NEWS: TETHYS4ADRION in Action: Spring Monitoring on the Soča-Isonzo Pilot River

On May 19 and 21, 2026, project partners from the Institute for Water of the Republic of Slovenia and National Institute of Chemistry carried out spring monitoring campaign on the Soča-Isonzo Pilot River.

The color of the Soča-Isonzo alone suggests how clean the river is. Nevertheless, TETHYS4ADRIONA values verification and careful observation, which is why our team visited three locations to collect data on pollution in the river and along its banks. Indeed, no litter has been seen floating in the Soča-Isonzo River itself. However, along the riverbanks, although not immediately visible, pieces of plastic, metal, and similar litter can still be found.

This monitoring campaign was carried out in Pieris (Italy), as well as Deskle and Kamno (Slovenia), in order to assess the presence of litter during the spring season.

Using a manta net and a water pump, a team collected samples of micro- and mesolitter from the water. The presence of floating macrolitter was recorded through 90-minute observations from bridges over the river. Finally, the team collected samples of macrolitter from the banks of the Soča-Isonzo River. All collected samples are being sent for laboratory analysis.

On May 21, in the settlement of Čezsoča, members of the team from the Institute for Water of the Republic of Slovenia also released 10 GPS devices into the Soča-Isonzo River, simulating the movement of litter along the river. By tracking these devices, researchers will obtain data on the speed of litter movement, stopping points, and other related patterns.

Due to the warm and sunny weather, the river’s water level was low and the river flowed calmly.

Comprehensive data on micro-, meso-, and macrolitter in the Soča-Isonzo River and along its banks will become available once the monitoring campaigns have been carried out during all four seasons of the year.

The activity was coordinated by Dr Tine Bizjak and Tamara Bizjak from the Institute for Water of the Republic of Slovenia.

Many thanks to Azra Kerić and Tamara Bizjak for the photos.

Read more about the winter monitoring campaign on the Soča-Isonzo Pilot River here.

This has been produced with the financial assistance of the European Union. The content of the website is the sole responsibility of TETHYS4ADRION project and can under no circumstances be regarded as reflecting the position of the European Union and/or IPA ADRION programme authorities.