DVINA, the name of two rivers of European Russia.
I. 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 meet in the neighbourhood of Vel ikiy-Ustyug, at a height of 30o ft. above the sea, in 61 ° 20' N. and 46°2o' E. The conjoint stream then flows north-west to the Gulf of Archangel, which it reaches 5o m. below the city of Archangel. From its mouth to the confluence of the co-tributary streams the distance is about 47o m., and to the source of the Sukhona 78o m. The drainage area is estimated at 141,00o sq.m. Except at the rapids the current of the Dvina is comparatively slow, as the aver age 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. Near Archangel it divides into three distinct arms, which form a regular delta, but of these that of Berezov alone is nav for sea-going vessels, and even it is impeded by a bar at the mouth, with not more than 144 or 151 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 conflu ence of the Vychegda the breadth is about 1,75o ft.; below that point it widens out to 3,50o ft.; and near Archangel it attains more than three times that measure. The channel is free from ice for about '74 days in the year. By means of the Duke Alexander of Wurttemberg Canal, the river is connected with the Neva and the Volga.
2. The Southern Dvina, or Dvina Zapadnaya (western Dvina) belongs to the Baltic basin, and takes its rise in a small lake about Boo ft. above the level of the sea, not far from the sources of the Volga and the Dnieper. It flows south-west through the province of Pskov, and through the White Russian S.S.R. But some dis tance west of Vitebsk it turns north-west, forming part of the boundary between White Russia and Poland, and then flows through Latvia where it enters the southern end of the Gulf of Riga. Its length is 64o m. and it drains an area of 3 2,96o sq.m. From Daugavpils (Dvinsk) to Riga, a distance of 135 m., there is altogether a fall of 295 ft., of which 105 ft. are in the 4o m. from Jakobstadt to Friedrichstadt. In the lower part of its course the river attains an ordinary depth of 3o ft. and an average breadth of 1,40o ft.; but during the spring flood it sometimes rises 14 f t. 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 White Russia 2 29. It is navigable from the conflu ence of the Mezha (i.e., from Vitebsk) downwards, but the num ber of rapids and shallows greatly diminishes its value. Naviga tion can also be carried on by the following tributaries : the Usvyat, Mezha, Kasplya, Ulla, Disna and Bolder-aa. Salmon and lampreys abound in its waters. The river was formerly called the Khezin or Turunt, and is known to the White Russians as the Polot and to the Latvians as the Daugava. It is the natural outlet for timber from the west of Russia, and timber rafts, usually in charge of gypsies living in grass huts on them, are still floated down it. Its strategic importance has always been great and Riga and Daugavpils (q.v.) have witnessed many struggles for power. The construction of a hydro-electric station on the Daugava to provide power equivalent to that from 3,000,00o tons of coal, are now under consideration by the Latvian Government.