Flood mitigation and urban planning in practice
- Use cases
Aabenraa Municipality is one of the Danish cities with the highest risk of flooding. This is perhaps why municipal planners in Aabenraa were among the first in Denmark to start using Scalgo Live for surface water planning and flood mitigation.
Today, climate adaptation officer Philip Asmussen and watercourse officer Tobias Knudsen can hardly imagine doing their jobs without the digital platform.
“Scalgo Live provides us with an invaluable overview of surface water movements – both during extreme events such as storm surges and in daily operations involving construction and planning,” says Philip.
Meet Philip and Tobias who work with surface water management in Aabenraa municipality.
Storm surges require quick decisions
When a water level of 216 cm was forecasted in Aabenraa for the storm surge in October 2023, municipal employees mobilised quickly. The city’s quay edge is only two meters high, with large parts of the city center situated lower.
Philip and Tobias were tasked with urgently assessing where to place water tubes to best protect the city. In Scalgo Live, they adjusted the elevation data along possible tube placements to identify locations where the tubes might be insufficient to fully protect the areas behind them.
“Scalgo Live provides us with an invaluable overview of surface water movements – both during extreme events such as storm surges and in daily operations involving construction and planning.”
Philip Asmussen, Aabenraa Municipality
Philip and Tobias used Scalgo Live to identify suitable locations for water tubes during the storm surge in 2023.
They efficiently identified the optimal placements for the water tubes and determined additional measures to enhance protection where the tubes were inadequate. For example, an extra embankment of big bags and plastic was constructed at a critical location.
Tobias recalls: “In the end, we only had 10-20 cm of water in the city center. That happened because, unfortunately, one of the tubes burst. Luckily, this happened late at night when the water level was already receding, so not much water entered the city. Otherwise, our simulations and barriers held up well.”
An embankment was extended with sandbags to protect Aabenraa.
Engaging with citizens
West of Aabenraa, you can today enjoy a beautifully restored nature area, called Bønderengene, where a remeandered stream and a re-created wetland now support natural hydrology and biodiversity. The area is also designed to serve as flood protection during extreme weather events.
“By staying ahead of the curve, we can prevent problems and create better urban spaces.”
Tobias Knudsen, Aabenraa Municipality
The area of Bønderengene was restored to a natural wetland.
Such large projects often include a lot of stakeholder engagement. For example, a neighbour to the newly established wetland raised a concern after the project was implemented.
“They were worried that Bønderengene had caused flooding on their property", Philip tells. "It was great to be able to quickly draw a profile from their garden down to the project area and show that the garden, in fact, was five meters higher than the area they believed was responsible for the flooding.”
With the profile tool it is easy to quickly evaluate elevation changes and explain surface water challenges to residents and stakeholders (example image of a profile).
In another project, a property owner wanted to add soil to a steep slope and Tobias needed to evaluate how this could affect nearby houses.
“It was important to assess whether the terrain change would affect flow velocity, so we ran a DynamicFlood simulation. It turned out that a depression at the top of the slope could absorb much of the water. So there was no risk to the houses at the base of the slope. In this case, we were the ones who were reassured,” says Tobias.
"It’s smart that all terrain and water data are accessible and easy to work with. You can check everything in Scalgo Live without being a water or GIS expert.”
Philip Asmussen, Aabenraa Municipality
Strengthening collaboration within the municipality
Surface water is traditionally one of the last things considered in municipal planning. Philip and Tobias know that addressing surface water early can save a lot of time and effort later on.
“With climate change, our colleagues will need to consider water just as much as they do population growth and traffic. That’s why it’s smart that all terrain and water data are accessible and easy to work with. You can check everything in Scalgo Live without being a water or GIS expert,” says Philip.
Going forward, Philip and Tobias will encourage colleagues to screen project areas from the earliest project stages. If they identify potential surface water issues, Philip and Tobias can assist in finding solutions.
“By staying ahead of the curve, we can prevent problems and create better urban spaces,” Tobias concludes.
Aabenraa Municipality has incorporated surface water management into its new municipal plan, which is currently under review. Once adopted, Philip and Tobias will visit several municipal departments to inform colleagues that surface water screening is now officially included in the planning process.
This way, Philip and Tobias continue to prepare Aabenraa for the future.
