During the night between August 3 and 4, 2023, northern Slovenia was hit by violent flash floods that developed after storms with extremely heavy rain. After the floods, landslides followed due to the wetness of the terrain. The heavy downpours lasted until August 6. Especially torrential streams and rivers of Mežiška dolina, Zgornja Savinjska dolina, and Gorenjska have grown exceptionally. A flood wave followed causing flooding downstream.
The rising rivers washed away everything, roads, bridges, residential buildings, factories, and of course all the hazardous materials that came in their way and deposited these materials when the water subsided in the flooded buildings, infrastructure, and flood plains, which are mostly used for agriculture. The deposited silt and sand pose a risk to the local population and crops in flooded areas.
On August 12, as part of the ELME (Ecological Laboratory with a Mobile Unit), which operates within the framework of the Civil Protection of the Republic of Slovenia, dr.Jože Kotnik carried out sampling in the Mežiška valley, which is particularly at risk due to the former lead and zinc mine in Mežica, the battery factory in Žerjav, the steel industries in Ravne, etc. The expert from ARSO (Agency of the Republic of Slovenia for the Environment) dr. Janja Turšič joined the sampling. We sampled the sediments of the river Meža upstream from its outlet into the river Drava in Dravograd up to Črna na Koroškem. Ten samples of alluvial material were taken and one sample was taken from the temporary landfill of already removed alluvial material. The alluvium consists of silty to sandy material, while upstream of the Mežica, the granularity of the deposited material increases when in Črna it reaches the dimensions of very coarse gravel with admixtures of sand and silt. In the alluvial material are many pieces of the plastic casing of the lead batteries, which are getting smaller downstream. A big problem is also the dried alluvial material on the roads and work sites where cleaning is carried out and dust is released into the atmosphere.
Researchers in our Department will carry out sample analyses.
Alluvial material with destroyed electrical, plumbing, and other installations in Dobrije near Ravne na Koroškem.
A flood plain in Poljana near Prevalje.
Partially cleared alluvial material in Črna na Koroškem.
Alluvial material and the consequences of the erosion of river embankments in Prevalje.
Flood plain in Dobrije near Ravne na Koroškem.
Sampling of alluvial material in Mežica.
dr. Jože Kotnik, Department of Environmental Sciences, IJS