Ecosystems could change ‘forever’, officials say

The destruction of a major dam and hydroelectric power plant on the front lines of the war in Ukraine may dry up the rich agricultural region of southern Ukraine, sweep pollutants into waterways and upend ecosystems that had developed around the massive reservoir whose waters are now rapidly flooding downstream, although the full impact could take months or even years to understand, officials and experts said.

The escape of the huge store of water from the reservoir will reshape Ukraine’s map, its habitats and its livelihood, endangering communities that depend on the water for drinking and growing crops, forcing farmers out of business, pushing towns to relocate and unsettling delicate ecological balances.

Ukrainian officials warned that at least 150 tons of oil stored inside the hydroelectric power plant in the Kakhovka dam were washed into the waterway. Water from the reservoir also fed the cooling ponds of Europe’s largest nuclear power plant, in Zaporizhzhia, although nuclear experts said there was no immediate threat.

‘‘There are catastrophic consequences for the environment,’’ Ukrainian Environment Minister Ruslan Strilets told reporters yesterday.

‘‘For some of our ecosystems,’’ he said, ‘‘we have lost them forever.’’

The biggest and most immediate impact is likely to be to residents of southern Ukraine who depended on water from the reservoir for daily needs, as well as the farming that is the source of much of the country’s significant agricultural exports.

Farming region

Water from the reservoir irrigated the thirsty farming region of southern Ukraine, which has grown to depend on canals fed by the water in the decades since the dam was built in the 1950s.

And although it was possible that Ukraine can pump water out of the ground to make up part of the loss from the reservoir, it may quickly deplete it, said Doug Weir, research and policy director at the Conflict and Environment Observatory, a British organisation that has been tracking the environmental impact of the war in Ukraine.

It will take weeks until the full consequences of such a massive and sudden shock to the river ecosystem will be clear, experts said.

Environmental sites

The flooding will come more quickly than that, crossing some of Ukraine’s prized environmental sites, including the Oleshky Sands National Nature Park and the Black Sea Biosphere Reserve at the littoral area where the Dnieper flows into the Black Sea, which is home to wild horses and protected snakes and falcons. Some fish breeding grounds inside the shallow parts of the reservoir will also disappear.

‘‘People will not have drinking water or cooking water,’’ said Anna Ackermann, a board member of Ecoaction, one of Ukraine’s leading environmental civic organisations, who added that she was concerned above all else about the human impact of the dam’s destruction. ‘‘There will be no water to grow fields.’’

She also said that pollutants from industries clustered along the banks of the Dnieper River, downstream from the dam, could easily be swept into the waterway and onward into the Black Sea. Warehouses and other industrial buildings in the city of Kherson and elsewhere already appear to be flooding.

Different pollutants

‘‘We don’t know yet what it will look like,’’ she said. ‘‘Imagine this flood that goes down, that washes away all of the dams and all of the landfills and all of the industrial areas. There will be many different pollutants in the water.’’

Ackermann said there could even be some radiation risk leftover from the 1986 Chernobyl nuclear disaster if contamination was trapped in sediments that had accumulated at the bottom of the reservoir that was now being washed away.

‘‘You have lots of different debris that will flow into the flooding, including from all the factories and workshops that are producing and using chemicals and different toxic things,’’ said Mohammad Heidarzadeh, an assistant professor of architecture and civil engineering at the University of Bath.

‘‘Dam breaks like this ultimately can release every hazardous material you can imagine. Everything gets washed away by the floodwater.’’

He noted that Brazil is still struggling to assess the impacts of similarly large dam breaks that took place years ago.

And since the Dnieper River has been a front line in the conflict, a sudden flood could hold other dangers, experts said, including sweeping away anti-personnel mines that had been placed on embankments.

Unexploded ordnance

‘‘There’s a huge amount of unexploded ordnance and mines which are now being scoured by pretty aggressive floodwaters,’’ Weir said. ‘‘Mines are being moved and remobilised.’’

A group of Swedish engineers had in October modelled the potential fallout in the event that Russia were to use explosives to destroy the dam.

The modelling, by the firm Damningsverket, predicted a wave of water 13 to 16 feet high would hit Kherson within 19 hours.

The model predicted water gushing from the reservoir faster than water pours out of Niagara Falls, and cautioned that riverside towns would be overwhelmed.

One of the authors of that study, Henrik Olander-hjalmarsson, said in a statement that the actual event will probably cause more damage. ‘‘It appears the real-world scenario is worse than the one I modelled since the water levels in the reservoir were significantly higher than in the model.’’

Ukrainian officials have also warned of a large release of oil – potentially more than 150 tons – that was stored inside the hydroelectric power plant inside the dam. That oil could have a significant impact, depending on how it behaves inside the massive rush of water, Ackermann said.

Because the Zaporizhzhia nuclear power plant uses water from the reservoir to fill its cooling pools, there are some concerns about the long-term impact of the dam failure.

But the International Atomic Energy Agency said the facility was positioned to avoid a meltdown, as it has access to alternate pools of water that can keep the reactors and fuel rods cool for at least the next couple of months. Operations at the Soviet-era plant were largely dormant before the dam failure, experts said.

IAEA Director General Rafael Mariano Grossi cautioned that the facility remains on a high state of alert, as any disruption of the remaining cooling ponds could quickly elevate the threat of a nuclear incident. –