Kuban River - Geography and Hydrology

Geography and Hydrology

The river originates on the slopes of Mount Elbrus and forms at the merge of its two tributaries, Ullukam and Uchkulam; from the source of Ullukam to the delta, its length is 906 km. Between the source and Nevinnomyssk, the river flows mostly in the deep and narrow gorge, has many thresholds and rapidly changes its elevation. Near Nevinnomyssk there is a dam to supply water to the Nevinnomyssk channel. In its central part, until the confluence of the Bolshaya Laba River, the Kuban River flows in a wide flat valley with terraced slopes. Then it bends to the west and develops a left-bank floodplain, which is 4 km wide near Ust-Labinsk. There it is winding and has many shoals and rapids. Below the mouth of Laba, the river widens up to 20 km. Between the mouths of the rivers Laba and Afips, there are Adyghe marshes covering an area of about 300 km²; and below river Afips, about 800 km² is occupied by the Zakubanskie marshes. At 116 km from the mouth, the Kuban converges with a major tributary Protoka (length 130 km). Near the mouth, the Kuban narrows to 3–4 km and then forms a delta covering about 4300 km². The delta contains numerous limans, some of which have gradually separated from the river. Until the 19th century, the Kuban River was discharging into both the Black and the Azov seas. However later, the raising grounds redirected the river entirely to the Azov Sea.

In the upper stream, the river is mostly fed by glaciers and high-mountain snow (49%). Near Krasnodar, this contribution drops to 32%; meanwhile, the water supply from the subsoil water increases from 21% to 32%, and of the rainwater from 27% to 32%. The river does not freeze over because of a relatively warm climate and rapid flow in the upper part. The Kuban River is characterized by numerous (6–7 through the year) floods due to rains and thaws, both in the winter and summer. The water level used to fluctuate by up to 5 meters, with the maximum in July and minimum in February. The amplitude of these fluctuations was reduced by construction of the Nevinnomyssk channel and the Tschikskoe, Krasnodar and Shapsug reservoirs. These measures also provided water for fish farming and rice fields.

The average annual water consumption from the Kuban River is at its maximum near Krasnodar at about 425 m3/s. It was higher by some 30 m3/s but was lowered by the reservoir construction. The average consumption near Armavir is 163 m3/s and it varied between 1160 and 0.95 m3/s before the filling of the Krasnodar Reservoir in the 1980s. The annual outflow to the Azov Sea is about 12–13 km3 of water, 8 million tonnes of sediments and 4 million tonnes of dissolved salts.

The average turbidity is 682 g/m3. Water salinity increases toward the delta; it normally varies between 50 and 400 mg/L and may reach 1000 mg/L in some areas. All major tributaries flow into the Kuban from the left and originate in the Caucasus Mountains. Those tributaries are Bolshoi Zelenchuk, Malyi Zelenchuk, Urup, Laba, Belaya and Pshish.