”The destruction of the Kakhovka HPP will have consequences for all Black Sea countries”. Interview with Serhiy Porovskyi, an expert on reservoirs

Oksana Kovalenko
Yevhen Spirin
”The destruction of the Kakhovka HPP will have consequences for all Black Sea countries”. Interview with Serhiy Porovskyi, an expert on reservoirs

Stas Kozlyuk / «Babel'»

In the first hours of June 6 Russian occupiers blew up the dam of the Kakhovka power plant. This unleashed massive flooding and the largest ecological catastrophe on the continent after 1986 Chornobyl NPP explosion. Babel conducts a series of express interviews about the situation in regions affected by the flood. Serhiy Porovsky is the head of the Energy Efficiency Committee of the Association of Environmental Professionals. He spoke about the fact that the explosion of the Kakhovka HPP carries risks for all the countries of the Black Sea region, as well as the fact that the Kyiv HPP is well protected.

What has happened to the Kakhovka Reservoir since the occupation of this territory by the Russians? They dumped water, then, on the contrary, collected it. Was it objectively necessary?

After the occupation, the Kakhovkaya HPP itself did not work and did not produce electricity. Its task was either to drain or accumulate water. In the fall of 2022, as the resistance movement reported and the Ukrainian president himself said about it, the Russians began planting explosives in the facilities [of the Kakhovka HPP]. The Kakhovka hydropower complex consists of many buildings. This is directly the dam of the HPP, where the machine rooms and hydraulic units are located. When water flows, it passes through hydraulic units. This is a channel dam. Then there are 16 channels — spillways, through which excess water is discharged. This is also a capital reinforced concrete structure. Then there is a shipping lock and an earthen dam — a bridge between the shipping lock and the hydroelectric power station. There are also administrative buildings, and further in the complex there is a water intake. The way the occupiers handled water regulation in the reservoir itself was sometimes very dangerous. Because if a disaster happens, and the water mark is at its maximum, the flood zone will be larger.

Is it clear why they either dumped water or accumulated it? Were there any objective reasons?

There were no objective reasons.

Can it be linked specifically to the moment when they planted the explosives? For example, does this require a lower water level or a higher one?

Technically, on June 6, based on the analysis of the level of destruction, it became clear that the explosives had to be planted in three places. This is the hydraulic unit of the HPP machine room, the technical galleries of the spillway and the poterna — this is an observation well that is located inside the earthen dam. An earthen dam cannot be destroyed by rockets. It can be destroyed either by a wave of overflow, which washes away everything in its path — this did not happen. Or it can be destroyed from the inside, that is, someone had to put explosives in this hole.

That is, the version that the dam broke due to too high a water level cannot be true?

No, it canʼt. These are very profound structures, built to last for 400 years with a safety margin. Before the occupation, the construction passed all stress tests. The capital class of such structures is designed for repeated missile hits. That is, if the rocket hit one span of the spillway, only it would collapse. Or part of the hydroelectric dam, just one part. And here the entire pressure front is destroyed — itʼs 16 spans of the spillway, itʼs an earthen dam and itʼs a hydroelectric power plant.

There was already information that in order to stabilize the situation, the mode of operation of reservoirs above the Dnipro River may be changed. Is it right?

As a result of the disaster, the Kakhovka Reservoir was completely emptied, which was actually one of the largest in Ukraine and the 48th largest reservoir in the world. All this water flows down. In order to reduce the area of flooding, the Ukrainian authorities immediately decided not to discharge water by other hydrotechnical structures in the cascade.

Are we talking about other reservoirs that are upstream?

Yes. They simply began to accumulate more water so as not to dump it and not to increase the flood zone below.

That is, I understand correctly that the level of these reservoirs and the Dnipro River north of the Kakhovka Reservoir may rise a little?

Absolutely correct. The level of reservoirs will be slightly increased in order to prevent larger flooding zones behind the destroyed Kakhovka HPP Dam.

And this can lead to flooding above the Kakhovka Reservoir?

No, because we have a lot of hydraulic structures, and now there are no floods — it isnʼt spring, itʼs not autumn, when seasonal floods occur.

Is a new dam needed? If it is not built, what can it affect?

We are talking about the most serious consequences of the destruction of the Kakhovka hydropower complex of the Kakhovka HPP. It served primarily to ensure water supply — many settlements received water from this reservoir. And also the Kakhovka Irrigation System and the North Crimean canal, which was directly fed from this reservoir. Now water supply to both systems is impossible.

The ground water level that was associated with this reservoir will be greatly reduced — this will have catastrophic consequences for agricultural crops.

In general, we have four blocks of problems. The first is water supply. The second is shipping. The entire cascade was designed in such a way as to ensure the necessary water levels for navigation on the Dnipro River. The third block is electricity generation. And the fourth block is the impact on ecology.

Without a new reservoir there will be a colossal problem. In the near future, the water supply to the North Crimean Canal will stop for at least a year. We have to do something about the irrigation of agricultural land, otherwise everything will just dry up. There will be no profitable economic solution without the creation of a reservoir. Even if we drill wells, it will not solve the problem.

To ensure navigation, we will need to create pressure structures. I would really advise you to follow the information provided by Ukrhydroenergo. As far as I understand, they will now work on providing water supply for the population first, specifically for the population, and then they have a decision that as soon as the territory is safe and liberated, they will gradually make bridges to create pressure and partially fill the reservoir itself, the one which was formerly Kakhovka Reservoir. And then there will be a decision whether to rebuild the HPP.

And what consequences did this catastrophe have for the whole world?

Extraordinary ones. First of all, for the production of agricultural products on a large international scale. The world will feel it later, we will feel it a little sooner.

During the explosions and during the destruction of the hydropower complex, there was an instant contamination of the water in the Dnipro with technical oil, which was used in the operation of the hydroelectric power plant. Itʼs about 150 tons of oil. There are still 300 tons of oil that was stored — it later got into the Dnipro River. We cannot yet assess the damage for all flood zones. We will be able to analyze this in two weeks in the best case. The entire flooded area — that is, cars, gas stations, households, chemical objects, objects that have a potential biological threat — all this got into the water and everything flows down to the Black Sea. The Black Sea is a fairly large body of water, and we will be able to assess the level of its pollution later. There is a threat that vacations on the Black Sea coast may be canceled this year.

For all countries on the coast of the sea?

Yes. For all Black Sea countries. There were reports that even some of the explosives and explosive objects floated across the Black Sea. Of course, it will be more dangerous for Ukraine itself and for our immediate neighbors, such as Bulgaria. But there are also risks for Turkey and other countries.

And then something can get into the straits and into the Mediterranean Sea?

I think not.

The next threat will be a drop in the [level of] groundwater, because it can have a desert effect and everything will start to die. A chain reaction will follow. For example, local winds will appear, because there will be a catastrophic change in the water balance.

Well, and a lot of fish died there. This fish begins to rot, infections begin to spread. And there were [toxic] deposits in the Kakhovka reservoir, which can now evaporate and pollute the air.

Letʼs talk about the Kyiv dam. Can it be destroyed by ballistic missiles? And if it suddenly happens, what area will be flooded? What are the consequences? What should we and the authorities prepare for?

This option is much worse than even the option with the Kakhovka Reservoir. For example, there is all the silt and deposits since the Chernobyl explosion. If they start getting into the air, itʼs going to be a big problem. Iʼm not even talking about the flooding of settlements located downstream, and Kyiv itself.

But calm down. It is impossible to destroy the Kyiv dam with a ballistic missile.

The most dangerous are only two options. Crazy option number one is the use of tactical nuclear weapons. And the crazy option number two is to plant explosives by analogy inside the elements of the structures of the pressure front. We control the Kyiv HPP, so planting explosives is impossible.

As for the use of tactical nuclear weapons, we have a really crazy occupier. We cannot predict [Russiaʼs actions], but we rely heavily on our air defense forces, which promise to defend this facility. It will be a completely different story on a global scale. I hope that never happens.

Translated from Ukrainian by Anton Semyzhenko.