“A major dam in southern Ukraine collapsed [last] Tuesday, flooding villages, endangering crops and threatening drinking water supplies as both sides in the war scrambled to evacuate residents and blamed each other for the destruction… Russian and Ukrainian officials used terms like ‘ecological disaster’ and ‘terrorist act’ to describe the torrent of water gushing through the broken dam and beginning to empty an upstream reservoir that is one of the world’s largest.” AP News

“Ukraine said on Monday its troops had recaptured seven villages from Russian forces along an approximately 100-km (60-mile) front in the southeast since starting its long-anticipated counteroffensive last week.” Reuters

Both sides argue that Russia is likely responsible for the destruction of the dam and lament the human and environmental damage:

“Russia had various incentives to flood the South. Some Ukrainian troops will now be diverted from their missions to conduct rescue operations; others hoping to advance in the South might now find the terrain impassable; Russian forces will have extra time to adjust and redeploy units strategically to counter whatever Ukraine seems to be planning; and millions might lose power, complicating military logistics and damaging Ukrainian agriculture…

“War crimes are always on the menu for the Kremlin and its mouthpieces, including and especially attacks on civilian infrastructure. If you were to wager on when an especially dramatic war crime might be rolled out, you couldn’t do better than gambling on the first few days of the new Ukrainian offensive. By blowing up the dam, Russia disrupted the momentum and showed Ukraine in an unusually stark way that this already awful ordeal can still get worse for its people if it doesn’t sue for peace. The harder they fight, the more it’ll cost them.”
Nick Catoggio, The Dispatch

“A country contemplating launching an offensive – that would be Ukraine — especially against an enemy force larger than its own, does not choose to immediately make things more difficult for itself. It's not the only reason, but it's the main reason why Ukraine did not blow the Kakhovka dam on the Dnipro River. They would be idiots to destroy the hydroelectric plant at the dam that supplies electricity to much of the Kherson region…

“Ukraine holds the west bank of the Dnipro, and Russia holds the east bank. Does anyone actually think Ukraine blew up that dam, turning a river into a mile-wide lake the Ukrainian army would have to cross in order to attack Russian positions on the east bank? The first thing an army calculates when planning for a river crossing is how much time its soldiers will spend in boats on the water, where they are most vulnerable to enemy fire. Alternatively, it was to the advantage of Russia to widen the water gap Ukrainian forces must cross.”
Lucian K. Truscott IV, Salon

“Russia had the motive… Russia had the means… Moreover, Russia has the mentality to pull off an operation this egregious — a classic scorched-earth tactic from the country that popularized the term. We don’t have to look back to the Napoleonic era for evidence of Russia’s will to salt the earth behind it in retreat, Vladimir Putin’s obsession with the 19th century notwithstanding. While falling back amid the Nazi onslaught in the summer of 1941, Soviet secret police acting on Stalin’s orders destroyed a dam on this same river not far from Nova Kakhovka to delay the German advance…

“By denying its involvement in this event, despite all evidence to the contrary, the Kremlin is tacitly admitting that the dam’s destruction is a great crime. The deniability Moscow is cultivating will complicate the message it likely hopes to send: Russia reserves the right to escalate its war, and it is not afraid to decimate population centers in the process. Those who are susceptible to the deterrent force of this threat don’t need convincing. But the atrocity of which Russia is likely guilty will steel the resolve of Ukrainians more than it will frighten them.”
Noah Rothman, National Review

“What should happen now? First, since Russia insists it is not at fault, it should agree to a technical investigation to determine the cause. Russia has veto power at the UN Security Council, but the United Nations General Assembly, even the frequently hapless UN Human Rights Council, can go into special session. They should condemn the incident and demand a probe. If Russia blocks it, it will amount to an admission of guilt…

“In July, [NATO] will hold a summit in Vilnius, Lithuania. The location is symbolically powerful. Lithuania is one of the Baltic nations that Moscow invaded and annexed during World War II and, like other Russian neighbors, it has been warning about the Kremlin’s expansionist intentions. At the summit, Western leaders should formally commit to maintaining their support for Ukraine even if the counter-offensive falters… The broken walls of the Nova Kakhovka dam, and its destructive rushing waters, should strengthen the resolve of Ukraine’s backers.”
Frida Ghitis, CNN

Other opinions below.