【作者】 李守波；

【导师】 冯兆东；

【作者基本信息】 兰州大学 ， 自然地理学， 2007， 硕士

【摘要】 水资源是干旱区经济社会发展的限制资源，干旱区竞争性的水资源使用已经诱发了各种冲突，严重影响到区域的稳定、安全与发展。同时，非理性的人类活动过多地占用了水资源，使得干旱区原本脆弱的生态环境日趋恶化。为了对干旱区有限的水资源进行合理配置，维护生态系统的良性发展，首先必须准确的了解水资源的分布和变化。本文选取黑河下游为研究区，属于典型的内流河尾闾区，降水极少，非地带行植被完全依赖地下水而生存，而地下水主要依靠黑河来水补给。过去几十年来，由于黑河中上游地区人口增长、工农业发展，用水量增加，使研究区内湖泊干涸、植被大面积死亡。本文在地质和水文地质勘察及大量水位观测数据的基础上，选取1990年～1999年10年的观测数据，以月为时间步长，结合GIS技术和FEFLOW地下水运动模拟软件，对研究区地下水位进行了数值模拟，并做出了短期预测，在此基础上，利用野外植被—地下水关系调查资料，模拟水分胁迫下的植被生长状况。初步得到以下研究结果：1．在GIS软件的辅助下，依据钻孔资料，建立了研究区空间三维含水层系统和水文地质模型，在此基础上，建立了三维地下水流数学模型，运用FEFLOW有限单元地下水模拟软件，完成了地下水流数值模型的校正、模拟及预测工作。2．研究区地下水的主要补给来源是河流入渗，主要排泄途径是潜水蒸发。整体上看，研究区地下水补给排泄处于一种负均衡状态。3．1990年以来，研究区地下水位整体有下降的趋势，但变化量较小，地下水位的年际变化主要受到中上游来水量的影响，研究区本身的工农业耗水量较小，对地下水位影响不大。4．研究区地下水年内变化较明显，最大一年内变化量可达4m。这是由于中游来水量在一年四季并不是平均分配的。5．研究区植被的生长主要受到地下水的胁迫，利用野外调查的资料建立研究区典型植被的盖度与地下水位埋深的数学关系，由模拟出的地下水位得到研究区典型植被的潜在分布状况。研究结果表明，虽然进几年由于政策原因，黑河向下游放水量有所增加，但地下水仍处于负均衡状态，虽然目前下降趋势较小，但长此以往，地下水位仍会逐渐降低。因此，为了保证下游的地下水位稳定，黑河向下游的放水量仍需增加。更多还原

【Abstract】 Water resource is limiting factor of the economic and social development in arid area. Now the competitions of water resource in arid area have arisen out of lots of conflict, which severely influenced the stabilization, safety and development of the area. At the same time, the excessive exploitation of water resources has caused severe deterioration of the eco-environment. In order to assign water resource reasonably and protect the local ecosystem in arid area, it is necessary to assess the distribution and changes of water resources exactly.In this paper, we select the water table fluctuant belt of the lower reaches of Heihe River as a study area. In this area, there is little precipitation. The groundwater level which depends on the river water from middle reaches of Heihe River, determines the distribution of vegetation. In the last decades of years, because of the growth of population, the development of agriculture and industry, the water use has increased in the up and middle reaches of Heihe River, in turn a lot of problems has occurred in our study area, such as dried up of the lake, degradation of natural oasis and grassland.Based on the field investigation of geology and hydrogeology and observation data of water resources from 1990 to 1999, combined the GIS technology and the FEFLOW software, the groundwater level was simulated. Using the relationship between the groundwater level and vegetation coverage, the potential distribution of the vegetation was modeled.The main research results are as follows:1. With the assistance of GIS technology, a three-dimensional aquifer system and hydrogeological model was constructed based on a lot of geological data. According to this model, a mathematical model of groundwater flow, which is solved by finite element method with FEFLOW, was established. The groundwater level were modeled and predicted in the study area.2. The main source of groundwater in study area is the infiltration of river water and the drainage mainly results from evaporation of phreatic water. The drainage is far bigger than the source in the whole area.3. From 1990, the groundwater level has declined slowly. The annual variation is influenced due to the water use in up and middle reaches.4. The change of ground water level in year is large actually, some time more than 4 meter a year.5. The vegetation in study area is intimidated by groundwater lever. After building the relationship between the groundwater level and vegetation coverage base on the field investigate, the potential spatial distribution of the representative vegetation is calculated.The results show that, the river water is limitation for the study area; even it is increase in recent year. If water delivery from the middle reaches decreases, the groundwater level has continually declined and the vegetation will not be survival.更多还原