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A thirty-year artificial recharge experiment in a coastal aquifer in an arid zone: The Teboulba aquifer system (Tunisian Sahel) 总被引:1,自引:0,他引:1
With the increased demand for groundwater resulting from fast demographic growth, accelerated urbanization, economic and agricultural activity diversification, and the increase of per capita consumption, ground water resources, in particular in coastal regions, remain relatively low, compared to demand. The groundwater quality and piezometric variations result mainly from intensive exploitation, agricultural activities and the intrusion of seawater. This phenomenon is observed mostly in semi-arid areas, such as the oriental Sahel of Tunisia, where an apparent reduction in rainfall in recent years can be seen. Groundwater becomes overexploited especially as its natural recharge by rainwater does not succeed in maintaining the hydrologic balance. The imbalance between water demand and resources induces the degradation of the water quality. In such a case, the artificial recharge of water-table aquifers by water from dams is a credible alternative to improve the hydrodynamic and physicochemical conditions of the groundwater. Like most coastal aquifers, the Teboulba water-table aquifer is threatened by overexploitation for at least three decades. This threat appears by a considerable piezometric level drop and by water salinisation, due to seawater intrusion. Given this alarming situation, since 1971, artificial recharge through wells with surface water from a dam was tested in order to restore the water levels and to improve water quality. The piezometric and chemical surveys of the Teboulba aquifer permitted one to describe the temporal and spatial piezometric and geochemical conditions of the aquifer and to show the effect of the artificial recharge. Indeed, the artificial recharge undertaken since 1971 made the geochemical and piezometric conditions of the Teboulba aquifer improve. This example is a rare, well-documented case-study of the benefits of artificial recharge in a coastal aquifer, over the long term. 相似文献
3.
Seawater intrusion is one of the most serious environmental problems in many coastal regions all over the world. Mixing a small quantity of seawater with groundwater makes it unsuitable for use and can result in abandonment of aquifers. Therefore, seawater intrusion should be prevented or at least controlled to protect groundwater resources. This paper presents development and application of a simulation‐optimization model to control seawater intrusion in coastal aquifers using different management scenarios; abstraction of brackish water, recharge of freshwater, and combination of abstraction and recharge. The model is based on the integration of a genetic algorithm optimisation technique and a coupled transient density‐dependent finite element model. The objectives of the management scenarios include determination of the optimal depth, location and abstraction/recharge rates for the wells to minimize the total costs for construction and operation as well as salt concentrations in the aquifer. The developed model is applied to analyze the control of seawater intrusion in a hypothetical confined coastal aquifer. The efficiencies of the three management scenarios are examined and compared. The results show that combination of abstraction and recharge wells is significantly better than using abstraction wells or recharge wells alone as it gives the least cost and least salt concentration in the aquifer. The results from this study would be useful in designing the system of abstraction/recharge wells to control seawater intrusion in coastal aquifers and can be applied in areas where there is a risk of seawater intrusion. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
4.
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
5.
J. Rey J. Martínez G. G. Barberá J. L. García-Aróstegui J. García-Pintado D. Martínez-Vicente 《Environmental Earth Sciences》2013,70(5):2271-2282
Anthropogenic pressure influences the two-way interactions between shallow aquifers and coastal lagoons. Aquifer overexploitation may lead to seawater intrusion, and aquifer recharge from rainfall plus irrigation may, in turn, increase the groundwater discharge into the lagoon. We analyse the evolution, since the 1950s up to the present, of the interactions between the Campo de Cartagena Quaternary aquifer and the Mar Menor coastal lagoon (SE Spain). This is a very heterogeneous and anisotropic detrital aquifer, where aquifer–lagoon interface has a very irregular geometry. Using electrical resistivity tomography, we clearly identified the freshwater–saltwater transition zone and detected areas affected by seawater intrusion. Severity of the intrusion was spatially variable and significantly related to the density of irrigation wells in 1950s–1960s, suggesting the role of groundwater overexploitation. We distinguish two different mechanisms by which water from the sea invades the land: (a) horizontal advance of the interface due to a wide exploitation area and (b) vertical rise (upconing) caused by local intensive pumping. In general, shallow parts of the geophysical profiles show higher electrical resistivity associated with freshwater mainly coming from irrigation return flows, with water resources mostly from deep confined aquifers and imported from Tagus river, 400 km north. This indicates a likely reversal of the former seawater intrusion process. 相似文献
6.
The integrated impacts of natural processes and human activities on groundwater salinization in the coastal aquifers of Beihai,southern China 总被引:1,自引:0,他引:1
Salinization in coastal aquifers is usually related to both seawater intrusion and water–rock interaction. The results of chemical and isotopic methods were combined to identify the origin and processes of groundwater salinization in Daguansha area of Beihai, southern China. The concentrations of the major ions that dominate in seawater (Cl?, Na+, Ca2+, Mg2+ and SO 4 2– ), as well as the isotopic content and ratios (2H, 18O, 87Sr/86Sr and 13C), suggest that the salinization occurring in the aquifer of the coastal plain is related to seawater and that the prevailing hydrochemical processes are evaporation, mixing, dissolution and ion exchange. For the unconfined aquifer, groundwater salinization has occurred in an area that is significantly influenced by land-based sea farming. The integrated impacts of seawater intrusion from the Beibuwan Gulf and infiltration of seawater from the culture ponds are identified in the shallowest confined aquifer (I) in the middle of the area (site BBW2). Leakage from this polluted confined aquifer causes the salinization of groundwater in the underlying confined aquifer (II). At the coastal monitoring site (BBW3), confined aquifer I and lower confined aquifer II are heavily contaminated by seawater intrusion. The weak connectivity between the upper aquifers, and the seaward movement of freshwater, prevents saltwater from encroaching the deepest confined aquifer (III). A conceptual model is presented. Above all, understanding of the origin and processes of groundwater salinization will provide essential information for the planning and sustainable management of groundwater resources in this region. 相似文献
7.
Monitoring and methods to analyse the groundwater quality degradation risk in coastal karstic aquifers (Apulia,Southern Italy) 总被引:1,自引:0,他引:1
A multi-methodological approach based on monitoring and spatio-temporal analysis of groundwater quality changes is proposed.
The presented tools are simple, quick and cost-effective to give service to all sorts of users. The chief purpose of the monitoring
network is the detection of the piezometric or potenziometric level in the aquifer. The spatial and multi-temporal analysis
of usual chemical and physical data provides both an assessment of the spatial vulnerability of the aquifer to seawater intrusion,
defining a salinity threshold between fresh groundwater and brackish groundwater and of the water quality trend in terms of
salinity. The evaluation of the salinity trend or of salinity-correlated parameters highlights the effects of groundwater
mismanagement. The multiparameter logging provides a rapid groundwater quality classification for each well. The whole approach
allows evaluating the effects of current management criteria and designing more appropriate management targets. The Apulian
karstic coastal aquifers have been selected as a case study (Southern Italy). Three types of aquifer zones can be distinguished:
(1) areas with low vulnerability to seawater intrusion, (2) areas with high vulnerability and (3) areas with variable vulnerability
in which the salt degradation largely depends on the ability to manage the well discharge. The water quality degradation caused
by seawater intrusion appears to be a combined effect of an anomalous succession of drought periods observed from about 1980
onwards and increased groundwater pumping, particularly during drought periods. A management criterion based on aquifer zones
is proposed. 相似文献
8.
GIS-based GALDIT method for vulnerability assessment to seawater intrusion of the Quaternary coastal Collo aquifer (NE-Algeria) 总被引:1,自引:0,他引:1
Boulabeiz Mahrez Stefan Klebingat Belgacem Houha Bousnoubra Houria 《Arabian Journal of Geosciences》2018,11(4):71
The overexploitation of groundwater in coastal aquifers is often accompanied by seawater intrusion, intensified by climate change and sea level rise. Heading long-term water quality safety and thus the determination of vulnerable zones to seawater intrusion becomes a significant hydrogeological task for many coastal areas. Due to this background, the present study focussed the established methodology of the GIS-based GALDIT model to assess the aquifer vulnerability to seawater intrusion for the Algerian example of the Quaternary coastal Collo aquifer. According to the result analysis overall, more than half of the total surface of the northern study area can be classified as highly vulnerable. Besides the coastline, the areas nearby the local wadis of Guebli and Cherka occur to be the most vulnerable in the region. In view of further map removal performance as well as single-parameter sensitivity analyses from a coupled perspective respectively the GALDIT parameters, distance from the shore (D) and aquifer hydraulic conductivity (A) have been found to be of key significance regarding the model results (mean effective weightings ~?18–19%). Overall, the study results provide a good approximation basis for future management decisions of the Collo aquifer region, including various perspectives such as identification of suitable settings for prospective groundwater pumping wells. 相似文献
9.
Groundwater resources protection and aquifer recovery in China 总被引:7,自引:0,他引:7
Zaisheng Han 《Environmental Geology》2003,44(1):106-111
The groundwater resources in China and especially the northern part represent a vital water resource. Both the shallow and deep aquifers are highly overexploited in a large area of north China. The heavy overexploitation of groundwater resources is causing major environmental damage. To protect groundwater resources, several technical feasibility studies were performed. Artificial recharge using floodwater and wastewater was tried. Surface spreading systems are applicable in many areas of the Yellow River basin and Hai River basin. Deep aquifer injections were undertaken in the urban area. A far better strategy is to reduce the extraction of groundwater, especially to stop or slow down land subsidence and seawater intrusion. To address the problem of falling groundwater levels and aquifer recovery, there is a need reduce groundwater extraction and artificial recharge. 相似文献
10.
海河流域地下水资源保护 总被引:8,自引:2,他引:8
韩再生 《水文地质工程地质》2001,28(1):25-28
地下水资源在海河流域至关重要的资源。海河平原的浅层和深层含水层大面积处于严重超采状态。地下水资源的的过量开采造成了严重环境问题。为了保护地下水资源,评价了可行的技术。利用洪水和废水进行人工回灌已进行了试验。在很多地区可以应用地表回灌系统,城市地区实施深层含水层的回灌。更好地策略是减少地下水的抽取量,特别是为了减缓地面沉降和海水入侵。应该联合运用减少地下水抽水量和人工回灌,以解决地下水位持续下降和含水层恢复的问题。 相似文献
11.
The Middle East and North Africa (MENA) region suffers from low precipitation and high evaporation. Coastal areas of the MENA region are usually densely populated; hence, the coastal aquifers are easily over-exploited beyond their safe yield, and seawater intrusion and aquifer salinization have been caused by the groundwater-level declines. Four studies in MENA coastal aquifers, on seawater intrusion modeling and aquifer recharge and salinization using isotopes, have been brought together in a topical collection and are discussed in this essay. A brief overview is given of managed aquifer recharge as an effective method to combat groundwater-level decline, seawater intrusion and aquifer salinization in MENA counties. 相似文献
12.
Emna Boughariou Moez Bahloul Ikram Jmal Nabila Allouche Jalila Makni Hafedh Khanfir Salem Bouri 《Arabian Journal of Geosciences》2018,11(4):69
Shallow groundwater is one of the main water resources in the arid and semi-arid regions. However, it is threatened by not only the reduced rainfall and recharge capacity, but also the water table drawdown and seawater intrusion. Such factors could cause a deterioration of the water quality and consequently the loss of a valuable hydraulic resource. This study aimed to improve our knowledge on the groundwater chemical quality evolution of the Sfax shallow aquifer, one of the most vulnerable areas in Tunisia, by developing a geochemical study using statistical and numerical methods. Salinization was identified by factorial analysis, PCA, and hierarchical clustering analysis in addition to the numerical MODPATH model. These findings confirmed that the groundwater quality has deteriorated due to natural and anthropogenic processes with a different influence of mineralization factors. They also revealed the location of seawater intrusion by focusing on the most vulnerable areas which are Chaffar and Djbeniana. Methodologically, the use of MODPATH model for seawater intrusion determination might be considered as the backbone for future studies in Tunisian coastal aquifers. The numerical model supports the results obtained by the geochemical analysis. Both methods are valuable tools as they contribute to trend determinations, management, and recovery plans. 相似文献
13.
Zakynthos, an island of 408 km2 in the Ionian Sea, is completely dependent on its groundwater resources for fulfilling the demands of the water supplies.
The use of groundwater resources has become particularly intensive during the last decades because of the intense urbanization,
the tourist development and the irrigated land expansion that took place. The main aquifers are developed in limestones (karstic),
sandstones of neogene deposits (confined) and alluvial deposits (phreatic). This paper focuses on the assessment of their
hydrogeological characteristics and the groundwater quality. For this investigation, groundwater level measurements, drilling
data, pumping tests and chemical analyses of groundwater samples were used. The average annual consumption that is abstracted
from the aquifer systems, is 4.9 × 106 m3 year−1. The exploitable groundwater reserves were estimated to be 3.3 × 106 m3 year−1. In the last decades, the total abstractions exceed the natural recharge, due to the tourist development; therefore the aquifer
systems are not used safely. The results of chemical analyses showed a deterioration of the groundwater quality. According
to the analyses the shallow alluvial aquifer and the confined aquifer are polluted by nitrates at concentrations in excess
of 25 mg L−1. High sulphate concentrations might be related to the dissolution of gypsum. Seawater intrusion phenomena are recorded in
coastal parts of aquifer systems. The increased Cl− concentrations in karstic aquifer indicate signs of overexploitation. Strengths, weaknesses, opportunities and threats (SWOT)
analysis was applied in order to evaluate the SWOT of the groundwater resources. Moreover, some recommendations are made to
assist the rational management that aim at improving the sustainability of the groundwater resources of Zakynthos Island. 相似文献
14.
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
15.
Review of coastal-area aquifers in Africa 总被引:3,自引:1,他引:2
The coastal aquifer systems of Africa are comprised of various geological formations. These aquifer systems consist of either folded, continental or alluvial deposits. Groundwater resource availability along the coastal areas of Africa is briefly reported and the current state of seawater intrusion has been summarized. A select number of notable examples are given to highlight the effect of saline intrusion on coastal development of cities and regional aquifers. The role of conflict resolution is briefly discussed, as well as management approaches, which include monitoring of contamination and governmental accountability. Regional cooperation is presented as a method of ensuring a sustainable water resource in an area, as well as strengthening social and political alliances. 相似文献
16.
Coastal aquifer assessment based on geological and geophysical survey,northwestern Crete,Greece 总被引:6,自引:3,他引:3
Pantelis M. Soupios Despina Kalisperi Asimina Kanta Maria Kouli Pavel Barsukov Filippos Vallianatos 《Environmental Earth Sciences》2010,61(1):63-77
Groundwater preservation comprises a major problem in water policy. The comprehension of the groundwater/hydraulic systems
can provide the means to approach this problem. Generally, drilling is expensive and time-consuming. On the other hand, new
techniques have been applied during the last few decades that provide useful information on the depth and quality of aquifers.
Among them, transient electromagnetic method (TEM) is an appealing method that provides fast results with minimum field crew
and solves several hydrogeological problems. Many portable systems for single-site measurements are commercially available.
The TEM-Fast 48HPC was used for acquiring 106 soundings in the northwestern Crete in Greece for defining the hydrogeological
characteristics of the study area, since there were no available data from boreholes. Detailed geological, hydrolithological
and tectonic survey was applied prior to the geophysical measurements. All the data were integrated to produce a secure and
reliable hydrogeological model for the study area prior to any future hydrowell. Specifically, geometrical and hydraulic data
of the study area groundwater were acquired. Two unconnected aquifers were detected and their possible contamination due to
saltwater intrusion was analyzed and eliminated. Moreover, a location for borehole construction and groundwater pumping based
on the potential of the aquifer system was proposed. Finally, the contribution of TEM (and electrical resistivity tomography)
geophysical methods in studying complex coastal aquifers is shown by this work. 相似文献
17.
大连市海水入侵现状与防治措施 总被引:2,自引:0,他引:2
李宝兰 《地质灾害与环境保护》2009,20(3):59-62
海水入侵是沿海地区的环境问题之一。大连是我国北方重要的港口和工业城市.处于三面靠海的半岛地理环境。同时.大连也是一个水资源十分紧缺的城市。自20世纪70年代开采地下水以来.出现了越来越严重的海水入侵问题.海水入侵问题对当地的工农业生产、生态环境及人们的身体健康均造成了不同程度的影响。目前大连市的海水入侵问题已得到控制,基本处于稳定状态。提出了因地制宜的海水入侵防治措施。 相似文献
18.
A review of seawater intrusion and its management in Australia 总被引:5,自引:3,他引:2
Adrian D. Werner 《Hydrogeology Journal》2010,18(1):281-285
Extended periods of below-average rainfall combined with a rising population density in the Australian coastal margin have led to higher stresses on coastal water resources, and the risk of seawater intrusion has increased. Despite reports of seawater intrusion in the majority of states and evidence that some Australian coastal aquifers are seriously depleted, comprehensive seawater intrusion investigations have only been completed for coastal systems in Queensland and to a lesser degree in Western Australia and South Australia. The degree of assessment appears to be linked to the perceived economic value of the groundwater resource. The most detailed studies include those of the Pioneer Valley and Burnett basins in Queensland, for which conceptual and mathematical models have been developed at the regional scale, and have been used to underpin trigger-level management approaches to protect against further seawater intrusion. Historical responses to seawater intrusion include the establishment of artificial recharge schemes; the most prominent being that of the Lower Burdekin aquifers in Queensland. Recommendations for future solutions include enhanced fit-for-purpose seawater intrusion monitoring, continuing research into investigation methods, and improved knowledge-sharing through education programs and the development of national guidelines for seawater intrusion assessment and management. 相似文献
19.
Groundwater recharge dams in arid areas as tools for aquifer replenishment and mitigating seawater intrusion: example of AlKhod, Oman 总被引:1,自引:1,他引:0
Groundwater depletion and seawater intrusion constitute major challenges along coastal aquifers in arid areas. This paper assesses the role of groundwater recharge dams constructed to replenish aquifers and fight seawater intrusion with reference to AlKhod dam, Oman, sited 7 km from the coast on a gravely unconfined aquifer. Water table rise in piezometers located downstream from the dam shows regular patterns correlating with magnitude of wadi flow, whereas upstream piezometers show irregular patterns. Controlled release of water captured by the dam optimizes water percolation and enhances artificial recharge which was estimated in the wet years 1997, 2003 and 2005 as 15, 22 and 27 Mm3, respectively, using water table fluctuation method. Recharge contributed 40–60 % of the total annual abstraction. Groundwater salinity increased in the 1980s and 1990s and the saline/freshwater interface advanced inland, but has receded partially after 1997 (highest rainfall) and completely after 2005 indicated by reduction in electrical conductivity and thickening of freshwater lens. The recession is attributed to the dam’s induced recharge and reduction of pumping in 2004 following the commissioning of Barka desalination plant. Integrating artificial recharge with groundwater resources management is therefore an effective measure to replenish aquifers in arid areas and mitigate seawater intrusion along the coasts. 相似文献
20.
Ahmed Y. S. Mansour Alper Baba Orhan Gunduz Celalettin Şimşek Alper Elçi Alim Murathan Hasan Sözbilir 《Environmental Earth Sciences》2017,76(22):775
Seawater intrusion is a major problem to freshwater resources especially in coastal areas where fresh groundwater is surrounded and could be easily influenced by seawater. This study presents the development of a conceptual and numerical model for the coastal aquifer of Karareis region (Karaburun Peninsula) in the western part of Turkey. The study also presents the interpretation and the analysis of the time series data of groundwater levels recorded by data loggers. The SEAWAT model is used in this study to solve the density-dependent flow field and seawater intrusion in the coastal aquifer that is under excessive pumping particularly during summer months. The model was calibrated using the average values of a 1-year dataset and further verified by the average values of another year. Five potential scenarios were analyzed to understand the effects of pumping and climate change on groundwater levels and the extent of seawater intrusion in the next 10 years. The result of the analysis demonstrated high levels of electrical conductivity and chloride along the coastal part of the study area. As a result of the numerical model, seawater intrusion is simulated to move about 420 m toward the land in the next 10 years under “increased pumping” scenario, while a slight change in water level and TDS concentrations was observed in “climate change” scenario. Results also revealed that a reduction in the pumping rate from Karareis wells will be necessary to protect fresh groundwater from contamination by seawater. 相似文献