On May 19, the first mosquito control of the year was carried out in the area along the lower Dalälven in the municipalities of Avesta, Sala, Sandviken, Heby and Gävle. But already on 22 May it was clear that a second round was needed, then also in the municipalities of Älvkarleby and Tierp.
"We haven't experienced such close floods before. Normally, the levels usually drop away and there is a drought period in between, but this time the flows remained at a high level and then only continued to increase from that, says Jan Lundström, operations manager at Biological Mosquito Control.
Overcast weather causes problems
The driving factor behind the floods is the amount of snow in the Dala mountains and how the snow melts takes place.
"If it happens with brilliant sun and heat, it ends up in the air, but if it is overcast, the melting goes straight into the river," says Jan Lundström.
Summer saved
Now, however, the flooding of the lower Dalälven river is over for this time and the flows are back to normal.
– It feels good that we were able to put the control back in place with full effect so quickly to be able to save the summer, says Jan Lundström.