MA Jin-zhu, LI Ji-jun

(College of Resources and Environment, Lanzhou University, Lanzhou 730000, China)

Abstract: Groundwater has been changing extensively affected by human activities combined with desiccating climate conditions. In modern times, population growth, accompanied by development of industrial and agricultural production and the petroleum exploitation, brought about rapid expansion of artificial oasis with abruptly increasing of water demand. As a consequence, the artificial hydraulic irrigation project took the place of natural river system, the reservoirs took the place of natural lakes which in turn enhanced the space-time redistribution of surface water based on natural evolution, and so did groundwater. The groundwater recharge reduced by 26.2% in 46 years from 1950 to 1995 in southern piedmont of the Tarim Basin based on mean yearly population increase rate of 27.7¡ë associated with water use rate increasing from 24.6% to 58.4%. At the same time seepage of artificial water system plays a leading role to groundwater recharge, which is up to 57.6% whilst that of the river bed reduce to 33.7%. As a result,groundwater table generally dropped by 3¡«5 m except some irrigated areas and surroundings of plain reservoirs. Spring water discharge also reduced by about 28.7% and discharge zone continuously moved away to the north with values of 0.5¡«1.2 kilometers in the past 40a. Meanwhile,groundwater contamination began to rise up quickly, especially in some towns and irrigated areas a lot of organic nutrients such as NH₄-N, DOC and SRP were brought to aquifers where groundwater was recharged by surface water. Besides, groundwater evolution has led to serious plant degradation and land desertification.

Keywords: human activity; groundwater; eco-environment; southern Tarim Basin