GROUNDWATER MANAGEMENT AT IRRIGATED LANDS OF UZBEKISTAN AND ITS INFLUENCE ON ECOLOGICAL SYSTEM

摘要

collector-drainage water is forming in the Uzbekistan territory. River water salinity in upstream is 1.5-3.0g/l, in midstream and downstream it fluctuates from 3.5-6.0 to 5-7 g/l. The half part of the collector-drainage water inflows to river and can be used again for irrigation in the lower located lands. Return water re-use is repeated several times along the river worsening river water quality. Irrigation water salinity in the midstream has reached to 1.0-1.1 g/l, in downstream more than 2 g/l (against initial 0.2-0.3g/l). Annual economic damage in Uzbekistan caused by high location of ground water, soil and irrigation water salinity is over 920 million USD.