Innovative climate change adaptation at Lemvig Harbour

For generations, the inhabitants of Lemvig have grown accustomed to a sea that will rise above quay level at least once a year and overflow not only the harbour area but also the adjacent streets and basements.

Earlier this century, in collaboration with the architectural firm Hasløv & Kjærsgaard and the consulting firm COWI, the Municipality of Lemvig established several solutions for Lemvig Harbour to manage the rising sea levels. These solutions include a wooden structure with aluminium gates and a pump to convey intruding water and backwater out into the fjord.

However, due to recent years' sea level rises, the defence structure is no longer high enough. On four occasions during the winter of 2011/2012, the town of Lemvig experienced elevated sea levels that threatened the town and which, on one occasion, penetrated the defences structure. During 9 to 11 December 2011, the sea rose as high as 182 centimetres above normal, corresponding to a 1-in-90-year event.

More frequent and more intense events, along with a desire to make better use of the harbour area, encouraged the town council set aside DKK 20 million for the conversion of the once busy fisheries and commercial harbour to an area suitable for a variety of activities, including recreational activities. "Climate change makes keeping the town going a huge challenge. In recent years we have therefore been planning how to reinforce our defence works to protect against rising sea levels and how to integrate this protection with various activities at and around the harbour. This year we have started work in earnest to change the harbour area," said Michael Haustorp, who works as a planner at the Municipality of Lemvig.

"A key element of the plan is to establish protection against rising sea levels and make room for new life at the harbour. The idea is to create an area with meeting places and a promenade to create a better link between the harbour area and the city," said Michael Haustorp.

The new protection against rising sea levels (the Urban Højvandsskærm©) at Lemvig Harbour consists of a curved wall (also known as Le Mur), which has been built from specially designed concrete elements.  The wall has been tailored for use in urban landscapes at risk of flooding. There will be many possibilities for passage via openings that can be closed with sliding gates during extreme weather. On a daily basis, the wall will serve as a sort of urban furniture in front of the harbour area, and with its curves and angles the wall will divide the large area into smaller urban spaces.

The wall functions optimally against sea levels of between 80cm and 120cm; the level against which existing low-lying areas of the town commonly need protection. Students from the local school will produce the specially designed furniture that can be fitted to the wall.

The Urban Højvandsskærm© system with its concrete elements, gates and urban furniture has been developed by Hasløv & Kjærsgaard, Oranje Beton, COWI, WoodPro and the local forge and refrigeration company Lemvig Maskin- og Køleteknik.

"We could have chosen to establish a dam further out at sea, however we preferred to approach the issue of changing sea levels as something to take advantage of; as an opportunity for making the harbour more organic and retaining the close link between the sea and the town and its inhabitants. By building the curved wall we will change the look of the harbour as well as its function, as we will leave space for new activity," said Michael Haustorp.

In addition to the curved wall, floating bridges will be established for guesting yachtsmen. The pier has therefore been extended by 40 metres, so that it functions as an effective breakwater. Also here, the recreational element has been incorporated in the solution, in that the pier has been equipped with peephole benches where people can sit protected from the wind.

"With the new wall against elevated sea levels, there is opportunity for Lemvig Harbour to again become an asset for the town and the municipality, providing a space for recreational activities for individuals, as well as for businesses which are showing renewed interest in using the harbour ," said Michael Haustorp.