Dvina, the name of two rivers of European Russia.
1. The Northern Dvina, or Dvina Syevernaya, belongs to the basin of the White Sea, and is formed by the junction of the Sukhona and the Yug, which, rising, the former in the south-west and the latter in the south-east of the government of Vologda, meet in the neighbourhood of Velikiy-Ustyug, at a height of 300 ft. above the sea, in 61° 20′ N. and 46° 20′ E. The conjoint stream then flows N.W. to the Gulf of Archangel, which it reaches 50 m. below the city of Archangel. From its mouth to the confluence of the co-tributary streams the distance is about 470 m., and to the source of the Sukhona 780 m. The drainage area is estimated at 141,000 sq. m. Except at the rapids the current of the Dvina is comparatively slow, as the average fall per mile is only 9 in. Till its union with the Vychegda, a river which exceeds it in volume, it flows for the most part in a single, well-defined and permanent channel; but below that point it often splits into several branches, and not infrequently alters its course. In the neighbourhood of Archangel it divides into three distinct arms, which form a regular delta; but of these that of Berezov alone is navigable for sea-going vessels, and even it is impeded by a bar at the mouth, with not more than 14½ or 15½ ft. of water at full tide. Just above the point where the delta begins the river is joined by a large tributary, the Pinega, from the right. Above the confluence of the Vychegda the breadth is about 1750 ft.; below that point it widens out to 3500 ft.; and near Archangel it attains more than three times that measure. The channel is free from ice for about 174 days in the year. By means of the Duke Alexander of Württemberg Canal, the river is connected with the Neva and the Volga.
2. The Southern Dvina, or Dvina Zapadnaya, in German Düna and in Lettish Daugava, belongs to the Baltic basin, and takes its rise in a small lake about 800 ft. above the level of the sea, in the government of Tver, not far from the sources of the Volga and the Dnieper. After dividing Tver in part from Pskov in part, it skirts the east and south of the government of Vitebsk, separates part of the latter from Vilna, and then divides Vitebsk and Livonia from Courland, and disembogues in the southern end of the Gulf of Riga. Its length is 640 m. and it drains an area of 32,960 sq. m. From Dvinsk (Dünaburg) to Riga, a distance of 135 m., there is altogether a fall of 295 ft., of which 105 ft. are in the 40 m. from Jakobstadt to Friedrichstadt. In the lower part of its course the river attains an ordinary depth of 30 ft. and an average breadth of 1400 ft.; but during the spring flood it sometimes rises 14 ft. above its usual level, and its waters spread out to a mile in width. Near the mouth the river is usually free from ice for 245 days in the year, and in the government of Vitebsk for 229. It is navigable from the confluence of the Mezha (i.e. from Vitebsk) downwards, but the number of rapids and shallows greatly diminishes its value. Navigation can also be carried on by the following tributaries: the Usvyat, Mezha, Kasplya, Ulla, Disna and Bolder-aa. This river was formerly called the Khezin or Turunt, and at the present day it has the name of Polot among the White Russians. Salmon and lampreys abound in its waters.
