【作者】 张二勇；

【导师】 万力；

【作者基本信息】 中国地质大学（北京） ， 水文学水资源， 2010， 博士

【摘要】 鄂尔多斯盆地内蒙古能源基地位于干旱半干旱地区,地表水短缺,地下水资源是能源基地规划建设的重要保障,由于生态环境脆弱,大规模开发地下水必将对地表植被产生影响,如何进行地表植被破坏的风险评价,破坏程度是否可以接受,是当地政府十分关心的问题。通过对遥感NDVI植被指数解译,结合野外典型路线和植被样方调查,详细分析了植被年际年内时空特征,并将植被划分为草甸草原、典型草原、荒漠化草原、草原化荒漠4类地带性植被和沙地、湿地2类非地带性植被。植被分布宏观上主要受大气降水的控制,湿地、洼地、梁地等微地貌对植被的生长也起着重要的控制作用,通过分析风积砂、风积砂盖风化基岩、粘土和粉土3种主要包气带含水率,指出风积砂包气带结构有利于水分的保存,对于干旱区植被生长十分重要。区域上地带性植被中的沙地植被总体上与地下水位埋深关系不大,非地带性植被中湿地植被与地下水关系密切。选择萨拉乌苏组地层分布区哈图才当水源地和白垩系地层分布区的浩勒报吉水源地为典型区,详细分析了地下水位、土壤含盐量和地下水矿化度与植被关系。综合前述研究,进行了基于地下水的植被敏感性区划,将其划分为敏感区和非敏感区,并将敏感区进一步划分为一级、二级和三级敏感区。利用GMS地下水数值模拟软件建立了研究区区域地下水数值模型,面积6.2万km~2,网格大小1000×1000m,剖分为322行249列,活动单元为62848个。以2006年为基准年,分别对地下水开采10年、20年、30年和50年的水位埋深进行了预测。在ArcGIS中对2006年8月的地下水位埋深图完成从等值线图到栅格数据的插值处理,离散为与植被覆盖率图像元一致的236×236m的单元网格,并统计建立地下水位与植被覆盖率的定量对应关系。通过未来不同时间点预测地下水位与植被覆盖率的耦合分析,对地下水开发条件下植被覆盖率变化状况进行风险评价,结果表明在地下水开采条件下,敏感区面积将缩小1.25万km~2,区内东南部和部分湖泊区的地表植被覆盖率将显著减小。更多还原

【Abstract】 Inner Mongolia Energy base is located in the Ordos Basin,and with the characteristics of arid and semi-arid climates. Due to the shortage of surface water, groundwater resources plays an important role for planning and construction of the energy base. For the fragile of ecological environment, large-scale exploitation of groundwater will impact on the vegetation. Thus the government is very concern how to evaluate the risk of vegetation damage, and whether the damage is acceptable or not.Through interpretation of remote sensing NDVI vegetation index, and combined with a typical field vegetation sampling survey, the interannual temporal and spatial characteristics of vegetation is analyzed detailedly. Then the vegetation is classified into four kind of zonal wegetations (Meadow steppe, typical steppe, desertification steppe, steppe desert) and two kind of azonal vegetations (Saudi, wetlands). The distribution of vegetation is macroscopically controlled by precipitation. The micro-topography such as wetlands, depressions, ridge also play an important control role on the growth of vegetation. The analysis of water content in three kinds of major unsaturated zone (sand, aeolian sand-covered weathered bedrock, clay and silt) indicates that aeolian sand vadose zone structure is favour of water conservation,and is very important for vegetation growth in arid areas.The sandy vegetation in regional zonal vegetation has little to do with groundwater depth, however the wetland vegetation in azonal vegetation is much related to groundwater. The relations of the water table, soil salinity and groundwater salinity to vegetation are analyzed detailedly in two typical water resource areas, one is the Hatucaidang water sources area in Salawusu Formation, and another is the Haolebaoji water resource in the Cretaceous strata. Integrated the above study, the sensitivity analysis of vegetation based on groundwater is carried out, the study area is divided into sensitive areas and non-sensitive areas. The sensitive areas are further divided into primary, secondary and tertiary sensitive areas.A numerical model of groundwater in the study area is built using GMS software, the area is 62,000 km~2 descretized 322 rows and 249 columns, the grid size is 1000×1000m, and the number of active cells is 62848. Based on the exploitation of groundwater in 2006, the groundwater table is predicted after exploitation of 10, 20, 30 and 50 years, respectively. The contour map of groundwater depth in Jun of 2006 is interpolated into raster data by using ArcGIS and to discrete vegetation coverage with the same image element unit 236×236m grid. The quantitative correspondence between the groundwater table and vegetation coverage is established statistically. By coupled analysis of the predicted groundwater water table and vegetation coverage in different time, the change feature of vegetation coverage under groundwater development is assessed. The results show that under the groundwater pumping conditions, the sensitive area will reduce the 12500 km~2, the vegetation coverage in the southeast of the study area and the lake area will be significantly reduced.更多还原