The picketers said that a new version of the project to build the Boguchanskaya hydropower plant on the Angara River, in the Siberian territory of Krasnoyarsk, will lead to a dangerously high reservoir water level of 208 meters.
"In that case, the Boguchanskaya reservoir will spread over to the Ust-Ilimskaya hydropower plant, and thousands of hectares of agricultural land, millions of cubic meters of timber, and scores of mineral deposits will be submerged," said Marina Rikhvanova, a co-chairman of a local ecological movement.
Earlier in the year, local environmentalists condemned the East Siberia-Pacific Ocean pipeline, an ambitious project Russia is developing to pump oil from Siberia to Russia's Far East for exports to the Asia-Pacific region, particularly to energy-hungry China.
President Vladimir Putin issued an order in April to reroute the oil pipeline from its original plan, which would have brought it to within 800 meters of Lake Baikal, the world's largest body of fresh water.
In late May, pipeline monopoly Transneft head Semyon Vainshtok said the new route will be 10 times farther away than the absolute minimum (40 kilometers, or 25 miles) that Putin had suggested.
Construction on the ESPO, preliminarily estimated at $11.5 billion, began in April 2006. Since then, more than 100 kilometers (62 miles) have been laid, and 330 kilometers (205 miles) have been prepared for pipe installation.
The pipeline is expected to pump 80 million metric tons (588 million bbl) of oil per year, including 30 million metric tons (220.5 million bbl) to China via an offshoot, whose construction is about to begin.
