河西走廊地下水水化学特征及其演化规律

Goechemical Properties and Evolution of Groundwater beneath the Hexi Corridor, Gansu Province

根据新一轮国土资源实际调查资料 ,结合前人研究成果 ,以大气降水水质分析结果为背景值 ,系统研究分析了河西走廊地区的水文地球化学特征 ,揭示了走廊平原地下水水化学组分在水平和垂直方向的演化规律 ,论证了下游盆地 2 0 0m以下深层淡水的形成机理 ,提出了颇具典型意义的水文地球化学分带模式。

The Hexi Corridor in Gansu Province is located in arid northwest China, it is far away from oceans, the annual precipitation varies in a range of 50～250 mm, but the proportion of precipitation during the period from June to September occupies 62%～77% of the annual precipitation; the annual evaporation, however, is as high as 2 000～3 000 mm, and it is in serious shortage of water resources. A peculiar water resources system of “river-groundwater” forms due to the peculiar landforms. The relatively independent stream systems including the Shiyanghe River, Heihe River and Shulehe River are distributed from the east to the west and maintain the extremely vulnerable ecological environment and the sustainable economic development in the Hexi Corridor. In this paper, the hydrological features and geochemical properties of groundwater beneath the Hexi Corridor are systematically researched based on the new and previous data of land resources surveys and the predecessors’ achievements by analyzing the water quality of precipitation and groundwater. The horizontal and vertical evolution of the chemical components of groundwater beneath the Hexi Corridor is mainly revealed, the formation mechanism of fresh groundwater in aquifer deeper than 200 m beneath the basins in the lower reaches is demonstrated, and the zonal mode of the hydrological features and geochemical properties of groundwater beneath the Hexi Corridor, which has a typical significance, is put forward.