Kura River - Economy and Human Use

Economy and Human Use

Formerly navigable up to T'bilisi, the largest city on the river, the amount of water in the Kura has greatly diminished in the 20th century because of extensive use for irrigation, municipal water, and hydroelectricity generation. The Kura is regarded as one of the most stressed river basins in Asia. Most of the water comes from snow melt and infrequent precipitation in the mountains, which leads to severe floods and an abundance of water for a short time of the year (generally in June and July), and a relatively low sustainable baseflow. Forest cover is sparse, especially in the Kura and Aras headwaters, and most of the water that falls on the highlands becomes runoff instead of supplying groundwater. Attempts at flood control include the constructions of levees, dikes and dams, the largest of which is at Mingachevir, an 80-metre (260 ft)-high rockfill dam impounding over 15.73 cubic kilometres (12,750,000 acre·ft) of water. However, because of the high sediment content of rivers in the Kura basin, the effectiveness of these floodworks is limited and decreases every year.

Irrigation agriculture has been one of the primary economic mainstays of the lower Kura valley since ancient times. Because of water taken out for irrigation use, up to 20% of the water that formerly flowed in the river no longer reaches the Caspian Sea. Over 70% of the water in the Iori (Gabirry) River, a major tributary of the Kura, is expended before it reaches Lake Mingachevir. Of the 4,525,000 hectares (11,180,000 acres) of agricultural land in the lower Kura River watershed, 1,426,000 hectares (3,520,000 acres), about 31%, are irrigated. Much of the water diverted from the river for irrigation goes to waste because of leakage from the canals, evaporation, poor maintenance, and other causes. Leaking water causes groundwater to rise, in some areas so high that about 267,000 hectares (660,000 acres) of land are so waterlogged that they are no longer suitable for agriculture. About 631,000 hectares (1,560,000 acres) of the irrigated lands have a dangerously high salt content because of mineral deposits from irrigation. Of this, 66,000 hectares (160,000 acres) are extremely salinated. Irrigation return water, returned to the river by an extensive but outdated drainage system, contributes to severe pollution. Some of this degradation also comes from industrial and municipal wastewater discharge.