Environmental Benefits of Reducing Collector-Drain Runoff and Ways to Improve Irrigation Water Quality in the Rivers of the Aral Sea Basin

Agriculture in the Central Asian Republics is suffering for several reasons, the main ones being the deficit of water for irrigation and the deterioration of water quality. Land reclamation and water management development in Uzbekistan, and in all the Central Asian Republics, were based on the availability of sufficient irrigation water of good quality in the years from 1960 to 1970. Sufficient supplies of water for irrigation created favourable conditions for regulation and maintenance of the soil-water-salt regime during these years, even with natural drainage. Improvement of irrigated lands, including those that were newly developed, was ensured by the installation of modern drainage systems (mostly subsurface horizontal and vertical drainage), and also by the annual maintenance of the irrigation systems and the collector-drains.