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1.
Factors affecting the groundwater chemistry in a highly urbanized coastal area in Hong Kong: an example from the Mid-Levels area 总被引：1，自引：0，他引：1
Chi-man Leung Jiu J. Jiao John Malpas Wing-tat Chan Yan-xin Wang 《Environmental Geology》2005,48(4-5):480-495
Coastal areas of Hong Kong Island are one of the most extensively urbanized areas in the world. Groundwater samples in natural
slopes and developed spaces in the regions centered by the Mid-Levels area, Hong Kong Island, were collected and analyzed
to investigate the natural and anthropogenic processes affecting the groundwater chemistry. The results presented may be of
value to other coastal areas in the world for the identification of possible groundwater contamination sources. Groundwater
samples in the natural slopes were in low total dissolved solid (TDS) (<100 mg/l), indicating that the waters were in the
early evolutionary stage. Using chloride as a normalizing factor, the “non-marine” components of different major ions in the
samples were calculated. The correlation analysis indicated the occurrence of weathering of plagioclase feldspars in the natural
slopes. However, the breakdown of biotite and K-feldspar seems to be limited by short groundwater residence time and high
resistance to weathering. The high variety in hydrochemical facies may suggest the presence of extremely heterogeneous subsurface
geological conditions. In the developed spaces, groundwater samples exhibited a high range of TDS (~100–5300 mg/l) and were
mainly dominated by Na–Cl and Na–Ca–Cl water types. Besides water-rock interactions, the groundwater chemistry was significantly
affected by leakage from service pipes and the dissolution of concrete materials. Some chemicals were used as signatures to
identify the leakage from various service pipes. The area generally suffered from widespread, but small amount of leakages,
and no obvious leakage was discovered. The strong correlations among major cations and chloride suggested that even a small
amount of leakage from salty flushing water pipes can significantly affect the groundwater chemistry. Groundwater is found
to be highly aggressive toward concrete as supported by three commonly used aggressiveness indices. Additional Ca2+ may be released to groundwater by corrosion of subsurface concrete materials such as building foundations and basements.
The strength of those subsurface engineering structures may be weakened. Besides, excess Ca2+ may deposit in the dewatering systems in the area, which may affect their performance in lowering high water tables. The
findings regarding leakage from service pipes will be useful for various government organizations such as the Water Supplies
Department and Drainage Services Department. Discussion of the behavior of Ca2+ is instructional to foundation and slope dewatering designs in the area. 相似文献
2.
Y. Srinivas D. Muthuraj D. Hudson Oliver A. Stanley Raj N. Chandrasekar 《Environmental Earth Sciences》2013,70(5):2143-2152
Coastal aquifers can become polluted due to natural and human activities, such as intrusion of saline water, discharge of effluents in industrial areas and chemical weathering of natural geological deposits. The present study is aimed mainly at understanding the geophysical and chemical characteristics of groundwater near Tuticorin, Tamilnadu, India by studying the electrical resistivity distribution of the subsurface groundwater by applying the Schlumberger vertical electrical sounding (VES) technique followed by chemical analysis of water samples. A total of 20 VES soundings were carried out to understand the resistivity distribution of the area and 21 water samples were collected to analyze the chemical quality. The interpretation and analysis of the results have identified different hydrogeologic behaviors, a highly saline coastal aquifer and freshwater locations. The results obtained from geophysical and geochemical sampling are in good agreement with each other. The approach shows the efficacy of the combination of geophysical and geochemical methods to map groundwater contamination zones in the study area. 相似文献
3.
为研究地下水"热"源对于渗流场的影响,选取某水库水源地辐射取水区及部分扩张区为研究范围,使用地下水通用软件FEFLOW对单一地下水热源作用下的Y型河道的渗流场和温度场进行研究,得出地下水热源对渗流场和温度场的影响规律,结果显示:地下水位受水源的影响,在不同位置水位不同,含水层内随着到水源点距离的增加,水位逐渐降低,到达某个位置时会保持稳定不变;靠近地表的地下水温会随着到水源点距离的增加逐渐降低,在垂向上,含水层内地下水温随着高程的降低逐渐降低,而在库水区,受库水的影响垂向水温变化规律则刚好相反,研究结论可为实际工程提供理论指导。 相似文献
4.
历史上淄河下游的人畜供水一直依赖地下水,但20世纪80年代以来区内淄河下游河道长期接纳上游污水,地表水和浅层地下水受到污染,浅层地下水已不适于人畜饮用。污染区沿淄河呈条带状展布,污染区边界距淄河约1.0~1.5 km,其中距淄河500 m以内的区域污染最为严重。中深层地下水水质良好,仅个别井点因井管损坏造成点状串层污染,可做为人畜用水水源。基本可满足2010年前区内人畜供水要求。人畜供水开采中深层地下水时,应根据地下水污染特征和中深层含水层水文地质特征,分区分层开采,实现地下水合理开发,防止中深层地下水串层污染,保护宝贵的地下水资源。 相似文献
5.
白洋淀渗漏对周边地下水的影响 总被引：3，自引：0，他引：3
为查明受污染的白洋淀地表水渗漏范围,对周边地下水主要离子水化学的影响,并评价地下水是否适用于灌溉,在该区域现场测定了地表水及地下水pH、EC(Electric Conductivity)和ORP(Oxidation-Reduction Potential)等参数,采样分析各水体D、18O和主要离子组成,结合判别分析和钠吸附比RSA(Sodium Adsorption Ratio)讨论。结果表明,淀水渗漏使浅层地下水电导率升高,氧化还原电位值降低,且更加富集重同位素;唐河污水库周边浅层地下水SO42-和Na+含量明显增大。浅层地下水的δ18O值结合水位埋深有效地标记了淀水渗漏影响地下水的范围。浅层地下水主要受到白洋淀渗漏的影响,唐河污水库附近的浅层地下水受污水库渗漏影响。污染地表水渗漏使得浅层地下水水质普遍下降,白洋淀西部和唐河污水库周边浅层地下水不适宜用于灌溉。 相似文献
6.
浅层地下水补给对人类活动影响的响应特征研究 总被引：3，自引：1，他引：2
本文通过数据整理分析, 查明滹沱河流域平原区1976-2005年以开采量、灌区引水量和河道过水量为代表的人类活动逐渐增强, 分析了浅层地下水补给在大气降水减少和人类活动逐渐增强背景下大幅减少的响应特征: 综合补给量所占比率由1976-1980年的21.6%下降到2000-2005年的11.3%。随后, 从开采量、河道过水量和灌区引水量三个方面分析了浅层地下水补给响应人类活动的变化特征: 地下水补给量与开采量呈y=65.412x-0.2576模式随降水量增减而负相关变化; 河道渗漏补给量和渠水入渗量在地下水位不同埋深条件下表现出随来水量、引水量增加而增大的态势, 但在不同埋深条件下, 河道渗漏补给量与来水量之间、渠水入渗量和引水量之间关系不同。 相似文献
7.
Understanding of saline intrusion into coastal aquifer is an important issue in management and protection of groundwater resource,
which can be well achieved by groundwater modelling. To explain some phenomena of correlation between groundwater level and
salinity in observation wells in coastal area, the authors compare the migration velocity of saline particles and transmission
velocity of water pressure and derive analytical equations of these two velocities for plane and radial flows. The driving
force and resistance of saline intrusion were analysed based on the analytical modelling. The destruction and reconstruction
of the equilibrium between fresh water seepage towards sea and saline dispersion to inland were considered as an essence of
whole intrusion process. The dynamic process of seepage and dispersion at different stages of saline intrusion were analysed
under groundwater over-exploitation. The basic equations of saline intrusion were derived and the mechanism of transitional
zone movement was discussed. These constitute coupled seepage–dispersion theory of saline intrusion, which becomes an important
supplement to existing theory of saline intrusion. As a case study on saline intrusion in Guangrao County in Eastern China,
this theory was applied to predict the development of saline intrusion in the study area. 相似文献
8.
Groundwater nitrate pollution in an alluvium aquifer, Eskişehir urban area and its vicinity, Turkey 总被引：1，自引：0，他引：1
A large amount of the water requirement (municipal, industrial, etc.) of Eskişehir city, Turkey, is supplied from groundwater
via wells in the urban area. The groundwater in the Eskişehir Plain alluvium has been polluted by municipal and industrial
wastewater, and agricultural activities. The nitrate concentrations at nine sampling points on Porsuk River, the main water
course in the plain, ranged from 1.5 to 63.3 mg/l during the period from July 1986 to August 1988. In the same period, the
nitrate concentrations measured in water from 51 wells ranged between 2.2–257.0 mg/l. The nitrate content of the groundwater
samples was 34.2% above 45 mg/l, the upper limit for nitrate in drinking water standards. High nitrate levels were observed
in water from wells in the central and eastern parts of the urban area. The nitrate content of the well water is subject to
seasonal fluctuation. In general, low nitrate concentrations were observed in wet seasons, and high ones in dry seasons.
Received: 16 April 1996 · Accepted: 2 October 1996 相似文献
9.
通过采用单位面积河流在单位水头差作用下的渗漏量来表征河流渗漏能力,建立渗流井取水理想模型,分别计算了在不同河流渗漏能力和含水层渗透性能条件下,竖井降深对渗流井出水量的影响。建立渗流井取水非稳定流模型,计算了在前期稳定竖井降深不同条件下,河流断流后渗流井出水量衰减过程及竖井降深发展过程。提出渗流井合理竖井降深应根据河流与地下水是否脱节以及含水层渗透性能,在岸边渗流井中部及一侧各布设一个观测孔,根据观测孔水位进行确定。对于含水层渗透性能较强地区,渗流井竖井降深应使得渗流井范围内地下水位与河流脱节,但高于辐射孔顶面;对于含水层渗透性能较差地区,渗流井竖井降深应使得侧部观测孔水位接近河床底面或刚出现脱节。 相似文献
10.
Distribution and origin of nitrate in groundwater in an urban and suburban aquifer in Mar del Plata,Argentina 总被引：2，自引：1，他引：1
Daniel Martínez Eleonora Moschione Emilia Bocanegra Melisa Glok Galli Ramón Aravena 《Environmental Earth Sciences》2014,72(6):1877-1886
The impact of urbanization on groundwater quality is of special concern for water managers dealing with the provision of drinking water to large urban centers. Nitrate is one of the most common contaminants found in urban aquifers. This paper presents a case study aiming at evaluating the distribution and sources of nitrate in an urban aquifer in the city of Mar del Plata, Argentina. Four study zones under different land uses, including a pristine, a semi-rural, an intermediate, and an urban area, were evaluated as a part of this study. The three latter zones are linked by the groundwater flow system. The average nitrate concentration in the pristine area is 6.7 mg/L as nitrate and is over the permissible level of 50 mg/L for drinking water in the other areas. In the semi-rural area it ranges from 39.2 to 107.1 mg/L with an average value of 38.2 mg/L and the nitrate concentration tends to decrease in the intermediate zone to an average value of 38.2 mg/L; however, values above 60 mg/L are also observed there. Then the nitrate concentration in the urban area water is higher than that in the intermediate zonewater ranging from 48.2 to 100.3 mg/L with an average value of 67.3 mg/L. Data on the stable isotopes 15N and 18O in nitrate show that the main sources of nitrate in the study area are manure associated to agriculture uses and cesspools in the semi-rural area, and leakage of the sewage distribution network in the urban area, respectively. This is supported by a previous study which found that 20 % of the water flooding many underground structures in the city came from leakage of the sewage network. No evidence of nitrate attenuation by denitrification was found in the groundwater. This study has shown that aquifers in urban areas can be affected by agricultural activity in the upstream areas and leakage of the sewage network in the urban area. 相似文献
11.
A. Lawrence D. Gooddy P. Kanatharana W. Meesilp V. Ramnarong 《Hydrogeology Journal》2000,8(5):564-575
Many cities and towns in South and Southeast Asia are unsewered, and urban wastewaters are often discharged either directly
to the ground or to surface-water canals and channels. This practice can result in widespread contamination of the shallow
groundwater. In Hat Yai, southern Thailand, seepage of urban wastewaters has produced substantial deterioration in the quality
of the shallow groundwater directly beneath the city. For this reason, the majority of the potable water supply is obtained
from groundwater in deeper semi-confined aquifers 30–50 m below the surface. However, downward leakage of shallow groundwater
from beneath the city is a significant component of recharge to the deeper aquifer, which has long-term implications for water
quality. Results from cored boreholes and shallow nested piezometers are presented. The combination of high organic content
of the urban recharge and the shallow depth to the water table has produced strongly reducing conditions in the upper layer
and the mobilisation of arsenic. A simple analytical model shows that time scales for downward leakage, from the surface through
the upper aquitard to the semi-confined aquifer, are of the order of several decades.
Electronic Publication 相似文献
12.
利用温度全局优化法探测堤坝多重集中渗漏 总被引：1，自引：0，他引：1
利用地温探测堤坝工程中的多重集中渗漏通道位置是一种反问题,为取得全局最优解及突破现有方法的局限性,采用不同优化算法相互配合的温度全局最优化方法,以达到有效准确探测显著集中渗漏通道的位置。结合各算法优势及目标函数不连续性等特点,选用全局搜索(GS)、多初始点(MS)及遗传算法(GA)3种方法联合补充优化。首先利用GS搜索局部最优点; 然后结合目标函数不连续点及上述局部最优点,人工增加MS优化起始点进行多初始点优化; 最后依据上述局部解,利用GA混合算法优化,从而有效提高全局最优化的概率。根据堤坝工程集中渗漏通道低温补给的特点,对优化目标函数进行了具有特定物理意义的修正; 为减少每次迭代的优化参数,基于温度测试精度提出分步优化方法,根据温度或修正目标函数残差吸引盆特征确定某步优化的集中渗漏数量; 由修正残差与温度测量精度相对大小确定优化是否终止,对应修正残差最小的优化结果为集中渗漏通道位置的真实解。结合工程实例,计算了某水库左坝肩的多重集中渗漏通道位置,分步优化了两个主要的集中渗漏位置,直接法优化3个集中渗漏位置。文献及工程实践证明了该法的正确性及有效性,为了堤坝等水利工程岩土体的集中渗漏整治提供了科学依据。 相似文献
13.
在分析介绍九江地区地下水类型(松散岩类孔隙水、碳酸盐岩裂隙岩溶水、基岩裂隙水)和地下水环境条件及其动态变化规律的基础上,采用《生活饮用水卫生标准》,对研究区地下水环境,包括地下水质量和地下水污染现状进行了评价。研究区内合格的地下水占56%,不合格的占12%,中等不合格占16%,严重不合格占16%。地下水污染形成了4个严重污染区块,全区未污染地下水仅占8%、轻微污染占36%、中等污染占20%、严重污染占36%。污染项目主要为PH、氨氮、硝酸盐、亚硝酸盐、氛等指标。由此提出了保护地下水资源的建议。 相似文献
14.
云南省的高原山间盆地是重要的水源汇集区,人口聚集和经济活动中心,也是对水环境影响和变化具有指标意义的环境水文地质单元。文章阐述了云南省高原主要山间盆地地下水质监测概况,并依据多年地下水水质监测数据,按照孔隙水、裂隙水、岩溶水三种地下水类型进行了水质评价。通过数据统计法、Piper三线图、小波神经网络时间序列分析,预测云南省地下水化学特征及水质变化趋势。研究发现:地下水化学类型种类复杂多样,以HCO3-Ca · Mg、HCO3-Ca型为主。氨氮、锰、氟化物、硝酸根离子等含量超标率较高,是导致地下水水质超标的主要指标,不同污染指标的污染来源不同,主要为生活污染和工业污染。根据统计分析结果显示云南高原主要盆地水质总体上呈稳定趋势,针对研究结果提出了地下水环境保护的措施建议。 相似文献
15.
水库岩溶渗漏及防渗研究综述 总被引：4，自引：0，他引：4
岩溶地区水库渗漏是可溶岩地区兴建水利枢纽的主要工程地质问题之一,尤其是在可溶岩广布、岩溶发育强烈、地形复杂地区,岩溶渗漏成为了该类地区水利水电工程的一个普遍问题.库区的岩溶渗漏不仅影响建坝后的正常蓄水,还将危及坝体的安全与稳定.因此,有必要对库区渗漏,特别是岩溶地区的库区渗漏进行渗漏机理、渗漏特征、渗漏条件等进行详细分... 相似文献
16.
广西南宁朝阳溪对浅层地下水污染特征研究 总被引：3，自引：2，他引：1
文章利用5个钻孔和3个水井监测资料,分析了广西南宁朝阳溪排污沟对周边浅层地下水的影响。结果表明,朝阳溪排污沟对周边浅层地下水产生了明显的污染,特征污染物为氨氮,浓度超过地下水环境质量Ⅲ类水质标准1~65.75倍,氨氮浓度随距朝阳溪的距离增大而逐渐减小,且具有季节变化特征,丰水期污染程度明显低于枯水期。分析认为,浅层地下水的三氮主要来源于排入朝阳溪的人畜粪便;多环芳烃主要来源于草、木、煤燃烧;DDT来源于历史残留,BHCs则来源于上游林丹的使用和远距离大气沉降。 相似文献
17.
磷石膏堆场特别是岩溶区堆场渗漏对地下水和地表水水质影响较大。根据现场连通试验、物探及钻探揭示资料分析,研究区主要有三种渗漏类型:裂隙型（双眼井泉）、裂隙-管道型（发财洞岩溶管道）和管道型（鸭草坝岩溶管道水系统）。天然不防渗条件下,库水通过地表落水洞、溶缝和溶隙等入渗地下水,产生岩溶渗漏。入渗补给独田地区的S1号泉、杨花冲地区的S23号泉、下摆郎地区的S13、S14号泉。其它泉水受隔水层的阻隔及地下水的补、排条件所限,没有受到污染。独田堆场运行后堆场存在渗漏情况,但是,防渗系统运行后渗漏的污染情况较之前有较为明显的下降。 相似文献
18.
某大型地下工程结构完工后出现普遍渗水现象,严重影响其使用功能,并造成了不良社会后果。通过建立区域三维渗流分析模型,结合现场结构渗漏水特征,研究了该工程的区域渗流场特征和结构渗漏水的主要来源。结果表明:①模型计算结果与工程现场实测数据基本吻合,为该地区地下工程建设中的渗流场分布问题提供一种分析方法。②工程区域内浅表层地下水主要接受大气降雨的补给,丰季时河流水位上涨,对浅表层地下水有一定反补,市政雨污管网的渗漏也是不容忽视的补给来源。③区内西溪河洪峰水位270.2m,北湖地表水体水位270.5m,工程主体的抗浮水位以270.20~270.50m考虑为宜。④根据地下结构病害特征和所在位置,提出相应的病害整治建议,整治效果良好,可在类似工程应用。 相似文献
19.
Nitrate is a common pollutant in surface water and groundwater of agricultural areas. It is essential to monitor this pollutant in groundwater, especially when it is used for drinking purposes without treatment. The present study was carried out in an intensively irrigated area which forms a part of Nalgonda district, Andhra Pradesh, India where groundwater meets all the water needs of the rural population living in this area. The objective was to assess the spatiotemporal variation in the concentration of nitrate in groundwater and soil. Based on the analysis of 496 groundwater samples collected from 45 wells over a period of 2 years from March 2008 to January 2010 by sampling every 2 months, it was observed that groundwater in 242 km2 of the total 724 km2 area had nitrate above the maximum permissible limit of 45 mg/l for drinking purposes. Nitrate concentration in groundwater showed a positive relation with potassium, chloride, and sulfate, indicating their source from fertilizers. Reasons for the high concentration of nitrate in domestic areas were the dumping of animal wastes and leakage from septic tanks. The pH of the soil samples showed that most of the area had basic soil. Apart from pH, organic carbon, available phosphorous, available potassium, ammoniacal nitrogen, and nitrate nitrogen were also analyzed in the 97 soil samples. 相似文献
20.
Spatial-temporal difference between nitrate in groundwater and nitrogen in soil based on geostatistical analysis 
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下载免费PDF全文 The study of temporal and spatial variations of nitrate in groundwater under different soil nitrogen environments is helpful to the security of groundwater resources in agricultural areas. In this paper, based on 320 groups of soil and groundwater samples collected at the same time, geostatistical analysis and multiple regression analysis were comprehensively used to conduct the evaluation of nitrogen contents in both groundwater and soil. From May to August, as the nitrification of groundwater is dominant, the average concentration of nitrate nitrogen is 34.80 mg/L; The variation of soil ammonia nitrogen and nitrate nitrogen is moderate from May to July, and the variation coefficient decreased sharply and then increased in August. There is a high correlation between the nitrate nitrogen in groundwater and soil in July, and there is a high correlation between the nitrate nitrogen in groundwater and ammonium nitrogen in soil in August and nitrate nitrogen in soil in July. From May to August, the area of low groundwater nitrate nitrogen in 0–5 mg/L and 5–10 mg/L decreased from 10.97% to 0, and the proportion of high-value area (greater than 70 mg/L) increased from 21.19% to 27.29%. Nitrate nitrogen is the main factor affecting the quality of groundwater. The correlation analysis of nitrate nitrogen in groundwater, nitrate nitrogen in soil and ammonium nitrogen shows that they have a certain period of delay. The areas with high concentration of nitrate in groundwater are mainly concentrated in the western part of the study area, which has a high consistency with the high value areas of soil nitrate distribution from July to August, and a high difference with the spatial position of soil ammonia nitrogen distribution in August. 相似文献