【作者】 许翔；

【导师】 魏国孝；

【作者基本信息】 兰州大学 ， 水文学及水资源， 2011， 硕士

【摘要】 通过对梨园河流域的水文地质条件及区域地下水演化历史信息资料的整理,综合利用水化学、同位素和反向水文地球化学模拟技术,对研究区内地下水水化学演化和水化学形成机理进行了研究,结合当地大气降水的同位素及水化学特征,基本找出研究区地表水与地下水的补给特征、地下水水流路径特征,示踪地下水运动及水文地质作用过程。首先,水化学研究表明梨园河流域水化学分布具有明显的分带特征,浅层地下水受到了一定程度的硝酸盐污染,识别了沿水流路径演化过程中的一些主要规律：蒸发浓缩作用；石膏、白云石的溶解以及方解石的沉淀；阳离子交换作用以及混合过程。其次,根据张掖站每月雨量同位素加权平均及年平均计算得到当地大气降水线(LWML):δ2H=7.05δ18 O+2.03(‰,R2=0.61)。最后,基于水化学、同位素特征分析,以同位素为重要约束变量利用PHREEQC进行水流路径模拟,研究表明区内地表水、地下水的相互作用非常活跃,且细土平原区域极有可能是深层地下水与浅层地下水相互作用高度活跃的区域,具有极大的环境指示意义,但是这种混合转化又不是单一的；水流方向的总体趋势是明确的,局地水循环可能是研究区地下水演化的又一特征。本次研究有效地揭示了地下水的演化特征并进行了水文地球化学模拟,最终获得梨园河流域地下水演化规律,为该地区不论是水文循环机理研究还是水资源的利用与保护都提供了重要的参考。更多还原

【Abstract】 In this study, we analysed both groundwater evolution and hydrogeochemistry mechanisms after collecting and sorting hydrogeology conditions and history information of local groundwater. We also found out the processes of recharge characters of surface water and groundwater, groundwater flow paths, hydrogeology effects on groundwater and groundwater movement by analysing the characteristics of deuterium and oxygen-18 isotopes and hydrochemistry. There are three main parts of this study. Firstly, the distribution of hydrochemistry is in striation evidently and some shallow groundwaters are contaminated by nitrate. Along the flow path, there are several physical and chemistry processes like strong evaporation, dissolution of dolomite and gypsum, deposition of calcite, cation exchange and mixing process. Secondly, Local Meteoric Water Line (LMWL):δ2H=7.05δ180+2.03(‰, R2=0.61) of Liyuan River Basin was reconstructed by weighted average of water isotopes in monthly rainfall records of Zhangye station. Finally, we ran hydrochemistry model (PHREEQC inverse modelling) for groundwater flow paths analysis by setting water isotopes as important bound variable. Results indicated that there are intense interactions between surface water and groundwater. And fine soil plain is possible the area for those interactions, which may make big sense for environmental indication. However, those interactions are not simple mixing or transformation. We knew the flow direction in total clearly, but local small water circulations could exist in some areas.This research effectively showed hydrogeochemistry characteristics of Liyuan River Basin. Groundwater evolution fully reached by PHREEQC inverse modelling at last. This is a very essential supplement for hydrology cycle research of this area. And it is also a good reference for sustainable water use in this place or other arid and semiarid basins.更多还原