"Karst waters in southern Croatia depend on precipitation more than other waters," state agency Hina said on Wednesday, citing experts, adding that "if the lack of rainfall continues, a shortage of drinking water could become a problem there as well because water consumption has increased due to the tourist season," referring to mainly areas in southern Croatia.

“Croatia has had high temperatures for some time now, and in late July they rose as high as 39 degrees Celsius, but the current water levels in rivers are significantly affected by the lack of precipitation in recent months,” the state meteorological service DHMZ said on Tuesday.

As a result, the availability of water could become a problem further south along the coast, which is what has already happened in Istria. Karst waters are particularly important for water supply, especially in areas where water resources are in short supply. Although river water levels in Croatia are lower than usual, they have not yet exceeded the absolute minimums, but the stagnation of river water levels is expected to continue in the days to come.

Istria County introduced water restrictions on 18 July banning watering public and private green areas, the use of showers on beaches, car washing, and washing streets and squares, except farmers’ and fish markets. County Prefect, Boris Miletic, confirmed on Tuesday that the measures would remain in force for at least another week.

Apart from rivers of the Adriatic basin, rivers of the Black Sea basin also flow through Croatia, and the situation there is somewhat better. The Danube and Drava, which are part of the Black Sea basin and whose sources are outside Croatia, are less dependent on local rainfall and reflect the hydrological situation of their basin.

Unlike the Danube and the Drava, the Sava river basin significantly depends also on local precipitation. For the time being, it is less likely that any record low river levels, will occur in these basins, the DHMZ said.