Hydrological measurements, such as water levels during floods and freshets, have been
recorded in Russia and other countries of Northern Eurasia for centuries, measurements
being taken irregularly at water mills and in monasteries set on rivers and lakes
(Sokolov, 1981). The first regular hydrological observations in Russia were organized
under the order of Peter the Great in the early 18th century on the Neva river at the
Petropavlovsk fortress in St. Petersburg. Soon, runoff was measured with some regularity
on a number of large rivers including the Volga. Regular observations began in the 19th
century and since then the hydrometric network was constantly improving until 1990. In
1960, the national stream-gauging network consisted of 5866 sites (Sokolov, 1964).
Hydrological statistics, used in many publications including atlases (e.g., Voskresensky,
1962; Protasyev, 1967; Lvovich, 1969, 1974) and employed in this chapter, have been
derived from this network. In addition, there were over 2800 sites which belonged to
various organizations. The density of the national network is on average one site per 3820
km2 (for comparison, in the United States there is one site per 1972 km2,
in Canada 8871, in France 548, in India 9735, and in China 3104 km2). The
spatial distribution of the sites is uneven and in the European territory the network is
much denser (one site per 1580 km2) than in the Asiatic part (one site per 7000
km2). Although after 1990 the monitoring program was reduced it still remains
substantial.
