Khakovka Dam collapse

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The dam and lock complex. Smoke rises from HIMARS strike on the road bridge over the lock Aug 29, 2022 Source


Dam background

Event, Immediate aftermath - June 6, 2023

Still from Russian video timestamped 2.46am (UTC+3) . Explosion seen here thought to be a mine striking the dam (unconfirmed). Video tweeted by Adam Larson
The HPP, July 2023
The dam of the Kakhovskaya HPP in the Kherson region has collapsed due to damage, flooding of territories is underway. This was reported to TASS by a source in the authorities. "It was quiet at night. There were no arrivals. The dam failed, one support collapsed, and flooding went on," he said. (Auto Translated)
Data from regional seismic stations show clear signals on Tuesday 6 June at 2:54 local time (01:54 Norwegian time). Time and location (coordinates: 46.7776, 33.37) coincide with reports in the media about the collapse of the Kakhovka dam. The signals indicate that there was an explosion.
The magnitude estimate is between 1 and 2.
UPDATE: Based on new analysis, we have also observed weak signals from an earlier seismic event from approximately 02:35 (local time in Ukraine) originating from the direction of the Kakhovka Dam.

Later photos of Dam's remnants

  • @osintjourno - The lowering water levels around the #Kakhovka HPP are revealing more and more details that can be helpful in the reconstruction of the collapse of the #kakhovkadam Dam

Prior incidents/speculation

Before & After. More photos from Maxar June 5 and 7 here
In the days prior to collapse
First we can now definitively say that the damaged sluice gate in this image that emerged last week is sluice gate 1. @gbrumfiel - March 12 on Twitter. More photos of damaged sluice gate here
Visible damage to front of central section, the gate immediately adjacent to the powerhouse. Screenshot from video
Layout of Barrage sections and HPP. Gate 1 would be gate 28 here (order reversed)
Another view of Gate 1
Damage to Gate 3
Another shot Gate 3
AFP visited the site of the Kakhovka power station and dam as part of a press tour organised by the Russian army, accompanied at all times by Russian soldiers armed with machine guns.Even though it is located away from the front line that runs further north, Russians vigilantly guard the strategic site that they say has been subject to attempts at "sabotage". "There were attempts to bring in explosive substances, but they were all thwarted," says Vladimir Leontyev, a Russia-appointed head of the civil and military administration of the Kakhovka district.
Citing sources in the Kherson region, Russian journalist Semyon Pegov wrote on his Telegram channel that Kirienko visited the Kakhovskaya hydroelectric power station, and then met with local Russian officials. When the meeting ended, and officials began to leave, Ukraine's armed forces attacked the hydroelectric power station, according to the journalist.
TASS, RT, Rambler, Nikolayevsky Vestnik, Kherson News all carried stories promising a 30% increase in power capacity after Russian specialists finish their “modernization” of the Kahkhovka Hydroelectric Power Plant.
As previously reported, the Defense Forces of Ukraine continue to attack bridges in the area of occupied Kherson. On August 8, they yet again targeted the Antonivskyi bridge and the dam in Nova Kakhovka.
The destruction of the road bridge of the Nova Kakhovka dam was ensured, with the result that it was taken out of operation," the Ukrainian army's Operational Command South posted to Facebook.
Water is discharged downstream of the Dnieper from the Kakhovka reservoir to lower the level and volume of water in it and minimize damage in case the HPP is destroyed, said Vladimir Leontyev, head of the Novokakhovsky urban district administration in the Kherson region, RIA Novosti reported.
Kovalchuk considered flooding the river. The Ukrainians, he said, even conducted a test strike with a HIMARS launcher on one of the floodgates at the Nova Kakhovka dam, making three holes in the metal to see if the Dnieper’s water could be raised enough to stymie Russian crossings but not flood nearby villages. The test was a success, Kovalchuk said, but the step remained a last resort. He held off.

Chronologies

Damaged Sluice Gates

Footage - Surfaced in March 2023

  • Video: @novakakhovka_ua March 11, 2023 - New video from the #Kakhovka Dam. The water level is dropping drastically.
  • Geoff Brumfiel - Twitter thread March 12, 2023 - Video and Photos of damage to sluice gate
  • Adam Larson: As far back as Nov. 12, there's turbulence from this leakage, but no such sign on October 18 (see images used above). This gate was probably damaged in between those dates. [2]

It seems that this was the damage reported by Russian media on November 6, 2022. Turbulent flow patterns from the dam are seen in satellite photos from November onwards. See this video from April 28 showing the turbulence.

  • RIA Novosti - ...one rocket hit the dam gateway, there is destruction, an emergency service representative of the Kherson region told reporters.
  • TASS - Five missiles were shot down by air defense units, one hit the Kakhov Dam gateway, which was destroyed, "the service representative said. The representative of the administration of the Novokakhovsky city district Ruslan Agayev added that the missile strike on the dam of the Kakhovskaya hydroelectric station did not cause critical destruction, the dam is intact.
  • Interfax - "Today at 10:00, 6 HIMARS were hit. The air defense units shot down 5 missiles, one hit the gateway of the Kakhov dam, which was destroyed, "the emergency services spokesman told reporters.

This incident would also seem to correlate with comments a Ukrainian commander subsequently made to the Washington Post reporters:

Kovalchuk considered flooding the river. The Ukrainians, he said, even conducted a test strike with a HIMARS launcher on one of the floodgates at the Nova Kakhovka dam, making three holes in the metal to see if the Dnieper’s water could be raised enough to stymie Russian crossings but not flood nearby villages. The test was a success, Kovalchuk said, but the step remained a last resort. He held off.

The Lock and its Road bridge

After a Ukrainian Himars strike on the road bridge over the lock canal, during Sept-Oct '22 the Russians apparently filled in the canal at that point to rebuild a road crossing. Presumably the lock canal would also have had the function of serving as an overflow to release high water around the dam. With the canal remaining blocked this safety feature would not have been there to manage the high levels in the reservoir above in spring '23.
Hastily constructing a replacement road crossing over the lock canal. Source Sept '22. See also photos (via @osintjourno) showing damage from Himars to main gate of the lock.]
Some sources from Adam Larson's blog piece:
August 21, 24
  • @cyrptobarbossa - NOVA KAKHOVKA DAM/LOCK: Russian convoy was targeted while attempting crossing the Lock. Recently Lock was targeted 2 times during 24/08 and once on 21/08. I assume that here we see the result of latest attack.
Views show major damage, flipped military vehicles and in some view, killed Russian soldiers. The location is on the road to the dam, at the twin buildings flanking the eastern canal.
August 29
  • @glasnostgone - Smoke is rising from the canal section of the Nova Kakhovka bridge - not the Hydroelectric Power Plant, which is further along the bridge. #Ukraine's hit this bridge area numerous times & each time made sure it missed the hydroelectric dam.

(Pro)Ukrainian accusations

'Car bomb' evidence of Russian guilt remains intact and in place after the collapse. Image June 7. (Click for more)
The roadway section approaching the powerhouse seen to have collapsed between 1-2 June Source
Two supports (nearest camera) of the roadway apparently collapsed between 1-2 June 2023. These are the supports on either side of the spillway for sluice gate 3. The shell impacts date from August '22. Crater on far side of road is directly over a supporting pillar (seen below) Video see this video also
Where washed away concrete supports of road bend should be are marked in green by @CL4SY

Russian accusations

Ukrainian forces shelled the Kakhovka HPP in the early morning hours on Tuesday, presumably using missiles fired from an Olkha multiple launch rocket system (MLRS). Slide gate valves on the plant’s dam collapsed as a result of the shelling, triggering an uncontrolled discharge of water.
Automatic Translation:
  • For the first time, information on mining by Ukrainian military dams and hydraulic structures of the Kakhovskaya hydroelectric station appeared on September 15, 2014. Voenkor.Info agency reports indicated that the sappers of the Armed Forces began installing engineering ammunition at the indicated facilities in order to avoid taking them under control of « separatists » New Russia. Kakhovskaya hydroelectric station came under control of the Russian military on the first day of the SVO – February 24, 2022. No fighting was carried out in the dam area. When retreating, Ukrainian sappers mined only the lock mechanisms of the North Krym Canal. The explosion was prevented...
  • In total, over the summer-autumn of 2022, more than three hundred missiles were fired from the RSE « HIMARS »...
  • On March 14, 2023, the head of the Novokakhovsky district, Vladimir Leontyev, said that the hydroelectric station was not only achieved to regular shelling, but also the DRG of the Armed Forces regularly tried to penetrate its territory and dam. According to him, snipers are also actively working, which do not allow repair and maintenance work at hydraulic structures.
  • Such methodological attacks by the Armed Forces of Ukraine at the hydroelectric station led to the destruction of its structures that began on June 6, 2023 and the uncontrolled discharge of water from the Kakhov reservoir downstream of the Dnieper.

Possible causes, attributions

The road bend section supports are joined with the supports for the vehicle entrance to the powerhouse. All forming part of the spillways channeling the flows from the sluice gates behind.
Adam Larson surmises that the concrete apron below the spillways was likely hit by HIMARS strikes. This combined with the intense and distorted flows could have eroded the foundations of the collapsed pillars.
The BBC published two images of the roadway that show the bridge's deteriorating condition between Thursday and Friday. The image from Friday, obtained by the BBC, shows a section of roadway missing from the bridge — damage that was not present on Thursday.
Investigating the source of the damag e further, Barr added: “The water level was at a record high before the breach, but usually a failure caused by overtopping in a dam like this would initiate on the earthen embankments and not on the reinforced concrete spillway, which is designed to manage regular discharges of water. If the sluice gates had been damaged leading to an uncontrolled discharge of water, this wouldn't be expected to cause the progressive collapse of the main concrete structure without significant additional damage elsewhere.” These factors have led Barr to support the claims that the failure was initiated by an explosion, though the subsequent damage is likely to have removed the evidence.
Ukrainian shelling of the top of the dam has consequence that likely the sluice gate and guides were damaged. The impact of the heavy 155 mm shells or the HIMARS warheads in the proximity of these mechanisms can definitely cause different levels of damage. The most likely damage is that the sluice gate may be stuck in the current position and the gentry cranes were not able to do any manipulations...
If the regulator gates are not functional the water mass will impact the dam creating enormous static pressure but also the waves will be formed adding additional stress in the form of induced vibrations.

High water level of Kakhovka reservoir

KakhovkaWaterLevels.jpeg

Analysis

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