70% complete, when due to difficulties obtaining financing after the fall of the Soviet Union the project was suspended until 2005, when President Vladimir Putin ordered its resumption. Construction was completed in 2011, and the formal opening of the complex was on 12 August 2011. At the opening ceremony, Putin said that the completion of the project was a "historic event" and meant that Saint Petersburg "is not just protected from floods, the ecological situation also improved." The entire project cost roughly 109 billion rubles ($3.85 billion), and resulted in a series of eleven separate dams measuring across the Gulf of Finland. Built into the structure are two openings to allow ships to pass through, six gates that can be closed to hold back water, and about 30 facilities for purifying water flowing into the gulf. It took of stone and soil, of reinforced concrete and about of steel structures and other materials to build the dam. The project was designed and implemented by over 100 scientific and design institutions, construction companies and suppliers of materials and equipment. Criticism Opponents have raised concerns and staged demonstrations during construction of the dam. The main concerns relate to water quality and impact on historically significant sites. Water quality Dam's opponents fear that the dam will constrain water flow, accumulating polluted water inside the dam. Damming an estuary and altering its flow pattern generates a number of physical and biological impacts; the disruption of the normal flow obstructs natural current and affects the water's habitat. The 60 canals and rivers that flow through Saint Petersburg will all discharge into the dammed area. Currently the Neva's water is good enough to serve as a source for drinking water. To address the problem of water pollution, the city's government adopted a plan to upgrade the city's sewage system to limit the amount of untreated wastewater release to less than 0.1%. The measures being taken seem to be quite efficient – after the launch of the modern long-awaited South-West Wastewater Treatment Plant in 2006 the amount of biological and phosphate waste is expected to be lowered by 60% and 25%, respectively. Over 30 water purification installations are placed around the complex, a part of a larger effort to clean the water in Neva Bay. World Heritage Site impacts The dam passes through the historic Northern Forts of Kronstadt, which is a World Heritage Site. See also