Activists claim that Russian officials are disrupting the flow of the biggest tributary to the Caspian Sea for political prestige -- regardless of the environmental impact.
Residents of Kazan, Russia, live 1,000 kilometers north of the Caspian but can witness directly the human activity affecting it. This is where the Kazanka River merges into the Volga, the largest source of water into the Caspian, and the flows here vary wildly.
In September 2023, the Kazanka was so low it slowed to a trickle. In October 2024, it was so high that the Kazan Kremlin's mirror image shimmered picturesquely in its waters.
This is not just because of the weather.
"The entire Volga is regulated," said Yulia Faizrakhmonova, an activist who monitored water levels there for 10 years until she fled Russia after it’s full-scale invasion of Ukraine in 2022.
"There is a cascade of reservoirs that are run by the Federal Water Resources Agency," she told RFE/RL’s Tatar-Bashkir Service.
These reservoirs, and the series of dams along the Volga, have long been linked to decreasing water flows into the Caspian Sea -- contributing to falling water levels there.
The Volga provides 85 percent of the water flowing into the Caspian, according to Kaspiisky vestnik, an analytical website.
Russian officials have admitted that flows are manipulated, for example to help spawning in the caviar-producing areas in the Astrakhan region near the Caspian coast -- leaving places like Kazan with much lower water levels.
"They have the most valuable commercial fish, sturgeon, in the Astrakhan region," Faizrakhmonova said. "But of course, our part of the Volga suffers."
In October 2023, the water levels at the Kuibyshev Reservoir, just south of Kazan, were at a record low, according to figures released by RusHydro, a hydroelectric company.
This led the heads of five regions to issue an appeal to Russian President Vladimir Putin for water levels on the Volga to be "stabilized."
The president of the Tatarstan region, Rustam Minnikhanov, warned at a meeting in Moscow that the lack of water was causing "social unrest."
A year later, the situation was reversed and the water was too high.
Yet some believe this was a political decision linked not to the appeal, but rather the desire to make Kazan look its best for foreign leaders at the BRICS summit in Kazan last month.
"Apparently, for an event like this, agreement was reached at the federal level with [officials from] the Caspian region," environmental activist Timur Eskarayev told Inkazan, a local news outlet.
Faizrakhmonova agrees. She told RFE/RL that in her years of work on the Volga, she had also noticed a correlation between water levels and prestigious events.
One such occasion was the FIFA World Cup in 2018, when Kazan hosted several matches. Others point to other causes for the high water levels.
Kazan-based biologist Anton Bortyakov told Inkazan it was a combination of heavy snow in the winter, Minnikhanov's warning, and increased support for Tatarstan's position on a government commission that considered the regulation of Volga flows.
In any case, in the wake of the summit, by early November it was observed that water levels had fallen again, according to official data cited by a nongovernmental group
RFE/RL wrote to Minnikhanov asking if the high water levels were connected with the BRICS summit, but received no immediate response.
RFE/RL has been classified as an "undesirable organization" by the Russian authorities.