Groundwater recharge of carbonate aquifers of the Silesian-Cracow Triassic (southern Poland) under human impact

A Triassic carbonate unit has been intensively drained by zinc and lead ore mines and numerous borehole fields since the nineteenth century. Its groundwater recharge has increased due to: pumping of water from boreholes, mining activity, and urbanization. An approach to determine the amounts of the recharge at a variety of spatial scales is presented in the paper. Different methods were used to identify and quantify recharge components on a regional and local scale: mathematical modelling was performed for four aquifers included in an aquifer system, an analytical estimation based on the assumption that an average recharge is equal to the average discharge of the hydrogeological system—for six man-made drainage centres, and the method of water level fluctuation (WLF) was applied in one observation borehole. Results of modelling have been supplemented by observation of environmental tracers (δ¹⁸O, δ²H, ³H), noble gases temperatures, and ⁴He_exc in groundwater. The regional aquifer’s current recharge according to estimations performed by means of modelling varies from 39 to 101 mm/year on average. Depending on the aquifer site the average precipitation ranges from 779 to 864 mm/year. In the confined part of the aquifer average recharge ranges from 26 to 61 mm/year. Within outcrops average recharge varies from 96 to 370 mm/year. Current recharge estimated by the analytical method for man-made drainage centres varies from 158 up to 440 mm/year. High values are caused by different recharge sources like precipitation, induced leakage from shallow aquifers, and water losses from streams, water mains and sewer systems. Pumping of water, mining and municipal activities constitute additional factors accounting for the intensified recharge.     

The interference of a deep thermal system with a shallow aquifer: the case of Sodere and Gergedi thermal springs, Main Ethiopian Rift, Ethiopia

An integrated survey program involving geological, hydrogeological and geophysical techniques has been employed to characterize the aquifer geometry, recharge and circulation dynamics of thermal springs within a shallow aquifer system in Ethiopia. The selected springs for the case study are Sodere and Gergedi, which are situated within the tectonically active Main Ethiopian Rift (MER). Geologically, the studied springs are located on Plio-Quaternary volcanic rocks. The geophysical results indicate the presence of subsurface weak zones represented by extensional tectonics and weathering zones which are responsible for thermal water circulation and facilitate recharge from the adjacent surface-water bodies. The structures inferred by the resistivity survey, both sounding and electrical tomography, present contrasts in rock resistivity response. The anomalous zones in the magnetic data are in good agreement with the zones that are revealed by geological mapping and surface manifestation of the thermal water discharge zones. The shallow aquifer of the central MER is under the influence of thermal water, which increases the groundwater temperature and mineral content.     

Assessing Groundwater Resource Vulnerability by Coupling GIS-Based DRASTIC and Solute Transport Model in Ajmer District,Rajasthan

Groundwater aquifer vulnerability has been assessed by incorporating the major geological and hydrogeological factors that affect and control the groundwater contamination using GIS-based DRASTIC model along with solute transport modeling. This work demonstrates the potential of GIS to derive a vulnerability map by overlying various spatially referenced digital data layers (i.e., depth to water, net recharge, aquifer media, soil media, topography, the impact of vadose zone and hydraulic conductivity) that portrays cumulative aquifer sensitivity ratings in Kishangarh, Rajasthan. It provides a relative indication of groundwater aquifer vulnerability to contamination. The soil moisture flow and solute transport regimes of the vadose zone associated with specific hydrogeological conditions play a crucial role in pollution risk assessment of the underlying groundwater resources. An effort has been made to map the vulnerability of shallow groundwater to surface pollutants of thestudy area, using soil moisture flow and contaminant transport modeling. The classical advection-dispersion equation coupled with Richard’s equation is numerically simulated at different point locations for assessing the intrinsic vulnerability of the valley. The role of soil type, slope, and the land-use cover is considered for estimating the transient flux at the top boundary from daily precipitation and evapotranspiration data of the study area. The time required by the solute peak to travel from the surface to the groundwater table at the bottom of the soil profile is considered as an indicator of avulnerability index. Results show a high vulnerability in the southern region, whereas low vulnerability is observed in the northeast and northern parts. The results have recognized four aquifer vulnerability zones based on DRASTIC vulnerability index (DVI), which ranged from 45 to 178. It has been deduced that approximately 18, 25, 34, and 23% of the area lies in negligible, low, medium and high vulnerability zones, respectively. The study may assist in decision making related to theplanning of industrial locations and the sustainable water resources development of the selected semi-arid area.     

Hydrogeological characterization of a carbonate aquifer using geophysical and geochemical approach: case of the Krachoua Formation in Tataouine area,Southern Tunisia

An integrated hydrogeological investigation involving geological surface data, well data (lithostratigraphical and piezometric data) and the vertical electrical sounding (VES) method was carried out in Tataouine area, Southern Tunisia to characterize the hydrogeology and the geochemistry of the Krachoua Formation aquifer. The electrical data were used to differentiate lithostratigraphic units and characterize their hydrogeological potentialities. Major elements contents within groundwater samples were assessed and some plots and diagrams have been established in order to investigate the hydrochemical properties of this aquifer and the origin of its mineralization. The Krachoua aquifer exhibits a general drawdown of the piezometric level from 2004 to 2015 reflecting a dramatic decrease in groundwater resources due to increased groundwater abstraction during the last decades. Flow directions shows that the recharge of this aquifer considered as a free aquifer is directly ensured by rainfalls over the outcropping fractured limestones. The geometry of the Krachoua Formation aquifer is tectonically controlled and structured in horst and graben features that impacted greatly the hydrogeology and the hydrodynamics of the area. Subsequent thickness and facies variations within this aquifer influenced the reservoir quality and the groundwater flows. The increased values of salinity to the northwest of the study area seems to be mainly related to the dissolution of the Upper Liassic gypsum of Mestaoua Formation which outcrops widely and can be dissolute easily by meteoric water and contaminate the Krachoua aquifer. This fact is also supported by the sulfated and calci-magnesian chloride facies of this aquifer related to the dissolution of evaporitic rocks (gypsum, anhydrite, and halite). However low salinity values are recorded within the zone where these evaporitic rocks are relatively deep.     

基于地质条件的海绵城市适宜设施类型选择

海绵城市建设过程中,根据城市所处区域的地形地貌、地质条件等特点,选择适宜的海绵城市设施类型是其关键问题之一。本研究以某航空港海绵城市拟建片区为研究对象,在广泛收集和分析研究区有关地质、水文地质资料的基础上对海绵城市建设影响因素进行分析,并建立指标评价体系;从地表适宜性、包气带适宜性以及含水层适宜性3个方面,选择7个影响因子作为海绵城市建设地质适宜性评价指标,利用层次分析法对各影响因子进行权重赋值;在对各影响因子分级评分的基础上,利用ARCGIS按照建立的指标评价体系进行加权叠加评分,根据评分结果选择海绵城市雨水管理的适宜设施。研究表明：地质与水文地质条件对雨水的入渗、地下储存和传导有显著影响,海绵城市建设应充分利用地质与水文地质条件,合理设计低影响开发（LID）工程设施的类型和建设方案;其中,包气带渗透性能和包气带厚度是海绵城市建设地质适宜性的最主要因素,决定着以雨水入渗为主要功能的LID设施建设的适宜性。     

临江市老三队地热水形成条件及成因探讨

介绍了临江市老三队地热水的自然地理概况和区域地质水文地质概况,分析了它的物理化学特征,含水岩组,补、径、排条件以及热储层、隔热盖层、地热水源等,最后探讨了其形成条件及成因。     

淄博孝妇河源区地下水资源的开发利用研究

在分析淄博市孝妇河流域源头的南神头－窑广地下水富水区水文地质条件的基础上，应用数值模拟方法建立了该区的地下水流模型，并根据当地的资源需求建立了地下水动态预测模型，研究了可能通过该区出流边界补给下游地区地下水的侧向排泄量。应用系统工程学和运筹学理论，以“开采费用最小”为目标函数，以研究区的需水量及开采井的供水作为约束条件，建立了该区的地下水最优控制模型。通过优化地下水开采布局对出流边界的流量进行了研究，既为富水区的地下水资源利用确定开采方案，又科学地评价地富水区北部边界对下游地区的地下水侧向补给量。     

Modelling of ground water recharge-potential in the hard-rock Aravalli terrain,India: a GIS approach

Modelling of ground water recharge-potential in hard-rock areas principally aims at water-resource evaluation. Various techniques are available to assess recharge-potential, and their capability in estimating recharge is also variable. However, the water level fluctuation method is found capable in computing actual ground water recharge. Demarcation of ground water recharge-potential zones in arid and semi-arid regions is of great importance for human survival and sustainable development. Remote sensing and geographic information systems (GIS) techniques have been widely used by numerous researchers for qualitative assessment of ground water potential of a basin or terrain. In the present study, a GIS-based water table fluctuation method has been attempted for quantitative modelling of ground water recharge of the hard-rock Aravalli terrain. This GIS-based model is further used to evaluate recharge-potential of the terrain by integrated assessment of infiltration capacity, normal rainfall, and its cumulative frequency.     

人工回灌条件下多组分溶质的反应迁移模拟

人工回灌技术在我国水资源管理中占据重要地位,但是其实施对地下水环境质量也造成了较大的影响。如何保障人工回灌条件下地下水环境质量的安全稳定性,已成为人工回灌技术发展的瓶颈。以上海市某人工回灌试验场为例,结合试验场的地质、水文地质勘探结果,以TOUGHREACT为数值模拟平台,模拟预测人工回灌条件下地下水中多组分溶质的迁移转化过程。模拟结果表明：地下水化学成分主要受混合作用、阳离子交换吸附作用及含水层矿物相溶解-沉淀作用等影响;含水介质中石英、白云石、钾长石、钠长石及蒙脱石发生溶解,方解石发生沉淀,伊利石与高岭石则先溶解后沉淀,但各矿物相反应量极其微弱;按不同压力方案回灌,水位恢复速率随压力增大而加快,但地下水中化学成分变化趋势几乎不受压力影响。     

Hydrogeology of thermal waters in Viterbo area, central Italy

A conceptual hydrogeological model of the Viterbo thermal area (central Italy) has been developed. Though numerous studies have been conducted on its geological, geochemical and geothermal features, there is no generalized picture defining the origin and yield of the hydrothermal system. These latter aspects have therefore become the objectives of this research, which is based on new hydrogeological and geochemical investigations. The geological setting results in the coexistence of overlapped interacting aquifers. The shallow volcanic aquifer, characterized by fresh waters, is fed from the area around the Cimini Mountains and is limited at its base by the semiconfining marly-calcareous-arenaceous complex and low-permeability clays. To the west of Viterbo, vertical upflows of thermal waters of the sulphate-chloride-alkaline-earth type with higher gas contents, are due to the locally uplifted carbonate reservoir, the reduced thickness of the semiconfining layer and the high local geothermal gradient. The hot waters (30–60°C) are the result of deep circulation within the carbonate rocks (0.5–1.8 km) and have the same recharge area as the volcanic aquifer. The upward flow in the Viterbo thermal area is at least 0.1 m³/s. This flow feeds springs and deep wells, also recharging the volcanic aquifer from below.     

Influence of an anticline structure on hydrogeological functioning and aquifer interactions in a multilayered aquifer system: the case of Villagrains-Landiras anticline (Gironde,France)

Geological deformations like anticlines have a prominent role in aquifer system functioning. Structural deformations control erosion patterns, areas of nondeposition, lateral facies variations and thickness variations. The nature and geometry of geological bodies have a major impact on the aquifers and interconnections between them. To characterize these features and to quantify their influence on overall hydrogeological functioning, a multidisciplinary approach is proposed at a local scale. In southwestern France, the Aquitaine Basin contains a regional multilayered aquifer system affected by numerous anticlines. The Villagrains-Landiras anticline is a major anticline of the Aquitaine Basin, and near its axis is the subcropping Cenomanian aquifer; thus, the Cenomanian aquifer has potential for drinking water supply. An extensive research program was developed, including reconnaissance drilling, water level measurements, geochemical analyses, and petrophysical tests, and the results were combined with existing data. This integrated work precisely defined the complex architecture of the aquifer and confining units linked with the uplift and the polyphase erosion of the anticline. It resulted in the characterisation of the deposits’ geometries, lithology, and aquifer properties. The areas of aquifer interconnection have been defined and recharge flows have been estimated. A new groundwater circulation pattern constrained by isotopic water residence times was developed. A new geological model was built, which enables a rethink of the local functioning of the aquifer targeted for drinkable-water supply, but also it allows an understanding of the importance of anticline structure on the recharge conditions of the aquifers of this regional multilayered aquifer system.

     

基于MODFLOW参数不确定性的地下水水流数值模拟方法

考虑到模型不确定性引起的地下水数值模拟不确定性对模拟过程的影响,在简要介绍含水层水文地质参数变异性研究进展和地质统计学的基础上,基于常用的确定性地下水流数值模拟软件MODFLOW开发了MODFLOW-Gslib软件,相较于传统的数值模拟方法,将地质统计学与数值模拟结合的方法能够模拟非均质含水层中的参数变异性问题。将MODFLOW-Gslib软件运用于模拟实例中,选择常见的不确定性因素进行模拟,并对其模拟产生的数据进行统计分析,结果表明,软件转化后的参数符合水文地质参数不确定性的相关特征;与原模拟结果进行对比,该软件能够更加真实地刻画含水层参数变异性特征。     

New system for the assessment of annual groundwater recharge from rainfall in the United Arab Emirates

In this study, the first groundwater recharge map for United Arab Emirates (UAE) was developed using the recharge potential and water table fluctuation methods. Recharge potential estimates were made using information about infiltration rate, soil type, ground slope, geological and hydrogeological factors, and the availability of rainfall harvesting infrastructure and were validated by measurements of water table rise in alluvial aquifers in wadis. Based on this information, the total recharge in the UAE is estimated to be about 133 million cubic meters per year (MCM/year). Annual recharge rates are calculated to vary between 1 and 28% of precipitation in the different regions of UAE depending on several natural and manmade parameters including, among others, recharge enhancing infrastructure. Estimates from the two methods are 98% in agreement; which suggests that the recharge potential method is suitable for estimating aquifer’s recharge in UAE and arid regions. The water table fluctuation method was found to be more suitable for assessing recharge through gravel plains and wadis in mountainous areas.     

Characterization of the groundwater flow system in the hillside and coastal aquifers of the Mersin-Tarsus region (Turkey)

In the region between Mersin and Tarsus cities, located along the Mediterranean Sea coast in southern Turkey, the demand for groundwater has increased dramatically as the available surface water supplies have already been developed. Fundamental information is required to characterize the existing groundwater system in this area in order to establish a sustainable groundwater-use policy. For this purpose, hydrochemical and environmental isotopic data were collected and integrated with available geological and hydrogeological information to develop a conceptual model of the system. Results, backed up mainly by depleted stable isotope composition and infinitesimal tritium content, suggest that most of the groundwater along the coastal zone is supplied by the neighboring mountain belt while local precipitation has also contributes to aquifer recharge. The validation of the conceptual perspective by a steady-state numerical groundwater flow model reveals that about 90% of the recharge to the aquifer system is supplied by the deep flow of karstic groundwater fed from the Taurus Mountains. Monitoring of changes in the recharge regime of the mountain sector seems to be critical in establishing future groundwater use policies.     

Three-dimensional hydrostratigraphical modelling to support evaluation of recharge and saltwater intrusion in a coastal groundwater system in Vietnam

Saltwater intrusion is generally related to seawater-level rise or induced intrusion due to excessive groundwater extraction in coastal aquifers. However, the hydrogeological heterogeneity of the subsurface plays an important role in (non-)intrusion as well. Local hydrogeological conditions for recharge and saltwater intrusion are studied in a coastal groundwater system in Vietnam where geological formations exhibit highly heterogeneous lithologies. A three-dimensional (3D) hydrostratigraphical solid model of the study area is constructed by way of a recursive classification procedure. The procedure includes a cluster analysis which uses as parameters geological formation, lithological composition, distribution depth and thickness of each lithologically distinctive drilling interval of 47 boreholes, to distinguish and map well-log intervals of similar lithological properties in different geological formations. A 3D hydrostratigraphical fence diagram is then generated from the constructed solid model and is used as a tool to evaluate recharge paths and saltwater intrusion to the groundwater system. Groundwater level and chemistry, and geophysical direct current (DC) resistivity measurements, are used to support the hydrostratigraphical model. Results of this research contribute to the explanation of why the aquifer system of the study area is almost uninfluenced by saltwater intrusion, which is otherwise relatively common in coastal aquifers of Vietnam.     

定水头补给半无限带状含水层矿坑涌水量评价

通过对广西某石灰岩矿区水文地质条件的分析,对该水文地质单元的水文地质模型进行概化,推导出了定水头补给半无限带状含水层中完整井流公式,并运用该公式对开采条件下矿坑涌水量作了评价。最后,运用传统的逐个干扰井叠加法对该公式的评价结果进行验证,结果表明,当映射叠加次数足够多时,其计算结果极为相近。但就其计算方法而言,映射叠加方法较为繁琐,而运用该公式计算则显得较为方便。     

Assessing hydrochemical evolution of groundwater in limestone terrain via principal component analysis

This paper describes the use of multivariate statistical analysis to trace hydrochemical evolution in a limestone terrain at Zagros region, Iran. The study area includes a deep confined aquifer, overlaid by an unconfined aquifer. The method involves the use of principal component analysis (PCA) to assess and evaluate the hydrochemical evolution based on chemical and isotope variables of 12 piezometers drilled in both the unconfined and confined aquifers. First PCA on all variables shows that water–rock interaction under different conditions with respect to the atmospheric CO₂ is the main process responsible for chemical constituents. As a result, combinations of several ratios such as Ca/TDS, SO₄/TDS and Mg/TDS with physico-chemical and isotope variables reveal different hydrochemical evolution trend in the aquifers. Second PCA on the selective samples and variables reveals that displacement of the unconfined samples from dry to wet season follows a refreshing trend towards river samples that is characterized by reducing electrical conductivity and increasing sulphate and tritium contents. However, the refreshing trend cannot be traced in the confined aquifer samples suggesting no recharge from river to the confined aquifer. Third PCA reveals that, chemical composition of water samples in the unconfined aquifer tends to have considerable difference from each other in the end of recharge period. In contrast, the confined aquifer samples have a tendency to show similar chemical composition during recharge period in comparison to end of dry period. This difference is caused by different mechanism of recharge in the unconfined aquifer (through the whole aquifer surface) and the confined aquifer (through the limited recharge area).     

人工井液电阻率测井在煤田水文地质勘查中的应用

为准确获取水文地质参数,进而为矿井防治水、矿井涌水量计算以及地下水评价等提供可靠的参数,以煤田地质勘探中实测的人工井液电阻率测井曲线为依据,结合岩心精细描述、抽水试验、常规地球物理测井等技术获得的资料进行综合分析。研究表明:人工井液电阻率测井技术在煤田水文地质勘探中不仅可以准确划分含隔水层的性质,确定其位置,分析含水层之间的补给关系,检查钻孔止水效果,计算各含水层钻孔截面流量,亦可研究地下水流体特征,评价地下水水质参数以及监测生产矿井导水裂隙带高度。因此,人工井液电阻率测井能够提高煤田水文地质勘探成果利用率,实现地质勘探信息的最大化利用,从而更好地为矿井设计、建设及矿井生产服务,保障矿井安全。      

水位与沉降双控模式下浅层地下水压力回灌试验研究

通过浅层地下水压力回灌对比试验研究,掌握上海地区特殊地质条件下浅层地下水回灌技术工艺,并对浅层地下水压力回灌技术控制地面沉降的效果进行了分析。研究表明,采用变压力、变流量地下水人工回灌可有效实现地下水位和地面沉降的双重控制,效果显著,可有效应用于上海地区地下空间开发引发的工程性地面沉降防治实践。     

Multivariate statistical analyses of the groundwater system in Darb El-Arbaein, Southwestern Desert, Egypt

In Darb El-Arbaein, the groundwater is the only water resource. The aquifer system starts from Paleozoic–Mesozoic to Upper Cretaceous sandstone rocks. They overlay the basement rocks and the aquifer is confined. In the present research, the performance of the statistical analyses to classify groundwater samples depending on their chemical characters has been tested. The hydrogeological and hydrogeochemical data of 92 groundwater samples were obtained from the General Authority for Rehabilitation Projects and Agricultural Development authority in northern, central, and southern Darb El-Arbaein. A robust classification scheme for partitioning groundwater chemistry into homogeneous groups was an important tool for the characterization of Nubian sandstone aquifer. We test the performance of the many available graphical and statistical methodologies used to classify water samples. R-mode, Q-mode, correlation analysis, and principal component analysis were investigated. All the methods were discussed and compared as to their ability to cluster, ease of use, and ease of interpretation. The correlation investigation clarifies the relationship among the lithologic, hydrogeologic, and anthropogenic factors. Factor investigation revealed three factors, namely, the evaporation process–agricultural impact–lithogenic dissolution, the hydrogeological characteristics of the aquifer system, and the surface meteoric water that recharge the aquifer system. Two main clusters that subdivided into four subclusters were identified in the groundwater system based on hydrogeological and hydrogeochemical data. They reflect the impact of geomedia, hydrogeology, geographic position, and agricultural wastewater. The groundwater is undersaturated with respect to most selected minerals. The groundwater was supersaturated with respect to iron minerals in northern and southern Darb El-Arbaein. The partial pressure of the groundwater versus saturation index of calcite shows the gradual change in PCO₂ from atmospheric to the present aquifer pressures.