Hydrogeologists taking a deep dive

04 June 2026

The Lindholmen Connection will take you by tram in a tunnel beneath the Göta River and under Gothenburg’s beloved city park, Slottsskogen. Planning a tunnel through rock and clay is no simple task.

When constructing a tunnel, groundwater is always a key factor. The section of the Lindholmen Connection between Linnéplatsen and Vegagatan is no exception, with local groundwater in different locations and at varying depths. Any leaks in the tunnel can affect groundwater levels both during construction and once the tunnel is in operation. This is where Maria Erlandsson, a technical responsible hydrogeologist for the Lindholmen Connection at COWI, steps onto the stage.

“My job is twofold. First, to map how groundwater levels may change and what risks are associated with those changes. Next, to identify potential solutions to prevent problems,” she says.

The Lindholmen Connection. Image: Land Development Department at the City of Gothenburg.

A pipe has been drilled into the ground to measure the ground water levels at Linnéplatsen.

Preventive measures

Changes in groundwater levels can affect the availability of groundwater for geothermal heating and the water supply for trees and plants. Also, the clay in Gothenburg is known to be sensitive to changes in groundwater levels, and in areas such as Olivedal, some buildings have particularly vulnerable foundations, which can lead to ground settlement.

The most obvious measure to avoid negative impacts is to build a watertight tunnel. Cracks can be sealed with, e.g., concrete, or the tunnel interior can be lined to block water.

“The local groundwater is particularly sensitive to pressure changes, and even a small lowering of the groundwater level can affect a large area. To counteract a drop in levels, another solution is to pump water back into the ground, both into rock and soil.”

“It’s an exciting challenge to work with the area’s sensitive environment, and such a complex project calls for collaboration among different areas of expertise"

Maria Erlandsson, Hydrogeologist

Expert to expert

The Lindholmen Connection is led by the Land Development Department at the City of Gothenburg, Which solutions will be used has not yet been decided. That decision will rely, in part, on the groundwater assessments carried out by Maria Erlandsson and her colleagues.

“It’s an exciting challenge to work with the area’s sensitive environment, and such a complex project calls for collaboration among different areas of expertise,” says Maria Erlandsson.

The groundwater input forms part of the railway plan and environmental impact assessment for the Lindholmen Connection, which is to be submitted to the Swedish Transport Administration at the end of 2027.

Hydrogeologists taking a deep dive

Preventive measures

Expert to expert

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