In January 2025, after seven years of legal battles, Poland’s General Directorate for Environmental Protection (GDOŚ) definitively revoked the environmental permit for the Siarzewo dam on the Vistula river. For a moment, it seemed like the fight to save the river had been won.
Save Polesia’s partner Polish Society for the Protection of Birds (BirdLife Poland) along with environmentalists and local communities celebrated – the project threatened the last major free-flowing stretch of the Vistula, 16 protected species, and three Natura 2000 sites.
GDOŚ’s arguments were rock-solid – the environmental impact assessment submitted by the state-owned investor, Polish Waters, was incomplete and insufficient, with serious errors in the analysis of alternatives, which is a key part of assessing environmental risks.
The planned compensation measures were deemed inadequate and unlikely to ensure long-term protection of affected habitats and species.
Polish Waters vs nature: the appeal and new threats
Instead of accepting defeat, the investor filed an appeal, meaning the court could overturn GDOŚ’s decision. This means a long legal battle is ahead to stop the Siarzewo dam. The appeal process at the provincial administrative court could take from 3 months up to a year, and a further appeal to the Supreme Administrative Court could drag the process out for over a year or even more.
The Siarzewo dam is first dam to be built for the controversial E40 waterway. While no construction works can start during the appeal, the threat remains.
The Vistula river: a vital ecological treasure of Poland
The Vistula with its sandbars, floodplains and oxbow lakes is still a wild and dynamic river, in spite of suffering heavily from river regulation in the past. It is home to rare bird species such as the Little Tern. Unsurprisingly, the river is part of the Natura 2000 network and a national treasure of Poland.
Halting the Siarzewo dam is the first step towards restoring the Vistula river. With no new dams, and targeted dam removal, migratory fish such as the Atlantic Salmon could return to streams and rivers connected to the Vistula across Poland.
Why is this dam dangerous?
The dam is part of the controversial E40 waterway, which poses serious ecological risks. On top of that, a long and uncertain legal battle means construction could move forward before environmental concerns are properly addressed, potentially causing irreversible damage.
Crucially: no construction can start during the appeal. The Vistula remains safe from the dam for now, but if Polish Waters wins, the threat returns.
The dam’s unacceptable risks
Even during the appeal, it’s vital to remember why this project must never happen. It would:
- Destroy the Vistula’s natural dynamics – turning a wild river into a stagnant reservoir.
- Wipe out critical habitats – sandbars, floodplains, and oxbow lakes, home to endangered birds like the little tern and fish like Atlantic salmon.
- Disrupt fish migration – existing dams already block fish migration; adding another would push species like sturgeon closer to extinction. Even with planned fish migration devices, the cumulative effect of Siarzewo and Włocławek dams would only allow moderate fish passage, insufficient to sustain populations.
- Waste public funds – costs ballooned from €470 million to €1.8 billion, with no proven economic benefit.
- Threaten three Natura 2000 sites, causing irreversible damage to species and habitats protected under EU law.
The fight continues
The Vistula is safe for now – but the battle isn’t won.
Environmental groups remain vigilant, legal pressure and public awareness must continue.
Public support is crucial as well. Without it, there’s a chance the project could be reconsidered and progressed despite its risks.
‘Siarzewo dam is a deeply flawed project – devastating environmental damage will be inflicted on the Polish Queen of Rivers at huge public expense,’ said Save Polesia Campaign Coordinator Helen Byron. ‘Now is the time to change perspective and see the value of free flowing rivers, as noticed by the Nature Restoration Law and invest in sustainable rail transport.’
The question remains: will Polish Waters force this dam through, or will the Vistula’s defenders prevail?
Further information
- Read the Frequently asked questions about E40 waterway
- Read our story “Victory for Poland’s Vistula river: Siarzewo dam project canceled”
- Read OTOP’s (BirdLife Poland) article in Polish “Decyzja GDOŚ ws. stopnia wodnego w Siarzewie”
- Learn more about the threats from the E40 waterway
Share the news and follow us on BlueSky and LinkedIn.
Sign petition to #savePolesia.
*Top image: the Vistula river. Photo credit: Marek Elas