张掖盆地地下水位上升成因探析

Exploration & Analysis on Causes of Groundwater Level Rising in the Basin of Zhangye

张掖盆地80年代中期以来,地下水位处于区域性持续下降过程。2001年9月以来,盆地中北部地下水位停止下降开始出现上升趋势,特别是2005年9月以来,张掖盆地地下水位突然大面积上升。分析认为,地下水位上升主要是补给量的增加所致,主要增加途径有两个:一是本世纪以来,受全球气候转暖的影响,祁连山中西部的冰川融水和降水量明显增加,使祁连山区各河流出山径流量亦相应的增加,而出山河流作为盆地内地下水的主要补给来源,它的增加则意味着盆地地下水补给量的增大;二是黑河河床过水时间增加,在流经盆地第四系粗颗粒相强导水的洪积扇地带,大量"线状"入渗,使地下水补给量增大,引发沿河地下水位上升,导致向黑河排泄的黑河以东地下水径流受阻。

Since Zhangye Basin in the mid -80s, the groundwater level has been is dropping continually. Since Jantem- bet2001, the groundwater level in the mid - north of the basin stop dropping and start to rise up, especially since Jantember 2005, Zhangye basin the groundwater level in the Zhangye Basin rise suddenly in the large area. According to the analysis, the groundwater table rise is mainly due to the increase in supply, the main increase in two ways ： First, since this century, by the impact of global climate warming, the central and western Qilian Mountain glaciers melt the water and the precipitation increased significantly, so that Qilian Mountains trails of the rivers is also a corresponding increase in traffic, and out of the mountains the river basin as the main recharge source of groundwater, which means an increase in the volume of groundwater recharge basin increased; Second, Heihe river bed water time has increased, in flow through Quaternary basin with strong coarse water zone of the alluvial fan, a large number of ＂ linear＂ infiltration, so that increasing the volume of groundwater recharge, along the river caused the groundwater level rise, resulting in excretion of Heihe Heihe to the east of the groundwater runoff blocked.