1911 Encyclopædia Britannica/Neva
|←Neuwied||1911 Encyclopædia Britannica, Volume 19
|See also Neva River on Wikipedia, and our 1911 Encyclopædia Britannica disclaimer.|
NEVA, a river of Russia, which carries off into the Gulf of Finland the waters of Lake Lagoda, Onega, Ilmen and many smaller basins. It issues from the south-west corner of Lake Lagoda in two channels, which are obstructed by sandstone reefs, so that the better of the two has a depth of only 7 to 16 ft. A little farther down it becomes completely navigable, and attains a breadth of 4200 ft.; but between the village of Ostrovski and that of Ust-Tosna it passes over a limestone bed, which produces a series of rapids, and reduces the width of the river from 1050 to 840 and that of the navigable passage from 350 to 175 ft. Nine or ten miles before reaching its outfall the river enters St Petersburg, and 5 or 6 m. lower down breaks up into the Great Neva (850 to 1700 ft. wide), the Little Neva (945 to 1365), and the Great Nevka (280 to 1205), this last, 2 m. farther on, sending off the Little Nevka (370 to 1130 ft.). Its total length is only 40 m. In front of the delta are sandbanks and rocks which prevent the passage of vessels except by a canal, 18 m. long, 124 to 226 ft. wide, and admitting vessels with a draught of 181⁄2 ft., from Kronstadt to St Petersburg. Most of its alluvial burden being deposited in the lakes, the Neva takes a long time to alter its channels or extend its delta. The ordinary rise and fall of the river is comparatively slight, but when the west wind blows steadily for a long time, or when Lake Lagoda sends down its vast accumulations of block-ice, inundations of a dangerous kind occur, as in 1777, 1824, 1879 and 1903.
According to observations extending from 1706 to 1899, the mean day of the freezing of the Neva is November 25th, the earliest October 28th, the latest January 9th, and the next latest December 26th. The mean day of opening is April 21st, the earliest March 18th, and the latest May 12th. The mean number of days open is 218, the least 172, the greatest 279.