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1.
海水入侵是影响海岛地下水封油库施工及运营安全的重要因素。海岛环境下建设地下水封油库,大规模的地下开挖将显著改变海岛天然地下水渗流场,海水入侵地下洞室一方面引发突水风险,另一方面海水中的氯离子将会对地下洞库结构设施造成侵蚀,影响地下油库的使用寿命。因此在海岛环境下建造地下水封油库,除了需要考虑水封可靠性与岩体稳定性外,还需要关注海水入侵等现象。科学设置水幕系统可以有效地减弱海水入侵风险,论文基于污染质运移相关理论,采用有限元数值模拟方法,以拟建浙江省舟山市某海岛大型地下水封油库为例,模拟了地下油库建造及运营期的海水入侵现象,研究表明:若不设置淡水水幕系统,开挖地下洞室会直接导致海水入侵;设置水平水幕后在确保水封可靠性的前提下,能在一定程度上减弱海水入侵;而设置垂直水幕系统则能较为明显地抑制海水入侵的发生。该成果为海岛环境下建造地下水封油库可能遇到的海水入侵问题研究提供了理论依据。 相似文献
2.
淡水透镜体作为海岛上珍贵的地下淡水资源,对于满足居民生活用水与维护生态系统具有重要作用,增加海岛地下淡水资源储量可有效缓解海岛地区普遍存在的水资源短缺问题。本研究提出通过在海岛外部区域采用低渗透性介质材料增加海岛地下淡水资源储量的方法,采用室内物理模型实验与基于变密度地下水流溶质运移模型的数值模拟相结合的方法对提出方法的有效性进行了验证,并通过野外尺度的数学模型分析工程实施可能性。实验与数值模拟结果较吻合,表明该方法具有抵御海水入侵、增加海岛地下淡水资源储量的巨大潜力。通过基于野外尺度的数值模拟分析工程实施的可能性,发现对于降雨入渗补给强度为0.005 7 m/d、长度为200 m,孔隙度为0.3的狭长形均质海岛,地下淡水储量为66.5 m3/m,在海岛外部区域采用渗透系数为1 m/d、厚度为5 m的低渗透性介质材料后,淡水透镜体经过约8 a时间可再次达到稳态,地下淡水储量为343.8 m3/m,增加约4倍,工程实施具备一定可能性。本研究为缓解海岛地区缺水问题、实现淡水资源可持续利用提供了一种新方法。 相似文献
3.
海水入侵研究现状与展望 总被引：13，自引：0，他引：13
文中讨论了海水入侵的研究进展：海岸带海水入侵界面或过渡带的模拟，海岛地下淡水透镜体的动力学研究，井孔在界面或过渡带上部抽水所引起的升锥问题以及岸边地下水位动态研究及海平面变化对海水入侵的影响。海水入侵研究经历了从理想假定到合理概化，从室内实验模型、理想模型到数值模型这一过程。数值方法已成为模拟和求解海水入侵问题的最有力工具，海水入侵的过渡带模型成为主要的研究方向。分析了研究中存在的困难，展望了海水入侵研究的未来趋势：边界条件确定，水文地质参数选取，含水层结构估计，海水入侵输运与化学作用的耦合以及海水入侵预报。 相似文献
4.
中国沿海地区海水入侵现状与分析 总被引：16，自引：1，他引：15
刘杜娟 《地质灾害与环境保护》2004,15(1):31-36
首先介绍了我国存在着严重海水入侵灾害的三大河三角洲——长江三角洲、珠江三角洲、老黄河三角洲(莱州湾地区)海水入侵现状。长江口和珠江口海水入侵主要受河流入海径流量和河口潮汐影响,莱州湾地区海水入侵的产生则主要是人类过量开采地下淡水所致。地下淡水和咸水之间存在着一个动态平衡的混合界面,淡水储存一旦减少,平衡状态被打破,该界面便会向陆移动。最终产生海水入侵。海水入侵的发生受着诸多因素制约,在中国沿海地区。地下淡水的储备与人类的用水需求之间存在着矛盾,人类过量开采地下淡水是产生海水入侵的主导因素。因而开源节流、人工回灌地下淡水、阻隔水流等措施在防治海水入侵方面是行之有效的。 相似文献
5.
海水入侵问题研究综述 总被引：37，自引：1，他引：37
在综合有关文献的基础上，分析了国内外海水入侵的研究现状，讨论了海水入侵的概念，认为海水入侵概念的核心是人为超量开采地下淡水造成海水与淡水的水动力平衡破坏；进行了海水入侵的影响因素和成因分析，指出发生海水入侵必须具备一定的水动力条件和水文地质条件；介绍了海水入侵的判别指标和三维动态监测方法，给出了海水入侵的防治措施，并提出了海水入侵有待加强研究的几个方面。 相似文献
6.
山东莱州湾地区是我国海水入侵研究的典型地区之一,为了进一步促进对莱州湾海水入侵的认识,本次研究选择莱州湾南岸的典型剖面(昌邑-柳疃)为研究对象,系统采集了不同类型水样(河水、淡水、微咸水、咸水、卤水和海水),分析了不同水体的水化学、δ18O、δ2H、离子比及饱和度等特征。根据不同水体的水化学特征分析,判断出研究区在海(咸)水入侵过程中首先发生了混合作用,在此基础上,发生了阳离子交替吸附作用和不同程度的溶解沉淀作用。特征离子比值分析表明,咸水、微咸水是由地下淡水与卤水混合形成;剖面上咸水体的分布特征、δ18O-Cl-关系显示部分深层地下淡水也受到了卤水下移侵入影响。氢氧同位素的分布特征表明,研究区地下淡水明显来源于大气降水,第四纪古海水成因的卤水受到了蒸发及浓缩作用,"氧漂移"现象比较严重;矿物饱和度显示,研究区所有水体中盐岩均处于未饱和状态,石膏与白云石在部分地下淡水和微咸水中未达到饱和,在卤水与咸水体中处于饱和状态,方解石则在所有水体中都基本呈饱和状态。 相似文献
7.
该研究目的在于介绍所监测地区内遥感技术的应用。简要地描述以往遥感技术的使用,从地质学的角度为地质科学研究环境问题提供多时相和多光谱的影像帮助。同时侧重于以下两个重点：1．通过研究多时相卫星影像显示的地表植被特征差异（耐盐植被或盐生植被指标）,在沿海沉积平原区监测和划分由于过度开采水导致的海水入侵区域;2．通过使用卫星热红外影像,探测沿海岸线岩溶侵蚀岩地区的水流排泄区域。本文以沿海地区的海水入侵为研究重点。该地区的海水入侵演化为一个水文地质问题,并由此引发了一系列其它问题,其中一个水文地质问题是海水与沿海地区大量未使用的地下淡水之间的交换。在我们的实验室,借助LANDSAT-5／TM卫星影像（30米分辨率）已经努力对这些沿海区域进行监测和划定工作。对上述影像使用数字处理技术,划定Pieria县（马其顿省,希腊）受盐度影响的区域。另外,通过使用TM数据第6波段（热红外波段）找出希腊中部Itea海湾区域内的淡水泉。以上研究结果能够帮助水文地质专家找出受海水入侵和沿海区地下水排泄的区域。 相似文献
8.
广东硇洲岛地下水化学演化及成因机理 总被引：4，自引：0，他引：4
地下水一直是广东硇洲岛唯一的水资源,但近年来许多地区地下水咸化趋势加剧,严峻威胁着岛上居民的用水安全,研究地下水化学演化及成因机理,对预防和减缓水质变咸意义重大。本文结合区域水文地质条件、地形地貌条件及水化学资料分析了整个岛屿地下水水质状况,在此基础上采用Piper三线图研究了水化学特征,并利用PHREEQC软件对水文地球化学演化规律进行模拟研究,结果表明:(1)海水入侵是造成地下水咸化的主要原因,咸化对水质的影响主要表现为Cl-的增加,Ca2+在区分该地区不同水体时反应灵敏,是良好的识别指标之一;(2)海水入侵的过程中,过渡带前缘不存在经受长期古海水演化而成的卤水与地下淡水的混合作用,地下水中Mg2+、Ca2+与Na+之间存在着强烈的离子交换,石膏、白云石及方解石处于不饱和状态;(3)浅层地下水与深层地下水之间无明显的水力联系,属于相对独立的地下水流系统。在全球变暖,海平面上升的总趋势下,海岛地下水开发必须合理规划、严格管理,以防引发大规模海水入侵灾害的发生。 相似文献
9.
我国地下水封油库多建造在沿海地区陆地岸线以内,在海岛建造地下水封油库尚未有先例。海岛四周为海水包围,地下洞室的开挖会导致海水入侵,影响地下油库的使用寿命。为保证地下洞库的水封可靠性需布置水幕系统,现今已建油库的水幕系统多以水平水幕为主,尚未有专门针对竖直水幕系统水封可靠性的相关研究。竖直水幕系统相比于水平水幕系统具有操作简单、对原岩扰动小等优点,且可以起到对海水的"屏障"作用,因此开展海岛环境下地下水封油库竖直水幕系统的水封可靠性研究具有重要意义。论文采用数值模拟方法,研究竖直水幕孔的布置方式,根据正交试验确定竖直水幕孔的最佳布置参数;以浙江某海岛地下水封油库为依托,通过无水幕、设置水平水幕和设置竖直水幕3种情况的对比分析,研究竖直水幕系统的水封可靠性。研究得出:在只设置竖直水幕系统情况下,可以满足水封条件,且相较于水平水幕系统,竖直水幕系统可以更好地隔绝相邻主洞室间的串油。该研究成果为海岛环境下地下水封油库水幕系统优化设置提供了理论依据。 相似文献
10.
通过遥感解译研究了日照市海水入侵现状,从人为因素、地质原因、气候原因和地理环境因素等方面,对海水入侵原因进行了分析。在沿海地区,地下水的储备与人类的用水需求之间存在矛盾,人类过量开采地下淡水是产生海水入侵的主要原因。因此,兴建地下水库、减少地下水的开采和人工回灌等是防治海水入侵行之有效的措施。 相似文献
11.
东海岛是一具有独特水文地质条件的大陆岛,浅层含水层与大陆以浅海湾相隔,中深层承压水含水层与大陆地下水系统紧密相连。为了深入地认识大陆岛地下水水动力学特征,以湛江东海岛为例,阐述了其水文地质条件,并分析了东海岛浅、中、深层地下水的流场和动态特征。分析结果表明,东海岛为一个典型且独特的大陆岛,岛内和大陆的部分浅层含水层由湛江湾相隔,岛内中、深层含水层和大陆中、深层含水层通过湛江湾相连,且具有统一的水位分布,并保持着密切的水力联系,岛内中、深层地下水由南向北径流补给湛江市区的降落漏斗中心;滨海及海水区域浅层含水层及其下伏的粘土层构成了防止海水入侵中、深层地下水的保护层;浅层地下水流场基本保持天然状态,水位动态特征主要为入渗径流型,水位变化与降雨量相关;中、深层地下水流场以人工流场为主,地下水由南向北径流,水位动态类型主要为开采动态型,水位变化主要受到开采量变化的影响;在近海岸地区,地下水动态表现为潮汐效应型,在潮汐作用下,地下水位动态具有周期性。 相似文献
12.
Yanguo Teng Jie Su Jinsheng Wang Ning Dai Jian Li Liuting Song Rui Zuo 《Environmental Earth Sciences》2014,72(9):3329-3338
Due to the sea level rise and the excessive exploitation of freshwater, seawater intrusion is becoming a critical issue. To clarify the degree of seawater intrusion in Donghai Island and the microbial community structure and functional response to seawater intrusion, groundwater samples and sediment samples were collected at profiles A, B; the profiles were along the direction of groundwater flow, perpendicular to the coastline, a hydrogeochemical survey and soil microbial community analysis were also performed. The hydrogeochemistry analysis showed that the chemical type of groundwater was Na–Cl, brackish water was dominant in the area, and coastal groundwater was strongly affected by seawater intrusion. The effect of seawater intrusion on structural and functional diversity of soil microbes was analyzed from soil samples of the study area, by polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE). The results of DGGE patterns and phylogenetic tree show that the extent of seawater intrusion has directly influenced soil microbial community structure. The changes of microbial community structure might be related to the major elements’ concentrations in groundwater. Phylogenetic affiliation indicated that γ-proteobacteria were dominated in the profile A, while β-proteobacteria were mainly appeared in the profile B. The Flavobacteriaceae was only appeared at the shrimp ponds nearby. 相似文献
13.
硇洲岛地下水海水入侵的特征分析及治理对策 总被引：2，自引：0，他引：2
根据湛江市硇洲岛的水文地质条件和近年来在开采地下水方面出现水质变咸的现象,对海水入侵的特点和地下水资源前景进行了定性分析.认为硇洲岛地下水海水入侵受当地超量开采和区域水文地质条件改变两个因素的共同影响,指出该岛中、深层承压水从此将表现静储量属性(即不可恢复的特性),提出了及早涵养和恢复浅层水,谨慎、合理开采中、深层承压水和调整产业发展规划等防治对策. 相似文献
14.
Adel Kharroubi Faten Tlahigue Belga?em Agoubi Chafai Azri Salem Bouri 《Environmental Earth Sciences》2012,67(7):2089-2100
Coastal aquifers are considered as major sources for freshwater supply worldwide, especially in arid zones. The weak rainfall as well as the intensive extraction of groundwater from coastal aquifers reduce freshwater budget and create local water aquifer depression, causing both seawater intrusion and a threat to groundwater. This phenomenon was observed in the Jerba Island which is located in southeast Tunisia. Jerba??s unconfined aquifer shows high values of groundwater salinity reaching, locally, 17?g/l and a strong contrast between some zones of the aquifer. High pumping rates and weak recharge disturb the natural equilibrium between fresh and saline water causing water salinization in most areas of the island. This study aims at establishing the salinity map of the aquifer and identifying the origin of groundwater salinization. The salinity map shows that zones characterized by low groundwater salinity are located in the center of the study area. High groundwater salinities are observed near the coast and in some parts having low topographic and piezometric levels. Groundwater geochemical characterization, and Br/Cl and Na/Cl ratios suggest that the origin of abnormal salinity is seawater intrusion. Considering groundwater salinity values and Br concentrations, a seawater intrusion map is established. It shows that many areas of the unconfined aquifer are contaminated by mixed groundwater and seawater. The statistical analysis demonstrates that high mineralization of the groundwater is due to gypsum and carbonate dissolution coupled with the mixed groundwater and seawater in many areas. 相似文献
15.
Determining groundwater protection zones for the Quaternary aquifer of northeastern Nile Delta using GIS-based vulnerability mapping 总被引：3，自引：2，他引：1
Hossam H. Elewa Ragaa E. Shohaib Atef A. Qaddah Ahmad M. Nousir 《Environmental Earth Sciences》2013,68(2):313-331
The area of study lies at the northeastern part of Nile Delta. Global shoreline regression and sea-level rise have their own-bearing on the groundwater salinization due to seawater intrusion. A new adopted approach for vulnerability mapping using the hydrochemical investigations, geographic information system and a weighted multi-criteria decision support system (WMCDSS) was developed to determine the trend of groundwater contamination by seawater intrusion. Six thematic layers were digitally integrated and assigned different weights and rates. These have been created to comprise the most decisive criteria used for the delineation of groundwater degradation due to seawater intrusion. These criteria are represented by the total dissolved solids, well discharge, sodium adsorption ratio, hydrochemical parameter (Cl/HCO3), hydraulic conductivity and water types. The WMCDSS modeling was tried, where a groundwater vulnerability map with four classes ranging from very low to high vulnerability was gained. The map pinpointed the promising localities for groundwater protection, which are almost represented by the very low or low vulnerability areas (53.69 % of the total study area). The regions having high and moderate groundwater vulnerability occupy 46.31 % of total study area, which designate to a deteriorated territory of groundwater quality, and needs special treatment and cropping pattern before use. However, the moderate groundwater vulnerability class occupies an area of about 28.77 % of the total mapped area, which highlighted the need for certain management practices to prevent the saltwater intrusion from expanding further to the south. There was a good correlation of the constructed vulnerability map with the recently gathered water quality data and hydrochemical facies evolution. The plotting of water quality data on Piper trilinear diagram revealed the evolution of freshwater into the mixing and the saline zones as an impact of seawater intrusion, which validates the model results. 相似文献
16.
Improvement of groundwater quality due to fresh water ingress in Potharlanka Island, Krishna delta, India 总被引：1，自引：0，他引：1
Hydrochemical study had been carried out on the groundwater resources of Potharlanka Island, Krishna delta, India. Groundwater
samples were collected and analyzed at 42 sites in December 2001 and October 2006. A comparative study of hydrochemical data
indicates: groundwater is mildly alkaline with a pH of 7.0–8.2; electrical conductivity (EC) varies from 605 to 5,770 μS/cm
in December 2001, and 652–5,310 μS/cm in October 2006. More than 62% of the groundwater samples in 2006 have TDS value <2,000 mg/l,
which is within permissible limit of potable water, but 57% of the samples in 2001, are higher than the maximum permissible
limit. Extremely low HCO3/Cl and variable high Mg/Ca (molar ratios) had been indicated the transformation of the fresh groundwater aquifer systems
to saline in 2001. Groundwater of this Island is mainly classified as Na–Cl and mixed types. A high percentage of Na–Cl type
of these waters indicates the possibility of seawater ingression/intrusion process during 2001 and comparatively mixed water
type indicates the dilution activities of groundwater. Excessive withdrawal of groundwater has caused the increase of saline
water intrusion. Improvement of groundwater quality in this Island due to artificial recharge structures made by NGRI under
RGNDWM project and affects of the flood due to heavy rainfall of the months of September–October 2005 are discussed in this
paper. 相似文献
17.
Groundwater resources assessment using numerical model: A case study in low-lying coastal area 总被引：4，自引：3，他引：1
S. M. Praveena A. Z. Aris Ph.D. 《International Journal of Environmental Science and Technology》2010,7(1):135-146
The impacts of climate change and human pressure in groundwater have been greatest threats facing small islands. This paper represents a case study of groundwater responses towards the climate change and human pressures in Manukan Island Malaysia. SEAWAT-2000 was used for the simulations of groundwater response in study area. Simulations of six scenarios representing climate change and human pressures showed changes in hydraulic heads and chloride concentrations. Reduction in pumping rate and an increase in recharge rate can alter the bad effects of overdrafts in Manukan Island. In general, reduction in pumping rate and an increase in recharge rate are capable to restore and protect the groundwater resources in Manukan Island. Thus, for groundwater management options in Manukan Island, scenario 2 is capable to lessen the seawater intrusion into the aquifer and sustain water resources on a long-term basis. The selection of scenario 6 is the preeminent option during wet season. The output of this study provides a foundation which can be used in other small islands of similar hydrogeological condition for the purpose of groundwater resources protection. 相似文献
18.
Assessment of seawater intrusion to the agricultural sustainability at the coastal area of Carey Island, Selangor, Malaysia 总被引：3，自引：0，他引：3
Mohamad Faizal Tajul Baharuddin Samsudin Taib Roslan Hashim Mohd Hazreek Zainal Abidin Nur Islami Rahman 《Arabian Journal of Geosciences》2013,6(10):3909-3928
Groundwater suitability for agriculture in an island with limited recharge area may easily be influenced by seawater intrusion. The aim of this study was to investigate seawater intrusion to the suitability of the groundwater for oil palm cultivation at the ex-promontory land of Carey Island in Malaysia. This is the first study that used the integrated method of geo-electrical resistivity and hydro-geochemical methods to investigate seawater intrusion to the suitability of groundwater for oil palm cultivation at two different land cover condition. The relationship between earth resistivity, total dissolved solids and earth conductivity was derived with crop suitability classification according to salinity, used to identify water types and also oil palm tolerance to salinity. Results from the contour conductivity maps show that area facing severe coastal erosion and area still intact with mangrove forest exhibits unsuitable groundwater condition for oil palm at the unconfined aquifer thickness of 15 and 31 m, respectively. Based on local sea-level rise prediction and Ghyben–Herzberg assumption (sharp interface), the condition in the study area, especially in severe erosion area, by the twenty-first century will no longer be suitable for oil palm plantation. The application of geo-electrical method combined with geochemical data, aided with the information on environmental history and oil palm physiography, has demonstrated that the integration of techniques is an effective tool in defining the status of agricultural suitability affected by salinity at the coastal aquifer area. 相似文献
19.
A. Z. Aris M. H. Abdullah B.Sc. M.Sc. Ph.D. A. Ahmed B.Sc. M.Sc. Ph.D. K. K. Woong B.Sc. M.Sc. Ph.D. 《International Journal of Environmental Science and Technology》2007,4(4):441-450
Factor analysis was applied to the hydrochemical data set of Manukan Island in order to extract the principal factors corresponding to the different sources of variation in the hydrochemistry. The application of varimax rotation was to ensure the clear definition of the main sources of variation in the hydrochemistry. The geochemical data of dissolved major, minor and trace constituents in the groundwater samples indicates the main processes responsible for the geochemistry evolution. By using Kaiser normalization, principal factors were extracted from the data for each location. The analysis reveals that there are four sources of solutes: (1) seawater intrusion; (2) leaching process of underlying rock mediated by pH; (3) minerals weathering process and (4) dissolution of carbonate minerals characterized by high loadings of Ca, Zn and Mg. Such processes are dominated by the significant role of anthropogenic impact from the over abstraction of fresh water from the aquifer. Those factors contributed to the changes of the groundwater geochemistry behavior explain the effect of rising extraction of freshwater from the aquifer. 相似文献