Grenen is the most northerly point in Jutland, and is effectively where the North Sea meets the Kattegat (which then meets the Baltic). Near the town of Skagen, it translates as 'the branch', as that is what it would be if Denmark were a tree. At the time of writing 'you can't stand up out there' which a resident of Skagen, John Skånberg, said. This is due to strong gales. This is because it is where the south westerly Atlantic maritime and Polar continental prevailing winds have gathered most energy before meeting each other and dispersing.
The spit is formed by a meeting of the Atlantic Ocean's currents and the Baltic's currents. As the Atlantic is far larger than the Baltic it carries far more energy and therefore it deposits some of its load where the two currents meet, thus creating 'Grenen'. It is as though the Atlantic is the sea and the Baltic is the estuary as you would find with the more conventional spits, such as Spurn Head. However a major difference with this particular landform is that the currents of the two seas defelct upwards, which allows more sediment to be deposited as both seas lose even more energy. Like a spit, it will not be able to reach its nearest landform, likely to be a Swedish island, depending on its direction, as the Atlantic current will be able to squeeze through. Once Grenen reaches its maximum length there will be wave refraction giving the end a hook shape.
However, as the Baltic loses a lower percentage of its energy as the Atlantic absorbs it, there is a problem on the eastern side of Grenen. This problem is erosion. The Danish government and Skagen council have an effective, cheap and environmentally friendly approach to this using soft coastal management. Stony wave breakers have been built. It is evident that this has stopped erosion, as the beach is about 10m back in areas where there are no wave breakers. However, as evident in the picture, the longshore drift may erode the longer strips of beach protected by the wave breakers and alienate them as islands, meaning a slightly harder approach is needed, which will unfortunately be unfriendly to finance and nature alike. As bathing is banned, a possible approach could be to line the vast majority of the east side with these wave breakers, without ruining the experience for tourists. A beach nourishment or sea wall scheme would also see erosion cut much less. A sea wall would help greatly as long as the wave breakers were kept, but this would be expensive and not aesthetically pleasing.
Due to changes in wind speed, temporary changes in prevailing winds, changes in sediment output and wave refraction, means that the tip of Grenen is changing on an almost daily basis. If you're a resident or regular visitor to the area this is what makes the experience every time and is one of the reasons why it's such a popular tourist destination, as well as the excitement of standing at the end of Denmark and Europe. It would be interesting to see what the trend change in Grenen is, so we could make a prediction into where this spit will soon travel.
Dedicated to Oliver Skånberg Tippen, whose family is from Skagen. Unfortunately whilst on a trip to Colombia in April he was kidnapped. Despite losing two fingers and his left ear in this messy process, the ransom money is slowly being coughed up. Hang on in there and kick the cocaine habit. FREE OLLIE!
No comments:
Post a Comment