Kakhovka Dam Flooding Detection In Ukraine For PEJ

Overview: The Kakhovka Dam Explosion, Flooding Of The Surrounding Areas

The Kakhovka Dam, near the Nova Kakhovka City, Kherson Region, held one of the largest water reservoirs in Ukraine. The Dam stood around 30 meters (98 feet) tall and stretched 3.2 kilometers (2 miles) in length, holding 18 cubic km of water. It provided irrigation water to Southern Ukrainian agricultural lands, cooling capacity for the Zaporizhzhia Nuclear Power Station, and household water for thousands of civilians.

On June 6, 2023, Russian forces exploded the Kakhovka Dam. The breached section measured approximately 85 meters (279 feet) in length. Two days after the breach, the average flood level in the Kherson Region reached 5.61 meters (18.4 feet).

This tragedy led to many homes being flooded, along with agricultural lands, cattle, and every aspect of the area’s human livelihoods. International organizations focused on the unfolding events, helping civilians and assessing the damage. Among them is Project Expedite Justice, a non-profit based in the US. Its mission is to empower victims of mass atrocities and serious human rights abuses to find justice through all available legal mechanisms. Since April 2022, PEJ has worked to ensure accountability for Russian actions in Ukraine. The organization has documented international crimes and harms throughout Ukraine.

PEJ turned to EOSDA to assess the consequences of the Kakhovka Dam destruction in the course of the preparation of the unique document, SUBMERGED: Study of the Destruction of the Kakhovka Dam and Its Impacts on Ecosystems, Agrarians, Other Civilians, and International Justice. The EOSDA’s goal in the project was to detect and visualize the flood caused by the destruction of the Kakhovka Dam based on remote sensing technologies using available optical and radar satellite images.

The report analyzes the impact of the Dam’s destruction and the resulting consequences for people and agribusinesses, including short and long-term ecological damage. Part of the report details PEJ’s investigation into how the detonation occurred and a legal assessment of the actions. PEJ submitted the report and its annexes to the International Criminal Court prosecutor and Ukrainian prosecutors for case consideration.

The report contains many visualizations. EOSDA provided is presented in the appendix and partially in the main text. The visualizations and calculations are used to demonstrate very vivid flooding and draining and, secondly, to showcase the losses of the agricultural sector in this region based on the PEJ’s agrarian analyst’s calculations. The raw data can sometimes speak louder than any sentiment.

Challenge: The Impact And Consequences Of The Kakhovka Dam Flood

Ukrainians face many challenges now, as the Kakhovka Dam has ceased to exist. The long-term impacts and consequences of the environmental and energy system will stretch for decades. Let us look at each of them in more detail.

The immediate and long-term impact of a Dam explosion primarily revolves around the water body itself and has the most apparent consequences ^{Potential Long-Term Impact of the Destruction of the Kakhovka Dam (June 9, 2023). UNCT Joint Analytical Note. (June 9, 2023).}. Health, water, and sanitation hazards are based on the water release and the fact that the Kakhovka Reservoir, now empty, served as a water source for many cities north of the Dam. The water interruption severely disrupted both citizens and businesses, making it difficult for them to continue their daily activities. Many people had to move to other regions, which led to a housing crisis and the addition of internally displaced people.

The southern surrounding areas suffered from significant flooding and sudden deaths of animals and humans, leading to that matter settling in the water bodies and soils. The Dam explosion also resulted in an oil spill from the hydropower plant itself, which also contaminated the ecosystem. The flooded industrial sites, wastelands, and sewage facilities released all their “products” into the water. That led to the contamination of natural resources for the entire country.

Many museums and architectural sites were flooded and destroyed. The cultural impact is long-lasting, as it concerns the entire region’s history. Russia, once again, targeted even the smallest bits of Ukrainian identity.

The environmental impact is more subtle and can lead to long-lasting changes in the entire region’s biodiversity. The hazardous substances mentioned above contaminated the Dnipro River and traveled to the Black Sea ^{Nguyen, L. (June 28, 2023). The Environmental Impact of the Kakhovka Dam Explosion in Ukraine. Earth.org.}. The aquatic ecosystems are now endangered. Many fish did not survive the Dam explosion. The hydrous life becomes more scarce as the water mines and other military objects are still in the sea.

Ecosystems on land were also disrupted as some of the water released from the Dam flooded certain areas, leading to wildlife death or sudden displacement. Another threat to animals and humans here is landmines that are located near the war zone and may be exposed due to erosion from the flooded ground.

Long-term agricultural consequences, however, will not only impact Ukraine. Ukraine is frequently referred to as “the breadbasket of Europe” and the world, the endangerment of its agricultural lands poses significant risks for everyone who relies on its crops. The flooded lands are no longer arable, and a lot of time will be required to restore them. The areas underwater are inaccessible now. Moreover, there is no way to irrigate those lands that remain above the water. Since the 1950s, the Kakhovka Dam has transformed the historically hot steppes — the deserted spots with wildlife used to heat season and strong winds — into agricultural lands ^{Kherson Region. Ukraine.ua.}. Currently, the system is not working anymore.

The energy system impact is even harder to calculate, as the Dam supplied power to 20,000 households and secured the operations of Zaporizhzhia Nuclear Power Plant and Kherson Hydroelectric and Power Plant, which account for another 140,000 or more users. The hydraulic structure of the Fam accounted for the annual electricity production of 1.4 billion kWh ^{Vyshnevskyi, V., Shevchuk, S., Komorin, V., Oleynik, Y. & Gleick, P. (2023). The destruction of the Kakhovka Dam and its consequences. Water International, 48, 1–17. https://doi.org/10.1080/02508060.2023.2247679.}. It was a significant power source, and the stability of the Ukrainian energy system is now under severe threat of crumbling.

The impact of the Kakhovka Dam collapse is too large to see from the ground, so satellite monitoring can come in handy. Here is where EOS Data Analytics was asked to contribute and calculate the flooding area for PEJ. Based on the data EOSDA provided, the experts gave an approximate prognosis of the ecological situation of the area flooded by the Dam destruction for the next five years. The report was also used to estimate the losses that occurred to the agricultural sector.

Our goal was to document, assess, and show the Dam collapse’s immediate impact, present enough evidence to demonstrate that the attack was deliberate, and share expert opinions to cover different consequences for the environment and civilian population. When environmental disasters happen because of deliberate attacks from a party to a conflict and cause widespread, long-term, and severe damage to the natural environment, the proportionality of the damage to the military advantage anticipated must be evaluated. If this damage is excessive, then the attack should be characterized and prosecuted as a war crime.

Alisa Goloshchapova

Ukraine Project Coordinator at Project Expedite Justice

Solution: NDWI Masks On Optical And Radar Satellite Images

In this custom project, the EOSDA’s science team needed to visualize different stages of flooding around the bed of the Dnipro River, part of its tributary, and the Ingulets River. They used the open-source images for the specific date range — June 5 to August 28, 2023. Then, they analyzed the photos and calculated the spatial (geometric) flood area of the zone below the Kakhovka Dam at different stages of water movement.

The team used natural-color images from Sentinel-2. The optical images taken on cloudless days during the specified date range needed slight adjustments using atmospheric correction. This process involves transforming the raw satellite data to reduce atmospheric noise and enhance clarity, making the images easier to interpret.

For the dates with high cloudiness levels, synthetic aperture radar (SAR) images from Sentinel-1 were used. The team used the Speckle function to remove the electromagnetic noise scattered by different surfaces and leave the objects’ sharpness. When all the noise was reduced, the team got the clearest set of images to calculate the flooding area.

Then, the science team put a “mask” on top of the images. The NDWI (Normalized Difference Water Index) was chosen to detect the water body surface. This index allows water bodies to stand out from other surfaces. The soil and vegetation are not visible within this mask, making it a perfect solution for determining floods, droughts, and other water changes. The team used the QGIS toolkit to calculate the flood areas. Each new image with an NDWI mask was compared with the image on the date before the explosion to see the difference. All the water bodies unaffected by the flood were excluded from the analysis, so only the Dnipro and Ingulets Rivers were analyzed.

This project was not very complicated for the team, as they had already performed a similar analysis in Northern Kazakhstan, where spring flood predictions were required. However, it still was a bit different in terms of constant cloudiness.

During these cloudiness periods, we needed to find a full-coverage image to complete the calculations. To overcome that factor, we had to use an additional methodology to detect it on SAR images as well. The water masks on optical and SAR images differ, so it was a challenge to set everything up and running.

Dmytro Zhylchenko

GIS Specialists Team Lead at EOS Data Analytics

It was also quite difficult to find high-resolution images. We needed them to look at individual areas in more detail. Those were the areas of interest (AOI) and the most flooded areas near the Dam. It was also kind of a difficult task because there were clouds. Therefore, it was necessary to select good-quality pictures and process them.

Oleksii Neskorovnyi

Business Analyst at EOS Data Analytics

Outcome: Calculated Flooded Area

The project was completed in four to six weeks, three to four of which were spent on the tech part — raw imagery processing and calculations. Then, corrections and report creation were required to meet the client’s demands. Thus, the whole process took less than two months.

This was an enlightening process for us. After consulting with the EOSDA team, we clarified our requirements and developed a technical task. By working collaboratively and systematically, we were able to produce a report that perfectly meets our needs and is ready to be presented to the reader.

Alisa Goloshchapova

Ukraine Project Coordinator at Project Expedite Justice

In the images, three masks were created to showcase the results. They were put in several locations so that the impact could be seen from different angles. The first part covers the bed of the Dnipro River from the Dam of the Kakhovka Hydroelectric Power Plant to the Black Sea. This part of the mask is located at the westernmost point of the AOI towards the sea. The second part of the mask covers the part of the bed of the Ingulets River, which is the tributary of the Dnipro River within the AOI boundaries. The third part covers the bed of the Dnipro River from Zaporizhzhia to the beginning of the Kakhovka Dam.

The image below shows the AOI from June 5 to August 28, 2023. The blue NDWI mask on the satellite images shows the water movement. The flooded area lower from the Dam is visible, along with the decrease in the Kakhovka Reservoir water level.

This cannot be considered just another project because these are places that even some team members may have seen with their own eyes before the explosion, or at least know about them. In any case, this is a sensitive and emotional story because we can now see the disaster scale and extent on the map. In some pictures, you can see how houses and whole streets are underwater, with only the roofs of houses visible, not to mention the fields, households, and so on.

Oleksii Neskorovnyi

Business Analyst at EOS Data Analytics

Below, you can see the representation animation of the flooded area on June 5 and 9. The animation shows the area of the water mask applied to the images and the difference in the flooding area. The spatial analysis allowed for the calculation of the geographical scope of the AOI. One can see that the area was indeed flooded and to what extent.

Further Development Of The Case

The report examines multiple facets of the Dam’s destruction, including evidence-based findings on potential war crimes, given the extensive damage disproportionate to the unclear military objectives pursued. It also addresses the consequences for the region’s economy and agricultural resources, the environmental impact on water resources, biodiversity, and soil health, and the human cost of the disaster, encompassing loss of life, displacement, and health risks.

As for the project itself, Project Expedite Justice has already shared its report at COP28 UAE and at the International Criminal Court Assembly in New York in 2023. PEJ further presented it at several events in 2024. The team wants to promote it at several environmental conferences worldwide so that wider audiences can learn about the Kakhovka Dam destruction case firsthand. On June 6, 2023, the world saw the Russian force’s cruelty, but many doubts emerged as to who blew up the Dam and if the videos that emerged were actual footage. Currently, satellite imagery analytics companies can assess the raw data and showcase the facts. There is no place for denial after the analysis of the data, and international audiences can see the results of this war by themselves.

If the International Criminal Court rules on the case and provides feedback that it requires more data, PEJ is ready to prolong its cooperation with EOS Data Analytics. It has yet to be determined if this will be necessary, but both parties are willing to participate.

This model can now be used again. Before, in Northern Kazakhstan, the EOSDA science team already used a similar model. That project was complicated, so here, it was a bit easier as it wasn’t as new. The team tested the model once again, making appropriate adjustments in the process. It can now surely be used for flooding areas calculations or changes in the landscape and relief, as well as the disappearance of water in nearby rivers, ponds, and lakes. All of those ecosystem disruptions might impact agriculture and adjacent farms, so there may be a possibility of developing the model in that direction.

In short, there are no boundaries for scaling for similar projects.