共查询到20条相似文献，搜索用时 46 毫秒
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Temperature profiles from 25 boreholes were used to understand the spatial and vertical groundwater flow systems in the Western Nile Delta region of Egypt, as a case study of a semi-arid region. The study area is located between the Nile River and Wadi El Natrun. The recharge areas, which are located in the northeastern and the northwestern parts of the study area, have low subsurface temperatures. The discharge areas, which are located in the western (Wadi El Natrun) and southern (Moghra aquifer) parts of the study area, have higher subsurface temperatures. In the deeper zones, the effects of faults and the recharge area in the northeastern direction disappear at 80 m below sea level. For that depth, one main recharge and one main discharge area are recognized. The recharge area is located to the north in the Quaternary aquifer, and the discharge area is located to the south in the Miocene aquifer. Two-dimensional groundwater-flow and heat-transport models reveal that the sealing faults are the major factor disturbing the regional subsurface thermal regime in the study area. Besides the main recharge and discharge areas, the low permeability of the faults creates local discharge areas in its up-throw side and local recharge areas in its down-throw side. The estimated average linear groundwater velocity in the recharge area is 0.9 mm/day to the eastern direction and 14 mm/day to the northwest. The average linear groundwater discharge velocities range from 0.4 to 0.9 mm/day in the southern part. 相似文献
3.
In a confined alluvial aquifer located between two rivers, discrete zones of anomalously high concentrations of redox species such as iron, are thought to be a result of groundwater flow dynamics rather than a chemical evolution along continuous flow paths. This new hypothesis was confirmed at a study site located between Nan and Yom rivers in Phitsanulok, Thailand, by analyzing concentrations of redox species in comparison with dynamic groundwater flow patterns. River incision into the confined alluvial aquifer and seasonally varying river stages result in truncated flow paths. The groundwater flow dynamics between two rivers has four phases that are cyclic, including: aquifer discharge into both rivers, direct flow from one river toward another, aquifer recharge from both rivers, and reverse of river-to-river flow. The resulting groundwater flow direction has a zigzag pattern and its general trend is almost parallel to the river flow. High iron anomaly appears as discrete zones in the transition areas of the confined alluvial aquifer because the lateral recharge from rivers penetrates into the aquifer only by tens of meters. The high iron anomaly, which is nearly constant in space and time, is a result of groundwater/surface-water interactions and related groundwater flow dynamics. 相似文献
4.
Geochemical processes controlling the elevated fluoride concentrations in groundwaters of the Taiyuan Basin,Northern China 总被引：1，自引：0，他引：1
High fluoride groundwater with F− concentration up to 6.20 mg/L occurs in Taiyuan basin, northern China. The high fluoride groundwater zones are mainly located in the discharge areas, especially in places where shallow groundwater occurs (the groundwater depth is less than 4 m). Regional hydrogeochemical investigation indicates that processes including hydrolysis of silicate minerals, cation exchange, and evaporation should be responsible for the increase in average contents of major ions in groundwater from the recharge areas to the discharge areas. The concentration of F− in groundwater is positively correlated with that of HCO3− and Na+, indicating that groundwater with high HCO3− and Na+ contents help dissolve some fluoride-rich minerals. The water samples with high F− concentration generally have relatively higher pH value, implying that alkaline environment favors the replacement of exchangeable F− in fluoride-rich minerals by OH− in groundwater. In addition, the mixing of karst water along the western mountain front and the evaporation may also be important factors for the occurrence of high fluoride groundwater. The inverse geochemical modeling using PHREEQC supports the results of hydrogeochemical analyses. The modeling results show that in the recharge and flow-through area of the northern Taiyuan basin, interactions between groundwater and fluoride-rich minerals are the major factor for the increase of F− concentration, whereas in the discharge area of the northern basin, the evaporation as well as the mixing of karst water has greater contribution to the fluoride enrichment in groundwater. 相似文献
5.
Groundwater flow in the Leon-Chinandega aquifer was simulated using transient and steady-state numerical models. This unconfined aquifer is located in an agricultural plain in northwest Nicaragua. Previous studies were restricted to determining groundwater availability for irrigation, overlooking the impacts of groundwater development. A sub-basin was selected to study the groundwater flow system and the effects of groundwater development using a numerical groundwater flow model (Visual MODFLOW). Hydrological parameters obtained from pumping tests were related to each hydrostratigraphic unit to assign the distribution of parameter values within each model layer. River discharge measurements were crucial for constraining recharge estimates and reducing the non-uniqueness of the model calibration. Steady-state models have limited usefulness because of the major variation of recharge and agricultural pumping during the wet and dry seasons. Model results indicate that pumping induces a decrease in base flow, depleting river discharge. This becomes critical during dry periods, when irrigation is highest. Transient modeling indicates that the response time of the aquifer is about one hydrologic year, which allows the development of management strategies within short time horizons. Considering further development of irrigated agriculture in the area, the numerical model can be a powerful tool for water resources management. 相似文献
6.
Rachmat Fajar Lubis Makoto Yamano Robert Delinom Sudaryanto Martosuparno Yasuo Sakura Shusaku Goto Akinobu Miyakoshi Makoto Taniguchi 《Environmental Earth Sciences》2013,70(5):2033-2038
Urbanization has become one of the domain processes for city development in Indonesia. The results of the extremely high densities of fast growing population have led to negative subsurface environmental impact. Jakarta, as one of the rapidly developed and urbanized cities in Southeast Asia, has become one of the interesting urbanization city to analyze its effects. In Jakarta, the use of groundwater has greatly accelerated conforming to the rise in its population and the development of the industrial sector, which consume a relatively large amount of water. The increase of groundwater exploitation in Jakarta city has already caused a negative impact on these resources. Therefore, an assessment of groundwater trends in the urban area, including their hazard and risk management, is a necessary action. This paper describes the assessment of urban groundwater loading caused by human concentration in Jakarta city. Subsurface heat contamination under the condition of surface warming shows significant effects of urban groundwater loading during the past century in Jakarta city. 相似文献
7.
Application of hydrochemical signatures to delineating portable groundwater resources in Ordos Basin, China 总被引：2，自引：0，他引：2
The Ordos Basin of China encompasses Shaanxi, Gansu, and Shanxi provinces, Ningxia and Inner Mongolia autonomous regions.
It lacks significant surface water resources. Among the water-bearing formations, the Luohe formation, with an area of 1.32×105 km2, is the most prospective aquifer. Groundwater quality data collected at 211 boreholes drilled into the Luhe formation indicate
a complex distribution of groundwater chemistry. The hydrochemical properties were used to study the recharge, runoff, and
discharge conditions of the groundwater in Ordos Basin and to evaluate sustainable groundwater resources. In the northern
part of the basin, the hydrochemistry types and the total dissolved solids (TDS) show a clear lateral transition from SEE
to NWW, indicating that the groundwater gets recharge in the northwest region and discharges in the southeast region. In the
southern part of the basin, maximum TDS occurs at the center of the Malian River valley, from which the TDS decreases radially.
Therefore, the groundwater in the southern basin gets recharge from the southeast and southwest regions, and the Malian River
valley is the discharge zone. As a result of this research, the areas with portable groundwater were delineated. They include
most of the southeast region of the Sishili Ridge, east of the Ziwu Mountain, and the southwest corner of the basin. The TDS
of the groundwater in these regions is less than 1 g/l, and the hydrochemistry type is either HCO3 or HCO3·SO4. 相似文献
8.
Karst groundwater management by defining protection zones based on regional geological structures and groundwater flow fields 总被引：2，自引：0，他引：2
Yonghong Hao Tian-Chyi J. Yeh Caihong Hu Yanrong Wang Xia Li 《Environmental Geology》2006,50(3):415-422
In a semiarid region, the karst aquifer generally forms a large groundwater reservoir that can play an important role in regional water supply. But because of the specific physical properties of karst aquifers, they are vulnerable to pollution and anthropogenic impacts. Karst groundwater management strategies are vital. As representative of karst springs in a semiarid area, Niangziguan Springs is located in the east of Shanxi Province, China with an annual average rate of discharge of 10.34 m3/s (1956–2003) (Y. Liang, unpublished data). The Niangziguan Spring Basin covers an area of 7,394 km2 with an annual average precipitation of 535 mm (1958–2003) (Hao et al. in Carsologica Sinica 23(1):43–47, 2004). Over the past three decades, accelerated groundwater exploitation has caused water-table decline in the aquifer, reduction of the spring discharge, and deterioration of water quality. In this study, three protection zones were defined to ensure the quality and capacity of this resource. The confluence of the 11 spring systems and the discharge areas were defined as I protection zone, the recharge basin was II protection zone, and the slack water area where there is little surface recharge was the III protection zone. Management strategies for each zone were suggested and evaluated to provide a scientific foundation for sustainable utilization. 相似文献
9.
The Krishni–Yamuna interstream area is a micro-watershed in the Central Ganga Plain and a highly fertile track of Western
Uttar Pradesh. The Sugarcane and wheat are the major crops of the area. Aquifers of Quaternary age form the major source of
Irrigation and municipal water supplies. A detailed hydrogeological investigation was carried out in the study area with an
objective to assess aquifer framework, groundwater quality and its resource potential. The hydrogeological cross section reveals
occurrence of alternate layers of clay and sand. Aquifer broadly behaves as a single bodied aquifer down to the depth of 100 m bgl
(metre below ground level) as the clay layers laterally pinch out. The depth to water in the area varies between 5 and 16.5 m bgl.
The general groundwater flow direction is from NE to SW with few local variations. An attempt has been made to evaluate groundwater
resources of the area. The water budget method focuses on the various components contributing to groundwater flow and groundwater
storage changes. Changes in ground water storage can be attributed to rainfall recharge, irrigation return flow and ground
water inflow to the basin minus baseflow (ground water discharge to streams or springs), evapotranspiration from ground water,
pumping and ground water outflow from the basin. The recharge is obtained in the study area using Water table fluctuation
and Tritium methods. The results of water balance study show that the total recharge in to the interstream region is of the
order of 185.25 million m3 and discharge from the study area is of the order of 203.24 million m3, leaving a deficit balance of −17.99 million m3. Therefore, the present status of groundwater development in the present study area has acquired the declining trend. Thus,
the hydrogeological analysis and water balance studies shows that the groundwater development has attained a critical state
in the region. 相似文献
10.
研究区位于西北干旱区,有两级储水洼地,地下水由山区侧向补给一级洼地,一级洼地通过泉水排泄地下水继而补给二级洼地,同时大气降水直接入渗、洪流间接入渗补给各储水洼地。通过氢氧同位素比例公式计算得到一级洼地大气降水占总补给量60%,其中直接补给量约占21%,山区洪流补给量约占79%,另外,山前侧向补给占40%;二级洼地降水补给量占38%,上游泉水补给量占62%。通过氚值指示,二级洼地不受现代降水影响;活塞流与全混合模型计算得到一级洼地浅层孔隙水平均年龄为32～60 a。 相似文献
11.
A catchment water balance model for estimating groundwater recharge in arid and semiarid regions of south-east Iran 总被引：1，自引：0，他引：1
This paper presents a new model of the rainfall-runoff-groundwater flow processes applicable to semiarid and arid catchments
in south-east Iran. The main purpose of the model is to assess the groundwater recharge to aquifers in these catchments. The
model takes into account main recharge mechanisms in the region, including subsurface flow in the valley alluvium in mountainous
areas and recharge from the bed of ephemeral rivers. It deals with the effects of spatial variation in the hydrological processes
by dividing the catchment into regions of broad hydrologic similarity named as highland, intermediate and aquifer areas. The
model is based on the concept of routing precipitation within and through the catchment. The model has been applied to the
Zahedan catchment and the results indicate that the groundwater level estimated by the recharge model generally is in agreement
with the behaviour of groundwater levels in observation wells. The sensitivity analysis indicates that when the rainfall in
the aquifer area is used to replace the values recorded in the intermediate area and the highland area, the recharge estimates
are reduced by 42-87%. This result supports the division of the catchment into different zones of hydrological similarity
to account for spatial variability of hydrological processes.
Electronic Publication 相似文献
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13.
《Applied Geochemistry》1993,8(3):223-233
Surveys of the distribution and migration of He and Rn were carried out in the well-characterized granitic terrane of the AECL Underground Research Laboratory (URL), Manitoba as part of a joint AECL Research, United Kingdom Department of the Environment, and United States Department of Energy research initiative. The investigations were designed to determine whether concentrations of He and Rn in soil gases could be used to identify locations of groundwater recharge and discharge from bedrock fractures. The results obtained indicate that subsurface transport of He and possibly Rn in this setting appears to be controlled largely by the groundwater flow system in the bedrock. Release of dissolved gases near the ground surface causes soil gas anomalies, which reflect discharge from the deeper flow system. In the recharge area of the deep groundwater flow system at the URL site, He abundances are close to the atmospheric level, but the discharge area of the deep flow system is characterized by significant He anomalies (up to 0.5 ppm above atmosphere levels). For Rn, the recharge area has broadly distributed high concentrations, probably caused by local Rn production in U-rich overburden, while the discharge area has only localized concentrations of Rn, which are not at the same location as the He anomalies. The general nature of the groundwater flow regime in both areas is reflected in the presence and distribution of the soil gas anomalies. In addition, major fractures in bedrock, which act as preferential groundwater flow paths, have been located from soil gas anomalies, even when obscured by overburden of variable thickness and character. The distribution of He in soil gas appears to be most representative of groundwater recharge and discharge conditions in the granitic rock, while Rn may be useful for locating specific channels where more rapid groundwater discharge is occurring from deep fracture zones. 相似文献
14.
柳林泉域滞流区岩溶水的热源及其Na+、Cl-来源探讨 总被引：1，自引：1，他引：0
柳林泉域滞流区岩溶水以高温、高Na+和Cl-浓度为主要特征。文章在区域地质及水文地质条件分析基础上,采用化学计量学原理,判断了该区岩溶水的热源及Na+和Cl-的来源。结果显示:在泉域的补给区、径流区和排泄区的上青龙、龙门会、杨家港和寨东泉组,岩溶水中的Na+和Cl-主要来源于岩盐的溶解,其中多余的Na+可能来自于阳离子交换、黄土中含Na+矿物的溶解及城市污水的排放;滞流区和排泄区的刘家疙瘩泉组岩溶水中高浓度的Na+和Cl-也主要来自于岩盐的溶解,而多余的Cl-可能由岩溶水中的Na+交换吸附介质中的Ca2+或Mg2+所致。西部滞流区岩溶水的热源主要包括地温梯度增热、当地正常地温、岩石中放射性元素产热和石膏的溶解放热,其贡献率分别为45%、28%、20%和7%。 相似文献
15.
地表水与地下水相互转化是中国西北干旱内流盆地水循环的显著特征,转化机制研究是盆地水循环规律认知和水资源可持续管理的重要基础。以我国西北干旱内流河黑河流域中游的张掖盆地和盐池盆地为研究区,建立了黑河主干河道时变水平衡模型和地表水地下水耦合数值模型,研究了长周期水文变化和人类活动双重影响下地表水与地下水转化机制,得到如下认识:（1）补给条件由以天然条件下河流渗漏为主的线状补给演变为以河流与引水渠道渗漏的线状补给和灌区田间入渗面状补给,排泄条件由以泉水溢出和天然湿地排泄演变为以泉水溢出与地下水开采为主的排泄。（2）张掖盆地黑河干流河道入渗段和溢出段大致以G312 大桥为界,亦称为地表水与地下水转化的转折点。莺落峡—G312 大桥段为悬河渗漏段,河道入渗补给主要受控于进入河道的实际过水量。其中,莺落峡—草滩庄段河道入渗补给率为28.20 %;草滩庄—G312 大桥段河道入渗补给量与河道过水量的关系可用分段函数表达,河道过水量大于或等于0.37×108 m3/mon时呈幂函数关系,小于则呈线性函数关系。G312 大桥—正义峡段为地下水溢出段,其中G312大桥—平川大桥段地下水溢出量约占全部溢出量的70%,溢出峰值出现在高崖水文站下游约6 km处,其单长溢出量可达0.46 m3/(s·km)。（3）研究区是一个相对完整的河流—含水层系统,近31年来经历了连枯和连丰的水文变化,地下水补给排泄条件及与地表水转化机制均发生了相应的变化。地表水与地下水转化最强烈的地区为张掖盆地中部的黑河—梨园河倾斜平原。1990—2001 年连枯期,灌区引水量总体逐年减少,以河道入渗和渠系渗漏为主的补给量平均以0.06×108 m3/a速率减少,农田灌溉面积增加导致灌溉用水增加,地下水开采量显著增加,地下水水位逐年下降,储存量累计减少5.77×108 m3,地下水溢出量平均减少0.16×108 m3/a;而2002—2020 年连丰期,灌区引水量总体逐年减少,河道入渗量呈增加趋势,地下水总补给量平均增加0.15×108 m3/a,灌溉面积继续扩大,农灌开采量随之增加,以河道入渗量增加为主导,地下水水位持续上升,储存量累计增加5.45×108 m3,地下水溢出量平均增加0.08×108 m3/a。总之,补给和排泄条件变化较大,地下水储存量先减后增,地下水溢出总量变化较为平缓,反映了该区巨厚含水层系统的巨大调蓄功能。（4）位于张掖盆地东部的诸河倾斜平原地下水水位长期处于持续下降状态,这是由于地表水开发过度,补给量锐减。黑河侵蚀堆积平原地下水水位基本稳定。30 多年来盐池盆地倾斜平原地下水水位长期处于持续下降状态,这是由于移民开垦导致地下水过量开采。（5）内流盆地天然悬河入渗段是珍贵的地下水补给通道,无论连枯期还是连丰期,河道实际过水量是河道渗漏补给量的关键,保护上游天然河道和一定的河道实际过水量是内流盆地水资源可持续管理的关键。 相似文献
16.
地下水是海原盆地唯一的供水水源,近年来部分地区地下水溶解性总固体(TDS)增高,引起了有关部门和水文地质工作者的高度关注。通过分析69组地下水样品的水化学和氢氧稳定同位素数据,对地下水补给来源和咸化的水文地球化学过程进行了研究。结果表明:地下水TDS值198.2~6 436.4 mg/L,沿着地下水流向,咸化程度增加,水化学类型从基岩区的HCO3—Ca·Mg型演化至滞留—排泄区的SO4·Cl—Na·Mg型。地下水补给来源主要为大气降雨和基岩裂隙水侧向径流,补给源—对地下水咸化贡献较小。溶滤作用具空间差异,基岩区和补给区以碳酸盐、硅酸盐风化为主,径流区和滞留—排泄区则为蒸发岩风化,硫酸盐是地下水中阳离子的主要来源。补给水、溶滤和蒸发对第四系地下水TDS的贡献比率分别为4.8%~81.2%、11.9% ~85.9%、1.7%~29.5%,溶滤作用是控制海原盆地地下水咸化的首要因素。当地有关部门应加大对基岩泉水的综合利用,同时注意控制海原县和西安镇等地区地下水开采量,防止地下水进一步咸化。另外,在微咸水分布区可引进地下水去除硫酸盐技术,提高微咸水利用程度。 相似文献
17.
Roland Otto 《Hydrogeology Journal》2001,9(5):498-511
In the southeastern Holstein region, located to the east of the metropolitan zone of Hamburg, northern Germany, a groundwater
investigation program was conducted from 1984 to 2000 by the State Agency for Nature and Environment (Landesamt für Natur
und Umwelt, LANU) of Schleswig-Holstein, Germany, with the aim of providing long-term, ecologically acceptable groundwater
management plans for the region. The focal point of the investigation comprised the determination of groundwater recharge
rates. The investigation method was based on the transfer of available lysimeter results from other regions to comparable
regions within the area studied. With the help of lysimeter equations, potential amounts of percolation water were calculated.
The groundwater recharge rate was then determined after subtraction of the surface runoff which was calculated for the entire
area. All computations were performed with a spreadsheet program. Groundwater recharge rates were calculated for two areas.
One consisted of roughly determining groundwater recharge rates for the total region (1,392 km2) of southeastern Holstein. The overall goal of these investigations was to identify potential areas of water exploitation.
Areas in which groundwater recharge rates are high and groundwater outflow is low are particularly suited to water exploitation,
since inflow rates into deeper aquifers are high. These areas are located on the flanks of the Elbe and Stecknitz River valleys.
Subsurface groundwater runoff to these lowlands would be reduced through groundwater withdrawal. However, the resulting decline
in shallow groundwater tables would be so small that it would have no detrimental ecological effects. Groundwater recharge
rates were also calculated for a 110-km2 area in the outskirts of Hamburg (Grosshansdorf model area) which is intensively developed for water supply. These investigations
showed that the amount of groundwater recharge is already being withdrawn to a large extent. Approximately 65% of the recharge
rate is currently withdrawn by the waterworks in this area, thus making further increases in exploitation rates unjustifiable
from an ecological point of view.
Electronic Publication 相似文献
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19.
Claus Kohfahl Christoph Sprenger Jose Benavente Herrera Hanno Meyer Franzisca Fernández Chacón Asaf Pekdeger 《Applied Geochemistry》2008
The objective of this study is to refine the understanding of recharge processes in watersheds representative for karstic semiarid areas by means of stable isotope analysis and hydrogeochemistry. The study focuses on the Granada aquifer system which is located in an intramontane basin bounded by high mountain ranges providing elevation differences of almost 2900 m. These altitude gradients lead to important temperature and precipitation gradients and provide excellent conditions for the application of stable isotopes of water whose composition depends mainly on temperature. Samples of rain, snow, surface water and groundwater were collected at 154 locations for stable isotope studies (δ18O, D) and, in the case of ground- and surface waters, also for major and minor ion analysis. Thirty-seven springs were sampled between 2 and 5 times from October 2004 to March 2005 along an altitudinal gradient from 552 masl in the Granada basin to 2156 masl in Sierra Nevada. Nine groundwater samples were taken from the discharge of operating wells in the Granada basin which are all located between 540 and 728 masl. The two main rivers were monitored every 2–3 weeks at three different altitudes. Rainfall being scarce during the sampling period, precipitation could only be sampled during four rainfall events. Calculated recharge altitudes of springs showed that source areas of mainly snowmelt recharge are generally located between 1600 and 2000 masl. The isotope compositions of spring water indicate water sources from the western Mediterranean as well as from the Atlantic without indicating a seasonal trend. The isotope pattern of the Quaternary aquifer reflects the spatial separation of different sources of recharge which occur mainly by bankfiltration of the main rivers. Isotopic signatures in the southeastern part of the aquifer indicate a considerable recharge contribution by subsurface flow discharged from the adjacent carbonate aquifer. No evaporation effects due to agricultural irrigation were detected. 相似文献
20.
Water resources in Taiwan are unevenly distributed in spatial and temporal domains. Effectively utilizing the water resources
is an imperative task due to climate change. At present, groundwater contributes 34% of the total annual water supply and
is an important fresh water resource. However, over-exploitation has decreased groundwater availability and has led to land
subsidence. Assessing the potential zone of groundwater recharge is extremely important for the protection of water quality
and the management of groundwater systems. The Chih-Pen Creek basin in eastern Taiwan is examined in this study to assess
its groundwater resources potential. Remote sensing and the geographical information system (GIS) are used to integrate five
contributing factors: lithology, land cover/land use, lineaments, drainage, and slope. The weights of factors contributing
to the groundwater recharge are derived using aerial photos, geology maps, a land use database, and field verification. The
resultant map of the groundwater potential zone demonstrates that the highest recharge potential area is located towards the
downstream regions in the basin because of the high infiltration rates caused by gravelly sand and agricultural land use in
these regions. In contrast, the least effective recharge potential area is in upstream regions due to the low infiltration
of limestone. 相似文献