【作者】 尹立河；

【导师】 万力； 侯光才； 胡伏生；

【作者基本信息】 中国地质大学（北京） ， 地下水科学与工程， 2011， 博士

【摘要】 地下水的补给量反映了含水层的可更新能力,是地下水资源管理与合理开发利用的关键参数之一。在干旱和半干旱地区,地下水的补给量较小,定量估算地下水的补给量尤为困难。鄂尔多斯高原地处西北地区东部,区内蕴藏着丰富的能源和矿产资源,是国家级的能源基地。但由于区内降水稀少,蒸发强烈,地表水资源缺乏,地下水是最重要的供水水源。随着地区经济的发展,特别是近年来能源基地的建设,地下水开发程度不断提高,迫切需要对区域地下水资源进行有效管理。因此,研究含水层的补给,对实现鄂尔多斯地区地下水资源的合理开发利用具有重要的理论和实际意义。每种地下水补给量的估算方法都具有一定的局限性,只有综合使用多种方法进行地下水补给量的估算,才能提高估算结果的可靠性。因为每一种方法都需要大量的数据支撑才能完成,因此数据不足是限制利用多种方法估算地下水补给量的主要因素。鄂尔多斯地区经过10多年的水文地质勘查,积累了大量的野外数据,使得综合利用多种方法计算地下水的补给量成为可能。本次研究在前人工作的基础上,以多方法、多视角和多尺度为技术路线开展地下水的补给量研究,即综合使用了八种方法,从地表水、包气带水和地下水的视角,从局部和区域尺度对鄂尔多斯高原地区地下水的补给进行研究。本文首先利用大气降水和地下水的氢氧稳定同位素分析了地下水的补给源和补给机理;然后利用七种方法估算了地下水的多年平均补给量,包括氯元素守恒法、地下水水位动态法、基于饱和带和包气带的达西定律法、基于遥感的水均衡方法、经验法和基流分割法;最后依据全球地下水补给的研究实例,在前人已完成的9种方法总结的基础上,对另外8种常用的地下水补给量估算方法从时/空尺度和精度方面进行了总结,从四个方面提出了选取地下水补给量方法的基本原则。大气降水和地下水的氢氧稳定同位素表明,地下水沿当地雨水线分布,表明鄂尔多斯高原的地下水起源于大气降水;地下水的入渗机理有两种,分别是活塞式入渗和优先通道式入渗,以活塞式入渗为主。利用七种方法估算出的地下水的补给量具有一定的差异,一般来说最大值来自基于包气带的达西方法,最小值来自氯元素守恒法。造成这种差别的原因是不同的方法估算不同时空尺度的地下水补给量和不同的方法估算不同类型的地下水补给。对于研究区的九大地下水系统来讲,位于东部的地下水系统地下水的补给量比较大,位于西部的地下水系统补给量较小。根据以上各个系统地下水补给量的变化范围,估算出鄂尔多斯高原地下水的补给量为35.3亿方/年~65.2亿方/年。相对应的,地下水的补给量占降水量的14%~26%,同世界上其他类似地区的补给量具有可比性。最后本次研究从地下水补给的研究目的、地下水补给类型/机理、可利用/可获取的数据和时间/费用方面提出了地下水补给量估算方法的选取原则。对16种常用的地下水补给量估算方法,从地下水补给类型、时间尺度、空间尺度、精度、计算复杂程度、获取所需数据的难易程度和费用七个方面进行了综合评价,为选取地下水补给方法提供了参考依据。总体上来讲,基于地表水和地下水的补给量估算方法具有较长的时/空尺度,可用于区域地下水资源管理;而基于包气带的方法具有较小的时/空尺度,适用于以地下水污染调查为目的的补给量估算。更多还原

【Abstract】 Groundwater recharge represents the renewable rate of aquifers and is one the key parameters for the management and rational development of groundwater resources. In arid and semi-arid regions, quantitiative estimates of groundwater recharge are remely difficute as the rate is very low. The Ordos Plateau is located in the east part of NW China and abundant natural resources are stored in the study area that makes it the largest energe base in China. Due to the sparce precipitation, strong evaporation, and undeveloped surface water sources, groundwater is the most important source of water supply. With development of local economy and the construction of the energy base, groundwater mining will increase gradually that requires effective management of groundwater resources. Therefore, groundwater recharge estimation is ndded to proper management of groundwater and has a pratical and theoretical siganificance.Due to uncertainties associated with each method for estimating recharge, the use of many different approaches is recommended to constrain the recharge estimates. Based on previous studies, eight methods were used to quantify groundwater recharge in the Ordos Plateau. Firstly, isotopic data of precipitation and groundwater were used to identify source and mechanism of groundwater recharge. Secondly, seven methods were used to estimate groundwater recharge based on surface water, soil water and groundwater, including the chloride mass balance method, the water table fluctuation method, darcian method for saturated and unsaturated zones, the water balance method based on remote sensing, the empirical method and the baseflow separation method. Finally, based on cases in the world, the spatial and temperal features of 16 commonly used methods were summarized.The isotopic data of precipitation and groundwater show that groundwater scaters around the local meteoric water line, indicating groundwater is of meteoric orgion. There are two mechanisms of groundwater recharge, the piston type and the preferential type. The dominant mechanism is the piston type. There is great difference among results from different methods. Generally speaking, The largest recharge was usually estimated from the Darcian method for saturated zones and the smallest estimates were usually from the chloride mass balance (CMB) method. The difference is caused by two reasons. The first reason is that each method has its space/time scale. The second reason is the distinctions among the various terms used to refer to groundwater recharge. Generally, groundwater recharge rates are higher in the eastern part where the land surface is covered by permeable sand that is favorable to infiltration. The total recharge rate in the Ordos Plateau varies between 3.35 billon m~3/yr and 7.43 m~3/yr. The average values of recharge in this study as a whole ranges from 14 to 30 % of precipitation, which is acceptable for arid and semi-arid regions.The guidelines for selecting groundwater recharge methods were proposed with respect to study goals, groundwater recharge type/mechanism, available data, and time/fund. A comprehensive summarization was made for 16 methods in terms of recharge type, spatial scale, temperal scale, accuracy, computation complexity, data aqucisition and fund. Generally, methods based on surface water and groundwater have large spatial and temperal scale, suitable for groundwater resources management, while methods based on unsaturated zones have smaller spatial and temperal scale, suitable for contamination studies.更多还原