Hydrologist: Poland is not currently threatened with desertification, but rivers require action "yesterday"

Simple and inexpensive solutions that should be implemented "yesterday" include, above all, ceasing river regulation and deepening, hydrologist Piotr Bednarek told PAP. On Monday, the Vistula River's level at the Warszawa-Bulwary station dropped to 9 cm – the lowest in recorded history.

Bednarek explained that the reason for this low water level is primarily rapid deep erosion, which is the deepening of the Vistula River bed due to river regulation and sand mine operations. "Above Warsaw, sand mines operate, trapping material carried by the river. Furthermore, the section of the Vistula flowing through the capital has been regulated. As a result, the riverbed is systematically deepening, and the water gauge readings are constantly dropping," Piotr Bednarek, a hydrologist and doctoral student at the Department of Hydrology at the Institute of Geography and Spatial Management of the Jagiellonian University, as well as president of the Free Rivers Foundation, told PAP.

The Siekierki CHP plant, which heats 55% of Warsaw's buildings, has been experiencing problems in recent years drawing water from the Vistula River to cool its facilities. As reported by "Gazeta Wyborcza" in January 2025, the canal from which the plant's water was originally drawn was filled with water for 10 days in 2024.

"The Siekierki CHP plant's water intake problems are largely due to the sand mines, which are lowering the Vistula River bed," Bednarek assessed. "Their operation is very harmful to both the Vistula ecosystem and the river's infrastructure. Currently, proceedings are underway by the Warsaw City Hall to determine whether the mines will receive environmental approval to continue operating."

As the hydrologist added, the current situation on the Vistula River is also influenced by drought resulting from the distribution and amount of rainfall – there was a lot of rain throughout the year, but in summer, not winter, and it was often short and heavy, so most of the water that fell was quickly depleted by plant vegetation and evaporation.

Apart from the Vistula, water levels below the periodic minimum are currently observed at 14 hydrological stations on the following rivers: Warta, Kaczawa, Moszczenica, Budzówka, Żylica, Nysa Kłodzka, Kwisa, Pilica, Prądnik, Skawica and Krasna.

"Currently, in many rivers marked in black on the IMWM map, meaning they are in the low-water zone, we are 1-2 cm from the lowest levels ever recorded. And this applies to a significant number of hydrological stations. The drought is severe; some rivers dried out completely some time ago," the hydrologist emphasized. "And this is still a better situation than at the beginning of July, before we had a month of heavy rainfall that temporarily improved river water levels," he added.

When asked if Poland was at risk of "desertification," Bednarek reassured them that there was no such risk at the moment. He explained that while low river levels could lead to the extinction of many ecosystems—including the disappearance of fish, mussels, and some amphibians—water levels are still far from sufficient to support tree growth.

"What we can realistically expect in the coming months and years is drought and low water levels, which, if they do rise, will only be temporary, along with rainfall. Groundwater levels are so low that we would need a really heavy snowfall in winter to replenish them. In the area where I live, in the Sandomierz Basin, for the past 14 years, the water balance has been negative, meaning more water is escaping, mainly from groundwater, than is being supplied by rainfall," he emphasized.

The hydrologist added that simple and cheap solutions that should be implemented "yesterday" include, above all, renaturalization, i.e. stopping the regulation and deepening of rivers and filling in drainage ditches, of which there are several times more in Poland than natural rivers.

"The State Forests boast about their low-impact water retention (local measures aimed at retaining or slowing down water – PAP), but in reality, the scale of their actions is too small. Eliminating even some of the drainage ditches in their area could have much better results," Bednarek said. "These are really very simple things to do, and there's no justification for not implementing them," he added.

When asked if nothing changes, there is a real risk that the Vistula will dry up completely, like some smaller rivers in Poland, Bednarek denied this. The hydrologist explained that due to the size of the river and its flows, such a scenario is completely unlikely, and that of the rivers in Poland that will dry up, "the Vistula will be the last to dry up."

Agata Gutowska (PAP)

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