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SGU: "Risk of difficult summer with low groundwater levels"

The groundwater situation in the run up to the summer has deteriorated since the recent drought. This is what the latest monthly report from SGU, Sweden's geological survey, indicates.
Foto: Fredrik Theolin, SGU

– It is a bad starting point and the consequences are probably that both the individual and the municipal water supplies may be affected if they are dependent on groundwater. This in particular applies to Götaland and Svealand, says Bo Thunholm, hydrogeologist at SGU.

The levels in the large groundwater reservoirs, which mainly municipalities use for their water supply, are below the normal levels for the season in almost the whole country. This was already evident in the SGU's previous report. But now the shortage of rainfall is also noticeable in the small groundwater reservoirs, as people with their own wells regularly take water away. This is shown in April's monthly report.

– There's been too little rain, especially in Götaland and Svealand. What we are seeing now is that even the small groundwater reservoirs have quickly deteriorated. The levels themselves are not critically low yet, but they are sinking quickly, says Bo Thunholm.

Plants are sucking up all the rain

The arrival of warmer temperatures is having a large effect on the groundwater situation. When vegetation starts to appear, it literally sucks up a lot of the rain we get.

So is it difficult to see whether the starting point prior to summer should be improved?

– Yes, it is very difficult. Very large amounts of rain are needed, since vegetation has started. It is a big difference compared with if we had a late growing season.  But now it is the other way around. High temperatures came and the growing season appears to have started relatively early instead, which makes the conditions more difficult.

Are we already in a situation in which municipalities to need to start taking measures to save water?

– This must be evaluated on the basis of more local conditions, depending on the conditions  for the water supply. Assessments are made on a case-by-case basis, but one should at least make an assessment and, if necessary, take action.

But although the situation looks worrying right now, prior years show that things can change. Before the summer of 2018, the groundwater baseline was good. However, it became extremely dry over the summer, creating problems for people with their own wells. Before the summer of 2017, there was a risk of water shortages over large parts of the country, but then August and September were rainy, saving the situation, according to Bo Thunholm.

– There's every reason to be vigilant and prepared. But, as we've seen previously, in 2017 for example, it can work itself out anyway. But based on probability, there's much more to indicate that we're going to have a difficult summer with low groundwater levels.'

What would help with the situation as it is just now?

– A lot of rainfall, a lot more than normal. That's what we need, and preferably in combination with cold weather so that it doesn't just evaporate,' says Bo Thunholm

Source: SGU
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