山东省莒县沭河盆地地下水资源评价

通过物探、钻探手段对沭河盆地的水文地质结构、补径排条件进行研究,建立水文地质模型,并利用GMS数值模拟和内梅罗综合指数法对地下水开采潜力及水质进行评价。结果表明:沭河盆地含水层分布具各向异性,按含水层厚度可划分为两个富水区;地下水补给来源以大气降水和河流侧渗补给为主,排泄途径主要为人工开采,地下水正均衡2 312.85万m3/a;经模拟不同开采情况下地下水变化情况,确定莒县沭河盆地地下水开采潜力为6.1万m3/d;地下水水质达到Ⅲ级及以上标准的区域占总面积的71.4%,基本满足供水质量要求。     

双孔干扰非稳定流抽水试验确定承压含水层水文地质参数

在大型地下水资源论证开发过程中,常通过群孔抽水试验以确定目标含水层相应水文地质参数,从而进一步探求地下水储量。而该方法对于一些小型地下水资源的开发而言其钻孔成本较高。为控制项目,采用双孔干扰抽水试验以获得目标含水层渗透系数。通过抽水试验数据以及水位恢复数据计算得到目标承压含水层导水系数为20.5~41.4 m~2/d。该结果表明双井干扰抽水试验既能有效获取目标含水层水文地质参数,也能大幅降低项目成本,较适用于小型地下水资源的论证及开发。     

锅称子抽水试验及地下水可采资源的评价

抽水试验是目前各种水文地质勘察中经常用来确定含水层水文地质参数的一种主要手段,在详细勘察阶段,更是其工作的主要内容。通过抽水试验来确定含水层的钻孔涌水量及其与水位降深之间的关系；含水层的水文地质参数；影响半径的大小、降落漏斗的形状及其扩展情况；含水层与含水层之间及其含水层与地表水之间的水力联系等。并通过多孔抽水试验及历年降雨和地下水动态观测与分析,初步对我地区地下水可开采资源做出评价,指导工农韭生产中的地下水开发利用,制定合理的灌溉制度,扩大灌溉面积。     

定边县城北防洪排涝工程对地下水环境的影响及对策

通过对区域水文地质、浅层地下水含水层、地下水及地表水水质现状等情况的调查及监测,采用数值模拟方法预测分析定边县城北防洪排涝工程对区域地下水环境的影响。结果表明,工程对地下水水量影响较小,地下水水位将抬升0 m~0.9 m,影响范围为58.11 km~2;工程对区域地下水水质、苟池和花麻池湿地水质、马莲滩水源保护区水质有一定影响。根据预测结果,提出控制来水水质、工程防渗、蓄水区水质保护等防治对策。     

盐城市地下水资源调查评价

在查明盐城市地下水各含水岩组的水文地质特征、开采现状和水位动态的基础上 ,运用数值法对盐城市地下水资源进行评价 ;核定了全市市、县 (市 )、乡 (镇 )三级行政区域地下水可开采量 ,其中Ⅱ ,Ⅲ ,Ⅳ承压含水层可开采量分别为 4992万m3 /a ,6 10 3万m3 /a ,5 478万m3 /a .最后制定了全市地下水合理开发利用规划 ,调减开采区面积 16 33km2 ,控制开采区面积 2 34 8km2 ,扩大开采区面积110 83km2 .     

盐城市地下水资源规划评价三维数值模型

根据盐城市地下水系统的水文地质机制,在概化出盐城市地下水系统水文地质概念模型的基础上,建立了盐城市地下水资源规划评价的三维数值模型,并针对盐城市对各含水层地下水水位的控制要求,给出了各含水层的最优开采量,为合理开发利用盐城市地下水资源提供了科学依据。     

库计水源地地下水水化学特征分析

以库计水源地地下水为研究对象,在分析研究区水文地质条件的基础上,系统研究了研究区地下水的水化学时空变化特征：从外围分水岭向内以及由内部分水岭向周边,地下水水化学类型总体上沿地下水流向,呈HCO₃型→HCO₃•Cl型→HCO₃•SO₄•Cl型→SO₄•Cl型逐步过渡变化规律;在垂向上,中、浅层地下水水力联系较为密切,分带规律不明显,深部地下水水质略差;在时间上,由于白垩系含水层厚度巨大,垂向水力联系密切,且水位埋藏普遍较深,季节性变化对地下水水质影响有限,地下水水质相对稳定。     

白洋淀千里堤周边地层及浅层地下水概况分析

通过对白洋淀周边地层的勘探、试验,初步查明周边地层、含水层,浅层地下水水质类型,并划分了两个渗流条件不同的类型段,对两个渗流段的有关水文地质参数分别进行了分析,为定量评价白洋淀的渗流安全提供了依据.     

基于Visual MODFLOW的黑龙江省巴彦县地下水流数值模拟

通过Visual MODFLOW软件建立黑龙江省巴彦县地下水流数值模型,对其进行识别、验证,得到相应的水文地质参数,并对巴彦县地下水资源进行预测。研究结果表明,该地区2020-2030年地下水位总体上呈逐年下降趋势,分析原因为巴彦县农业用水主要依赖地下水,且随着城市规模的不断扩大,用于工业、生活的地下水水量不断增长,地下水水位逐年下降。此外,确定巴彦县地区的渗透系数分别为:河漫滩地区0. 8 m/d;山区1. 4 m/d;山前地区1. 7 m/d。以期为巴彦县的水资源合理开发利用和城区规划方案的制定提供科学的理论依据和重要的参数基础。     

江汉平原地下水位动态变化特征分析

通过辨识江汉平原含水系统的水文地质结构,深入分析了地下水位动态变化特征及其影响因素,进而揭示了研究区地下水时空演变规律。结合地下水流系统分区分析了研究区的降雨-径流关系和地下水动态类型。同时,运用数理统计方法分析了累计水位升幅和累计降雨量之间的关系。结果表明:研究区内地表水除丰水期补给地下水外,其余时段地下水补给地表水;研究区不同含水层地下水位关系总体为深层孔隙承压水位中层孔隙承压水位浅层孔隙潜水位;研究区地下水对降雨入渗产生的滞后效应表现为低水位期滞后5~7 d,高水位期滞后1~2 d。研究结果对该地区地下水资源的评价管理具有现实意义。     

基于剖面数值模拟的地下水流系统结构控制因素——以鄂尔多斯白垩系盆地北部典型剖面为例

针对解析法计算难度大,且难以描述水流系统复杂边界条件和含水层结构的问题,利用GMS软件建立水流系统的剖面二维数值模型,通过软件自动生成流网图,并以鄂尔多斯白垩系盆地北部典型剖面为例,分析影响水流系统结构的各种控制因素。结果表明,水流系统的水平发育规模主要受地形(边界条件)控制,而垂向循环深度主要受控于含水层各向异性,水平渗透系数和垂向渗透系数的比值与含水层的结构有关,并且依赖于模型剖分单元格尺寸的变化,具有一定的尺度效应。     

分层抽水在大厚度含水层水文地质勘查中的应用

为查明深埋于 240 m 以下总厚度达 660 m 的多个大厚度含水层的渗透系数、涌水量、水质等参数, 基于钻孔 岩心和测井资料划分 6 个抽水试段, 利用分层抽水试验进行取样和计算相关参数。研究表明: 研究区洛河组和环 河组平均渗透系数均为上段小于下段, 同一含水岩组上下段含水层之间几乎没有水力联系; 洛河组上段含水层富 含锶优质淡水资源, 可作为城镇集中水源地的目标开采层, 同时要防止过度开采导致水质变差; 单孔多层段含水 层分层抽水试验不仅可以精确获取大厚度含水层的水文地质参数, 还对厘清含水层间越流关系及合理规划地下水开发 利用具有重要意义。     

核磁共振法寻找岩溶裂隙水的地质效果

核磁共振找水方法是目前唯一可用来直接找水的地球物理方法 .在武汉地区岩溶裂隙水的勘查中 ,以核磁共振方法为主 ,配合使用电阻率法 ,进行资料的综合解释 ,取得了令人满意的地质效果 .核磁共振工作结果显示 ,在勘探范围内地下水存在四个含水层 ,其中深部的两个含水层为承压含水层 ,自旋—自旋弛豫时间反映出含水层孔隙度较大 ,地下水连通情况较好 ;电阻率资料反映 ,承压含水层对应着高阻基岩赋存的部位 ,推断是碳酸盐岩类岩溶裂隙水含水层 .钻探验证了两种物探方法的推断结果 ,打出了优质地下水 ,单井日出水量超过 10 0 0t .     

陡河流域地表水与地下水转化关系

通过对陡河流域地表水-地下水水样的氢氧同位素分布特征进行分析,发现研究区河岸带第Ⅰ含水层除了受大气降水、灌溉回归水入渗补给外,还接受河水早期的渗漏补给,第Ⅱ含水层对第Ⅲ含水层有越流补给,第Ⅱ含水层同时也受大气降水和灌溉回归水的影响,而远离河岸带的第Ⅳ含水层与上覆各含水层稳定同位素组成显著不同,河岸带水库附近的第Ⅳ含水层可能受地表水库渗漏影响。河岸带地下水与地表水水力联系的变迁严格受河岸带地下水水位变化控制,如景庄子剖面的地下水埋深为5m,雨季时河水补给地下水,旱季时地下水补给河水,而靠近地下水漏斗中心的越河乡剖面地下水水位埋深达25m,其常年受地表水补给。     

人类开采活动影响下的衡水地区地下水水质特征及演化

衡水地区地下水普遍存在"上咸下淡"的水质格局,受深部淡水持续超采影响,浅层咸水有逐年下移而使淡水咸化的趋势。选择衡水地区典型剖面,通过水质长期监测,结合地下水开采情况,分析2011至2014年该剖面上地下水水位与水质监测资料,总结了衡水地区地下水水化学特征及其演化规律。研究结果表明,浅层含水层中水平径流微弱,地下水水质由西向东逐渐好转,其中西部地下水离子浓度变化较大;深部含水层中水平径流明显,地下水水质整体良好,但有逐年恶化的趋势;人类开采活动一定程度上增强了浅层和深层含水层间的水力联系,使二者中离子浓度随时间的波动呈现出一定的相关性。     

Assessment and Management of a Desert Basin in Kuwait

ABSTRACT

The study area, Umm Gudair, is located in the southwest corner of Kuwait. It occupies an area of ≈ 4.84 × 10⁹ ft². The brackish ground water is derived from the two main aquifers within the Cenozoic sequence. These are: the Kuwait Group aquifer (Miopleistocene) and the Dammam aquifer (Eocene). In the study area, the two aquifers are treated as a single reservoir Forty-one production wells, locally called “dual completion wells” were finished in the aquifers. This research identifies the hydrogeologic properties and the water quality of the aquifers. In addition, the article discusses the application of the surface electrical method Schlumberger configuration to correlate and delineate the areal distribution of the apparent resistivity with the aquifer salinity, and the occurrence of a water-bearing formation. The results will be use for assessment and management of the groundwater reservoir The water quality of the two aquifers is relatively poor The T.D.S. ranges between 3,130-4,740 mg/L. The hydrochemical facies are calcium-sodium cation facies and chloride-sulphate anion facies. The ground water is classified as a NaCl water type, however two genetic water types are identified: the MgCl₂ and CaCl₂ are of marine origin and are old marine formations. The aquifer is semiconfined to confined The average transmissivity, which increases toward the N and N-E, is 20,965 Igpd/ft. The geophysical studies conducted along seven profiles with 19 vertical electrical soundings reveal three distinct layers. The first layer is composed of dry gravel and has a resistivity of 80–220 m. For the second layer, the resistivity ranges between 5–9 Ωm. It is assumed to be a clayey layer saturated with brackish water; whereas the third layer corresponding to a limestone formation, has a resistivity of 25–700Ωm. The apparent resistivity decreases in the direction of the increasing salinity From the flow-net analysis, the amount of ground water entering the aquifer along the border with the Saudi Arabia is 2.3 × 10⁶ Igpd, while the average daily production from the Umm Gudair field is 13.5 × 10⁶ Igpd, It is obvious that the daily abstraction rate is higher than the daily flow toward the aquifer Therefore, in the future, if the daily abstractions continue to exceed the daily water flow through the aquifer a serious decline in the water level will result.     

Stochastic and Robust Multi-Objective Optimal Management of Pumping from Coastal Aquifers Under Parameter Uncertainty

Combined simulation-optimization approaches have been used as tools to derive optimal groundwater management strategies to maintain or improve water quality in contaminated or other aquifers. Surrogate models based on neural networks, regression models, support vector machies etc., are used as substitutes for the numerical simulation model in order to reduce the computational burden on the simulation-optimization approach. However, the groundwater flow and transport system itself being characterized by uncertain parameters, using a deterministic surrogate model to substitute it is a gross and unrealistic approximation of the system. Till date, few studies have considered stochastic surrogate modeling to develop groundwater management methodologies. In this study, we utilize genetic programming (GP) based ensemble surrogate models to characterize coastal aquifer water quality responses to pumping, under parameter uncertainty. These surrogates are then coupled with multiple realization optimization for the stochastic and robust optimization of groundwater management in coastal aquifers. The key novelty in the proposed approach is the capability to capture the uncertainty in the physical system, to a certain extent, in the ensemble of surrogate models and using it to constrain the optimization search to derive robust optimal solutions. Uncertainties in hydraulic conductivity and the annual aquifer recharge are incorporated in this study. The results obtained indicate that the methodology is capable of developing reliable and robust strategies for groundwater management.     

Current Practice and Future Challenges in Coastal Aquifer Management: Flux-Based and Trigger-Level Approaches with Application to an Australian Case Study

The control of groundwater abstraction from coastal aquifers is typically aimed at minimizing the risk of seawater intrusion, excessive storage depletion and adverse impacts on groundwater-dependent ecosystems. Published approaches to the operational management of groundwater abstraction from regulated coastal aquifers comprise elements of “trigger-level management” and “flux-based management”. Trigger-level management relies on measured groundwater levels, groundwater salinities and/or ecosystem health indicators, which are compared to objective values (trigger levels), thereby invoking management responses (e.g. pumping cut-backs). Flux-based management apportions groundwater abstraction rates based on estimates of aquifer recharge and discharge (including environmental water requirements). This paper offers a critical evaluation of coastal aquifer management paradigms using published coastal aquifer case studies combined with a simple evaluation of the Uley South coastal aquifer, South Australia. There is evidence that trigger-level management offers advantages over flux-based approaches through the evaluation of real-time resource conditions and trends, allowing for management responses aimed at protecting against water quality deterioration and excessive storage depletion. However, flux-based approaches are critical for planning purposes, and are required to predict aquifer responses to climatic and pumping stresses. A simplified modelling analysis of the Uley South basin responses to different management strategies demonstrates the advantages of considering a hybrid management approach that includes both trigger-level and flux-based controls. It is recommended that where possible, trigger-level and flux-based approaches be adopted conjunctively to minimize the risk of coastal groundwater degradation and to underpin strategies for future aquifer management and well-field operation.     

Water quality as an indicator of hydrogeological conditions: a case study of the Belgrade Groundwater Source (Sava/Danube confluence area)

The City of Belgrade receives most of its drinking water supply from the alluvial aquifer of the Sava River. The wells are radial, placed in the lower part of the aquifer, so they partly run below the Sava riverbed. However, the groundwater quality of the wells in one part of the source (near the confluence of the Sava and Danube rivers) is found to differ somewhat from the groundwater quality of the other wells. The finding gave rise to additional investigations. The results revealed the existence of a deeper, limestone aquifer which is isolated from upper alluvial sediments by a thick layer of clay in most of the terrain. The naturally potential hydraulic contact of the two aquifers was additionally maintained by well operation in this part of the source. According to multiple analyses of groundwater flow using a hydrodynamic mathematical model, a hydrogeological and hydraulic system of groundwater flow was defined. Although the wells are situated adjacent to the river, and some well laterals are below the riverbed, most of the groundwater that flows to the wells is partly from the wider zone of the alluvial aquifer, and partly from the deeper aquifer. The initial results of hydrochemical investigations also showed an unexpected, inverse oxic character of the groundwater in these two aquifers.     

A Suitable Tool for Sustainable Groundwater Management

Artificial recharge is used to increase the availability of groundwater storage and reduce saltwater intrusion in coastal aquifers, where pumping and droughts have severely impaired groundwater quality. The implementation of optimal recharge methods requires knowledge of physical, chemical, and biological phenomena involving water and wastewater filtration in the subsoil, together with engineering aspects related to plant design and maintenance operations. This study uses a novel Decision Support System (DSS), which includes soil aquifer treatment (SAT) evaluation, to design an artificial recharge plant. The DSS helps users make strategic decisions on selecting the most appropriate recharge methods and water treatment technologies at specific sites. This will enable the recovery of safe water using managed aquifer recharge (MAR) practices, and result in reduced recharge costs. The DSS was built using an artificial intelligence technique and knowledge-based technology, related to both quantitative and qualitative aspects of water supply for artificial recharge. The DSS software was implemented using rules based on the cumulative experience of wastewater treatment plant engineers and groundwater modeling. Appropriate model flow simulations were performed in porous and fractured coastal aquifers to evaluate the suitability of this technique for enhancing the integrated water resources management approach. Results obtained from the AQUASTRESS integrated project and DRINKADRIA IPA CBC suggest the most effective strategies for wastewater treatments prior to recharge at specific sites.