分层监测孔现场分级联合试验确定含水层参数

以华北平原中部咸淡水过渡带的多层含水系统(第Ⅰ含水组底部至第Ⅱ含水组顶部的含水系统)为研究对象,建立了地下水位-水质分层监测系统。通过在多层含水系统开展分层分级抽水试验、微水试验以及分层示踪试验等现场综合试验,借助解析法和数值模拟识别法等多种手段确定各分层水文地质参数。求参结果表明:Ⅰ含底部含水层渗透系数为4.320～7.550m/d,储水系数为4.53×10-4～2.19×10-3;弱透水层渗透系数为2.20×10-3～7.65×10-3 m/d,纵向弥散系数为0.023～0.428m2/d,纵向弥散度为0.010～0.051m;第Ⅱ含水层顶部含水层渗透系数为0.142～0.929m/d,储水系数为4.53×10-4～2.19×10-3。     

辽中县滨水新城供水水文地质勘察

辽中县滨水新城水源地为中型供水水源地。本次勘察通过物探、勘探等多种勘察方法分析水源地水文地质条件;根据现场二组抽水试验,一组干扰井抽水试验数据,考虑在稳定流和非稳定流两种状态下计算确定含水层渗透系数、影响半径等水文地质参数,分析抽水井出水量合理性;根据现场水样水质分析确定水源地水质质量;根据上述数据综合评定水源地适用性。     

保定市一亩泉水源地水文地质条件分析与评价

通过对区域水文地质条件、地质钻探、物探和水文地质抽水、单井回灌、渗坑入渗、示踪试验等资料的综合分析,对保定市一亩泉水源地水文地质条件进行了系统研究,查明了地层岩性、地质结构及地层渗透性等基本参数,为地下水回灌方案设计提供了可靠依据。研究结果表明,入渗场80m深度内揭露含水层7~8层,含水层岩性主要为卵砾石,渗透性较好,是较理想的入渗场地;回灌水有利于补给第1~2含水组,回灌水向西南方向流失及向下部3~4含水组渗流的可能性很小;入渗场垂直渗透系数为37．16~39．79m/d,单井影响半径为199．53m。     

多含水层稳定流非干扰多孔混合井流理论及示踪测井方法

本文提出了一种多含水层稳定流非干扰混合多孔井流理论，研究了在不抽水（或不注水）条件下，通过测定多含水层中各层的垂向流速，流向，渗透流速等求解各含水层的渗透系数，静水头、降深与流量的关系等水文地质参数的一种方法、该方法完全是在天然流场下进行渗流场的测试，可以获得比抽水流试验更多的水文地质参数。     

傍河地下水源地水文地质特征及水资源量评价

傍河地下水源地主要是通过激发临河侧补给地下水的开采资源量,达到稳定地下水持续开采量的目的。通过水文地质测绘、水文地质钻探、多孔稳定流抽水试验、室内试验等手段查明水源地水文地质条件,确定含水岩组的空间分布特征、含水层水力联系、水文地质参数等。在查明水源地水文地质条件后,评价地下水资源量及地下水水质情况,为合理开采地下水资源、确定经济合理的地下水开采方案提供科学依据。     

天津地区微水试验求取含水层渗透系数的应用

为解决抽水试验求取含水层渗透系数周期长、操作复杂的问题,以天津某场地潜水含水层和承压含水层的微水试验为例,采用Hvorslev模型、Cooper模型和Bouwer&Rice模型计算含水层渗透系数,并与抽水试验结果对比,Bouwer&Rice模型分析潜水含水层微水试验数据求得的渗透系数与抽水试验结果相比误差小,结果准确;...     

区域地下水资源量计算及水位动态变化分析

本文根据水源地水文地质条件,结合抽水试验数据资料,确定该区域含水层平均厚度、单井涌水量、渗透系数、影响半径及水力坡度等水文地质参数,采用水均衡法计算地下水资源量,分析补给量与排泄量平衡情况,采用开采系数法确定地下水可开采量,并分析区域地下水位动态变化趋势。     

在均質承压含水岩层中帶淹沒式过滤器的不完整鑽孔抽水試驗計算岩层渗透系数的新公式

对于在均质承压含水层中,用鑽孔抽水试验计算岩层的渗透系数,巴布希金氏根据流线理论导出在均质承压无限厚含水层中带淹没式过滤器的不完整鑽孔抽水试验计算岩层渗透系数的公式,并用B.M.纳斯贝尔格氏的近似方法,即以距离原点为层厚m远的无限长度Nm的汇流(设其水流强度为Q/m,及N→∞),代替汇流的无穷反映体系,导出在均质承压有限厚含水层中带淹没式过滤器的不完整鑽孔抽水试验计算岩层渗透系数的公式。作者现用反映法将在均质承压有限厚含水层中的汇流变化为在均质承压无限扩展含水层中的汇流无穷反映体系情况,导出在均质承压有限厚含水层中带淹没式过滤器的不完整鑽孔抽水试验计算岩层渗透系数的公式。公式中不含有影响半径R,以免计算时假设其值。     

安阳市地下水含水层抽灌试验分析

为查明安阳市含水层的回灌能力,采用自然重力回灌法按一抽一灌方式在不同富水地段进行了3组抽水回灌试验。结果表明:1在抽灌井结构相同或相近的情况下,含水层回灌能力和含水层的富水性有关,含水层富水性越好,同等条件下单位涌水量和单位回灌量越大。2含水层回灌能力和渗透系数正相关,渗透系数愈大,愈容易回灌。渗透系数大,不仅使抽水能力增强,也会加大回灌井的回灌能力;反之,亦然。3含水层回灌能力和岩性有关,含水层颗粒越粗,越容易回灌。     

孟村县地下水压采专用井抽水试验数据分析

通过介绍抽水试验原理,结合孟村县压采井影响深度范围内含水层抽水试验实例,确定含水层组的水文地质参数,为制定科学合理的地下水开采量和开采方案提供依据。     

多含水层渗流系统电导示踪模型

在利用钻孔测定含水层水文地质参数时,如遇到多含水层情况,需使用栓塞系统对各含水层进行隔离探测,由于现场操作较为不便且钻孔条件要求高,故提出多含水层渗流系统电导示踪模型。在不使用栓塞系统的情况下,考虑含水层涌水或吸水等不同情况,通过测定抽水条件下各含水层的电导率,建立多含水层渗流系统电导示踪模型确定含水层渗透性参数。当钻孔中只存在涌水层时,直接利用电导率曲线面积与溶质质量的比例关系求解出流量;当钻孔中同时出现涌水层和吸水层时,根据溶质质量曲线的斜率可较准确地确定吸水层的位置,再由斜率的变化计算出含水层的流量。基于某工程实例采取3种方法求解各含水层的渗透系数、静水头、渗流速度、导水系数等水文地质参数,结果表明,采用电导示踪模型计算结果与同位素示踪测试及注水试验测试结果吻合较好,且电导示踪模型方法现场操作更为简便,可极大地提高含水层水文地质参数的测定效率。     

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.     

苏丹中部半干旱地区含水层特征的评价

苏丹中部的北杰济拉(Gezira)省的含水层为杰济拉含水层和白垩系含水层.在确定含水层水文地质参数的基础上,绘制了地下水水位等值线图,并通过矿化度的空间分布对地下水的化学特性进行评价.对水文地质参数的计算采用了雅各布方法和泰斯恢复水位法,通过对地下水中主要化学成分的分析来评价地下水水质,并绘制有关的水化学特性图.测得杰济拉含水层的平均导水系数和渗透系数分别为368 7m2/d和34 03m/d,均小于白垩系含水层的407 2m2/d和43 17m/d.杰济拉含水层物理化学成分的浓度明显高于白垩系含水层.白垩系含水层水质较好,适宜用作生活用水及饮用水.     

止水不良孔导致地下水串层污染的机制研究——以衡水某试验孔为例

华北平原长期存在"上咸下淡"的水质格局,近年来,咸水下移问题不断威胁深层淡水资源。根据衡水市某止水不良孔(GK井)修复前后其周边观测孔(XK4井)内水质变化情况,通过构建考虑钻孔串层污染的溶质运移模型,对止水不良孔作为优势通道引导咸水下移的机制进行了研究。结果表明:原本水力联系微弱的相邻含水层通过止水不良孔发生了越流,上层咸水在水头差作用下沿井管下移,经滤水管进入淡水层,导致下层淡水迅速咸化;GK井在14个月内形成的污染晕半径为20~75 m,导致XK4井地下淡水矿化度在5个月内升高约5倍;GK井封填后,污染物在水动力作用下发生扩散、稀释,被污染淡水在4个月后又恢复至原有浓度。止水不良孔造成的串层污染不容小觑,应及时发现及早治理。     

3D Variable Density Flow Simulation to Evaluate Pumping Schemes in Coastal Aquifers

A three dimensional model is presented for the simulation of seawater intrusion in coastal aquifers by considering the development of a transition zone and thus the variable density flow approach. The model is applied to a heterogeneous coastal aquifer to study the effects of the pumping rate, the salinity of freshwater inflow and the thickness of the aquifer, on the degradation of pumped water quality through wells in certain location. Even for an optimum pumping scheme solution based on a simple two-dimensional flow model, we simulate freshwater degradation in pumped water which depends on the salinity of freshwater inflow and aquifer thickness.     

Groundwater Response to Tidal Fluctuation in an Inhomogeneous Coastal Aquifer-Aquitard System

This paper investigates tide-induced groundwater fluctuation and submarine groundwater discharge (SGD) in a leaky inhomogeneous coastal aquifer system with an upper unconfined aquifer, a lower confined aquifer, and an aquitard between them. The upper left aquifer is formed due to land reclamation. The SGD defined as the groundwater flow from land into the sea is controlled mainly by the hydraulic gradient between land and sea. An analytical expression is developed to discuss and assess the effect of inhomogeneity on the groundwater head fluctuation in the leaky aquifer system. Joint effects of aquifers’ parameters such as leakage and hydraulic diffusivity on the groundwater head fluctuation and SGD are investigated. The predicted results from the analytical expression indicate that the groundwater head fluctuation in both unconfined and confined aquifers is dependent on dimensionless leakages and increases with dimensionless hydraulic diffusivity.     

Characterization of a Regional Aquifer System in the Maritimes Basin,Eastern Canada

A regional hydrogeological study was carried out in the Maritimes provinces, in one of the main aquifer systems in Canada. The study area covers a land surface of 10,500 km², of which 9,400 km² is over Carboniferous and younger rocks. The sedimentary fractured bedrock is composed of a sequence of discontinuous strata of highly variable hydraulic properties, and is overlain by a thin layer of glacial till (mostly 4 to 8 m). Depending on areas, 46 to 100% of the population relies on groundwater for water supply. Almost all residential wells are shallow (28 m on average) open holes that are cased only through the surficial sediments. This paper describes a regional hydrogeological investigation based on targeted fieldwork, the integration of a wide variety of existing multisource datasets and groundwater flow numerical modelling. The aim of this paper is to present the current state of understanding of the aquifer system in a representative area of the Maritimes Basin, along with the methodology used to characterize and analyze its distinct behaviour at the regional, local and point scales. This regional hydrogeological system contains confined and unconfined zones, and its aquifer lenticular strata extend only a few kilometers. Preferential groundwater recharge occurs where sandy tills are present. The estimated mean annual recharge rate to the bedrock aquifers ranges between 130 and 165 mm/year. Several geological formations of this Basin provide good aquifers, with hydraulic conductivity in the range of 5 × 10⁻⁶ to 10⁻⁴ m/s. Based on numerical flow modelling, faults were interpreted to play a key role in the regional flow. Pumping test results revealed that the aquifers can locally be very heterogeneous and anisotropic, but behave similarly to porous media. Work performed at the local scale indicated that most water-producing fractures generally have a sub-horizontal dip along a north-east (45°) strike.     

Aquifers Overexploitation in SE Spain: A Proposal for the Integrated Analysis of Water Management

Integrated water resources management is a paradigm that incorporates technical, scientific, political, legislative and organizational aspects of a water system. This study presents a methodology for undertaking an integrated analysis of water systems supplied by groundwater. This methodology is here applied to examine the water system of the Altiplano region in Murcia, where the water extraction from the aquifers greatly exceeds recharge and the irrigated areas supplied by those aquifers have a very high agrarian profitability. First, the hydrological problematic of the case study was conceptualized. Then, a sectorial study on each aspect related to the water management of the system was developed. As Bayesian Networks was the chosen technique for the integrated analysis, the information obtained by the sectorial studies was translated into specific variables, which together with the relations among them, modelled the real situation. As from a hydrogeological point of view the water system is comprised of four autonomous aquifers, a Bayesian Network for every aquifer was designed. This decision-support system enables us to evaluate the impacts generated under diverse water management scenarios.     

北运河流域土沟段地下水水力截获效果评估

选择北运河流域土沟段于2016年开展为期69 d的水力截获试验。结果表明:20 m含水层降深为2 m,影响半径为80.2 m;60 m含水层降深为1.54 m,影响半径为150.6 m。试验期间,多数地下水水质指标浓度呈下降趋势,其中硫酸盐浓度下降幅度达57.9%,痕量有机污染物—邻苯二甲酸(2-乙基己基)酯的最大下降幅度达96.3%。污染物浓度的变化与其所在含水层介质中发生的稀释作用、阳离子交换吸附及黏土矿物的吸附作用等密不可分。试验结果表明水力截获试验可有效控制和修复地下水污染。     

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.