The Bernese Zealand is sinking. The surface of the Grand Marais, in the Three Lakes region, is now located, depending on the location, up to 2.4 meters lower than a hundred years ago, reveals a study published in the Swiss Journal of Geoscience.
This data could be useful for taking soil remediation measures, study author Claudia Röösli of the University of Zurich told Keystone-ATS.
Over the past two centuries, this landscape characterized by peatlands has been drained by a complex system of canals to enable agriculture on extremely fertile soil. The region has become the market gardening belt of Switzerland.
But as the peat has deteriorated due to overexploitation of agriculture, the situation has sometimes become critical for agricultural production, write the Zurich researchers. Measures are therefore necessary, but the exact extent of this degradation over the last 100 years was not known until now for the entire region.
Maps discovered by chance
Precise measurements are made possible by a unique collection of maps dating from 1920, discovered by chance, explained Ms Röösli. ‘The altitude had been calculated by hand for 44,000 points,’ she stressed. ‘It must have been a lot of work. For us the effort was already enormous and we only clicked on the points on the computer.’
By scanning the map and comparing it with current data, the researchers were able to show precisely how the surface had changed for each of the points. They thus know in which region the land subsidence was the strongest. According to scientists, this will help determine areas where soil remediation is most important.
/ATS
#Swiss
