An Evaluation Of Irrigation Water Re-Use In Water Drainage And Collection Networks In Karakalpakstan, Uzbekistan

Abstract

Availability of water is a pre-condition for sustainable land use in anygiven area. Reclaiming water from irrigation is an alternative optionthat must be examined in order to meet water demands under conditions ofincreasing water deficits in the Aral Sea basin. In the territory ofKarakalpakstan, Uzbekistan, water flowing in the irrigation drainagenetwork is mostly diverted beyond the boundaries of irrigated lands. Asa result, a significant volume of water in the region is wasted due to alack of return/re-use in the irrigation process. Additionally, in placeswhere irrigation drainage waters accumulate with different levels ofmineralization, the lands are degraded ecologically. Some Central Asianand Near Eastern countries have had positive experiences with returnwater re-use, including water with low levels of mineralization, forgrowing different agricultural crops and for supplying water forpastures. Some scientists from Uzbekistan also have conductedfragment-based pilot research to identify the relationships between themineralization levels of irrigation drainage water for irrigation andyields. The research was experimental in character. It was conducted byselecting the optimal level of mineralization. However, the mechanismsthat explain this relationship in terms of the quality of irrigationdrainage water are yet to be studied. Researching the interrelationshipsbetween water quality structure and soil conditions, physical-chemicalprocesses, the transformations of main pollutants (within soil-watersand plant systems) that occur in the processes of irrigation that userun-off water, will enable determination of the optimal ratio ofirrigation water and run-off water mix in order to achieve not onlysustainable crop yield but also improve soil conditions and quality ofproduced crops.