, the capacity of vessels calling at the ports of Västerås and Köping is being increased. Accessibility and safety are also being improved.

The current maximum dimensions for vessels calling at Västerås and Köping are 135 x 18 x 6.8 metres. With adaptations to Södertälje, the fairway and the ports (including the guide structures at Hjulsta Bridge), the maximum vessel dimensions will be up to 150 x 24 x 7 metres.

Once Södertälje Lock and Canal have been rebuilt, the fairway and harbour basins dredged, and Hjulsta Bridge rebuilt, the maximum vessel dimensions can be increased to 160 x 24 x 7 metres. The Swedish Transport Administration is continuing its work on the Hjulsta Bridge issue.

The fairway is being dredged, all blasting work is carried out underwater, and additional navigational aids are being installed along the fairway.

Why do you want to accommodate larger vessels?

Transport costs are reduced because vessels can carry more cargo. Larger vessels mean that fewer vessels are needed to transport the same amount of goods, which provides environmental benefits. There is also an opportunity to shift freight currently transported by road and rail to shipping.

This reduces congestion on roads and railways while also improving the overall safety of the transport system.

How does accommodating larger vessels affect the risk profile?

The project will provide significantly greater safety margins in the fairways of Lake Mälaren. The navigational aids in the fairways are being adapted to the planned changes and to international safety recommendations.

The distance between vessels’ keels and the seabed will increase, and the fairway will be widened, reducing the risk of grounding.
The safety distance between the keel and the seabed (known as clearance) will increase by 75 per cent as a result of the planned measures.

What happens if a fully loaded tanker runs aground or collides in Lake Mälaren?

Greater safety margins reduce the risk of accidents, and the regulations governing tankers are strict.

All tankers must have double bottoms to minimise the risk of spills in the event of an accident, and having a pilot on board will continue to be mandatory.

Tankers are divided into sections. This limits the amount of fuel that can leak in the event of an accident. The tanks contain approximately 1,200 to 2,800 cubic metres. A larger vessel does not mean larger tanks; instead, it has more tanks.

How do you protect Lake Mälaren, which is an important source of drinking water?

By implementing measures to improve safety, the risk of accidents is reduced. Dangerous goods have long been transported on Lake Mälaren, and the larger tankers do not carry more fuel in each individual tank than the vessels currently operating in the Mälaren fairways.

Existing safety regulations are and will continue to be followed. These include requirements for a pilot on board and double hulls. As part of the project, an analysis has been carried out of possible accident scenarios and the protective measures that need to be taken. This includes the level of preparedness required to minimise the consequences of a potential accident.

How do you know that the fairway design works for larger vessels?

Pilots and ship officers have carried out full-scale simulations in which they navigated vessels through the fairways under realistic conditions. This has made it possible to test the fairways under different weather and wind conditions and determine what restrictions may be needed in narrow passages.

Even today, vessels operating on Lake Mälaren can carry significantly larger loads than trucks and trains.

Why does the fairway need to be expanded for even larger vessels?

It will improve the competitiveness of Swedish businesses while also providing environmental benefits. See also the answer to the first question in this FAQ.

Where is the dredged material permanently deposited?

The majority has been deposited on the seabed in four deep areas close to the dredging sites.

Contaminated material has been handled on land by the ports of Västerås and Köping respectively. Material assessed as moderately contaminated was placed at the bottom of the deep area known as “Blacken”, east of Kvicksund, and was then covered with clean dredged material.

Approximately one million cubic metres of dredged material is involved, around half of which comes from the ports of Västerås and Köping.

How do you ensure that the dredged material remains in place on the seabed?

The dredged material is placed in valleys and deep areas on the seabed where it will remain in place in the future.

Dredging and deposition normally result in a small amount of temporary and localised spillage. Since the vast majority of the dredged material concerned is not contaminated, this spillage does not result in the spread of contaminants. Contaminated material is dredged using special techniques, such as an environmental grab, which minimises spillage. An environmental grab encloses the material inside the grab to minimise leakage as it is lifted from the seabed.

Was the water affected by the dredging during the project?

Lake Mälaren is naturally turbid. In the areas where dredging was carried out, turbidity increased further during the approximately four to five months in which the work was underway.

The turbidity decreased after the work was completed and should not cause any permanent damage. The Land and Environment Court has established guideline values for permitted levels of turbidity. Measurements will be carried out continuously to ensure that turbidity remains within the established limits.

Who protects the environment in a project like this?

The Swedish Maritime Administration is required to demonstrate what environmental impact the project will have. During the period 2011–2013, the conditions in areas that could be affected by the project were surveyed and the consequences of the project were investigated.

The project’s positive and negative impacts on health and the environment were summarised in an environmental impact assessment, which, together with the application for a permit for water operations – that is, permission to carry out work in water – was submitted to the Land and Environment Court.

The court grants permits and establishes the framework for the project. Based on this, an environmental monitoring programme is established, with the County Administrative Board acting as the supervisory authority.

When did the dredging project start?

Following the preparatory work, dredging began on 1 August 2021 and was expected to be completed by the end of the year.

How were those affected informed?

During September and October 2012, initial consultations were held at six locations with relevant authorities, organisations and others. Public information meetings were also held, with invitations published in the local press. At this early stage, information about the project was provided and views were gathered on the proposed changes and how they should be implemented.

A second consultation was held in March 2013 with a broader group, including the general public. The results of the environmental impact studies were presented at these consultations. The website www.sjofartsverket.se/malarfarlederna is continuously updated with information, and the latest developments in the project are regularly published in the website’s news archive.

What did you do to minimise disruption and noise during dredging?

The Swedish Maritime Administration follows the Swedish Environmental Protection Agency’s guidelines for noise at construction sites. Dredging was carried out in different sub-areas, and the impact on any individual property did not continue for an extended period.

Were islets and skerries blasted away?

No, all blasting was carried out below the water surface.

How did you monitor whether the blasting caused any damage?

Before blasting began, facilities within the risk zone were inspected. Property owners were contacted prior to these inspections.

Where there were masonry fireplaces and chimneys, smoke ducts were tested for leaks, and chimneys and fireplaces were inspected. Drinking water was also sampled if the property had its own well. After the blasting work was completed, follow-up inspections were carried out on the facilities that had previously been inspected.

Were fishing waters affected?

Extensive investigations were carried out ahead of the proceedings in the Land and Environment Court. According to the court ruling, dredging was restricted to certain times of the year, from 1 August until the formation of ice, but no later than 1 March of the following year.

An extensive monitoring programme during the work period ensured that the dredging had as little impact as possible.

Was it possible to swim while dredging was underway?

Yes, it was possible to swim. However, it should be noted that turbidity in the areas where dredgers were operating could increase while the work was underway. The turbidity then decreases rapidly and no permanent damage occurs. The Land and Environment Court establishes guideline values for permitted levels of turbidity. Measurements are carried out continuously to ensure that the established limits are observed.

Don’t larger vessels mean more noise and wake?

Vessels generally produce very little noise while underway, and only during the short period in which they are passing.

The vessels themselves do not create large wakes, but water movement can occur because the vessel pushes water ahead of it, which then returns to its normal level. This can be experienced as the vessel drawing water away from the shoreline.

Larger vessels do not generally generate larger wakes. Wake and waves depend largely on the vessel’s design and speed.

Don’t larger vessels stir up more water, which in turn disturbs contaminated sediment? What do you do to prevent this?

Since contaminants are removed when the fairway is dredged, there is less risk of contaminated sediment being disturbed and spreading.
In addition, the fairway is made wider and deeper, which increases the distance to the seabed and thereby reduces the impact of propellers and vessel movements.

Was commercial shipping affected in any way during the dredging period?

As far as we can tell, commercial shipping was able to operate to and from Västerås and Köping just as before. A local communication centre was established between the ports concerned and the pilotage area to plan traffic on Lake Mälaren while dredging work was being carried out.

Was recreational boating affected during the dredging period?

Only minimally, but we encouraged recreational boaters to maintain a sufficient distance from dredgers, barges and other work vessels.

What about birdlife?

Extensive investigations were carried out ahead of the proceedings in the Land and Environment Court.

According to the court ruling, dredging was restricted to certain times of the year. In addition, an extensive monitoring programme was established during the work period to ensure that dredging had as little impact as possible on birdlife.