Water availability and state of water resources within water-economic basins in Kazakhstan

Abstract

Water is one of the most important natural resources. The water availability and scarcity depend on various natural and anthropogenic factors. Based on generalization and analyses of the numerous cartographic materials, and long-term runoff data, the water-economic basins (WEBs) in Kazakhstan were classified in order to identify the basin affected by human activities the most, to show the dynamics of river runoff within Kazakhstan, as well as to estimate the demand for water resources in the WEBs. Additionally, the water availability in the WEBs was determined by share (%) of water resources (rivers, lakes, water reservoirs). The Zhaiyk-Caspian WEB has the highest share (94%) of river water. By water resource (43.8 km3), the Ertis WEB is the most water-rich basin. A significant anthropogenic transformation was observed in the Aral-Syrdarya and Esil WEBs. Both basins are characterized by a deteriorated water quality. Due to natural factors and human activities, the total runoff decreased by 39.4 km3/year (23 km3/year is transboundary and local runoff is 16.5 km3/year) since 1965. Water consumption has decreased to 57% due to reduction of irrigation areas and industrial activities. However, the water consumption has increased by 1.33 and 1.25 km3/year in communal services and other needs due to the population growth. The water demand in Zhaiyk-Caspian WEB is very high and estimated in crisis degree (fourth class). The Balkash-Alakol WEB is characterized by a critical degree of water demand and belongs to the third class of water demand.