floods

THE NEVA PROJECT: RIVER AND CITY
Floods on the Neva River

	But driven by winds from the Gulf
	The Neva in her confinement
	Turned back, seething, belligerent,
	And swamped the islands.
	-- Pushkin, "The Bronze Horseman"

Floods are a way of life on the Neva. Russians call it a "full-water" river, meaning it normally fills its banks. The pressure of water flowing from Lake Ladoga is great, and the Neva's current is fast. But the cause of flooding is generally not from additional water flowing downstream, as in most rivers, but from water backing up from the Gulf of Finland. Most such floods happen not in the spring but in the late fall.

It was formerly believed that high winds from the Gulf initiated the floods (Pushkin cites this as the cause, for example). But scientists now know there is a more complex hydrometeorological chain of events behind the flooding. A low pressure region in the North Atlantic gives rise to cyclones on the Baltic Sea. The center of the cyclone sucks up huge amounts of water, which are then released in long, low waves. When the waves reach the narrow, shallow Neva Bay, they become much higher, allowing them to spill over the Neva embankments.

The flood of 1777

Since the founding of the city of St. Petersburg there has been an average of about one flood per year, in which the water rose more that 160 cm. above its long-term average depth. Catastrophic floods (more than 300 cm above average level) have occurred in 1777, 1824, 1924, and 1997 (?). To avert flood damage in the early days of the city, the government issued decrees mandating the height of building foundations. It also engaged in "spin control," meting out harsh punishments to anyone who spread rumors about flood dangers or damage (Ageeva 84-5).

The flood of 1824

The worst flood in St. Petersburg history occurred in November, 1824, when the water level rose to 421 cm. above normal. "The view from the window was awful," wrote playwright A. S. Griboedov. "Where an hour before there had been a lively, passable street, now fierce waves rolled by, roaring and foaming, and the winds howled .... Nevsky Prospect had become a tempestuous strait; ... 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, the city discovered the flood's terrible toll: 569 people dead, thousands more injured or made ill, and more than 300 buildings washed away.

What can be done to prevent future catastrophic floods? The main effort is a dam across the Neva Bay, with the island of Kronstadt at its center. The dam extends for 25.4km. and stands 8m. above water level. It has two large openings for shipping, which can be closed when high water threatens. Dam construction began in 1979 and stalled in the political and economic upheavals of the 1990's. Not everyone agrees that the dam will have the desired effect, and many contend that the partially-competed dam is worse than no dam at all, because of the way it affects the hydrology of the bay, and because decay has occurred on the completed sections. The main benefit that most people cite is not flood control but traffic control: the completed dam will complete a much-needed ring road around the congested city.

Above: Plan of the dam, with Kronstadt in lower left and Petersburg at top.

Left: A completed stretch of the dam.

QUESTIONS FOR OUR READERS: What would St. Petersburg without floods be like? Are floods essential to the city's self-image? Do the floods still serve an ecological purpose, or are they purely destructive? How will the dam affect the current and quality of the river and the feel of the city? Please share your thoughts with us.

Further topics and interdisciplinary essays
Peter the Great and the Neva River Delta	Land and Sea in the Russian Traditional World View	Floods on the Neva River	The Neva Embankments: Hydrology and Aesthetics	Society and River Environment	Referen ces and links	The sites