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1.
A 480-square-mile region within Will County, in northeastern Illinois, was used as a test region for the development of a methodology to map the sensitivity of aquifers to contamination. An aquifer sensitivity model was developed using a geographic information system (GIS) to overlay and combine several data layers. The components used for our model are: (1) depth to sand and gravel or bedrock, (2) thickness of the uppermost sand and gravel aquifer, (3) glacial drift thickness, and (4) bedrock geology. The model is an improvement over many previous aquifer sensitivity models because it combines specific information on depth to the uppermost aquifer with information on the thickness of the uppermost sand and gravel aquifer. This county-wide model results in an aquifer sensitivity map that can be a useful tool for making land-use planning decisions regarding aquifer protection and management of groundwater resources. 相似文献
2.
生物曝气技术对石油类污染地下水的修复效果及去除机制 总被引：1，自引：0，他引：1
针对东北某石油污染场地水文地质条件进行模拟,按照试验场地地层现状进行实验室缩放,研究微生物在含水层介质为砾砂、粗砂和中砂中的迁移速度以及含水层介质吸附的微生物量。选取苯和二甲苯作为目标石油污染物,研究生物曝气技术对被污染地下水的修复效果及其去除污染物的机制。实验结果表明:微生物在介质中的迁移速度从大到小为砾砂、粗砂、中砂;介质吸附微生物量的顺序从大到小为中砂、粗砂、砾砂;生物曝气4个月后,苯和二甲苯去除率分别为86.4%和81.7%,BS对中砂层中的苯和二甲苯去除效果好于砾砂层和粗砂层,苯的去除效果好于二甲苯。由挥发机制去除的污染物为46.24%,生物降解去除的污染物为36.98%,BS技术可以有效去除地下水中石油类污染物。 相似文献
3.
4.
吉林省龙井市石井金银矿位于长白山系老爷岭南麓的丘陵地貌中,区内地下水的形成、分布、埋藏条件严格受地质构造、岩性、地貌等条件控制,地下水的补给来源为大气降水。矿区含水层主要类型为：第四系砂砾石孔隙潜水含水层、基岩风化构造裂隙水含水层、构造裂隙脉状水含水层（带）;三种地下类型水富水性都较小,对矿床影响不大,该矿区水文地质条件属简单类型。 相似文献
5.
This paper describes a natural-gradient field tracer test to characterise solute-transport properties in a sand and gravel
aquifer in the Hebei Province, northern China. Some laboratory-scale column tests on aquifer material and a local-scale field
borehole-dilution test have been conducted previously, but the field test reported herein represents the only large-scale
tracer test in the aquifer, which is the sole water supply to the city of Shi Jiazhuang and which is threatened by urban pollution.
The aim of the study was to quantify the transport behaviour of nonreactive pollutants in this aquifer. Little quantitative
data are available concerning its solute-transport properties; thus, the results of the tracer test are significant and critical
for understanding pollutant transport and fate. The in-situ tracer test was carried out in the aquifer using a slug injection
of the geochemically conservative, radioactive iodine tracer 131I. The longitudinal (α
L
) and transverse (α
T
) hydrodynamic dispersivities for solute transport in the field are 1.72 and 0.0013 m, respectively. The ratio of longitudinal
dispersivity α
L
and the flow length at the field scale is 1:10. The ratio between α
L
and α
T
from the in-situ test (~1,300:1) demonstrates a dominant longitudinal dispersion in this fluvial sand and gravel aquifer.
The tracer test further indicates a relatively short transit time for the aquifer (linear velocities ~13 m/d) under natural-gradient
conditions.
Electronic Publication 相似文献
6.
高压旋喷桩主要适用于淤泥质土、黏性土、粉土、砂土、黄土和碎石土等地层，在卵砾石地层或动水条件下的应用较少。我国某露天矿在施工旋喷桩止水帷幕的过程中，采用RJP工法进行帷幕施工，成功将高压旋喷注浆技术应用于卵砾石含水层中，通过试桩和筛分试验将卵砾石层特征对桩径大小的影响进行了分析研究，结果表明，RJP工法在卵砾石含水层中成桩效果良好、质量可靠，其桩径大小与卵砾石颗粒大小及含砂量有关。围井试验结果显示，高压旋喷桩帷幕墙完整，止水效果显著。研究成果表明高压旋喷注浆技术可在卵砾石含水层的加固和止水领域进行推广应用。 相似文献
7.
The central part of the Murrumbidgee River meanders across an alluvial plain which is 1.5 km to 5 km wide, and confined between low hills composed of granite and folded lower Palaeozoic rocks. Deposition commenced under humid and reducing conditions during the Miocene, and continued during Pliocene time. Oligomict quartz‐sand and gravel beds are dominant in the sequence, and are interlayered with grey to black clay and silty clay, which contain a prolific pollen fauna. During Pleistocene time, a marked reduction in rainfall and consequent change in vegetation resulted in the deposition of a widespread coarse polymict poorly‐sorted gravel associated with yellow and brown clay and silt. The quartz‐sand and gravel beds within the Pliocene deposits constitute a major aquifer system and contain low salinity water suitable for irrigation and town water‐supply purposes. Since 1968, increasing demand has been made on this aquifer system, and wells sunk for various State and Local Government bodies have a total installed capacity of approximately 1000 litres/sec. The most concentrated exploration and development has been effected east of Wagga Wagga, where a well field was constructed to provide water for a regional water supply scheme. Following a refraction seismic survey, test drilling, and mathematical simulation, four production wells were constructed. Mathematical simulation models developed on a mini‐computer were designed primarily to study the behaviour of the aquifer system in response to pumping from the Pliocene aquifers. An analytical model was used to assist in the location of production wells, and a numerical model was used, after construction of the wells, to determine what additional losses from the Murrumbidgee River would be induced by pumping them. These losses were found to correspond to approximately 90% of the pumping rate during long term pumping. 相似文献
8.
Usama Abu Risha Sayed Mosaad El Sayed El Abd Abdel Mohsen Hasanein 《Arabian Journal of Geosciences》2017,10(21):461
The groundwater extracted from the unconfined Quaternary aquifer is the main source of water supply in El-Tur area. The area is bounded from the east by the elevated basement complex of Southern Sinai and from the west by El-Qabaliyat Ridge. The wadis dissecting these highlands form effective watersheds of the Quaternary aquifer. These wadis form areas of focused recharge. Recharge also occurs directly via the Quaternary sediments covering El-Qaa Plain. Subsurface lateral groundwater flow from the fractured basement contributes significant recharge to the aquifer as well. The aquifer sediment facies affect the type and quality of groundwater. In the eastern part where the aquifer is composed mainly of gravel and coarse sand with fragments of weathered basement, the Na-Cl-SO4 water dominates. In the west where the facies change is rapid and complex, many water types arise. The base exchange index (BEX) is positive in this part reflecting the role of clay minerals in changing the water types via cation exchange. In the east where clays are insignificant in the aquifer, the BEX is negative. In the western part next to El-Qabaliyat Ridge, the wells discharging from the calcareous sand zone have low groundwater salinities compared to the wells discharging from the alluvium. In general, the groundwater salinity increases in the direction of groundwater flow from the northeast to the southwest which reflects the dissolution of aquifer sediments. The concentration relationships between the major ions on one hand and chloride on the other reflect the dissolution of calcium carbonates, precipitation of K- and Mg-bearing minerals, and cation exchange of Ca for Na on clay minerals. The hydrochemical models support these reactions. In addition, they show that the effect of evaporation on the recharge water in the western catchment is about four times its effect on the eastern recharge water which reflects the rapid recharge through the wadis draining the fractured basement. Moreover, the contribution from the eastern catchment in sample No. 23 is more than four-folds the contribution from the western recharge area. The stable isotopes (2H and 18O) show that the Quaternary aquifer is recharging from recent rainfall. However, upward leakage of Paleogene groundwater (depleted in 18O) also occurs. The groundwater level map shows strong overpumping impact especially in the areas close to El-Tur city. 相似文献
9.
Characteristics of groundwater and urban emergency water sources optimazation in Luoyang,China 
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下载免费PDF全文 The construction of emergency water sources is the material basis for ensuring urban water safety, and it is also an inherent requirement for maintaining social stability and development. The hydrogeological characteristics of groundwater in Luoyang City from the aspects of the division of groundwater aquifer groups, water yield property and groundwater dynamics were described in this paper. Two emergency water sources were selected on basis of comprehensively considering groundwater resources and ecological environmental effects, groundwater quality and exploitation technology, etc. Then it further analysed the aquifer types, water yield properties and groundwater recharge, runoff and discharge conditions of the two emergency water sources, and evaluate the groundwater resources quantity of the water sources. The results are that the shallow underground aquifer in Luoyang City is thick, coarse, and stable in lithology and thickness. The two water sources enjoy good exploitation potential and can be used as backup water sources to supply water in the event of a water source crisis. 相似文献
10.
Jinlong Zhou Guomin Li Feng Liu Yiping Wang Xiaojing Guo 《Environmental Earth Sciences》2010,60(5):1055-1063
According to the characteristics of groundwater in arid area, this paper proposes DRAV model for groundwater vulnerability
assessment, where D is groundwater depth, R is the net recharge of aquifer, A is the aquifer characteristics, and V is the lithology of vadose zone. As a case study, the paper assesses the vulnerability of pore phreatic water in Tarim Basin
of Xinjiang, China by using the DRAV model. The results indicate that the areas of phreatic water with vulnerability index
ranges of 2–4, 4–6, 6–8 and >8 accounting for 10.1, 80.4, 9.2 and 0.2% of the total plain area of the Tarim Basin respectively,
and the areas with the latter two vulnerability ranges (6–8 and >8) are mainly located in the irrigation districts with thin
soil layer (20–30 cm thick surface soil of vadose zone, mainly with underlying sandy gravel) and with silty and fine sand
layer. Such vadose zone generally lacks sandy loam and clayey soil and has larger recharge by infiltration of irrigation water. 相似文献
11.
The Memphis aquifer in southwestern Tennessee is a confined to semi-confined unconsolidated sand aquifer and is the primary
municipal water source for the Memphis metropolitan area. Leakage of modern water from shallow unconfined aquifers through
the upper Claiborne confining unit locally degrades water quality in the Memphis aquifer and makes the aquifer more vulnerable
to contamination. Major solute chemistry, tritium, and 3H/3He data were used to investigate the source and mixing proportions of modern water in the Memphis aquifer in the Davis well
field, Memphis, Tennessee. Water quality in several production wells in the Davis well field has declined over the past 30 years,
mainly through increased total dissolved solids, iron, alkalinity, and hardness. Trends in chemical data, tritium, and other
hydrogeologic data support a source for the leakage from the Mississippi River Valley Alluvial aquifer. Mixing proportions
of alluvial water in production well water obtained by inverse chemical modeling with PHREEQCi range from 7 to 45%. For two
of the production wells, MLGW 414 and 432, 3H/3He data yield mixing ratios similar to those obtained from PHREEQCi in three of four cases; the dissimilar ratio is likely
due to a poor solution from the PHREEQCi inverse modeling. Modeling of the age distribution obtained from MLGW 414 and 432
using an exponential-piston flow model (EPM) with an inverse solution computer code yielded mixed results. The EPM solution
obtained for MLGW 414 converged with difficulty only for a 5-year transit time in the shallow aquifer and is consistent with
a source from the Mississippi River Valley Alluvial aquifer; however, the modeled age of the water is greater than that observed.
In comparison, the EPM solution for MLGW 432 converged for the 5- and 7-year transit periods in the shallow aquifer and yielded
model ages consistent with observed 3H/3He ages; however, the extent of the maximum radii for infiltration source is not consistent with a Mississippi River Valley
Alluvial aquifer source. Other potential sources for leakage to MLGW 432 include water from the Fluvial-terrace aquifer migrating
along a fault east of the well field or infiltration of water from a lake south of the well field. 相似文献
12.
A combination of major and trace elements have been used to characterize surface- and groundwater in El Minia district, Egypt. Surface water versus groundwater chemistry data enabled geographical zonation and chemical types to be differentiated. The main target of this research is to investigate the groundwater quality and hydrochemical evaluation. The situation is further complicated by contamination with lithogenic and anthropogenic (agricultural and sewage wastewaters) sources and low plan exploitation techniques. The investigated Pleistocene aquifer is composed of sand and gravel of different sizes, with some clay intercalation. The semi-confined condition was around the River Nile shifted to unconfine outside the floodplain. The groundwater flow generally from south to north and locally diverts towards the western part from the River Nile. Fifty-six, 11, five, and two water samples were collected from the Pleistocene aquifer, River Nile, Ibrahimia canal, and Al Moheet drain, respectively. The collected water samples were analyzed for major and trace elements. The toxic metal concentrations of Al Moheet drain are higher than those in the River Nile and the Ibrahimia canal. Cr, Hg, As, and Cd concentrations in the River Nile and Ibrahimia canal are fluctuated above and below the WHO drinking standards. Se concentration in River Nile and Ibrahimia canal is below WHO drinking and irrigation guidelines. Total dissolved solid content in groundwater is generally low, but it is increased due to the western part of the study area. The geographic position of the River Nile, Ibrahimia canal, and Al Moheet drain impact on the groundwater quality. The PHREEQC confirm the high mixing proportions from the River Nile into the groundwater and decline away from it. In addition to the thicknesses of the Pleistocene, aquifer and aquitard layer enhance the River Nile and agricultural wastewaters intrusion into the aquifer system. The toxic metal concentrations (Pb, Cd, Cr, PO4, Se, Mn, As, Hg, Ni, Al, Fe, and SIO2) in groundwater were increased mainly in the northwestern and southeastern part (far from the River Nile). It is attributed to anthropogenic, high vulnerability rate (unconfined), and partially to lithogenic. In most localities, the groundwater are unsuitable for drinking and irrigation purposes with respect to Se concentration, while they are unsuitable for dinking according Mn, As, and Hg contents. There are some Cd and Pb anomalies concentrations, which cause severe restriction if used in irrigation. The results suggested that significant changes are urgently needed in water use strategy to achieve sustainable development. 相似文献
13.
N. Opiyo-Akech D. O. Olago E. W. Dindi M. M. Ndege F. Njue 《Environmental Geology》2000,40(1-2):99-110
The area studied is a north–south oriented, V-shaped, clayey lagoonal depression bordered by Pleistocene sands on the west
and Recent dune sands on the east. The freshwater aquifer in the area is the main source of potable water for the urban centres
of Gongoni and Timboni and the main Mombasa Salt Works processing plant. The aim of the study was to look at the impact of
sand harvesting, and possible saline contamination of the aquifer by activities at the nearby salt harvesting plant and by
seawater intrusion. The major factor abetting pollution of the freshwater aquifer is the sand harvesting activity, which exposes
the aquifer to the atmosphere. Extension of the salt works closer to the aquifer field, combined with high abstraction rates,
may also lead to saline water intrusion and contamination of the aquifer.
Received: 6 April 1999 · Accepted: 23 May 2000 相似文献
14.
海南岛北部浅海海砂资源丰富,以砂砾质沉积为主,集中于琼州海峡东口潮流沙脊区、河口三角洲和沿岸水下岸坡等海域。本文通过对海南岛北部海域的地形地貌、地层、底质类型等方面的调查,分东、西两个区域研究了海砂资源的分布、范围、规模和类型等地质特征,并估算了海砂资源量,结合沉积环境,评价了各区域海砂的资源潜力。研究区海砂分布广泛,但东、西区特征和规模具有较大差异,西区海砂以砂质砾和泥质砂为主,厚度5~10 m;东区海砂以砂、砾质砂和砂质砾为主,厚度10~50 m,规模远超西区。研究区共圈定出9处资源潜力区,资源量为91.4亿m3,其余区域为远景区,其资源量为71.5亿m3。根据地形地貌、水动力和沉积环境等因素,研究区海砂可分为潮流沙脊堆积体系、河口水下三角洲堆积体系、岬湾海岸水下岸坡堆积体系和侵蚀残留体系几种类型。其中位于琼州海峡东口浅滩区的潮流沙脊堆积体系海砂连续分布面积达328 km2,平均厚度超过25 m,资源量83.9亿m3,最具潜力。 相似文献
15.
The main aim of the present study is to detect the status of groundwater resources in west Mallawi area which represented one of the new reclamation lands. In order to achieve this aim, the hydrogeological and hydrogeochemical studies are carried out, based on the results of 21 pumping tests and chemical analysis of 29 water samples. Two water-bearing units are detected in the study area, namely, the Eocene fractured limestone aquifer which occupies the east portion of the studied area. The second aquifer consists of friable sediments of sand and gravel and may be related to the late Oligocene–early Miocene age and overlies the limestone rocks in the west, and this aquifer were studied for the first time in this work. Regionally, the groundwater flow in the area under study occurs toward the north and east directions. There is a hydraulic connection between both aquifers through the structural pattern affected the area. The partial recharge of the both aquifers takes place through the upward leakage from deep aquifers and the Nile water. There is a general decrease in the water salinity from west to east direction. The groundwater of both aquifers was evaluated for the different purposes and concluded that, it is considered suitable for different uses. 相似文献
16.
研究神府东胜矿区煤炭开采对水资源的影响机制,对于保护当地水资源及脆弱的生态环境具有重要意义。以窟野河为例,分析了煤炭开采对该流域水资源量与水质的影响机制,并计算出吨煤开采的基流损失量约为2.038 m3(1997—2005年)。研究结果表明,煤炭开采时形成的裂隙将萨拉乌苏组含水层中的水导入矿坑中,导致潜水由水平径流、排泄为主转化为以垂向渗漏为主,引发地下水位大幅下降,河流基流量减少以及泉流量衰减甚至干枯;煤炭开采使含水层中的水进入到矿坑,在物理作用和化学作用下形成硬度更大、矿化度更高的矿坑水,矿坑水排入河流后对河流造成污染。 相似文献
17.
The present work studies the environmental isotopes assess groundwater characteristics of the different parts of the main aquifer in the northeast Missan Province in south of Iraq.Water samples of groundwater and surface water were collected for two dry and wet seasons during the water year of 2011–2012.The study shows that most of the groundwater in the aquifer falls above the global meteoric water line,and all the samples fall below the Mediterranean meteoric water line,indicating that these samples are a mixture of two water types.The tritium content of these samples supports this conclusion.The overall conclusion of this study indicates that there are two sources of groundwater recharge in the studied area:the ephemeral streams(Teeb and Dewerge) and major precipitation sources.According to the tritium levels at or below one tritium unit(TU) obtained from the water,supply wells are highly confined or "not vulnerable".Overall,the 3H results imply that recent recharge has taken place during the last four to five decades.In the recharge area,the high tritium content in the southern part of the Teeb area suggests that the recharge originates from rapid infiltration of surface runoff.Therefore,the groundwater resources in the study area should be protected from contamination,because it will influence the aquifer in a relatively short period of time if any contamination enters the recharge areas of the aquifer. 相似文献
18.
在我国某露天煤矿截水帷幕建造过程中，由于受架空高压线、地埋光缆、地埋排水管等多处障碍物影响，局部区域直接成槽工艺无法施工，因此，选择可以"全方位"施工的MJS工法完成此类区段建造。MJS试桩结果表明，该工法在东西两侧卵砾石层施工区成桩质量差异明显，为查明成桩差异性原因，采用地质勘探、重力触探试验和抽水试验等方法，从砾石层厚度、砾径、含砂量、地层密实度和含水层渗透能力等方面进行分析。结果表明，在砾石层厚度大、含砂量小、地层密实、含水层渗透性强的施工东区无法成桩，而在条件相反的施工西区成桩质量符合要求。研究成果拓宽了MJS工法的应用范围，对类似条件下MJS工法施工参数的选择具有指导意义。 相似文献
19.
Rogers Martina Sukop Michael C. Obeysekera Jayantha George Florence 《Hydrogeology Journal》2023,31(4):1031-1049
The Biscayne Aquifer (Florida, USA) is a coastal, shallow, unconfined, and heterogeneous aquifer with high water tables, composed of less-permeable sand to highly permeable karstic limestone. These properties make the Biscayne Aquifer one of the world’s most productive groundwater resources. The aquifer’s high yield and non-Darcian flow cause challenges for estimating aquifer parameters, which are essential for understanding groundwater processes and managing and protecting the groundwater resources. Water-table fluctuations in the Biscayne Aquifer are associated with astronomical tidal forces and gate operations on canal water-control structures. Analysis of observed groundwater level fluctuations can provide an understanding of the connectivity between the aquifer, Biscayne Bay, and the water level in the canals. Further, groundwater level fluctuations can be used for aquifer parameter estimation. In this research, observed ocean water levels measured at tidal stations and groundwater levels are fitted to Jacob’s analytical solution, where the amplitude of the groundwater head fluctuation decreases exponentially, and the time lag increases with distance from the shore. Observed groundwater levels were obtained from monitoring wells along the Miami-Dade shore and the barrier island of Miami Beach. Results indicate that Jacob’s solution is effective for aquifer parameter estimation in Miami Beach, where monitoring wells are closer to the shore. Estimated hydraulic conductivity appears to increase by four orders of magnitude to approximately 1 m s–1 as the distance from shore increases. Constructing monitoring wells closer to the shore in Miami-Dade County and elsewhere would permit improved aquifer parameter estimation and support enhanced groundwater modeling efforts.
相似文献20.
I. Arrate J. M. Sanchez-Perez I. Antiguedad M. A. Vallecillo V. Iribar M. Ruiz 《Environmental Geology》1997,30(3-4):257-265
As a result of diverse changes in land use and in water-resource management in the high basin of the Zadorra River (Basque
Country), an important loss of water resources and an intense contamination by nitrogen compounds has taken place. The purpose
of this paper is to detail the land transformations that have taken place on the aquifer since the 1950s: increase of drainage
network, change from dry to irrigated farming, and diversion of rivers at the aquifer unit inlet. Furthermore, we analyze
the impact of these transformations on the hydrodynamics and water quality of this aquifer system.
Received: 12 January 1996 · Accepted: 10 March 1996 相似文献