河套灌区粮食水足迹与虚拟水净输出时空演变

为了正确评价灌区内水资源使用对改善现有水资源管理的影响,文中引入水足迹与虚拟水概念,同时考虑降雨和灌溉用水,计算了1960—2008年内蒙古河套灌区粮食水足迹与虚拟水净输出量的时空变化,进一步评价了灌区水资源在区域内和区域间的分配.结果表明：1960—2008年河套灌区粮食水足迹由3.534×109m3减小为1.634×109m3,自2000年灌区粮食虚拟水净输出量呈下降态势,两者构成均以蓝水为主（90%）;空间分布上,河套灌区中部地区（杭后、临河和五原）的粮食水足迹和虚拟水净输出量较大,而其他地区（磴口和前旗）较小;1960—2008年,粮食生产用水在灌区用水总量中所占比例呈显著下降趋势,年均下降1.07%.粮食生产用水的大部分以虚拟形式输送到灌区外部,该比例近年有所降低,但2008年仍高达76.22%.未来河套灌区应注重绿水和蓝水资源利用效率的提高.该研究为灌区水资源管理宏观政策的制定和可持续发展的实现提供理论依据.

Temporal and spatial variation of grain production water footprint and net virtual water export in Hetao Irrigation District

Properly evaluating utilization of water resources in an irrigation district is of great significance for improvement of the existing water resources management; thus two concepts,namely water footprint and virtual water are introduced and their temporal and spatial variations are analyzed in Hetao Irrigation District from 1960 to 2008.The analysis is focused on green and blue water and based on two indexes,such as the ratio of water for grain production to totally consumed water,R1,and the ratio of virtual water for grain export to water for grain production,R2.The results show that the grain water footprint is decreased to 1.63 × 109m3in 2008 from 3.53 × 109m3in 1960,and the net virtual waterexport demonstrates a decreasing trend in 2000s.Besides,the blue water accounts for 90% of both the grain water footprint and net virtual water export.The grain water footprint and net virtual water export in the central irrigation district（Hanghou,Linhe and Wuyuan） are larger than those in the other areas（Dengkou and Qianqi）.Further,R1is decreased at an averaged rate of 1.07% during the studied period,while R2is showed a fluctuating rise.The value of R2is decreased in 2000s,but it still is as high as 76.22% in 2008.In future,water use efficiency of green and blue water should be improved in Hetao Irrigation District.This study can provide a theoretical basis for policy-making in water resources management and sustainable development of an irrigation district.