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1.
Surface water and groundwater are the main water resources used for drinking and production. Assessments of the relationship between surface water and groundwater provide information for water resource management in Sanjiang plain, Northeast China. The surface water (river, lake, and wetland) and groundwater were sampled and analyzed for stable isotopic (δD, δ 18O) composition, tritium, and chlorofluorocarbons concentrations. The local meteoric water line is δD = 7.3δ 18O–6.7. The tritium (T) and chlorofluorocarbon (CFC) contents in groundwater were analyzed to determine the groundwater ages. Most groundwater were modern water with the ages <50 years. The groundwaters in mountain area and near rivers were younger than in the central plain. The oxygen isotope (δ 18O) was used to quantify the relationship between surface water and groundwater. The Songhua, Heilongjiang, and Wusuli rivers were gaining rivers, but the shallow groundwater recharged from rivers at the confluence area of rivers. At the confluence of Songhua and Heilongjiang rivers, 88 % of the shallow groundwater recharged from Songhua river. The combination of stable isotopes, tritium, and CFCs was an effectively method to study the groundwater ages and interrelation between surface water and groundwater. Practically, the farmlands near the river and under foot of the mountain could be cultivated, but the farmlands in the central plain should be controlled.  相似文献   

2.
Environmental tracers sampled from the carbonate Madison aquifer on the eastern flank of the Black Hills, South Dakota, USA indicated the approximate locations of four major karst conduits. Contamination issues are a major concern because these conduits are characterized by direct connections to sinking streams, high groundwater velocities, and proximity to public water supplies. Objectives of the study were to estimate approximate conduit locations and assess possible anthropogenic influences associated with conduits. Anomalies of young groundwater based on chlorofluorocarbons (CFCs), tritium, and electrical conductivity (EC) indicated fast moving, focused flow and thus the likely presence of conduits. δ18O was useful for determining sources of recharge for each conduit, and nitrate was a useful tracer for assessing flow paths for anthropogenic influences. Two of the four conduits terminate at or near a large spring complex. CFC apparent ages ranged from 15 years near conduits to >50 years in other areas. Nitrate-N concentrations >0.4 mg/L in groundwater were associated with each of the four conduits compared with concentrations ranging from <0.1 to 0.4 mg/L in other areas. These higher nitrate-N concentrations probably do not result from sinking streams but rather from other areas of infiltration.  相似文献   

3.
Corrected groundwater 14C ages from the carbonate aquifer in Yucca Flat at the former Nevada Test Site (now the Nevada National Security Site), USA, were evaluated by comparing temporal variations of groundwater 36Cl/Cl estimated with these 14C ages with published records of meteoric 36Cl/Cl variations preserved in packrat middens (piles of plant fragments, fecal matter and urine). Good agreement between these records indicates that the groundwater 14C ages are reasonable and that 14C is moving with chloride without sorbing to the carbonate rock matrix or fracture coatings, despite opposing evidence from laboratory experiments. The groundwater 14C ages are consistent with other hydrologic evidence that indicates significant basin infiltration ceased 8,000 to 10,000 years ago, and that recharge to the carbonate aquifer is from paleowater draining through overlying tuff confining units along major faults. This interpretation is supported by the relative age differences as well as hydraulic head differences between the alluvial and volcanic aquifers and the carbonate aquifer. The carbonate aquifer 14C ages suggest that groundwater velocities throughout much of Yucca Flat are about 2 m/yr, consistent with the long-held conceptual model that blocking ridges of low-permeability rock hydrologically isolate the carbonate aquifer in Yucca Flat from the outlying regional carbonate flow system.  相似文献   

4.
An investigation was conducted in Beijing to identify the groundwater evolution and recharge in the quaternary aquifers. Water samples were collected from precipitation, rivers, wells, and springs for hydrochemical and isotopic measurements. The recharge and the origin of groundwater and its residence time were further studied. The groundwater in the upper aquifer is characterized by Ca-Mg-HCO3 type in the upstream area and Na-HCO3 type in the downstream area of the groundwater flow field. The groundwater in the lower aquifer is mainly characterized by Ca-Mg-HCO3 type in the upstream area and Ca-Na-Mg-HCO3 and Na-Ca-Mg-HCO3 type in the downstream area. The δD and δ18O in precipitation are linearly correlated, which is similar to WMWL. The δD and δ18O values of river, well and spring water are within the same ranges as those found in the alluvial fan zone, and lay slightly above or below LMWL. The δD and δ18O values have a decreasing trend generally following the precipitation → surface water → shallow groundwater → spring water → deep groundwater direction. There is evidence of enrichment of heavy isotopes in groundwater due to evaporation. Tritium values of unconfined groundwater give evidence for ongoing recharge in modern times with mean residence times <50 a. It shows a clear renewal evolution along the groundwater flow paths and represents modern recharge locally from precipitation and surface water to the shallow aquifers (<150 m). In contrast, according to 14C ages in the confined aquifers and residence time of groundwater flow lines, the deep groundwater is approximately or older than 10 ka, and was recharged during a period when the climate was wetter and colder mainly from the piedmont surrounding the plain. The groundwater exploitation is considered to be “mined unsustainably” because more water is withdrawn than it is replenished.  相似文献   

5.
The Gavbast karstic aquifer located in southern Iran is in direct contact with an exposed salt diapir. To assess the influence of the diapir on the quality of groundwater in the karstic aquifer, electrical conductivity, total dissolved solids, flow rate, temperature and major ion concentrations were measured at 57 sampling sites, including springs, surface waters and wells. A conceptual model of groundwater flow is proposed for the Gavbast karstic aquifer based on the geological setting, water budget, local base of erosion, and hydrochemistry of the sampling sites. The model suggests two subbasins in the Gavbast Anticline draining into two distinct discharging alluvial sections. Unexpectedly, groundwater discharging from the carbonate Gavbast aquifer is saline or brackish and water is of chloride type. The study indicates that the source of salinity of the Gavbast aquifers is infiltration of surface diapir-derived brine into the aquifer. The contribution of the diapir brine in the Gavbast karst aquifer is calculated about 4 L/s, using chloride mass balance. Construction of salt basins to evaporate brine discharging from the diapir springs is proposed to reduce the salinity of karst water. A row of strategically placed wells in the Gavbast karst aquifer would potentially exploit large volumes of fresh groundwater before it is contaminated by the salt. Such low-cost remediation should allow the agricultural exploitation of 40 km2 of currently barren land.  相似文献   

6.
The groundwater of major karst systems and submarine springs in the coastal limestone aquifer of Syria has been investigated using chemical and isotopic techniques. The δ18O values of groundwater range from ?6.8 to ?5.05‰, while those for submarine springs vary from ?6.34 to +1.08‰ (eastern Mediterranean seawater samples have a mean of +1.7‰). Groundwater originates from the direct infiltration of atmospheric water. Stable isotopes show that the elevation of the recharge zones feeding the Banyas area (400–600 m a.s.l.) is higher than that feeding the Amrit area (100–300 m a.s.l.). The 18Oextracted (18O content of the seawater contribution) for the major submarine springs suggests a mean recharge area elevation of 600–700 m a.s.l., and lower than 400 m a.s.l. for the spring close to Amrit. Based on the measured velocity and the percentage of fresh water at the submarine springs outlet, the estimated discharge rate is 350 million m3/year. The tritium concentrations in groundwater (1.6–5.9 TU) are low and very close to the current rainfall values (2.9–5.6 TU). Adopting a model with exponential time distribution, the mean turnover time of groundwater in the Al-sen spring was evaluated to be 60 years. A value of about 3.7 billion m3 was obtained for the maximum groundwater reservoir size.  相似文献   

7.
Groundwater from karst subterranean streams is among the world’s most important sources of drinking water supplies, and the hydrochemical characteristics of karst water are affected by both natural environment and people. Therefore, the study of karst groundwater hydrochemistry and its solutes’ sources is very important to ensure the normal function of life support systems. This paper focused on the major ion chemistry and sulfate isotope of karst groundwater in Chongqing for tracing the sulfate sources and related hydrochemical processes. Hydrochemical types of karst groundwater in Chongqing were mainly of the Ca-HCO3 type or Ca(Mg)-HCO3 type. However, some hydrochemical types were the K + Na + Ca-SO4 type (G25 site) or Ca-HCO3 + SO4 type (G26 and G14 sites), indicating that the hydrochemistry of these sites may be strongly influenced by anthropogenic activities or unique geological characteristics. The δ34S-SO4 2? of collected karst groundwater sample fell into a range of ?6.8 to 21.5 ‰, with a mean value of 5.6 ‰. In dolomite aquifer, the δ34S-SO4 2? value ranges from ?4.3 to 11.0 ‰, and in limestone aquifer, it ranged from ?6.8 to 21.5 ‰. The groundwater samples from different land use types showed distinctive δ34S-SO4 2? value. The δ34S-SO4 2? value of groundwater samples had range of ?6.8 to 16.7 ‰ (mean 4.0 ‰, n = 11) in cultivated land areas, 1.5–21.5 ‰ (mean 7.2 ‰, n = 20) in forested land areas, and ?4.3 to 0.8 ‰ (mean ?1.7 ‰, n = 2) in coalmine areas. The δ34S-SO4 2? values of groundwater samples collected from factory area and town area were 2.2 and 9.9 ‰, respectively. According to the δ34S information of potential sulfate sources, this paper discussed the possible sulfate sources of collected karst groundwater samples in Chongqing. The variations of both δ34S and 1/SO4 2? values of the groundwater samples indicated that the atmospheric acid deposition (AAD), dissolution of gypsum (GD), oxidation of sulfide mineral (OS) or anthropogenic inputs (SF: sewage or fertilizer) contributed to sulfate in karst groundwater. The influence of oxidation of sulfide mineral, atmospheric acid deposit and anthropogenic inputs to groundwater in Chongqing karst areas was much widespread. For protecting, sustaining, and utilizing the groundwater resources, the sewage possibly originating from urban, mine or industrial area must be controlled and treated, and the use of fertilizer should be limited.  相似文献   

8.
A hydrochemical investigation was conducted in the Ejina Basin to identify the hydrochemical characteristics and the salinity of groundwater. The results indicate that groundwater in the area is brackish and are significantly zonation in salinity and water types from the recharge area to the discharge area. The ionic ration plot and saturation index (SI) calculation suggest that the silicate rock weathering and evaporation deposition are the dominant processes that determine the major ionic composition in the study area. Most of the stable isotope δ18O and δD compositions in the groundwater is a meteoric water feature, indicating that the groundwater mainly sources from meteoric water and most groundwater undergoes a long history of evaporation. Based on radioactive isotope tritium (3H) analysis, the groundwater ages were approximately estimated in different aquifers. The groundwater age ranges from less than 5 years, between 5 years and 50 years, and more than 50 years. Within 1 km of the river water influence zone, the groundwater recharges from recent Heihe river water and the groundwater age is about less than 5 years in shallow aquifer. From 1 km to 10 km of the river water influence zone, the groundwater sources from the mixture waters and the groundwater age is between 5 years and 50 years in shallow aquifer. The groundwater age is more than 50 years in deep confined aquifer.  相似文献   

9.
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   

10.
A fracture-karst aquifer is a karst aquifer with a fractured rock matrix, and its parameters are difficult to determine. Two sequential pumping tests in a fracture-karst aquifer system at the Zhangji well field of China are considered, one carried out before (in 2000) and one after (in 2005) the operation of a pumping station in the well field (2003–2005). The sequential tests serve multiple purposes. First, they provide a cross check of the parameters obtained. Second, they can be used to assess the effect of long-term groundwater exploitation of the aquifer. A three-dimensional finite-element transient flow model has been developed to simulate groundwater flow at the site. Generally good agreement has been found between the simulated and observed hydraulic heads for both tests. The hydraulic parameters obtained from the 2005 test are generally consistent with their counterparts from the 2000 test. However, a small but steady increase of hydraulic conductivities from 2000 to 2005 at the site has been observed. A 10-year prediction of groundwater resources has been made and indicates that the well field can accommodate the proposed 8.0?×?104 m3/day exploitation rate under relative drought conditions without causing a steady decline of groundwater levels.  相似文献   

11.
The unique hydrogeology of karst makes the associated groundwater respond quickly to rainfall events and vulnerable to anthropogenic pollutions. In this study, high-frequency monitoring of spring discharge, temperature, electrical conductivity (EC) and pH, along with monthly hydrochemical and microbial analyses, was undertaken at the outlet of Laolondong karst underground river in Nanshan, southwestern China. The aim was to explore the environmental effects of the catchment’s urban area on the karst groundwater resources. The monitoring data of a tracer test and the response of discharge to rainfall events demonstrate that conduits and narrow fissures coexist in the Laolongdong karst aquifer. The EC, Na+, Cl? and SO42? values (840 μS/cm, 33.7, 38.6 and 137.2 μg/L, respectively), along with high concentrations of fecal coliform bacteria, at the outlet indicate considerable urban pollution in this area. The contaminants sulfate and nitrate showed different relationships with discharge and EC in different stages of a rainfall event. This behavior provided information about aquifer structure and the influence of transport properties. Meanwhile, the hydrological processes of groundwater flow could be modified by urbanization and result in increasing magnitude of urban floods in the underground river. In addition, sulfuric and nitric acids introduced by urbanization not only impact the karst groundwater quality, but also result in a significant perturbation to the carbon cycling system in the karst area.  相似文献   

12.
Solutes in saline groundwater (total dissolved solids up to 37 000 mg/L) in the Lake Cooper region in the southern margin of the Riverine Province of the Murray Basin are derived by evapotranspiration of rainfall with minor silicate, carbonate and halite dissolution. The distribution of hydraulic heads, salinity, percentage modern carbon (pmc) contents, and Cl/Br ratios imply that the groundwater system is complex with vertical flow superimposed on lateral flow away from the basin margins. Similarities in major ion composition, stable (O, H, and C) isotope, and 87Sr/86Sr ratios between groundwater from the shallower Shepparton Formation and the deeper Calivil – Renmark aquifer also imply that these aquifers are hydraulically interconnected. Groundwater in the deeper Calivil – Renmark aquifer in the Lake Cooper region has residence times of up to 25 000 years, implying that pre-land-clearing recharge rates were <1 mm/y. As in other regions of the Murray Basin, the low recharge rates account for the occurrence of high-salinity groundwater. Shallow (<20 m) groundwater yields exclusively modern 14C ages and shows a greater influence of evaporation over transpiration. Both these observations reflect the rise of the regional water-table following land clearing over the last 200 years and a subsequent increase in recharge to 10 – 20 mm/y. The rise of the regional water-table also has increased vertical and horizontal hydraulic gradients that may ultimately lead to the export of salt from the Lake Cooper embayment into the adjacent fresher groundwater resources.  相似文献   

13.
The study area is located in the border of the high and low folded zone having a semi-arid climate area. This study initiated in 2009–2010, deals essentially with the investigation of the stable isotope (18O and deuterium 2H) as well as radioactive isotope represented by tritium 3H in rain, carbonate springs, intergranular aquifer, and surface water in order to investigate the source and relative ages of the groundwater and to show the influence of the altitude variations of the isotope composition. In this study and for the first time in the area, a local meteoric water line have been drawn with an empirical formula δ 2H?=?7.7δ 18O?+?14.4. The δ 18O–altitude effect was determined using isotopic data for several samples taken from groundwater and surface water; it was approximated at ?0.79?‰/100 m for the entire area of the study. The output of the tritium concentrations in the springs and water well samples revealed to the conclusion that the values closely resembles to the present time tritium concentration in precipitation.  相似文献   

14.
Beljanica Mountain in eastern Serbia is a part of the Carpathian Balkan arch (northern Alpine branch). It covers an area of about 300 km2 and consists mostly of Jurassic and Cretaceous limestones. Numerous surface karst features, long caves and several large karstic springs located in Beljanica’s piedmont along the contact of karstic and non-karstic rocks are all indicators of an intense karstification. Currently, the large karstic water reserves of Beljanica Mountain are not properly utilized because of their distance from main consumers, the objection by national water managers that the springs lack a stable and sufficient discharge particularly during recession periods. Due to its unpolluted and high quality water, the area is a great prospect for future water supply, and provides an opportunity for artificial regulation and for the design and implementation of specific tapping structures. This paper includes an analysis of the created 3D ArcGIS model of karst interior and its correlation with historical and newly collected data of spring discharges and groundwater physico-chemical characteristics. The results of karst aquifer monitoring (both quantitative and qualitative) are linked with the results of extensive field geological and speleological survey of the upper non-saturated part of the karst (such as sinkholes, pits and caves) and with the investigation of the permanently saturated deeper part of the aquifer (including the diving methods). The model of karst interior is based on the data from the 69 caves, 15 sinks and 1,682 dolines (sinkholes) surveyed. The total length of the karst channels network, calculated using the GIS model and presented in a 3D environment, is 647 km. The catchment areas of five major springs that drain the areas are estimated to range from only 7 km2 (Malo Vrelo Spring) to 124 km2 (Vrelo Mlave Spring). The groundwater exploitable reserves of Beljanica karst aquifer are estimated to be over 4 m3/s. The waters are low mineralized, unpolluted and have a great potential for water supply.  相似文献   

15.
The main results that derived from this study is the quantitative determination of subsurface water balance and the water loses along flow line during drought decade (before 2000–2009), with intense exploitation of groundwater from water wells. The hydrogeological data are presented as spatial distribution maps and three dimensional models. The results are correlated with the main hydrogeologic control points including (storage and transmissivity coefficients, groundwater depths, aquifers thickness, lateral extensions, well productivity) to determine the preferable hydrogeologic districts for development and exploitations, avoiding groundwater depletion as captured zone flow. Based on the isotope analysis of deuterium, oxygen-18, tritium, carbon-13, and carbon-14, the recharge of the aquifer is originated to direct infiltration of atmospheric water through exposure outcrops within Hauran catchments area. The isotope compositions also show that the groundwater is a mixture of an old groundwater with modern recharge in the areas adjacent to Rutba. The fact that the Mullusi aquifer is of major importance as the water supply of people in Rutba region, particularly, for increasing demand of water resources and sustainability assessment in the future, this study developed a reliable strategic suggested plan in groundwater supply, based on groundwater exploitation and amount of safe yield within Dhabaa basin.  相似文献   

16.
大兴迭隆起隐伏岩溶水资源评价及开采方案预测   总被引：2，自引：2，他引：0  
大兴迭隆起地区隐伏岩溶地下水是北京市的重要水源,为保障水源地能持续为大兴、通州地区提供优质的城镇生活用水,需对研究区岩溶地下水进行水资源评价和开采规划预测分析。利用数值模拟法,应用GMS模拟软件对研究区岩溶水系统进行地下水流数值模拟及水位变化预测。建立的岩溶水系统模型分为5层,模拟验证期为12年9个月。由模型评价的岩溶水系统补给资源量为14 425.74×10^4m3/a,可开采资源量为14 310.52×10^4m3/a,其中岩溶含水层可开采量为2 309.36×10^4m3/a。在模型识别验证后,分4种开采方案对水源地进行开采预测,通过对典型观测孔水位过程线拟合和研究区水均衡分析可知,按2020年之前维持现状开采,2020年后停采念坛水源地,2025年后全区按可开采量进行开采的开采方案最为合理,可分批逐次实现水源地的采补平衡。  相似文献   

17.
Groundwater potential map is important for environmental assessment and water resources management. In this work, a groundwater recharge potential map was established for the watershed of Oued Djelfa Hadjia in Algeria, based on new multiparameters hybrid model. The model has hydroclimatic parameters, geological settings, slope factor, and stream network density factor as inputs. The groundwater recharge estimated by the model range from 0.71 to 14 mm. The model allows delineation of potential area of recharge. The total water abstraction in Djelfa city is about of 14 hm3; however, the calculated groundwater recharge is about 3 mm/year (min 0.71 mm and max 14 mm), which correspond to an average recharge volume of 3.9 hm3 which mean that the aquifer is under over exploitation.  相似文献   

18.
Radioactive isotopes were used to estimate the rate of seawater intrusion into the coastal aquifer of Israel, the connection between the different sub-aquifers, and the connection between the sub-aquifers and the sea. This was done by dating both fresh and saline groundwaters from the vicinity of the shoreline, which were analyzed for their 14C and tritium content together with their chemical and stable isotope composition. The results indicate that the distinct sub-aquifers differ in their water chemistry and age. The saline groundwater in the lower sub-aquifers is older than ca. 10,000 years, as evidenced by the absence of tritium and low 14C activity (<12 PMC). On the other hand, saline groundwaters in the upper sub-aquifers contain tritium and are thus younger than 50 years, indicating recent intrusion of seawater. The ages of the saline groundwaters become younger upward from the lower sub-aquifers to the upper ones, reflecting the sea-level rise since the last glacial period. The older ages also imply slow groundwater flow in the lower sub-aquifers. The fresh groundwaters in most cases in the lower sub-aquifers were found to be older than ca. 10,000 years and this implies that the flow to the sea is blocked or restricted.  相似文献   

19.
丰沛平原区地下水开采利用现状及潜在水源地分析   总被引：1，自引：0，他引：1  
通过总结丰沛平原区水文地质条件和特征,对该区地下水开采利用现状及潜在水源地进行分析,计算了华栖隆起区岩溶水可利用资源量,探讨裂隙岩溶水利用的可行性。研究表明: 丰沛平原区地下水主采层位为中上更新统孔隙含水层和新近系—下更新统孔隙含水层,已形成丰县城关—孙楼—常店和沛县—龙固2个大型超采漏斗区,总面积超过750 km2,引发了大面积地面沉降; 华栖隆起区为裂隙岩溶水的富水地段,总可采资源量为667.51万m3/a,可作为潜在水源地进一步开展地下水勘查评价工作; 裂隙岩溶水过量开采可能引发地面沉降、岩溶地面塌陷等地质灾害,后期应对裂隙岩溶水开采情况进行长期监测,合理开发利用水资源。华栖隆起区岩溶水距离城区近,水量大,水质好,开发难度小,具有可观的经济价值。  相似文献   

20.
Measured concentrations of environmental tracers in spring discharge from a karst aquifer in the Shenandoah Valley, USA, were used to refine a numerical groundwater flow model. The karst aquifer is folded and faulted carbonate bedrock dominated by diffuse flow along fractures. The numerical model represented bedrock structure and discrete features (fault zones and springs). Concentrations of 3H, 3He, 4He, and CFC-113 in spring discharge were interpreted as binary dilutions of young (0–8  years) water and old (tracer-free) water. Simulated mixtures of groundwater are derived from young water flowing along shallow paths, with the addition of old water flowing along deeper paths through the model domain that discharge to springs along fault zones. The simulated median age of young water discharged from springs (5.7  years) is slightly older than the median age estimated from 3H/3He data (4.4  years). The numerical model predicted a fraction of old water in spring discharge (0.07) that was half that determined by the binary-dilution model using the 3H/3He apparent age and 3H and CFC-113 data (0.14). This difference suggests that faults and lineaments are more numerous or extensive than those mapped and included in the numerical model.  相似文献   

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