Northern Dvina River: Encyclopedia Arctica 10: Soviet North, Geography and General

^ 960 ^ NORTHERN DVINA River, one of the largest in the European north of the Union of Soviet Socialist Republics, is formed by the junction of the Sukhona and Yuga Rivers. It drains Vologda and Arkhangelsk Oblasts and empties into Dvina Bay of the White Sea. 465 miles in length, its watershed covers an area of 139,670 square miles. Flowing almost un– interruptedly from southeast to northwest, it moves through a low p [: ] plain of glacial origin, which declines in altitude from 500 feet in the south to [: ] 65-82 feet in the north. The vegetation of the plain is virgin taiga forest, consisting of ^ spruce ^ fir and pine with some admixture of larch and fir. However, fully one-half of the basin of the Dvina is marshland. The Northern Dvina and its tributaries are typical plainland rivers with a [: ] small rate of incline, many meanderings and broad valleys. ^ ¶ ^

Five sections of the river may be dis– tinguished. The uppermost, 43 miles in length, between the junction of the Sukhona and Yuga and the mouth of the Vychegda, is called the Malaya (Lesser) Northern Dvina. Here the river flows in a broad val– ley, averaging two to two-and-a-half miles in width, and abounds in islands and shoals. The next section, 195 miles in length, down to the mouth of the Vaga, is called the Bolshaya (Greater) Northern Dvina. The river as such does not differ in nature from the upstream section, but the banks, here of sand and clay composition, attain in places a height of 100 to 130 feet. The following section, lying be– tween the mouths of the Vaga and Pinega, 130 miles in length, is dif– ferent in character. Here the valley narrows; the channel is more stable, having fewer islands; and the banks, chiefly of limestone, are 30 to 50 feet in height. The section from the Pinega to the delta is characterized by tidal phenomena. ^ For ^ T^t^he first 3.6 miles of this sec– tion the rivers flows in a single channel between high, dry banks, but then divides into numerous, branches, which unite again into one at Arkhangelsk. In this section the channel clings to the right bank, The In its lowest reaches, below the city, the river forms

Northern Dvina

the river forms a large triangular delta, some 30 miles in length. Here there are five main branches, the Nikolsk, Murmansk, [: ] Korabelnyi (Ship), Maimaksa and [: ] Kuznechikha. The delta consists of a series of low, muddy islands, flooded for the most part during spring high water and cut up by arms and natural canals.

The most important tributaries of the Northern Dvina, other than the Sukhona and Yuga, of which it is formed, are the Vychegda (677 miles long) and the Pinega to from the east, and the Vaga and Emtsa from the west, but the [: ] rivers of its basin total some 600. There is also a large number of lakes, of which the most important are the Kuben (142 square miles), which is the source of the Sukhona River, and the Shai, connected to the [: V]olshaia Dvina by the Pukshenga River.

The Dvina is fed by snow. It reaches its lowest point before the ice melts, about the middle of April. The rise takes place rapidly, and recedes over a period of a month and a half, so that the river returns to its banks at the beginning of June. Thereafter the level is stable, but there is a considerable rise for a month in the F ^f^all, decreasing with the [: ] appearance of ice on its surface. The river opens again in its upper reaches at the end of April, and at Arkhangel [: ] at the beginning of May. The river is free of ice within six to eight days after it begins to break up. In the F ^f^ all floating ice makes its appearance at the end of October, and it is between 10 and 20 days be– fore the river is frozen solid. The riveris free of ice 170 to 175 days in the year, and blocked 160 to 190. At Arkhangelsk the average is 181 days. The average thickness of ice, measured at Kholmogor, is [: ] 3' 4", but it is considerably less along the middle and upper [: ] reaches of the river.

The flow of water fluctuates, widely during the year. 50 to 70% of the annual flow takes place during the spring; 25 to 30% during the summer; and only 10 to 20% during the winter. The current is negligible.

Northern Dvina

The composition of the water has been little studied. The effects of tide may be observed as far as 80 miles upstream. In the delta the tide reaches four feet, but declines progressively upstream.

Flowing as it does through the most important timber country of the European portion of the USSR, an area, furthermore, which is poor– ly served by railroads, and not at all by through roads., the Northern Dvina is of considerable importance for transport. It hauls but a single freight: felled trees in the rough, moving downstream to the largest lumber milling and exporting center of the USSR, Arkhangelsk. It also carries small quantities of mineral ^ , ^ building materials and grain. It is connected to the Mary system of inland waterways and the Volga through the Northern Dvina canal. The very low height of the Marshy watershed in which it takes its rise, coupled with the fact that northward, rather than southward ^ , ^ flow , is determined by the curvature of the earth, has given rise to a project, since World War II, to di– vert the river at its source (this will not affect the lower [: ] tributaries and their lumber-carrying capacity, while dredging can main– tain Arkhangelsk) into the Volga. The purpose of this major operation is to help prevent the drying up of the Caspian Sea, into which the Volga empties, a phenomenon which can have catastrophic effects upon the Baku petroleum industry, shipping and agriculture. Thus the snows of the Arctic are to be made to [: ] meet the needs of a sub-tropical desert region.

^ William Mandel ^

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