Saint Petersburg Dam
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The Saint Petersburg Flood Prevention Facility Complex [1] (Russian: Комплекс защитных сооружений Санкт-Петербурга от наводнений), unofficially the St Petersburg Dam, the Leningrad Dam or the Kronstadt Dam, is a 25-kilometer complex of dams for flood control under construction near St Petersburg, Russia, from Lomonosov to Kronstadt and Lisy Nos (Russian: Лисий Нос). It is intended to protect St Petersburg from storm surges.
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[edit] Specifications
The dam is being constructed across the Neva Bay, with the island of Kotlin (Kronstadt) at its center. It extends for 25.4 kilometers and stands eight meters above water level. It has two large openings for shipping, which can be closed when floods threaten. Construction began in 1980 and stalled in the political and economic upheavals of the 1990s. The main benefit that most people cite is not flood control but for traffic, as it will complete a ring road around St Petersburg.
[edit] Floods on the Neva
St Petersburg suffers from frequent floods (289 in recorded history), some being natural disasters. It is on drained marshlands, isles and lowlands in the estuary of the Neva River, where flooding is common. Flow from Lake Ladoga is significant and the Neva's current is rapid, but flooding is generally caused by water backing up the Neva from its outlet, the Gulf of Finland. Most rivers flood in periods of exceptionally high flow, but the Neva typically floods in the late fall[2].
In the early literature, high winds from the Gulf of Finland were frequently given as the cause of Neva fooding, but scientists now understand the more complex hydrometeorological chain of events behind it. A low-pressure region in the North Atlantic moves onshore, giving rise to cyclonic lows on the Baltic Sea. The low pressure of the cyclone draws greater-than-normal quantities of water into the virtually land-locked Baltic. As the cyclone continues inland, long low-frequency[3] seiche waves are established in the Baltic. When the waves reach the narrow and shallow Neva Bay, they become much higher, ultimately breaching the Neva embankments[4].
The worst such flood occurred in November 7, 1824, when the water level rose 4.21 meters above normal. The playwright Alexander Griboyedov wrote, "The embankments of the various canals had disappeared and all the canals had united into one. Hundred-year-old trees in the Summer Garden were ripped from the ground and lying in rows, roots upward." When the waters receded 569 people were dead, with thousands more injured or made ill - more than 300 buildings had been washed away. The 1824 inundation is the setting for Alexander Pushkin's famous poem, The Bronze Horseman (1834). Other disastrous floods took place in 1777 and 1924. The most recent flood occurred on 18-October 19, 1998, when the water level rose to 2.2 meters [5].
[edit] The dam project
For years, prominent scientists and statesmen of imperial Russia developed various plans for flood protection, and the Soviet Union implemented the idea. The flood of 1955 finally made it clear that St Petersburg needed a protection dam. Many options were considered before the Soviet government decided on a 25.4-kilometer complex of 11 dams, including a six-lane highway on the top.
In 1978 the project was officially approved and two years later construction began. However, work stopped for over 15 years due to lack of money, and to environmental protests. In 2003 construction resumed and in 2005 it received a boost with the announcement of a new manager and a large increase in financial aid. It is believed that the Russian President Vladimir Putin - a native of St Petersburg - has been personally involved in finding a solution. Thanks to the pressure at federal level, the project is now due for completion in 2008.
[edit] Criticism
Environmentalists have raised concerns and staged demonstrations during construction of the dam. The main concerns relate to water quality and impact on historically significant sites. Due to protests and financial problems, the dam is regarded as one of the most notorious legacy construction projects from the former Soviet Union.
[edit] Water quality
Untreated wastewater from St Petersburg is the Baltic’s single biggest pollution point source [6]. Environmentalists 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 St Petersburg will all discharge into the dammed area. Beaches in this area are already seriously polluted. Only the Neva’s water is currently good enough to serve as a source for drinking water. Activists remain concerned the dam will transform the mouth of the Neva into "a cesspool of unpurified sewage" and endanger the water supply. At the same time, water quality in the Baltic beyond the dam has improved.
[edit] World Heritage Site impacts
The dam passes through the historic Northern Forts of Kronstadt, which is a World Heritage Site[7]. Builders of the dam have used the territory of the forts to stage building materials and dump construction waste, causing severe damage.
[edit] References
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- No longer flows the Neva - Leningrad grapples with a crisis in water quality, by Peter Riggs, In the Whole Earth Review, Spring ed. 1990.
- The Neva Project : Ecology and Cultural History in an Urban River, In honour of Saint Petersburg's Tricentennial, 1703-2003.
- Pressure On Dam Finally Threatens Break through, The St. Petersburg Times, November 1, 2005.
- St. Petersburg's Dam Gets Funding Inflow, The Moscow Times, November 8, 2005.
- Saint Petersburg’s way of fighting floods, by Dmitry Generalnicky, In eJournal, December 21, 2005.
- Saint Petersburg and Related Groups of Monuments, Unesco World Heritage
- ^ Before 2003 when construction resumed after a 15-year pause, the dam was officially called the "Leningrad Flood Prevention Facility Complex"
- ^ B. P. Usanov, Dialog between the city and the sea (in Russian), Leningrad: Knowledge Society Publishing House, 1989
- ^ Waves with wavelengths up to several hundred kilometers.
- ^ This is similar to a tidal bore, where incoming tides are funneled into a shallow, narrowing river via a broad bay. The funnel-like shape increases the height of the tide above normal, and the flood appears as a relatively rapid increase in the water level.
- ^ K.I.Krasnoborodko et al, The development of water supply and sewerage systems in St Petersburg, in European Water Management, Volume 2, Number 4, 1999
- ^ Baltic Marine Environment Commission
- ^ Saint Petersburg and Related Groups of Monuments.
