The Hovedgrøften water course which runs through the landscape in a straight line from Copenhagen Airport to the Sound plays a key role in Dragør's open-countryside planning.
A key problem for the Municipality of Dragør has been whenever the Hovedgrøften watercourse, which drains the low-lying fields, has breached its banks during extreme rain events. Previously, these flood events have resulted in compensation claims from landowners, however in recent years the municipality has entered into collaborations with landowners to find durable solutions.
"We have examined several different opportunities for improving conditions for landowners. Amongst other things, we have looked into whether we can expand the watercourse, however this has not proved possible. We have also looked at whether building a weir at the end of Hovedgrøften would be an option. This would make it possible to pump the water out, however the watercourse would overflow before the water reached the weir," Jesper Horn Larsen explained.
"We ended up with a solution in which the individual landowner protects his land against backflow from the watercourse by cutting off the water so that it cannot flow back through the drain and up into the fields. At the same time, we will raise the banks of the watercourse where they are most exposed. This will limit the damage. "With time, when talking about sea level rises, it may be that we will have to close off the estuary to the Sound, however would also require that we do something upstream, otherwise this would be to no avail," he said.
By looking at solutions for Hovedgrøften, we were able to dismiss a hard-dying myth that drainage from the airport causes the watercourse to overflow.
"The airport has carried out extensive adaptation on its own turf, so we can't blame them. We and the public have grown considerably wiser," Jesper Horn Larsen explained.