Case

The Aarhus River Project – improved water quality and flood prevention in one

We have reopened the cased Aarhus River so that people are once again able to enjoy the open water areas in the centre of Aarhus. The opening of the river is also an important part of Aarhus Vand’s project about flood prevention and preventing wastewater from overflowing into lakes, streams and bay.

The Municipality of Aarhus decided years ago to improve the quality of the water hygiene in the receiving waters through the so-called Aarhus River project. This to support the opportunities for recreational use of Lake Brabrand, the Aarhus River and the Port of Aarhus. Today we have reopened the cased Aarhus River so that people are once again able to enjoy the open water areas in the centre of Aarhus. Furthermore, the water quality in the upstream lakes is significantly improved, transforming the water bodies into accessible and safe areas for recreational use. So we have made swimming in the harbour possible. This is possible due to the many implemented projects that reduce pollution into the water environment.

The reopening of the river is also an important part of our project about flood prevention and preventing wastewater from overflowing into lakes, streams and bay. We use the Aarhus River as a retarding basin in connection with major rainfall events to protect the citizens against flooding. The lock works as a regulator for holding back the water and the associated pumping system ensures that water can be pumped out into the bay at any time when the tide is up.

We have invested heavily in constructing trunk sewers, storage tanks and increasing rainwater handling capacity at our wastewater treatment plants. And as an integrated part of the Aarhus River project, we have implemented one of the world’s most advanced systems in which the control of all installations is coordinated from one point. Efficient and flexible operation, especially during rainfall events, are secured by integrated control and an early warning system.

We have developed a real-time control and warning system, which has saved nearly half of the needed storage capacity for less than 5% of the total costs. The control system optimises the use of the storage capacity in the combined sewer system through real-time control of weirs and pumps, which subsequently minimises combined sewer overflows during heavy rain.

The warning system forecasts deteriorated water quality in the receiving waters based on automatic operation of integrated models of the sewer system and receiving waters. The models use real-time data from the sewer systems and wastewater treatment plants as well as forecasted rainfall data from a local area weather radar.

This improves the water hygiene, also during expected climate change scenarios like intense rainfall and rising sea levels. This also means that we prevent flooding as a result of climate change in the centre of Aarhus and at the same time we secure proper water quality for the beautiful harbour bath designed by the famous Danish architect Bjarke Ingels.

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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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