In future, a sluice and pump unit at the mouth of Aarhus Å will protect central parts of Aarhus against flooding. The project also involves a new protective barrier running some way into the city from the new community and arts centre, DOKK1.
The sluice is open during normal water levels. During raised sea levels, the sluice gate is closed to prevent the water in the bay from flowing up the river.
The gates close automatically when the water level exceeds 1.4 meters above normal.
The sluice gates will probably be closed around 25-30 hours annually and no more than eight hours at a time. The periods during which the gates are kept closed will be as short as possible to allow fish in the river to migrate between the river and the sea.
The gates will also be closed during raised water levels in the river, and six built-in pumps will make sure that the excess water in the river is pumped out into the sea, preventing the river from overflowing its banks.
The pumps can move a total of 18,000 litres of water per second, corresponding to 65,000 cubic metres of water an hour.
If a cloudburst occurs when there is already raised water levels in the river, the pumps at the sluice will pump river water out into the bay, which means the river can serve as a cloudburst reservoir.
In order to provide further protection for the low-lying parts of the city during high water levels, the two streets Havnegade and Europaplads, as well as the area around the sluice itself, have been raised. The streets form a 300-meter long, invisible dyke along the river.