Enisei

(loanesi in Evenki, literally “big water,” “river”), one of the largest rivers in the USSR and the world.

The Enisei rises from two sources: the Bol’shoi (Great) Enisei, or Bü-Khem, and the Malyi (Little) Enisei, or Ka-Khem. It flows toward the north along the border of Eastern and Western Siberia, mainly in the Krasnoiarsk Krai of the RSFSR, and into the Enisei Gulf of the Kara Sea. The length of the Enisei from the sources of the Malyi Enisei is 4,102 km, and from the confluence of the Malyi and Bol’shoi Enisei near the city of Kyzyl (the Enisei proper), 3,487 km. If the source of the Selenge were taken as the beginning of the Enisei, then its length would be about 5,075 km. In terms of the area of its basin (2.58 million sq km) the Enisei ranks second among rivers of the USSR (after the Ob’) and seventh among rivers of the world.

The Enisei River basin is characterized by sharp asymmetry: its right drainage basin is 5.6 times larger than the left. The basin consists mostly of mountainous country; it lies in the mountains of Southern Siberia and, for the most part, the Middle Siberian Plateau. Most of the basin is covered by taiga, and perennially frozen rock is spread throughout much of it. The hydrographic network of the Enisei includes (within the USSR) 198,620 rivers with a total length of 884,754 km and 126,364 lakes with a total area of 51,835 sq km.

According to the structure of the valley and the river bed and the nature of the current and the hydrologic regime, the Enisei is divided into three principal sections: the upper Enisei—from the confluence of the Bol’shoi and Malyi Enisei rivers in the Tuva ASSR to its emergence from the Zapadnyi Saian Mountains into the Minusinsk Basin near the settlement of Oznachennoe, 474 km in length; the middle Enisei— from Oznachennoe to the Angara River confluence, 876 km in length; and the lower Enisei—from the Angara River to its mouth, 2,137 km in length.

Over the length of the first 188 km (after the confluence of the Bol’shoi and Malyi Enisei rivers), the Enisei flows under the name of the Verkhnii Enisei, or Ulug-Khem, on the northern side of the Tuva Bowl toward the west. The river divides into branches, and the bed abounds with shoals. The width varies from 100 to 650 m. Depths in reaches are 4–12 m; in shoals, not more than 1 m. Receiving the Khemchik River from the left, the Enisei turns northward and for a distance of about 290 km cuts through a system of mountainous ranges of the Zapadnyi Saian Mountains: here the Enisei flows through a narrow valley, at times in canyons (about 100 m wide) that create numerous rapids (Bol’shoi, Dedushkin, Dzhoiskii, and others) and falls. The Bol’shoi Rapids, very dangerous and unnavigable, are situated near the mouth of the Kazyrsuk River. Their drop (at different levels) is 2–6 m; flow velocity is 6–8 m/sec (the velocity of other rapids is 3.5–4.5 m/sec); their length is 320 m. Below the Bol’shoi Rapids are found lakelike pools (“pits”) where depths exceed 20 m. After the construction of the Saian Hydroelectric Plant at the emergence of the Enisei from the Zapadnyi Saian Mountains and the formation of a reservoir, these rapids will be flooded.

Below Oznachennoe the Enisei flows through the Minusinsk Basin. The river valley broadens here, and many islands appear in the channel. Below the confluence of the Abakan River, a left tributary, the width of the valley becomes 5 km, and the channel widens to over 500 m. Flow velocity here is less than 2 m/sec. Below the Abakan River confluence is the beginning of the Krasnoiarsk Reservoir, formed by the dam of the Krasnoiarsk Hydroelectric Plant, near the city of Divnogorsk at the point where the Enisei crosses the spurs of the Vostochnyi Saian Mountains. The depth near the dam is nearly 100 m. On this section of the river the Tuba and Syda tributaries flow from the right into the reservoir; the Mana empties in below the dam. Near Krasnoiarsk, where the Enisei crosses the spurs of the Vostochnyi eastern Saian Mountains, the mountains of the right bank close to the river end abruptly in picturesque cliffs called “pillars.” The Enisei valley again widens between Krasnoiarsk and the mouth of the Angara. The river loses its mountainous character, but there are still underwater ridges in the bed. extensions of the spurs of the Enisei Ridge. One of these ridges forms the Kazachinskii Rapids. Its length, including falls, is nearly 4 km; the total drop is 3.8 m; the width of the channel is 550–600 m instead of 800–1,300 m, the usual width in this section. These rapids are almost impassable.

Below the confluence of the Angara the nature of the Enisei valley and channel changes sharply. The right bank remains mountainous, the left becomes a low floodplain. Above the Angara spit the breadth of the Enisei channel is 800 m, but below, it is not less than 2,000 m. Depths increase to 10–17 m; flow velocity falls to 0.8–1.1 m/sec. The width of the Enisei Valley at the mouth of the Nizhniaia Tunguska River is about 40 km; at Dudinka and Ust’-Port, up to 150 km. Channel width here is 2,500 to 5,000 m. Minimum depths of the entire lower Enisei range from 5 to 8.5 m. Above the mouth of the Podkamennaia Tunguska River the Enisei cuts through spurs of the Enisei Ridge, forming the Osinovskii rapids. Over the rapids depths fall to 2.5 m, and flow velocity is 2–3 m/sec. Below the rapids the river passes through a rocky gorge where the width of the channel is 740 m; depths increase up to 60 m. Below the Nizhniaia Tunguska confluence depths are usually 14–20 m; below Dudinka depths range from 20 to 25 m. The channel divides into branches, forming islands up to 20 km long. Below the mouth of the Kureika River, where tidal fluctuations are observed, begins the estuary of the Enisei. Cape Sopochnaia Karga is taken as the estuary area of the Enisei, but actually the Enisei delta begins below the settlement of Ust’-Port. The Enisei river bed is divided by the Brekhov Islands into a large number of channels: the Okhotskii Enisei, the Kamennyi Enisei, the Bol’shoi Enisei, and the Malyi Enisei; the total width of the channel is about 50 km. Below this point the Enisei flows in a single channel, in a “throat.”

The Enisei has mixed feeding. Snow feeding predominates, accounting for almost 50 percent of the total. Rain accounts for 36–38 percent and groundwaters up to 16 percent in the upper reaches, less in the lower reaches. Lengthy spring flooding and summer high waters are characteristic of most of the Enisei. In the winter there is a sharp reduction in runoff, but water levels fall slowly because of ice jams. Extended spring flooding is characteristic of the upper reaches of the river. Flooding on the Enisei begins in May, sometimes in April; it starts somewhat earlier in the middle Enisei than in the upper reaches; on the lower Enisei it commences in the middle of May or the beginning of June (Dudinka). The variation of water levels is 5–7 m in wider parts of the upper reaches and 15–16 m in the narrower parts; the changes are greater in the lower reaches (28 m near Kureika) but grow smaller toward the river mouth (11.7 m near Ust’-Port). In volume of discharge the Enisei ranks first (624 cu km) among rivers of the USSR. Maximum discharge near Igarka is 154,000 cu m per sec. The increase in discharge downstream occurs rather uniformly (see Table 1).

Freezing of the Enisei begins in the lower reaches (early October). Extensive formation of underwater ice and autumn ice flow are characteristic of the Enisei. There is complete ice cover in the lower parts from the end of October; in the middle courses and at Krasnoiarsk, by the middle of November; and in mountainous areas, by the end of November and early December. Massive sheets of overflow ice appear in several sections of the channel. The opening of the Enisei occurs first in the upper reaches (end of April), then in the middle (first half of May), and finally in the lower (early June). Spring ice flows are accompanied by ice jams.

The Enisei is the most important waterway of Krasnoiarsk Krai. There is a regular navigation from Oznachennoe to the mouth of the river (3,013 km). Most freight traffic proceeds from Krasnoiarsk to Dudinka. The chief ports and landings are Abakan, Krasnoiarsk, Strelka, Maklakavo, Eniseisk, Turukhansk, Igarka, and Ust’-Port. Seagoing vessels travel up the river to Igarka. With the construction of the Krasnoiarsk Hydroelectric Power Plant the waterway was divided into two separate parts; in 1970 construction of a ship elevator was begun. There is local navigation on the Enisei in the Tuva ASSR (the chief landing is Kyzyl). Wood is floated in rafts along the Enisei. The energy resources of the Enisei are enormous. Construction (1971) of the Krasnoiarsk Hydroelectric Power Plant has been completed; the Saian Hydroelectric Power Plant (1972) is under construction. The following fish are found in the Enisei: omul and muksun (species of whitefish), herring, white salmon, sterlet, and sturgeon. In the summer regular cruises for tourists on comfortable ships are organized along the Enisei from Krasnoiarsk to Dudinka and to Dikson.