Bart Schultz
Because Finland was under a thick layer of snow and ice during the Ice Ages, there is no subsidence, but the land is now rising almost a centimetre per year after an originally faster rise. For comparison, the rise in sea level is about three millimetres per year. Because the seabed bordering the land is also slowly rising, Finland is growing by 700 hectares per year. So you don't really expect polders in Finland.
However, there are at least three polders in Finland. They are located in the west of the country, in the area around Vaasa. One of them, the polder Söderfjärden, is a very special polder. This polder was constructed and developed in a meteorite crater. The impact of the meteorite took place about 520 million years ago. The almost round crater with a diameter of about 6.5 kilometres is still very clearly visible from the air. Originally, the crater seems to have been about 300 metres deep. Gradually, however, the lake that was created was almost completely filled with sediments.
At the beginning of the nineteenth century it was decided to drain the lake, which was completed in 1927. A fertile agricultural polder of approximately 2,300 hectares was created with a rather unusual parcelling pattern, which is nicely attuned to the almost round shape. In addition to its agricultural use, the polder offers cranes a resting place for a few weeks in the autumn each year.
In the sixties of the last century the original pumping station was replaced by a new pumping station. In the original pumping station there is now a museum, where the reclaiming and water management of the polder are shown. The new pumping station is also an art museum. In the polder itself there is also a museum where attention is paid to meteorites.
The most special polder in the world that I have been able to find lies in a meteorite crater. The polder, in a very sparsely populated country where you would not expect polders, has yielded a fertile agricultural area, which also offers an annual resting place to cranes.
