民勤盆地沙漠化、贫困化与水资源开发利用

以3S技术与PR A工具,通过对民勤盆地水资源状况的变化与沙漠化、贫困化发生发展规律对比研究,表明自然条件恶劣、基础设施弱是沙漠化、贫困化产生的内在因素,而人类活动则是强大的驱动力。石羊河流域武威盆地不合理的水资源利用造成进入民勤盆地水量日益减少,从20世纪50-70年代的4×108～6×108m 3下降到目前的0.5×108m 3,民勤盆地内大规模开采地下水导致水位下降达30m,同时造成地下水水质恶化、植被退化与沙漠化。沙漠化导致了贫困,贫困反过来加剧沙漠化,两者不断恶性循环。为此,要加强流域内水资源管理,严禁超采地下水;以“退耕还林,种草养畜”为出发点促进流域产业结构调整和节水;加大资金投入和科技扶贫,实现可持续发展。

The Impact of Water Resources Development on Desertification and Pauperization in the Minqin Basin

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.