雷州半岛防海水入侵最优地下水开采方案探讨

雷州半岛地表水资源缺乏 ,地下水资源较丰富 ,近年开采量剧增 ,局部已形成大面积降落漏斗 ,面临海水入侵的威胁。通过对研究区内地下水流的数值模拟 ,建立了一个以预防海水入侵为目的的地下水资源管理模型 ,并以管理区为单元给出了不同区域地下水资源的最优开采量。认为在防止海水入侵的前提下 ,区内地下水总体上尚有开采潜力 ,但要适当分散开采区域 ,滨岸地区基本维持现状 ,内陆可不同程度地增大开采量。     

State of seawater intrusion and its adaptive management countermeasures in Longkou City of China

Longkou City is a coastal area,and lacks water resources.The overexploitation of groundwater causes seawater intrusion.At present,seawater intrudes an area of 68 km2.With the decrease of groundwater extraction,the seawater intrusion area has generally declined.The paper expounds the development process of seawater intrusion as well as the corresponding prevention and control measures of using groundwater replenishment and groundwater throttling in Longkou City.In view of the seawater intrusion problem in Longkou City,some adaptive management countermeasures are put forward,which include:Adjusting industrial and agricultural structure,promoting economic and social development to match water resources;improving water usage structure,optimizing the utilization of water resources;advancing the construction of a water-saving society,using water resources efficiently;implementing inter-basin water transfer,using water resources rationally;developing and utilizing unconventional water sources,making full use of water resources;strengthening water infrastructure construction,increasing the development and utilization potential of water resources;carrying out ecological restoration,protecting water resources and ecological environment;improving the management informationalization level,strengthening the capabilities of groundwater monitoring and management;increasing publicity,improving public awareness of participation.     

A review of seawater intrusion and its management in Australia

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.     

大连市海水入侵现状与防治措施

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。     

Groundwater resources protection and aquifer recovery in China

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.     

Numerical simulation of sea water intrusion near Beihai, China

 A leaky aquifer system occurs in the coastal plain near Beihai, China. Seawater intrusion into the confined aquifer took place along the northern coast. Chloride concentrations at some observation wells increased steadily from 1988 and were at their peak in 1993. A quasi-three-dimensional element model has been developed to simulate the spatial and temporal evolution of hydraulic heads and chloride concentrations of the groundwater near the northern coast. The simulation model was based on the transition zone approach, which requires simultaneous solution of the governing water flow and solute transport equations. An irregular grid of a quadrangle was used to discretize the flow domain. Various aquifer parameters were verified with the numerical model in order to obtain satisfactory matches between computed values and observed data from an investigation. Three pumpage schemes were designed to use the calibrated model for prediction of future changes in water levels and chloride concentrations in groundwater in the study area. Results show that seawater intrusion would worsen in the confined aquifer if the current rates of groundwater pumpage continue. The alternative, to eliminate pumpage in the intruded area and to moderate pumpage rates from water supply wells far from the seashore, may limit seawater intrusion significantly and is considered attractive in the area. Received: 27 September 1999 · Accepted: 27 December 1999     

The integrated impacts of natural processes and human activities on groundwater salinization in the coastal aquifers of Beihai,southern China

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.     

Modeling of seawater intrusion in a coastal aquifer of Karaburun Peninsula,western Turkey

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.     

华北平原地下水人工补给模式研究

地下水人工补给是防止地下水资源持续匮乏、维护地下水系统活力的重要举措.在华北地区,按照水文地质条件、补给水源条件、地下水环境问题等的不同,组合筛选出五大代表性区域:山前浅层超采区、中东部平原深层超采区、山东半岛滨海海水入侵区、农业灌溉区和城市地区.针对不同区域,分别阐述了储水空间条件、补给水源条件及实施人工补给的首要目...     

海河流域地下水资源保护

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。     

环境同位素特征对滨海岩溶地区海水入侵过程的指示意义

大连大魏家水源地位于中国北方典型滨海岩溶地区。近30年来,地下淡水的不合理开采造成的地下水位降落漏斗引发了严重的海水入侵。以大魏家水源地为研究对象,通过大量的水文地质调查和水化学及同位素采样测试分析,探讨海水入侵形成的水动力条件,通过分析滨海岩溶含水层中地下水主要水化学和多种同位素(δ2H-δ18O,δ34S,δ13C)组成特征,识别了海水入侵过程中发生的主要水文地球化学作用,并对其进行了定量模拟,从而阐明了岩溶含水层中的海水入侵机理。研究结果表明:大连大魏家海水入侵主要通道为大魏家地区存在的导水断裂、岩溶裂隙以及第四系松散地层。对δ2H-δ18O同位素的组成分析表明,研究区地下水主要来自大气降水补给,结合Cl-浓度分布,认为除海水入侵淡水含水层后增加了地下水中的盐分外,浅层地下水的蒸发也对地下水中盐分的累积起到了重要作用。根据不同水体中δ34SSO4,δ13CHCO3等同位素特征,结合水化学成分(如SO2-4,Cl-)分析认为,研究区微咸水和咸水并不是地下水淡水和海水简单混合而成。利用反向水文地球化学模拟揭示了控制滨海岩溶含水层中水化学演化的主要水文地球化学反应有方解石、蒙脱石和石膏的溶解作用,伊利石的沉淀作用以及Ca-Na离子交换作用,伴随着CO2的释放。     

Intervention scenarios to manage seawater intrusion in a coastal agricultural area in Oman

The Batinah coastal plain in northern Oman has experienced a severe deterioration of groundwater quality due to seawater intrusion as a result of excessive groundwater abstraction for agricultural irrigation. Upgrading all farms to fully automated irrigation technology based on soil moisture sensors may significantly reduce the water demand and lead to recovering groundwater levels. This study compares the effects of smart irrigation technology, recharge dams, and a combination of both on seawater intrusion in the coastal aquifer of the Batinah. A groundwater flow and transport model is used to simulate the effect of reduced pumping rates on seawater intrusion for various intervention scenarios over a simulation period of 30 years, and an economic analysis based on cost-benefit analysis is conducted to estimate the potential benefits. Results indicate that a combination of smart irrigation and recharge dams may prevent further deterioration of groundwater quality over the next 30 years. In conjunction with increased efficiency, this combination also generates the highest gross profit. This outcome shows that the problem of seawater intrusion needs to be tackled by a comprehensive, integrated intervention strategy.     

Groundwater quality of porous aquifers in Greece: a synoptic review

Greece is dependent on groundwater resources for its water supply. The main aquifers are within carbonate rocks (karstic aquifers) and coarse grained Neogene and Quaternary deposits (porous aquifers). The use of groundwater resources has become particularly intensive in coastal areas during the last decades with the intense urbanization, tourist development and irrigated land expansion. Sources of groundwater pollution are the seawater intrusion due to over-exploitation of coastal aquifers, the fertilizers from agricultural activities and the disposal of untreated wastewater in torrents or in old pumping wells. In the last decades the total abstractions from coastal aquifers exceed the natural recharge; so the aquifer systems are not used safely. Over-exploitation causes a negative water balance, triggering seawater intrusion. Seawater intrusion phenomena are recorded in coastal aquifer systems. Nitrate pollution is the second major source of groundwater degradation in many areas in Greece. The high levels of nitrate are probably the result of over-fertilization and the lack of sewage systems in some urban areas.     

大连大魏家水源地海水入侵过程中水文地球化学作用分析及定量模拟

大连大魏家水源地位于中国北方典型滨海岩溶地区。近年来,地下淡水不合理开采造成的地下水位降落漏斗引发了严重的海水入侵。本文以大魏家水源地海水入侵为研究对象,通过大量的水文地质调查和水化学样品测试分析,探讨了海水入侵形成的水动力条件,通过绘制Piper图、以Cl^-为天然示踪剂计算了海水和地下淡水的混合比例、实际浓度和理论浓度的对比、水化学组成特征分析等方法,探讨了该区岩溶含水层在海水入侵过程中所发生的主要水文地球化学作用,并对其进行了定量模拟,进而阐明了岩溶含水层中的海水入侵机理。研究结果表明,研究区微成水和成水并不是地下水淡水和海水简单混合而成。利用反向水文地球化学模拟揭示了控制滨海岩溶含水层中水化学演化的主要水文地球化学反应有方解石、蒙脱石和石膏的溶解作用,伊利石的沉淀作用以及Ca—Na离子交换作用,伴随着CO2的释放,石膏的溶解并没引起白云石化作用。     

基于多变量统计分析和水化学特征的海水入侵特征研究——以青岛市崂山区为例

沿海地区地下水环境问题日益突出,进行地下水水化学特征及演化规律的研究,能够更有效地开展地下水环境的监测和保护。以青岛市崂山区地下水为研究对象,综合运用统计分析、主成分分析、Piper图解法、HFE-D图解法、Chadha’s矩形图法等方法,对研究区海水入侵特征与地下水化学特征演化进行分析,探究地下水水化学特征及演化规律,并进一步评价了海水入侵现状。结果表明,研究区地下水以Na+、Ca2+、Cl−、${\rm{SO}}_4^{2-}$为主要优势离子,地下水化学类型多为Cl·SO4-Na型和SO4·Cl-Ca·Mg型。地下水中Cl−浓度变化幅度较大,且其均值超出了有无海水入侵的分界值（250 mg·L−1）,地下水可能发生一定程度的海水入侵;青岛市崂山区地下水呈中性至弱碱性（pH均值=7.0~8.0）,是沿海地区长期的水文地球化学过程的影响;地下水化学变化主要受自然因素（岩石与水的相互作用）或人为因素（农业和家庭活动）的控制;采用反距离加权（IDW）方法,结合地理信息系统（GIS）,进行海水入侵位置的空间映射,研究结果表明崂山区海水入侵主要分布于江家土寨东−浦里社区北入侵段,王哥庄−港西−港东入侵段、仰口湾入侵段、登瀛村−栲栳岛入侵段。     

Assessment of hydrochemistry and groundwater quality in the coastal area of South Chennai,India

An attempt has been made to evaluate the water quality in the fast-growing coastal area of South Chennai. Groundwater samples were collected from selected locations and analyzed for major physico-chemical parameters. Experimental results show that the water has alkaline with pH varying from 7.2 to 8.2. Concentrations of Na and Cl were positively correlated with EC and elevated levels of these parameters near the coastal region, especially in the northern end of the study area, indicating the influence of seawater intrusion. Piper diagram identified Na–Cl as the dominant type of water in most of the samples. The presence of Ca–Cl facies in the groundwater suggests the possible ion exchange (Na with Ca) reaction in the aquifer. Molar ratios of Cl/HCO₃ and Mg/Ca showed a higher value (>1) in many samples, which confirmed the influence of seawater intrusion on water quality. The Water Quality Index (WQI) of the study area ranged between 8 and 116, the highest recorded being at Thiruvanmiyur and the lowest at Muttukkadu. However, total hardness values show that 64% of the samples were hard or very hard in nature. The results of SAR, Na%, and PI show that majority of the samples are suitable for irrigation purposes. A comparison of spatial distribution maps of water quality parameters with those of WQI shows that groundwater quality has highly deteriorated in the Thiruvanmiyur region, located on the northeast part of the study area. Good-quality water is found at the southeast part of the study area, namely, Muttukkadu. This study indicates that urbanization and seawater intrusion have heavily affected the groundwater quality of South Chennai coastal area.     

Review: Safe and sustainable groundwater supply in China

Exploitation of groundwater has greatly increased since the 1970s to meet the increased water demand due to fast economic development in China. Correspondingly, the regional groundwater level has declined substantially in many areas of China. Water sources are scarce in northern and northwestern China, and the anthropogenic pollution of groundwater has worsened the situation. Groundwater containing high concentrations of geogenic arsenic, fluoride, iodine, and salinity is widely distributed across China, which has negatively affected safe supply of water for drinking and other purposes. In addition to anthropogenic contamination, the interactions between surface water and groundwater, including seawater intrusion, have caused deterioration of groundwater quality. The ecosystem and geo-environment have been severely affected by the depletion of groundwater resources. Land subsidence due to excessive groundwater withdrawal has been observed in more than 50 cities in China, with a maximum accumulated subsidence of 2–3 m. Groundwater-dependent ecosystems are being degraded due to changes in the water table or poor groundwater quality. This paper reviews these changes in China, which have occurred under the impact of rapid economic development. The effects of economic growth on groundwater systems should be monitored, understood and predicted to better protect and manage groundwater resources for the future.     

Coastal-zone shallow-aquifer characterization study using geoelectrical and geochemical methods in Zirconium Complex,Atomic Energy,Pazhayakayal, Thoothukudi,India

Groundwater is a very important component of water resources in coastal aquifers in Thoothukudi. It has been established that the groundwaters in the coastal zone of the Zirconium Complex, Pazhayakayal, Thoothukudi district, Tamilnadu, India, are subjected to wave and tidal impact. The groundwater quality was studied by hydrogeological methods, 2D electrical resistivity imaging (ERI) techniques (six profiles), 11 Wenner vertical electrical sounding (VES), and well log analysis. Also, nine geochemical water samples were taken from the study area. The 2D ERI and VES surveys were carried out using WGMD-4 Ltd., Chennai, resistivity meter, multicore cable, and multielectrodes with Wenner array. The collected resistivity data were interpreted using the Res2DINV software. The research shows that the groundwaters are the result of the paleoriver flow along the Tamirabarani Channel in the western area and of the seawater intrusion in the eastern area. The fresh water is characterized by resistivity of about 10–100 Ohm?m in the study area. The resistivity of 10–50 Ohm?m indicates that the subsurface section is made up of sand, clay, and caliche. Resistivity values of more than 200 Ohm?m are specific to sand dunes. The very low resistivity (<5 Ohm?m) layer might be due to the seawater intrusion in the study area. Six water samples from the well drilled in the coastal area were analyzed, which made it possible to determine the concentrations of major and trace elements in the groundwaters. These data were used to establish the seawater intrusion and coastal environment characteristics in the study area.     

Groundwater salinization processes in shallow coastal aquifer of Djeffara plain of Medenine, Southeastern Tunisia

Urban and industrial development and the expansion of irrigated agriculture have led to a drastic increase in the exploitation of groundwater resources. The over-exploitation of coastal aquifers has caused a seawater intrusion and has seriously degraded groundwater quality. The shallow coastal aquifer of the Djeffara plain, southeastern Tunisia constitutes an example of water resource suffering an intensive and uncontrolled pumping for irrigation. Intensive exploitation of the aquifer and climate aridity caused a decrease in piezometric level and an increase in salinity. According to the hydrochemical data (Cl⁻, SO₄ ²⁻, NO₃ ⁻, HCO₃ ⁻, Br⁻, Ca²⁺, Mg²⁺, Na⁺, K⁺) and the stable isotope composition (oxygen-18 and deuterium content), groundwater salinization in the investigated system is caused by three main processes: (i) salts dissolution especially in the central part of Jerba and around Medenine plain; (ii) evaporation process; and (iii) seawater intrusion which caused the increase in salinity in the peninsula of El Jorf, in Jerba and in the North of Ben Gardane.     

控制海水入侵的地下水多目标模拟优化管理模型

为实现滨海含水层地下水开采-回灌方案优化、控制海水入侵面积和降低海水入侵损失等多重管理目标,建立了海水入侵条件下地下水多目标模拟优化管理模型SWT-NPTSGA。模拟模型采用基于变密度流的数值模拟程序SEAWAT来模拟海水入侵过程。优化模型采用小生境Pareto禁忌遗传混合算法NPTSGA来求解,该算法在保证多目标权衡解的收敛性和计算效率的前提下,能维护整个进化群体的全局多样性。将SWT-NPTSGA程序应用于一个理想滨海含水层地下水开采方案和人工回灌控制海水入侵的优化设计中,结果表明该管理模型能够同时处理最大化总抽水流量、最小化人工回灌总量和最小化海水入侵范围等3个目标函数之间的权衡关系。通过采用人工回灌海水入侵区的减灾策略,既能增加滨海地区的供水量,又可减少海水入侵的范围,由此进一步验证了模型的有效性和可靠性。