Land subsidence inflicts extensive damage every year in the villages of Kanis, Kamerik and Kockengen, which are built on peat. Peat oxidation caused by exposure to air, and peat compaction as a result of loading, are two important causes. However, until now, it was not known how much land subsidence could be attributed to oxidation and how much to compaction. An interdisciplinary team of researchers from Utrecht University and Deltares conducted a study of the three villages going back 1000 years. They published their findings in Science of the Total Environment. The results can be used as a basis for effective action to slow down subsidence and to structure the peat-rich area on more sustainable lines.
The land in Kanis, Kamerik and Kockengen has subsided by up to four metres in the past 1000 years. In recent years, the rate of subsidence has been 14 centimetres a year in some locations as a result of drainage and the loading of the peaty subsurface to make the area suitable for agriculture and habitation. These villages are therefore forced to spend large amounts on raising, and repairing damage to, roads, mains networks and buildings. There is also more damage as a result of flooding.
Effective measures to combat or reduce land subsidence depend on a proper understanding of the processes involved. Biologists and physical geographers from Utrecht University and land subsidence experts from Deltares therefore decided to quantify the relative contributions of the compaction and oxidisation of peat as factors in the overall process of land subsidence in the three villages. A better understanding of the subsidence process will also help to decide who is responsible for mitigating the effects.