The Authority for Community Protection and Preparedness, MSB, has mapped flood risks at large watercourses in Sweden. It is important for municipalities to be able to make risk assessments and take measures early when there are torrential rains or high water flows. But such maps do not exist for smaller watercourses, and SKR now wants to change that.
– What has happened this week is that several smaller watercourses have flooded and had major consequences for property owners and socially important functions, says Greta Hebel, climate adaptation expert at SKR.
SKR thinks that the expert authorities MSB and SMHI should produce such maps for the municipalities free of charge. According to Greta Hebel, a risk assessment can cost several hundred thousand kroner.
– These are quite expensive investigations, above all too small for the municipality, which has no funding.
Misinterpreting MSB’s flood maps
At the same time, researchers warn that municipalities often misinterpret MSB’s flood maps and do not understand that the risk area extends further than the maps give the impression.
– There is no sharp line, but rather we are talking about a zone of uncertainty, and somewhere within that zone the flood will reach, says Anders Brandt, docent in geospatial information science at the University of Gävle.
At Testeboån in Gävle, there is a difference of one kilometer between MSB’s flood map and the flood map produced by researchers at the University of Gävle.
– This can be especially the case in flat areas. If it is more hilly, the maps match better.
When the risk is not taken into account, it can have financial consequences.
– The flood in Gävle in 2021 cost over one billion kroner. Building in more suitable locations is cheaper in the long run, says Anders Brandt.
SKR: “Need to train the municipalities”
Greta Hebel at SKR says that the municipalities do a good job of planning for floods, but agrees that there are large uncertainties in the calculations.
– It is difficult to read a map. Knowledge-raising efforts are required to interpret the material, and there I also see a need for our national authorities to educate the municipalities.