新疆玛纳斯河流域典型剖面地下水位动态分析

新疆玛纳斯河流域是水资源开发力度较大、经济发展水平较高的地区。对玛纳斯河流域13眼监测井组成典型剖面的2010年-2014年监测数据进行趋势性分析得出,整个监测剖面地下水位呈持续下降趋势,上部冲洪积平原单一潜水区地下水位下降速率为0.65~0.83m/a(平均0.74m/a);中部潜水溢出带地下水位下降速率为1.12m/a;冲积细土平原区上部、下部地下水位下降速率分别为0.59~3.07m/a(平均1.77m/a)和0.35~3.98m/a(平均2.41m/a);地下水位年下降速率由上游至下游呈增大趋势。在年内变化上,冲洪积平原单一潜水区埋深变化为"降-升-降";潜水溢出带及以北区域为"升-降-升"。地下水动态类型除上部冲洪积平原单一潜水区为入渗-径流型外,潜水溢出带至冲积细土平原区均为开采型。区域地下水位持续下降使现状地下水埋深(5.89~67.46m)远大于6.0m荒漠化临界埋深,生态环境面临恶化。通过对石河子市、玛纳斯县水资源利用分析得出,地下水位持续下降的因素是地下水超采、区域水资源高效利用使地下水补给量减小双重作用下形成的。提出必须科学规划用水,缩减灌溉面积和地下水开采量,开展生态补偿机制,使流域经济社会可持续发展。

Analysis of groundwater table regime along the typical cross-sections of the Manas River Basin, Xinjiang

Manas River Basin of Xinjiang is a region with a high exploitation level of water resources and a high level of economic development.Based on the trend analysis of the monitoring data of a typical profile constituted by 13 monitoring wells from 2010 to 2014 in Manas River Basin,we found that the groundwater level of the entire profile showed continual declination.The decreasing rate of groundwater level in the single unconfined groundwater area of the upper alluvial plain was 0.65-0.83 m/a (averaging 0.74 m/a);the decreasing rate of groundwater level in the middle overflow zone was 1.12 m/a;the decreasing rates of groundwater level in the upper part and lower part of the alluvial fine soil plain area were 0.59-3.07 m/a (averaging 1.77 m/a) and 0.35-3.98 m/a respectively (averaging 2.41 m/a).The annual decreasing rate of groundwater level tended to increase from upstream to downstream.In terms of the annual variance of groundwater level,the change of groundwater depth in the alluvial plain was down-up-down;the change in the overflow zone and its northern area was up-down-up.The groundwater dynamic type in the single unconfined groundwater area of the upper alluvial plain was infiltration-runoff type,while in the overflow zone and the alluvial fine soil plain area was exploitation type.Because the regional groundwater level continued to decline,the present groundwater depth (5.89-67.46 m) was much larger than the critical depth of desertification (6.0 m).The ecological environment was deteriorating.Based on the analysis of water resources utilization in Shihezi City and Manas County,the continual declination of groundwater level was caused by both groundwater overexploitation and effective utilization of regional water resources which reduced the groundwater recharge.Finally,we proposed that water resources utilization must be scientifically planned and the area of irrigation and groundwater exploitation quantity must be reduced,while the mechanism of ecological compensation must be carried out,so as to ensure sustainable economic and social development in the basin.