Climate adaptation and rainwater management at the surface

Increasing rainfall means that pipe capacity is too small in many places, with excess water – a hazardous mixture of wastewater and rainwater – flowing into lakes, streams or sea untreated. The excess water also causes flooding of cellars, roads and green areas. In other words, we lack space in our sewer system, and Aarhus Vand is doing something about this seeing surface water as a valuable resource.

We in Aarhus Vand are hard at work on separating rainwater and wastewater in areas where this has not already been done. We disconnect rainwater from the combined sewer system to ensure optimal capacity and maintain water quality. In our attempt to adapt the city of Aarhus to climate change and avoid damage to properties or infrastructure following heavy rain, we handle rainwater on the surface – wherever it is possible. In some areas though, rainwater is lead through new pipes, and in other areas we handle rainwater through a combination of surface solutions and through new pipes.

But primarily we handle rainwater on the surface. We do so because there is a potential for separating large areas for the same amount that it would cost to lay pipes. In addition, it offers a unique opportunity to use rainwater in a new way – for embellishment and recreational purposes.

Making Aarhus an even more attractive place to live

We make rainwater a visible element in the form of rainwater lakes, rainwater beds and rainwater drains. We also establish hollows and dams; we create entirely new urban spaces and find new ways to lay out green areas. The municipality of Aarhus has a vision of making Aarhus an even more attractive place to live, and we support this ambition with our climate adaptation projects on the separation of rainwater and wastewater.

Whether we choose to lead rainwater through new pipes to a stream or handle it on the surface, we develop and prepare our sewer system for heavy rain – a direct consequence of climate change. Our choice of solution always depends on the local conditions. Furthermore, we keep measuring our efforts against the risk of flooding and the cost of the damage caused by flooding.

Aarhus Vand has carried out two major climate adaptation projects with rainwater being handled at the surface – one in Lystrup north of Aarhus and one in Risvangen in the northern end of Aarhus. In Lystrup all 12 climate adaptation solutions involved surface treatment. In Risvangen, rainwater is handled in a combination of surface handling and pipes. In Malling, a small town to the south of Aarhus, a new urban area has been planned to the south of the town, with the establishment of a drainage system for rainwater handling based solely on a surface solution.

At Aarhus Vand, we have taken up the challenge because we believe that handling of rainwater at the surface in the form of green solutions will provide significant added value to the citizens and support the municipality’s vision for the city.

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A 3VAND partner

We are an active partner in 3VAND – a strategic collaborative partnership consisting of the leading water utilities in Denmark: HOFOR, BIOFOS, Aarhus Vand and VCS Denmark.

About author

As one of the most innovative water companies in Denmark, we feel obliged to support the water industry. We have extensive knowledge of the operation of various facilities, establishment of organisations, analysis, tendering, planning, project management, training and commissioning of facilities. We would like to do our share towards ensuring innovation of the Danish water industry. By also taking a global perspective, we contribute knowledge and support for Danish exports and help set the global agenda for sustainable development.

Primary contact
Flemming Fogh Pedersen

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