UK scientists have conducted an unprecedented rapid assessment of the environmental aftermath of the breach of the Kakhovka Dam, aiming to aid in the recovery of a critical biodiversity hotspot.

Following the breach of the dam located in southern Ukraine, amid a warzone, the UK Centre for Ecology & Hydrology (UKCEH) and HR Wallingford collaborated to undertake the first independent evaluation of the impacts within weeks of the incident occurring in June. Leveraging cutting-edge technologies, the assessment estimated that approximately half a million hectares of protected freshwater and terrestrial habitats faced various hazards, including exposure to pollutants from over a thousand sites and sediment erosion. This ecological crisis was exacerbated by widespread flooding downstream and the near-complete depletion of the upstream Kakhovka Reservoir.

Traditionally, environmental assessments of this magnitude have only occurred post-conflict when it's deemed safe for scientists to conduct thorough field studies. However, this approach has constrained targeted biodiversity restoration within post-conflict recovery plans. The rapid assessment of the Kakhovka Dam breach sets a precedent for early intervention in future conflict situations, allowing for more effective restoration efforts.

The report, commissioned by the Foreign, Commonwealth and Development Office (FCDO), utilized hydrological modelling, digital mapping, satellite imagery, and ecological data to identify affected habitats and species promptly. 

The reports key findings were:

  • Downstream flooding encompassed approximately 83,000 hectares, equivalent to the size of Kyiv, with an initial discharge rate of 30,000m³ per second, significantly surpassing the daily average.
  • The near-complete drainage of the Kakhovka Reservoir resulted in the displacement of thousands of fish, including an estimated 28,000 crucian carp, valued at approximately US $108 million.
  • Over 1000 potential pollution sources, ranging from wastewater treatment facilities to industrial sites, further exacerbated environmental degradation.
  • Sediment erosion post-flooding raised concerns about the release of historic pollutants stored within the sediment, posing additional risks to the ecosystem.
  • Furthermore, the breach impacted over half a million hectares of habitats of national or international significance, including the Black Sea Biosphere Reserve. Notably, 28 out of the 567 affected species are globally threatened or worse, including the Great Bustard and the slender-billed curlew, which is teetering on the brink of extinction.

Professor Bryan Spears of UKCEH emphasized the assessment's importance as a baseline for evaluating biodiversity and habitat recovery post-breach. “It is now important that the results of this and other assessments are scrutinised fully by the wider scientific community, allowing biodiversity restoration to be incorporated within post-conflict recovery planning at an early stage,” he said.

Emma Brown, technical director at HR Wallingford, added: “I am very proud of the work we’ve done with UKCEH to assess the environmental impacts of the Kakhovka Dam breach. Combining our expertise in dam breach modelling, hydrology and earth observation with UKCEH’s expert biodiversity knowledge enabled the team to produce a detailed report in just 16 days, which I hope will be instrumental in helping with recovery efforts in the region.”

The report, which contributed to a broader UN Environment Programme assessment, also outlined potential long-term ramifications on the environment, human health, and economies. Recommendations for future action were provided, emphasizing the imperative of utilizing scientific insights to inform humanitarian and environmental responses to global disasters and emergencies.

The full report is accessible on the Zenodo website, accompanied by a commentary authored by Professor Spears in the journal Nature, Ecology & Evolution.