关键词: 水资源, PRA, 沙漠化, 贫困化, 种草养畜, 民勤盆地

Abstract: Based on the GIS,RS,GPS and PRA,the impact of water resources on desertification and pauperization in the Minqin basin is studied.The water in the Shiyang River,which is the main river feeding the basin,is over-used for irrigation with little or no surface water now reaching the Minqin Basin itself.Large-scale water conservancy construction and water resources exploitation were carried out with the dramatic growth of population beginning in 1949 when new P.R.China was founded.In 1995,the total water storage of 23 reservoirs was about 450×106m3.Accordingly,the canalled surface runoff amounted to 1.406×109m3 yearly in the 1990s,being about 89% of the total runoff.As a result farms in the Minqin Basin are now dependent on the pumping of groundwater for both irrigation and drinking purposes.This has caused a gradual reduction in the level of groundwater and a huge lake,approximately 500km₂ in extent in the centre of the basin has now disappeared completely.Freshwater can now only be obtained by pumping from wells of 300m deep and the number of wells has reached 10 000.The increasing utilization of water resources has led to great environmental problems such as groundwater exhausting,water level decline,deterioration of water quality,vegetation degradation,soil salini-zation and land desertification,which in turn result in pauperization.It is necessary to step up a higher stage of water management and increase the water saving techniques.A water laws is needed to strictly forbid excessive mining of ground water and provide unified development and allocation within the river basin for socioeconomic development and fragile ecological protection.Meanwhile,it is a possible way to control desertification,eliminate pauperization,convert farmland into forest and plant grass for stock raising.

Key words: water resources, PRA, desertification, pauperization, stock raising, Minqin Basin