The Kiev, perhaps in league with the U.S., blew up the Kakhovka Dam is the most plausible hypothesis. From Andrew Kobyko at theautomaticearth.com:
I had some discussion with Andrew about this article, since the December 2022 WaPo article he refers to was not the first time Kiev’s plans to blow up the dam were mentioned. There was this, for instance, 2 months earlier. Then again, Andrew is right in saying that the WaPo piece is the first where people other than Zelensky mention it. And we agree that now blaming the attack on Russia is really out of left field. Those darn Russkies keep on aiming for their own feet. And that’s the only thing(s) they can hit. (From Raúl Ilargi Meijer)
Andrew Korybko:
The partial destruction of the Kakhovka Dam on early Tuesday morning saw Kiev and Moscow exchange accusations about who’s to blame, but a report from the Washington Post (WaPo) in late December extends credence to the Kremlin’s version of events. Titled “Inside the Ukrainian counteroffensive that shocked Putin and reshaped the war”, its journalists quoted former commander of November’s Kherson Counteroffensive Major General Andrey Kovalchuk who shockingly admitted to planning this war crime:
“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.”
His remark about how “the step remained a last resort” is pertinent to recall at present considering that the first phase of Kiev’s NATO–backed counteroffensive completely failed on Monday according to the Russian Ministry of Defense. Just like Ukraine launched its proxy invasion of Russia in late May to distract from its loss in the Battle of Artyomovsk, so too might does it seem to have gone through with Kovalchuk’s planned war crime to distract from this most recent embarrassment as well.