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1.
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   

2.
Degradation of groundwater quality by human activities is a widespread environmental problem in Vietnam. Groundwater there is a major source of water for domestic and industrial purposes. This paper reviews, compiles, and comprehensively analyzes spatiotemporal variations of hydrological and hydrogeological characteristics of shallow and deep groundwater aquifers in northern Hanoi industrial zones and in nearby Red River water. Groundwater level, electrical conductivity, and water temperature were measured in six monitoring wells, complemented by anion, cation, and stable isotope analyses of ground and surface water. The results show that the groundwater in both shallow and deep aquifers was fresh, but mainly calcium-bicarbonate type contaminants and human activities affect groundwater and surface water composition. With the goal of devising sustainable water use regulations, more research must be directed toward long-term monitoring of groundwater and surface water quality, as well as toward detailed investigation of the hydraulic characteristics of local aquifers in the study area.  相似文献   

3.
The groundwater reserves in Kharga Oases have been studied for the long-term socioeconomic development in the area. The Nubian Sandstone, which consists of a thick sequence of coarse clastic sediments of sandstone, sandy clay interbedded with shale, and clay beds, forms a complex aquifer system. The Nubian Aquifer has been providing water to artesian wells and springs in the Kharga Oases for several thousand years. Groundwater in the Kharga Oases is withdrawn from springs and shallow and deep artesian wells Nearly all the wells originally flowed, but with the exploitation of ground-water from deep wells for irrigation beginning about 1959. the natural flows declined as more and more closely spaced deep wells were drilled By 1975 many deep wells had ceased to flow The water demand in the area has been met by pumping both shallow and deep wells The total annual extraction from deep wells has fluctuated over the year, however, the annual withdrawal from deep wells has exceeded extraction from shallow wells About 17 billion m3 of water was withdrawn from the combination of shallow and deep wells during the period 1960–1980 The Nubian complex aquifer in the Kharga Oases has a very large groundwater potential that could be exploited and beneficially used for a long-term agricultural development in the area, provided proper well spacing and management are implemented Other major environmental considerations for which precise hydrogeologic data are needed include
  1. Determination of the long-term yield available from properly constructed and producing artesian wells that will support a planned migration of population from the overcrowded Nile delta and flood plain areas
  2. Development of an effective management program and adequate staff to maintain groundwater production over an extended period of years
  3. The impact on climate caused by extensive irrigation in the oases of the Western Desert of Egypt
  4. Protection against water logging of soils from irrigation practices
  5. Protection against salinization of soils from irrigation practices
  6. Development of effective surface and subsurface drainage practices
  7. The impact of farming and pest control practices on the shallow groundwater of the oases
  8. Determination of the long-term development of the artesian water on the quality of the water from the aquiter systems in the Western Desert
This paper addresses items 1, 2 and 8.  相似文献   

4.
The impact of groundwater withdrawals on the interaction between multi-layered aquifers with different water qualities in the Viterbo geothermal area (central Italy) was studied. In this area, deep thermal waters are used to supply thermal spas and public pools. A shallow overlying aquifer carries cold and fresh water, used for irrigation and the local drinking-water supply. Starting with a conceptual hydrogeological model, two simplified numerical models were implemented: a steady-state flow model of the entire groundwater system, and a steady-state flow and heat transport model of a representative area, which included complex interactions between the aquifers. The impact of increased withdrawals associated with potential future development of the thermal aquifer must be considered in terms of the water temperature of the existing thermal sources. However, withdrawals from the shallow aquifer might also influence the discharge of thermal sources and quality of the water withdrawn from the shallow wells. The exploitation of the two aquifers is dependent on the hydraulic conductivity and thickness of the intervening aquitard, which maintains the delicate hydrogeological equilibrium. Effective methods to control this equilibrium include monitoring the vertical gradient between the two aquifers and the residual discharge of natural thermal springs.  相似文献   

5.
Cities have a negative impact on the quality of shallow groundwater. Many of Lithuania's urban residents drink water from dug wells. Moreover, polluted shallow groundwater contaminates deeper aquifers of fresh drinking water. Therefore, this situation should be controlled and managed, as far as possible. In order to evaluate the quality of shallow groundwater in an urban area and to create an optimal monitoring system, an original methodology for groundwater mapping has been proposed. It resembles the GIS (geographical information system) technologies. The set of maps, laid one over another, consists of the following: (1) urbanization map, (2) geological-hydrogeological map, (3) groundwater chemistry map, (4) resulting groundwater chemistry factorial analysis map, and (5) pollution and pollutant transport map. The data obtained from studies on dug and geotechnical wells have been used for compilation of the maps. The system for shallow groundwater monitoring in the city with an area of 70 sq km and a population of 140,000 is proposed to consist of about 30 monitoring wells and several dug wells.  相似文献   

6.
Unplugged abandoned oil and gas wells in the Appalachian region can serve as conduits for the movement of waters impacted by fossil fuel extraction. Strontium isotope and geochemical analysis indicate that artesian discharges of water with high total dissolved solids (TDS) from a series of gas wells in western Pennsylvania result from the infiltration of acidic, low Fe (Fe < 10 mg/L) coal mine drainage (AMD) into shallow, siderite (iron carbonate)-cemented sandstone aquifers. The acidity from the AMD promotes dissolution of the carbonate, and metal- and sulfate-contaminated waters rise to the surface through compromised abandoned gas well casings. Strontium isotope mixing models suggest that neither upward migration of oil and gas brines from Devonian reservoirs associated with the wells nor dissolution of abundant nodular siderite present in the mine spoil through which recharge water percolates contribute significantly to the artesian gas well discharges. Natural Sr isotope composition can be a sensitive tool in the characterization of complex groundwater interactions and can be used to distinguish between inputs from deep and shallow contamination sources, as well as between groundwater and mineralogically similar but stratigraphically distinct rock units. This is of particular relevance to regions such as the Appalachian Basin, where a legacy of coal, oil and gas exploration is coupled with ongoing and future natural gas drilling into deep reservoirs.  相似文献   

7.
In recent years, voices in Jordan became lauder to exploit the fresh to brackish deep groundwater overlain by fresh groundwater bodies. In this article the implications of such a policy on the existing fresh water bodies are worked out through studying the sources of salinity in the different aquifer systems and the potentials of salinity mobilization by artificial changes in the hydrodynamic regimes. It is concluded that extracting the groundwater of deep aquifers overlain by fresh water bodies, whether the deep groundwater is fresh to brackish, brackish or salty, is equivalent to extracting groundwater from the overlying fresh groundwater bodies because of the hydraulic connections of the deep and the shallow aquifers’ groundwaters. The consequences are even more complicated and severe because exploiting the deep groundwater containing brackish or salty water will lead to refilling by fresh groundwater leaking from the overlying aquifers. The leaking water becomes salinized as soon as it enters the pore spaces of the emptied deep aquifer matrix and by mixing with the deep aquifer brackish or saline groundwater. Therefore, the move to exploit the deep groundwater is misleading and damaging the aquifers and is unjust to future generation's rights in the natural wealth of Jordan or any other country with similar aquifers’ set-up. In addition, desalination produces brines with high salinity which cannot easily be discharged in the highlands of Jordan (with only very limited access to the open sea) because they will on the long term percolate down into fresh water aquifers.  相似文献   

8.
北京北部地区深层热水开发对浅层冷水的影响   总被引：1，自引：1，他引：0  
北京北部有小汤山和沙河2个地热田,呈三角形展布,东部边界为黄庄-高丽营断裂,西部边界为南口-孙河断裂．北部边界为阿苏卫-小汤山断裂。热储层为蓟县系雾迷山组、铁岭组和寒武系-奥陶系碳酸盐岩岩溶裂隙含水层．热储盖层为青白口系页岩、石炭系-二叠系砂页岩和侏罗系火山岩隔水层。该区雨水、浅层基岩冷水和深层基岩热水的H、O同位素组成基本上都落在克雷格降水线上,表明区内冷水与热水均来源于大气降水。热水的^3H值表现出北高南低的特点．说明热水与冷水一样自北向南流动。重点分析了深层热水开采对浅层地震观测井中冷水动态的影响,以及这种影响在不同的水文地质条件、离开采井不同距离和不同测项方面表现出的差异。结果表明,北京北部深层热水开采对浅层冷水动态的影响距离约为5km．对位于导水断裂带附近的观测井的影响最为明显。  相似文献   

9.
开采条件下河北平原中部咸淡水界面下移   总被引：3，自引：0，他引：3  
河北平原中部上层咸水入侵下层淡水已造成局部地下水污染,本文调查统计了地下水质监测资料和2700多眼深井孔的测井物探资料。以水化学方法和数理统计方法,从水文地质条件和地下水开采利用状况入手,对研究区咸淡水界面下移的机理进行了分析。结果认为,咸淡水界面从20世纪70年代以来年均下移约0.4m,开采地下水造成上下层水头压力变化,加大上部浅层水向下越流是其主要原因之一。  相似文献   

10.
The WR-2 watershed is located in the Deccan trap basaltic terrain of Maharashtra State, India. The watershed area incorporates a rich orange orchard belt that requires a huge quantity of water for irrigation. This requirement is mostly met through groundwater, extracted from the shallow aquifers of the WR-2 watershed. However, over the years, excess withdrawal of groundwater from these aquifers has resulted in depletion of groundwater level. The declining trends of groundwater level, both long term and short term, have had a negative impact on the groundwater quality of the study area. This effect can be gauged through the rising electrical conductivity (EC) of groundwater in the shallow aquifers (dug wells) of the WR-2 watershed. It is observed that the long term declining trend of groundwater level, during 1977–2010, varied from 0.03 to 0.04 m per year, whereas the corresponding trend of rising EC varied from 1.90 to 2.94 μS/cm per year. During 2007–2010, about 56% dug wells showed a positive correlation between depleting groundwater level and rising EC values. The groundwater level depletion during this period ranged from 0.03 to 0.67 m per year, whereas the corresponding trend of rising EC ranged from 0.52 to 46.91 μS/cm per year. Moreover, the water quality studies reveal that groundwater from more than 50% of the dug wells of the WR-2 watershed is not suitable for drinking purpose. The groundwater, though mostly suitable for irrigation purpose, is corrosive and saturated with respect to mineral equilibrium and shows a tendency towards chemical scale formation.  相似文献   

11.
The Plavinas run-off river scheme in Latvia is founded on fine-grained deposits with artesian aquifers. These aquifers are drained with free flowing wells to assure the stability of the structures. In March 1979, one of these wells suddenly discharged high amounts of solids together with the drainage water. After a few days the water discharge stopped, the artesian pressures in the foundation increased and dirty water flew from the bottom of the tailrace channel area. Foundation failure could be mitigated by turning piezometers into free flowing relief wells. However, it was a critical situation for the powerhouse and caused significant permanent displacements of the concrete structures. A root-cause analysis was performed which is presented in this paper. It was found that caverns at the interface of alluvial and fine-grained deposits formed due to erosion of the fine fractions of the alluvium through the drainage wells. Such a cavern collapsed which caused the well blowout and the plugging of the drainage well resulting in increasing pore water pressures and local liquefaction of the powerhouse foundation.  相似文献   

12.
The Jharia coalfield is the most important and active minig region; it experiences groundwater inflow and affects groundwater levels in overlying aquifers, and it provides the basis for a conceptual model of the hydrogeological impacts of coal mining. The several sandstone aquifers of the overburden are separated by aquitards that limit vertical hydraulic connection, but the inflow responds to seasonal events and seems to be linked to shallow groundwater behavior. The mine drainage behavior suggests a hydraulic connection between the mine and the shallower groundwater system. The greatest declines are directly above the panels, with an immediate response to coal mining. The inflow is localized by natural and induced fracture zones and is mostly into recent workings. The groundwater behavior is controlled by hydraulic property changes caused by mine-induced fracturing. The hydrological and chemical qualities of the shallow groundwater regime in 13 mining collieries in Mukunda Block have been investigated. Water samples collected from 30 shallow monitoring dug wells were chosen for the study. Rainfall, runoff, and infiltration rates have been calculated in the area. The water-quality plottings were used to interpret the distribution of individual chemical parameters and in predicting the water quality. The underground mine water has been classified as: (1) unconfined groundwater in the calcareous siltstone and sandstone—its composition is Na, Ca, SO4 and Na-MgHCO3 with moderate total dissolved solids (TDS) 200–1480 ppm; (2) the deep groundwater originating from the coal seams and associated sediments in the near-surface environments—this is a Na-HCO3 water with higher TDS; and (3) spoil dump waters are essentially Na-HCO3 with high TDS. This article presents some hydrologic results and conclusions relating to the hydrogeological and environmental impacts of the coal mining in the Jharia coalfield.  相似文献   

13.
In the Djerid-Nefzaoua region, southern Tunisia, about 80% of agricultural and domestic water supply is provided by the complex terminal (CT) aquifer. However, 20% of this demand is provided by other hydraulically connected aquifers, namely the continental intercalaire (CI) and the Plio-Quaternary (PQ). Overexploitation of the CT aquifer for agricultural practices has contributed to the loss of the artesian condition and the decline of groundwater level which largely increased the downward leakage from the shallow PQ aquifer. Excess irrigation water concentrates at different rates in the irrigation channels and in the PQ aquifer itself. Then, it returns to the CT aquifer and mixes with water from the regional flow system, which contributes to the salinization of the CT groundwater. A geochemical and isotopic study had been undertaken over a 2-years period in order to investigate the origin of waters pumped from the CT aquifer with an emphasis on its hydraulic relationships with the underlying and the overlying CI and PQ aquifers. Geochemistry indicates that groundwater samples collected from different wells show an evolution of the water types from Na-Cl to Ca-SO4-Cl. Dissolution of halite, gypsum and anhydrite-bearing rocks is the main mechanism that leads to the salinization of the groundwater. Isotopic data indicate the old origin of all groundwater in the aquifer system. Mixing and evaporation effects characterizing the CT and the PQ aquifers were identified using δ2H and δ18O relationship and confirmed by the conjunction of δ2H with chloride concentration.  相似文献   

14.

In the Bandung basin, Indonesia, excessive groundwater pumping caused by rapid increases in industrialization and population growth has caused subsurface environmental problems, such as excessive groundwater drawdown and land subsidence. In this study, multiple hydrogeochemical techniques and numerical modeling have been applied to evaluate the recharge processes and groundwater age (rejuvenation). Although all the groundwater in the Bandung basin is recharged at the same elevation at the periphery of the basin, the water type and residence time of the shallow and deep groundwater could be clearly differentiated. However, there was significant groundwater drawdown in all the depression areas and there is evidence of groundwater mixing between the shallow and deep groundwater. The groundwater mixing was traced from the high dichlorodifluoromethane (CFC-12) concentrations in some deep groundwater samples and by estimating the rejuvenation ratio (R) in some representative observation wells. The magnitude of CFC-12 concentration, as an indicator of young groundwater, showed a good correlation with R, determined using 14C activity in samples taken between 2008 and 2012. These correlations were confirmed with the estimation of vertical downward flux from shallower to deeper aquifers using numerical modeling. Furthermore, the change in vertical flux is affected by the change in groundwater pumping. Since the 1970s, the vertical flux increased significantly and reached approximately 15% of the total pumping amount during the 2000s, as it compensated the groundwater pumping. This study clearly revealed the processes of groundwater impact caused by excessive groundwater pumping using a combination of hydrogeochemical methods and modeling.

  相似文献   

15.
Analyses of environmental isotopes (18O, 2H, and 87Sr/86Sr) are applied to groundwater studies with emphasis on saline groundwater in aquifers in the Keta Basin, Ghana. The 87Sr/86Sr ratios of groundwater and surface water of the Keta Basin primarily reflect the geology and the mineralogical composition of the formations in the catchments and recharge areas. The isotopic compositions of 18O and 2H of deep groundwater have small variations and plot close to the global meteoric water line. Shallow groundwater and surface water have considerably larger variations in isotopic compositions, which reflect evaporation and preservation of seasonal fluctuations. A significant excess of chloride in shallow groundwater in comparison to the calculated evaporation loss is the result of a combination of evaporation and marine sources. Groundwaters from deep wells and dug wells in near-coastal aquifers are characterized by relatively high chloride contents, and the significance of marine influence is evidenced by well-defined mixing lines for strontium isotopes, and hydrogen and oxygen stable isotopes, with isotopic compositions of seawater as one end member. The results derived from environmental isotopes in this study demonstrate that a multi-isotope approach is a useful tool to identify the origin and sources of saline groundwater. Electronic Publication  相似文献   

16.
深层地下水的属性、深浅层地下水的水力联系(越流)是水文地质工作者一直研究和争论的问题。在对邯郸、邢台东部四县深、浅层地下水的氢、氧同位素样品的采集与测试中,发现该区地下水中氚同位素含量较高(15～30 TU,最高达51.1 TU)。本文利用区域大气降水中氚同位素衰减规律与特征,结合研究区地下水的水位和水质动态特征、含水层及隔水层的岩性特征,对特定水文地质条件下浅层地下水向深层地下水越流的可能性进行了分析研究,认为:本区存在浅层地下水越流至深层地下水的可能,在深层地下水中出现的高氚含量是其重要的证据。  相似文献   

17.
The semi-arid Sahel regions of West Africa rely heavily on groundwater from shallow to moderately deep(100 m b.g.l.)crystalline bedrock aquifers for drinking water production.Groundwater quality may be affected by high geogenic arsenic(As)concentrations(10μg/L)stemming from the oxidation of sulphide minerals(pyrite,arsenopyrite)in mineralised zones.These aquifers are still little investigated,especially concerning groundwater residence times and the influence of the annual monsoon season on groundwater chemistry.To gain insights on the temporal aspects of As contamination,we have used isotope tracers(noble gases,~3H,stable water isotopes(~2 H,~(18)O))and performed hydrochemical analyses on groundwater abstracted from tube wells and dug wells in a small study area in southwestern Burkina Faso.Results revealed a great variability in groundwater properties(e.g.redox conditions,As concentrations,water level,residence time)over spatial scales of only a few hundred metres,characteristic of the highly heterogeneous fractured underground.Elevated As levels are found in oxic groundwater of circum-neutral pH and show little relation with any of the measured parameters.Arsenic concentrations are relatively stable over the course of the year,with little effect seen by the monsoon.Groundwater residence time does not seem to have an influence on As concentrations,as elevated As can be found both in groundwater with short(50 a)and long(10~3 a)residence times as indicated by ~3He/~4He ratios spanning three orders of magnitude.These results support the hypothesis that the proximity to mineralised zones is the most crucial factor controlling As concentrations in the observed redox/pH conditions.The existence of very old water portions with residence times10~3 years already at depths of50 m b.g.l.is a new finding for the shallow fractured bedrock aquifers of Burkina Faso,suggesting that overexploitation of these relatively low-yielding aquifers may be an issue in the future.  相似文献   

18.
Continual expansion of population density, urbanization, agriculture, and industry in most parts of the world has increased the generation of pollution, which contributes to the deterioration of surface water quality. This causes the dependence on groundwater sources for their daily needs to accumulate day by day, which raises concerns about their quality and hydrogeochemistry. This study was carried out to increase understanding of the geological setup and assess the groundwater hydrogeochemical characteristics of the multilayered aquifers in Lower Kelantan Basin. Based on lithological data correlation of exploration wells, the study area can be divided into three main aquifers: shallow, intermediate and deep aquifers. From these three aquifers, 101 groundwater samples were collected and analyzed for various parameters. The results showed that pH values in the shallow, intermediate and deep aquifers were generally acidic to slightly alkaline. The sequences of major cations and anions were Na+ > Ca2+ > Mg2+ > K+ and HCO3? > Cl? > SO42? > CO32?, respectively. In the intermediate aquifer, the influence of ancient seawater was the primary factor that contributed to the elevated values of electrical conductivity (EC), Cl? and total dissolved solids (TDS). The main facies in the shallow aquifer were Ca–HCO3 and Na–HCO3 water types. The water types were dominated by Na–Cl and Na–HCO3 in the intermediate aquifer and by Na–HCO3 in the deep aquifer. The Gibbs diagram reveals that the majority of groundwater samples belonged to the deep aquifer and fell in the rock dominance zone. Shallow aquifer samples mostly fell in the rainfall zone, suggesting that this aquifer is affected by anthropogenic activities. In contrast, the results suggest that the deep aquifer is heavily influenced by natural processes.  相似文献   

19.
同位素技术是研究区域地下水循环规律的主要手段之一。本文对平原区地下水进行了取样分析,运用同位素技术并结合水文地质条件,研究了北京市平原区地下水循环演化规律。运用^3H和^14C的测年技术确定了地下水年龄;利用D和18^O关系曲线探讨了地下水的起源;按照是否积极参加了现代水循环的原则将第四系地下水划分为浅层水和深层水;对浅层水和深层水的更新状况进行了研究。研究表明,浅层水广泛分布于北京平原区,径流条件好,更新快;深层水主要分布于永定河、潮白河冲洪积扇下部及冲洪积平原的深部地区,补给条件相对差,与现代大气降水联系弱,径流条件差,更新慢。  相似文献   

20.
文章研究了湛江市50年来的地下水流场变化特征，得出以下结论：市区中、深层承压水经过近50年的集中开采．已形成了以人工开采区为中心的区域水位降落漏斗；浅层水一直未作为集中供水水源，未形成区域水位降落漏斗。影响地下水流场变化的因素主要为开采量，其次为地下水的开采方式及水文地质条件。  相似文献   

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