表面活性剂增强修复地下水中PCE的砂箱实验及模拟

在石英砂充填的二维砂箱中开展表面活性剂（Tween 80）冲洗四氯乙烯（PCE）的修复实验,基于图像分析技术监测不同污染源区结构条件下NAPL相的去除过程.由于实验条件限制,实验中缺乏溶解相浓度数据.为此进一步基于UTCHEM数值模拟方法来理解NAPL相和溶解态之间的质量传输过程,并探讨表面活性剂浓度、注入速率等因素对修复效率的影响.综合砂箱实验和数值模拟结果表明：介质均质和非均质条件下会形成不同类型DNAPL污染源区结构,表现为离散状PCE与池状PCE体积比（GTP）差异.由于离散状污染物与表面活性剂的接触面积更大,更易被优先去除;初始GTP值越高,污染物的修复速率和修复效率也越高.增大表面活性剂浓度或提高表面活性剂的注入速率,虽然能提高DNAPL的修复速率,但会明显降低表面活性剂的修复效率,实验过程中修复效率降幅可达93%.线性驱动溶解模型可以有效地模拟表面活性剂修复DNAPLs过程,基于数值模拟方法选择合适的表面活性剂配比可有效的节省实际污染场址修复经费和时间成本.     

潜水含水层水位观测孔水位伪变化的观测与分析

结合CIRP试验场包气带的介质结构及渗透性特征，在S9孔进行了短期的孔中水位、孔口气压和温度测量，测量结果表明，观测孔水位波动与大气压变化有关，水位波动具有伪变化。水位伪变化对于试验场潜水位的监测有一定影响，因此，应对带有伪变化的水位观测结果进行必要的修正，以反映潜水位的真实动态。     

海潮引起的海底承压含水层系统中地下水位的波动——海底弱透水层的弹性储水效应

研究了由潜水含水层、在海底延伸的承压含水层和介于其间的弱透水层构成的滨海含水层系统中,弱透水层的弹性储水以及含水层的海潮荷载效应对承压含水层中的地下水位的影响.研究结果表明,当海底弱透水层延伸足够长时,它的弹性储水对承压含水层中的海潮引起的水头波动有增强作用.     

淮河流域平原区第四系含水层划分及特征分析

以中国地质调查局资助的《淮河流域环境地质调查》项目为依托,对收集到的区域基础地质和水文地质资料进行了二次开发。并根据近三年来淮河流域环境地质调查项目新取得的水文地质钻孔资料、水化学及同位素样品分析结果,科学地对淮河流域平原区第四系含水层进行了划分和印证,结合项目阶段研究成果,对淮河流域平原区第四系含水层特征进行了初步分析和总结。     

TRANSIENT RESPONSE FUNCTIONS FOR CONJUNCTIVE WATER MANAGEMENT IN THE SNAKE RIVER PLAIN,IDAHO1

ABSTRACT: Increasing demands on western water are causing a mounting need for the conjunctive management of surface water and ground water resources. Under western water law, the senior water rights holder has priority over the junior water rights holder in times of water shortage. Water managers have been reluctant to conjunctively manage surface water and ground water resources because of the difficulty of quantification of the impacts to surface water resources from ground water stresses. Impacts from ground water use can take years to propagate through an aquifer system. Prediction of the degree of impact to surface water resources over time and the spatial distribution of impacts is very difficult. Response functions mathematically describe the relationship between a unit ground water stress applied at a specific location and stream depletion or aquifer water level change elsewhere in the system. Response functions can be used to help quantify the spatial and temporal impacts to surface water resources caused by ground water pumping. This paper describes the theory of response functions and presents an application of transient response functions in the Snake River Plain, Idaho. Transient response functions can be used to facilitate the conjunctive management of surface and ground water not only in the eastern Snake River Plain basin, but also in similar basins throughout the western United States.     

Interconnectivity between the Superficial Aquifer and the Deep Confined Aquifers of the Gnangara Mound, Western Australia

Perth groundwater resources are obtained from three major aquifers that occur beneath the Perth metropolitan area: the Superficial aquifer, Leederville aquifer and Yarragadee aquifer. Each aquifer has a unique seasonal water level pattern controlled by soils, geomorphology and geology. Landuse is mainly responsible for variations in recharge; however, the hydraulic properties control aquifer response and water level pattern to a greater degree. Groundwater in the three aquifers is generally of very good quality except in localised areas. Salinity increases with depth and in direction of groundwater flow in the three aquifers. The best water quality is in the Superficial aquifer in the Wanneroo well field area. The geochemistry and stable isotope signatures from the three major aquifers revealed distinct water types that suggest very little hydraulic connection or mixing of waters between these aquifers at the present abstraction and recharge regimes. The results also show that the Leederville and Yarragadee aquifers were recharged during earlier cooler times while the Superficial aquifer is being recharged at present.     

后寨河流域岩溶含水层脆弱性及其对土地利用方式的响应

由于强烈的溶蚀作用,岩溶地区溶蚀裂隙、管道等高度发育,并相互贯通,形成岩溶区特有的地下、地表“双层空间”结构体系,地下空间成为地下水存储和运移的重要场所。岩溶地区由于土层浅薄或缺失,并且溶蚀裂隙、管道、落水洞、竖井等高度发育,使含水层更易受地表状况的影响,土地利用/覆被变化在很大程度上影响着地下水的水质、水量,岩溶水质的变化能集中反映人类活动胁迫下岩溶含水层脆弱性程度的增加。以典型岩溶单元--贵州普定后寨河流域为例,分析了流域水文地质背景下的岩溶含水层本质脆弱性,结合流域地下河水近20年的水化学资料,分析了含水层脆弱性对土地利用变化的响应。结果显示：土地利用/覆被变化、农业活动、城镇建设及居民活动都对地下水质变化有明显影响。因此,调整土地利用结构,恢复岩溶植被,改善生态环境是保护和改善岩溶水资源的重要途径。     

非水相硝基苯在含水层中的迁移释放规律

通过室内模拟实验,探讨了在非水相硝基苯污染含水层的条件下,其在含水层中的迁移及释放规律。迁移规律表明,非水相硝基苯并非在含水层中直接进行垂向迁移,而是一方面在自身重力作用下向含水层下部迁移,另一方面在地下水流的作用下随地下水同向运移,整体表现为随地下水流的侧向运移,并最终迁移至含水层底部。释放规律表明,非水相硝基苯在含水层迁移的过程中会向地下水大量释放,释放出的硝基苯在水流的作用下随地下水同向运移,污染源及迁移至含水层底部的非水相硝基苯均存在再次释放。     

Seawater Intrusion and Sustainable Yield of Basal Aquifers1

Liu, Clark C.K. and John J. Dai, 2012. Seawater Intrusion and Sustainable Yield of Basal Aquifers. Journal of the American Water Resources Association (JAWRA) 48(5): 861‐870. DOI: 10.1111/j.1752‐1688.2012.00659.x Abstract: Basal aquifers, in which freshwater floats on top of saltwater, are the major freshwater supply for the Hawaiian Islands, as well as many other coastal regions around the world. Under unexploited or natural conditions, freshwater and the underlying seawater are separated by a relatively sharp interface located below mean sea level at a depth of about 40 times the hydraulic head. With forced draft, the hydraulic head of a basal aquifer would decline and the sharp interface would move up. It is a serious problem of seawater intrusion as huge amounts of freshwater storage is replaced by saltwater. Also, with forced draft, the sharp interface is replaced by a transition zone in which the salinity increases downward from freshwater to saltwater. As pumping continues, the transition zone expands. The desirable source‐water salinity in Hawaii is about 2% of the seawater salinity. Therefore, the transition zone expansion is another serious problem of seawater intrusion. In this study, a robust analytical groundwater flow and salinity transport model (RAM2) was developed. RAM2 has a simple mathematical structure and its model parameters can be determined satisfactorily with the available field monitoring data. The usefulness of RAM2 as a viable management tool for coastal ground water management is demonstrated by applying it to determine the sustainable yield of the Pearl Harbor aquifer, a principal water supply source in Hawaii.