That there could be a water shortage in several parts of the country after what many Swedes experienced as an exceptionally wet summer is not really that strange, says Carl-Erik Hjerne, hydrogeologist and groundwater specialist at the Geological Survey of Sweden (SGU).
– We went out with these messages earlier this summer when it was dry. But it takes a while for rain to become groundwater. We expect to be able to remove the warning fairly soon.
The reason the water shortage is not quite over yet is that it can take a long time for the rain to run down through the ground and become groundwater. In small water reservoirs the increase is noticeable more quickly, but in large ones it can take months.
– Anyone who has a well that takes water from a small reservoir will definitely notice the difference.
Low groundwater levels increasingly common
In recent years, low groundwater levels have become more common. According to Carl-Erik Hjerne, this is an expected effect of climate change. Groundwater levels usually do not recover until September or October. However, due to the rainy summer, the levels return to normal much faster.
– This year the dry season will end earlier. It also means that the risk of water shortage disappears sooner.
It is true that the rain from Hans helps to restore the groundwater, but a storm like this can also bring problems. Partly because the water rushes away when it comes in such large quantities, without it having time to penetrate the ground properly.
In some places, it can even go so fast once all the water penetrates the ground that it brings pollution into the groundwater.
– That we get a good replenishment, that is positive. But I would have rather seen this amount of rain over a month, instead of a week, or as in some places a day or two, says Carl-Erik Hjerne.