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浅层地下水动态是影响与制约我国西北干旱区黑河流域下游额济纳绿洲生态系统维持与修复的根本要素之一。本文通过梳理近年来额济纳绿洲浅层地下水动态变化的研究成果,结合典型观测站点的地下水水位与盐分自动监测(2010~2013年),回顾了该地区地下水监测站网的发展阶段,归纳了地下水年际动态变化特征及其空间变化类型,综述了其驱动因素。地下水动态长期观测的综合分析结果表明,该地区浅层地下水水位自20世纪50年代起开始下降,一直持续到20世纪90年代末期,2000年生态输水之后,地下水位整体得到回升。根据地下水时空动态变化特征及其驱动因素,可以将研究区划分为4个典型区域:以河道渗漏补给与植被蒸腾作用为主的河岸带;以区域地下水侧向补给与潜水蒸发作用为主的荒漠戈壁带;以地下水依赖型生态系统蒸散发与区域地下水侧向补给作用为主的天然绿洲区;以地下水开采与人工回灌作用为主的人工绿洲区。研究认为,间歇性河流的渗漏补给以及荒漠-绿洲生态系统的蒸散发是该地区浅层地下水系统动态变化的主要驱动因素。此外,人为配置地表水资源与局部开采地下水资源加剧了地表水与地下水之间的相互转化,改变了浅层地下水系统的天然动态。为了定量识别生态输水配置下的地表水-地下水相互转化及其与生态环境之间的关系,下一阶段的研究应以地表水/地下水系统动态联合监测为基础,深入开展关键水文过程野外试验研究,同时强化人类调控下的水文过程多尺度综合模拟。
The dynamic of shallow groundwater is one of the essential factors that influence and restrain the maintenance and restoration of the Ejina Oasis ecosystem in the lower reaches of the Heihe River in the arid region of northwestern China. In this paper, the research results of the dynamic changes of shallow groundwater in Ejina Oasis in recent years are summarized. Combined with the automatic monitoring of groundwater level and salt in the typical observation sites (2010 ~ 2013), the development stages of groundwater monitoring stations in this area are reviewed. The characteristics of the dynamic changes and their types of spatial change are summarized, and the driving factors are summarized. The comprehensive analysis results of long-term dynamic groundwater observation show that the shallow groundwater level in this area has been decreasing since the 1950s, and continues until the late 1990s. After the ecological water conveyance in 2000, the groundwater level has generally recovered. According to the characteristics of temporal and spatial dynamics of groundwater and its driving forces, the study area can be divided into four typical areas: riparian zone with river channel leakage recharge and vegetation transpiration; regional groundwater lateral recharge and submersion evaporation dominated Desert gobi belt, natural oasis with groundwater-dependent ecosystem evapotranspiration and regional groundwater lateral recharge, and artificial oasis with groundwater exploitation and artificial recharge. The study suggests that intermittent river leakage recharge and desert-oasis ecosystem evapotranspiration are the main driving forces for the dynamic changes of shallow groundwater system in this area. In addition, the artificial allocation of surface water resources and local exploitation of groundwater resources exacerbate the interconversion between surface water and groundwater and change the natural dynamics of shallow groundwater systems. In order to quantitatively identify the interconversion of surface water and groundwater under ecological water allocation and its relationship with the ecological environment, the next stage of research should be based on the dynamic joint monitoring of surface water / groundwater systems and conduct in-depth field experiments of key hydrological processes Research, at the same time strengthen the multi-scale synthetic simulation of hydrological processes under human regulation.