地下水运动数值模拟过程中边界条件问题探讨

本文对地下水运动数值模拟过程中边界条件的涵义 和处理方法进行了分析和讨论。阐述了边界条件所包含的双重意义。指出随着人类活动影响 强度的日益增大，边界条件的处理要面临一些新的更为复杂的问题。在模型预报之前必须首 先对边界条件做出预报。边界条件的预报既要考虑自然因素的作用，同时也要考虑人类活动 (人工开采和人工补给)的影响及由于邻区水流条件变化而产生的耦合效应。之后，给出了两 个应用实例。     

尾矿堆场对地下水及其水质影响的联合模拟研究

矿产资源开发利用后的废弃物堆场常处水文地质条件复杂、区域内外边界不规整的地带。为了客观评价堆场渗漏对地下水及其水质的影响,本文提出了适宜于复杂水文地质条件、复杂内外边界条件的地下水与地下水中污染物分布规律联合模拟分析的非构造网格FVM数值模型,通过在某化工行业尾矿堆场渗漏评价的具体应用,取得了很满意的结果。     

Optimal Locations of Groundwater Extractions in Coastal Aquifers

A regional water supply management model for coastal aquifers was developed. One of its outcomes is the definition of the optimized locations for groundwater withdrawal. Such a tool permits the analysis of alternative plans for groundwater extraction and the sustainable use of water resources in a coastal aquifer subject to saltwater intrusion. The principal components are the evolutionary optimization and the analytical/numerical simulation models. The optimization technique looks for the best well locations taking into consideration the economic results and the satisfaction of the societal water demand. However these two concerns are conditioned by trying to control the saltwater intrusion, i.e., preserving the environmental equilibrium. The simulation model uses the governing mathematical equations for groundwater movement to find the interface between freshwater and saltwater. Because of the non-linearity in the system and the possibility of a jumping interface, a security distance was defined. This is a controlling variable which can be set by the decision makers. The model was applied to a typical case with interesting results. For example, diagrams showing the relationship between the location of the wells and the security distance(s) are of importance to the managers. It was also crucial to have an understanding of the tradeoffs between groundwater withdrawals, positions of the wells from the coast line, and the security distance. The model was also applied to a real case in order to relate the extractions, distances and artificial recharge (not presented in this paper).     

地下水污染修复的活性渗滤墙技术

活性渗滤墙是一种现场修复受污染地下水的新型技术，具有原理简单，施工方便，运行费用低廉等特点，活性渗滤墙垂直于地下水流动方向设置，当地下水流通过活性渗滤墙时，污染物与墙体材料发生化学反应，从而达到环境修复的目的。文中综述了活性渗滤墙技术的修复机理和实际应用，大量研究表明，应用金属铁作为活性渗滤墙材料，可以去除地下水中的重金属以及有机污染物，目前活性渗滤墙已经在世界各地应用，是一种非常有发展前景的环境污染修复技术。     

山前平原地下水侧向补给潜力空间变异模拟

SWAT模型利用分辨率较高的DEM数据,可以估算山前地下水侧向补给的空间变异,并可以计算不同降水年型下补给量的差别。模拟需要对研究区进行填洼、流向确定、汇流和河网水系的提取四步运算,并对河道临界支撑面积的取值进行分析。分别模拟了平水年和丰水年两种降雨年型下研究区13个出水口的地下水侧向补给潜力。在研究区,由于地形的变化,导致山与平原交接断面上出水口的集水面积变异非常大,因此山前平原所接受的地下水侧向补给量的空间变异也非常大。不同的降雨年型下,降雨量转化为地下水侧向补给量的比例也不同。平水年的转化比例较小,丰水年的转化比例较大。应用SWAT模型时,与ArcView的拓展模块有机结合,可以更方便提取完整的大流域,划分出合理的子流域。     

吉林省中西部地区地下水开发策略

吉林省中西部地区地下水资源的开发，应以中长期保护利用为第一出发点，并统筹规划，合理安排。文中依据这种思想提出了该地区中长期规划思想、可开采量、评价方法、单井控制面积、水费征计标准。     

Contamination of the Chalk Aquifer by Chlorinated Solvents: A Case Study of the Luton and Dunstable Area

A detailed investigation of contamination by chlorinated solvents of the Chalk Aquifer underlying the towns of Luton and Dunstable was undertaken to assess the extent, causes and mechanisms of pollution. The research programme incorporated land-use surveys, regional groundwater surveys, monitoring of groundwater abstraction points and aquifer profiling by means of the drilling of observation boreholes, the analysis of the recovered core material and the depth sampling of these and other boreholes.
Low-level solvent contamination of the Chalk Aquifer was found to be widespread with 'hotspots'of higher concentrations. At the drilling sites, both the saturated and unsaturated zones were contaminated with solvents, although free product was not observed. The presence of an additional contaminant, oil, at some sites was noted to influence the distribution of solvents within the aquifer.
Clean-up of the aquifer is not a practical option, and treatment of the groundwater at the abstraction points has been adopted.     

Impacts of green roofs and rain water use on the water balance and groundwater levels in urban areas

Ohne Zusammenfassung

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Impacts of green roofs and rain water use on the water balance and groundwater levels in urban areas

     

基于级差最大化组合赋权法的地下水功能评价

针对地下水功能评价中单独采用主观赋权法或客观赋权法存在的问题,结合二者的优点,采用基于主观赋权的层次分析法与客观赋权的熵权法相结合的级差最大化组合赋权法评价地下水功能,并通过计算不同赋权方法权重结果与平均值的相对偏差来衡量级差最大化组合赋权法的准确性。将该方法应用于伊犁河谷西北部平原区浅层地下水功能评价,评价结果基本符合评价区实际情况,验证了该评价方法在地下水功能评价中的可行性。     

河套盆地晚更新世以来黄河改道对高砷地下水分布的控制机制

针对河套盆地开展了历时多年的水文地质环境地质调查,利用采集的298组浅层地下水样品以及收集并甄选的382个水文地质钻孔记录分析发现:河套盆地内95%的高砷地下水(As质量浓度10μg/L)集中在黄河决口、改道形成的古河道影响带及黄河决口扇裙带。其中,盆地南部首次发现了较为集中的高砷地下水,其分布范围与黄河北岸的晚更新世以来黄河决口、改道形成的4个大型决口扇,在空间上有着良好的对应关系。黄河古河道带及决口扇裙带表现为较强的还原环境及蒸发浓缩作用以及较弱的地表水补给强度。受pH值、含铁氧化物的还原性溶解等因素影响,决口扇裙带浅层地下水中砷的含量略低于平原中部黄河古河道带。结果表明:黄河古河道带及决口扇裙带特定的沉积环境控制着地下水的水文地球化学过程,进而对高砷地下水的分布具有决定性的作用。