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1.
A detailed hydrogeological investigations comprising well inventory, water level monitoring, lake bathymetry, infiltration and pump tests were carried out in a few selected observation wells in order to estimate transmissivity (T) and storativity (S) in all major lakes which are highly polluted by the discharge of sewage and other chemical effluents in greater Hyderabad. The salient features of results are presented lake wise which would be of immense use in restoration of all lakes. Also, the outcome of this study along with infiltration rates may be used for modeling in future to simulate the surface water-ground water interaction.  相似文献   

2.
TheZhalingandElinglakes,whichplayanimportantroleinadjustmentandstorageofwaterfortheupstreamareaoftheYel lowRiver,aretwoofthelargestnaturalfreshwaterlakesintheYellowRiverdrainagearea .Thewaterenvironmentofthetwolakesandtheiradjacentregionsisquiteunique.S…  相似文献   

3.
The analysis and interpretation of physical and limnological parameters combined with hydrochemical (major ions and stable isotopes) analyses enabled us to evaluate the hydrogeological functioning and the hydrogeochemical evolution of groundwater in two adjacent lakes related to a karstic aquifer (Archidona, southern Spain). Lake water, groundwater and the outflow from a spring, were monitored periodically from 1998 to 1999 and sporadically from 2000 to 2006. The evolution of groundwater chemistry from recharge (dolines) to discharge areas (spring) showed an increment of 20% in magnesium and 15% in sulphate, and such higher increments were recorded for the water from the lakes, suggesting the existence of different hydrogeological paths. A simple water budget model, together with morphological interpretation, suggests that groundwater discharge into the lakes is of relative importance to the input into these systems. Finally, we believe that the development of a new typology for hydro-morphological elements, by means of several hydrological factors and the assessment of pressures and impacts will be useful for the correct management of these lakes and other semi-arid aquatic ecosystems.  相似文献   

4.
《Applied Geochemistry》1999,14(5):669-687
Thirty-five mines in Nevada currently have, or will likely have, a pit lake. The large bulk mineable deposits in Nevada mined below the water table are of several types, including Carlin-type Au, quartz-adularia precious metal, quartz-alunite precious metal and porphyry-Cu (-Mo) deposits. Of the 16 past or existing pit lakes at 12 different Nevada mines, most had near neutral pH and low metal concentrations, yet most had at least one constituent (e.g., SO4) which exceeded drinking water standards for at least one sampling event. Water quality data indicate that, in general, poor water quality will not develop in Carlin-type Au deposits. Wall rocks in the geologic environment typical of these deposits, and in the specific pits sampled, contain substantial amounts of carbonate, which buffers the pH at slightly basic conditions and thereby limits the solubility of most metals. Similarly, the quartz-adularia precious metal deposits generally have geologic conditions that buffer pH and naturally prevent the development of poor water quality. In both of these deposit types, certain elements such as As and Se that are mobile in neutral to basic waters may accumulate to levels near or exceeding drinking water standards. Pit lakes forming in quartz-alunite precious metal deposits hosted in volcanic rocks or in porphyry-Cu (-Mo) deposits in plutonic rocks are of greatest environmental concern in Nevada, as both deposit types have relatively high acid-generating potential and low buffering capacity. However, the sampled Nevada pits in these deposit types indicate that the water may not be of poor quality. In addition, water quality in some pits may actually improve with time due to the increased water-rock ratio as the pit fills with water, as suggested by pit waters at one mine in a Carlin-type deposit (Getchell) that improved between 1968 and 1982. Although water quality in pits in each deposit type is generally good, local, site specific conditions (e.g., surface water inflow) and variations (e.g., evaporation rates) result in some pit lakes (e.g., Boss) in the quartz-adularia deposit type being of substantially poorer water quality than other lakes (e.g., Tuscarora) in the same deposit type. Despite underlying geologic controls based on deposit type, site specific variations in hydrogeologic conditions and surface geologic features can result in differing water quality in pit lakes in the same deposit types, and these factors may, in some cases, provide an overriding control on the geochemical evolution of specific pit lakes.  相似文献   

5.
Major ion and stable isotope geochemistry allow groundwater/surface-water interaction associated with saline to hypersaline lakes from the Willaura region of Australia to be understood. Ephemeral lakes lie above the water table and locally contain saline water (total dissolved solids, TDS, contents up to 119,000 mg/L). Saline lakes that lack halite crusts and which have Cl/Br ratios similar to local surface water and groundwater are throughflow lakes with high relative rates of groundwater outflows. Permanent hypersaline lakes contain brines with TDS contents of up to 280,000 mg/L and low Cl/Br ratios due to the formation of halite in evaporite crusts. These lakes are throughflow lakes with relatively low throughflow rates relative to evaporation or terminal discharge lakes. Variations in stable isotope and major ion geochemistry show that the hypersaline lakes undergo seasonal cycles of mineral dissolution and precipitation driven by the influx of surface water and evaporation. Despite the generation of highly saline brines in these lakes, leakage from the adjacent ephemeral lakes or saline throughflow lakes that lack evaporite crusts is mainly responsible for the high salinity of shallow groundwater in this region.  相似文献   

6.
Multivariate statistical techniques, such as cluster analysis, principal component analysis (PCA) and factor analysis (FA) were applied to evaluate and interpret the water quality data set for 13 parameters at 10 different sites of the three lakes in Kashmir, India. Physicochemical parameters varied significantly (p?<?0.05) among the sampling sites. Hierarchical cluster analysis grouped 10 sampling sites into three clusters of less polluted, moderately polluted and highly polluted sites, based on similarity of water quality characteristics. FA/PCA applied to data sets resulted in three principal components accounting for a cumulative variance of 69.84, 65.05 and 71.76% for Anchar Lake, Khushalsar Lake and Dal Lake, respectively. Factor analysis obtained from principal components (PCs) indicated that factors responsible for accelerated eutrophication of the three lakes are domestic waste waters, agricultural runoff and to some extent catchment geology. This study assesses water quality of three lakes through multivariate statistical analysis of data sets for effective management of these lakes.  相似文献   

7.
巴尔喀什湖是中亚干旱区最大的湖泊生态系统之一,其保护对中亚地区具有重要意义,但同时对相关区域也产生了较大的水资源压力.分析其水量平衡,对提出合理的保障措施具有重要的理论与实践价值.根据巴尔喀什湖形态、水文特征,在分析识别其水量平衡主要影响因素与作用机制的基础上,根据水量平衡原理与东西湖分治的思想,反演了1936-200...  相似文献   

8.
Isotopic fractionations associated with two primary processes (evaporation and freezing of water) are discussed, which are responsible for the formation and evolution of saline lakes in deserts from both low-latitude and the Polar regions. In an evaporative system, atmospheric parameters (humidity and isotopic composition of water vapor) have strong influence on the isotopic behavior of saline lakes, and in a freezing system, salinity build-up largely controls the extent of freezing and associated isotope fractionation. In both systems, salinity has a direct impact on the isotopic evolution of saline lakes. It is proposed that a steady-state “terminal lake” model with short-term hydrologic and environmental perturbations can serve as a useful framework for investigating both evaporative and freezing processes of perennial saline lakes. Through re-assessment of own work and literature data for saline lakes, it was demonstrated that effective uses of the isotope activity compositions of brines and salinity-chemistry data could reveal dynamic changes and evolution in the isotopic compositions of saline lakes in response to hydrologic and environmental changes. The residence time of isotopic water molecules in lakes determines the nature of responses in the isotopic compositions following perturbations in the water and isotope balances (e.g., dilution by inflow, water deficit by increased evaporation, and/or reduction in inflow). The isotopic profiles of some saline lakes from the Polar regions show that they switched the two contrasting modes of operation between evaporative and freezing systems, in response to climate and hydrological changes in the past.  相似文献   

9.
Recent commentaries have expressed growing concern about the present state of limnology in the United States. Two basic problems are perceived: l) there are no separate, dedicated funding programs in the US for basic limnologic research; and 2) limnology has failed to enter the global big science era of the 90's. While both the oceans and atmosphere are subjects of large, multinational global-scale scientific programs, similar large studies of lakes have been limited, at best, to regional studies. There are over 250 large lakes worldwide, spanning the globe from 80° N to 60° S, and ranging from hypersaline to fresh water. Altogether they contain over 68% of the earth's fresh liquid surface water. However, these large ecosystems are increasingly threatened by global anthropogenic change such as illconceived diversions, uncontrolled consumption, and progressive degradation of water and overall ecosystem quality. Global climate change is but another anthropogenic global-scale problem with potential future effects on large lakes. An organized, multinational framework for the study of large lakes on a global scale is outlined.GLERL Contribution No. 793  相似文献   

10.
The methods of Quaternary paleoecology have proven useful for understanding the effects of anthropogenic acid deposition on lakes. The pH history of lakes has been inferred from diatom remains in 210Pb dated cores of sediment. In several of these studies, the cores have also been analysed for chrysophyte scales, trace metals (Pb, Zn, V, Cu), soot, and polycyclic aromatic hydrocarbons. Combined with historical studies of watershed vegetation and disturbance, these approaches have produced important insights relating to the effects on lakes of acid deposition: (1) certain clear water lakes with present pH 4.3–5.0 have rapidly acidified in recent decades; (2) these lakes were acidic (pH 5.0–6.4) prior to the acidification; (3) the most likely cause of the acidification is acid deposition; (4) the acidification began decades after high levels of acid deposition had been reached; and (5) in certain lakes acidification may have caused a marked decrease in humics, reducing the availability of organic ligands for ‘detoxification’ of metal ions (e.g. Al) mobilized by acidification. Diatom analyses have also revealed long term lake acidification in Late-glacial and Holocene time before the Industrial Revolution. This acidification is much slower than the modern acidification. The present pHs in anthropogenically acidified lakes are unprecedentedly low.  相似文献   

11.
The Larsemann Hills area represents a unique environmental setting between marine and glacial ecosystems. One of the promontories of this region, named Bharti, depicting similar set up was selected for the study of chemical parameters with special reference to its ionic characters. Water samples from 6 selected lakes of Bharti promontory, Larsemann Hills area were collected during the austral summer of 2004–05 and analysed for major ionic concentration and Total Dissolved Solid (TDS). This study is aimed at understanding the water chemistry of lakes of this island with emphasis on correlation between different ionic concentrations, TDS and its possible causes. The study will provide baseline data that will be useful for planning further studies. Analytical result shows that the water chemistry of these lakes is mainly governed by the lithology, precipitation, drainage and marine environment. Minor contribution of evaporation, has also been observed on the chemistry of one of the lake water. The main source of water for these lakes comes mainly from snow precipitation and its melting. The drainage line mostly goes towards eastern direction for these lakes.  相似文献   

12.
Characterizing vertical profiles of water columns is important to understanding the biochemical cycles and nutrient dynamics of an aquatic ecosystem. Physical and chemical properties of surface water in Mongolian saline lakes have been studied over the past decade, but chemical composition along a vertical profile of the water column has not been well documented. Four major saline lakes (Lakes Telmen, Oigon, Tsegeen and Khag) in northwestern Mongolia were studied to determine geochemical behavior of microelements and to assess major ionic components and trace elements associated with vertical profile of various water samples and sediments. Water samples were vertically collected from each sampling depth with a vacuum deep-water sampler in July 2013. Physical–chemical parameters, major ionic components and trace elements were analyzed by conventional methods and inductively coupled plasma-mass spectrometry. Concentrations of microelements and mineralogical composition of sediment samples from near shore were characterized by X-ray fluorescence spectrometry and X-ray diffraction. This study was apparently the first to characterize chemical composition along vertical profiles of these lakes. Sodium, chloride and sulfate ions were largely conserved in all water samples except Lake Oigon. Depending on salinity type, these lakes were divided into sodium-sulfate lake (Lake Khag) or chloride lakes. Due to geomorphological characteristics, strontium (≤3.18 mg/l) was the only ion in the highest concentration across all depths of water and sediment samples among the lakes. Sediments were comprised mainly of quartz, anorthite, albite and orthoclase. In conclusion, physical and chemical properties in Lake Oigon were highly variable and dissimilar among lakes. Furthermore, we inferred that vertical profiles of water columns were intimately linked to variations in chemical composition of salt lakes in the western Mongolia.  相似文献   

13.
为查明青藏工程走廊热融湖塘水理化特性及其理化特性与湖塘分布之间的关系,选取青藏工程走廊楚玛尔河至风火山段为研究区域,沿青藏公路从北向南依次选取19个热融湖塘进行水深、面积等几何特征调研并取水样,进行阴阳离子等理化参数测定。分析了热融湖塘水的理化特性,并结合调研资料探讨了热融湖塘理化特性与区域环境及湖塘分布之间的相关性。结果表明在3个研究亚区湖的水理化特性有较大差别,楚玛尔河高平原从北向南湖水矿化度逐渐升高,水质由淡水向咸水再到强咸水过渡,主要与该区域"碟"状湖的分布特征和寒旱多风及蒸发量大有关;可可西里山区和北麓河盆地的湖水矿化度较低,水质以弱咸水或淡水为主。这两个亚区湖较深,地形以丘陵盆地为主,降低了湖面的蒸发量。  相似文献   

14.
This study examines some relevant limnological and hydrogeochemical characteristics of 22 mine pit lakes of the Iberian Pyrite Belt (IPB). The studied pit lakes include some of the largest and historically most important mines of the IPB (including Corta Atalaya and Cerro Colorado in Riotinto, Filón Norte, Filón Centro and Filón Sur in Tharsis, Aznalcóllar, or San Telmo) and many other of minor size. As a whole, these lakes constitute, at present, a large volume of highly acidic and metal-polluted water. Some of these pit lakes are very recent (e.g., Corta Atalaya, 2.5 a; Los Frailes, 6 a) and present a continuous hydrological and geochemical evolution, although many others were abandoned decades ago and show nearly constant water volume. Depth profiles obtained in several pit lakes (e.g., San Telmo, Confesionarios, Cueva de la Mora, Concepción) indicate that many of them have developed meromixis and show, at present, a permanent thermal and chemical stratification with a well defined chemocline separating an anoxic, Fe(II)-rich monimolimnion, and a well mixed, oxygenated and Fe(III)-rich mixolimnion. In the upper layer, the bacterial oxidation of Fe(II) competes with photoreductive processes which take place in the surface water, thus provoking diel cycles of Fe(II) concentration. The observed water chemistry reflects the oxidation and dissolution of pyrite and other sulphides and gangue aluminosilicates from the country rock. The pit lakes of the IPB cover a wide range of water compositions, from circumneutral and relatively low-metal (e.g., Los Frailes, pH 7.2, 0.07 mg/L Fe, 3.8 mg/L Mn, 30 mg/L Zn), to extremely acidic and metal(loid)-rich (e.g., Corta Atalaya, pH 1.2, 36.7 g/L Fe, 6.7 g/L Zn, 1.3 g/L Cu, 159 mg/L As). Most pit lakes, however, are comprised within the pH range of 2.2–3.6 and appear to be strongly buffered by the hydrolysis and precipitation of Fe(III) in the form of schwertmannite, which forms colloids that can sorb trace elements from the aqueous phase.  相似文献   

15.
The feasibility of a hydrogeological modeling approach to simulate several thousand shallow groundwater-fed lakes and wetlands without explicitly considering their connection with groundwater is investigated at the regional scale (~40,000 km2) through an application in the semi-arid Nebraska Sand Hills (NSH), USA. Hydraulic heads are compared to local land-surface elevations from a digital elevation model (DEM) within a geographic information system to assess locations of lakes and wetlands. The water bodies are inferred where hydraulic heads exceed, or are above a certain depth below, the land surface. Numbers of lakes and/or wetlands are determined via image cluster analysis applied to the same 30-m grid as the DEM after interpolating both simulated and estimated heads. The regional water-table map was used for groundwater model calibration, considering MODIS-based net groundwater recharge data. Resulting values of simulated total baseflow to interior streams are within 1% of observed values. Locations, areas, and numbers of simulated lakes and wetlands are compared with Landsat 2005 survey data and with areas of lakes from a 1979–1980 Landsat survey and the National Hydrography Dataset. This simplified process-based modeling approach avoids the need for field-based morphology or water-budget data from individual lakes or wetlands, or determination of lake-groundwater exchanges, yet it reproduces observed lake-wetland characteristics at regional groundwater management scales. A better understanding of the NSH hydrogeology is attained, and the approach shows promise for use in simulations of groundwater-fed lake and wetland characteristics in other large groundwater systems.  相似文献   

16.
17.
This paper presents results from the numerical modelling of the transport of atmospheric noble gases (He, Ne, Ar, Kr, Xe), tritiated water and 3He produced by radioactive decay of 3H, in unconsolidated lacustrine sediment. Two case studies are discussed: (1) the evolution of 3H and 3He concentrations in the sediment porewater of Lake Zug (Switzerland) from 1953 up to the present; and (2) the response of dissolved atmospheric noble gas concentrations in the sediment porewater of a subtropical lake to an abrupt climatic change that occurred some 10 kyr before the present. (1) Modelled 3H and 3He porewater concentrations are compared with recent data from Lake Zug. An estimate of the effective diffusion coefficients in the sediment porewater is derived using an original approach which is also applicable also to lakes for which the historical 3H and 3He concentrations in the water column are unknown. (2) The air/water partitioning of atmospheric noble gases is sensitive to water temperature and salinity, and thus provides a mechanism by which these environmental variables are recorded in the concentrations of atmospheric noble gases in lakes. We investigate the feasibility of using noble gas concentrations in the porewater of lacustrine sediments as a proxy for palaeoenvironmental conditions in lakes. Numerical modelling shows that heavy noble gases in sediment porewater, because of their comparatively small diffusion coefficients and the strong temperature sensitivity of their equilibrium concentrations, can preserve concentrations corresponding to past lake temperatures over times on the order of 10 kyr. Noble gas analysis of sediment porewaters therefore promises to yield valuable quantitative information on the past environmental states of lakes.  相似文献   

18.
龙湖周边机井开采对地下水流影响的数值模拟   总被引:2,自引:0,他引:2  
人工湖、库和河流等将改变区域水文循环过程,特别是地表水与地下水交换关系。本文对郑州市规划的龙湖入渗水利用和龙湖周边机井布设方案进行比较分析。龙湖水体形成后,湖区与周围地下水位的2.5m落差将使湖水大量入渗补给地下水,大范围抬升湖区周围地下水位,龙湖周围低洼处将有发生盐碱化的危险,威胁到紧靠龙湖的西部国家森林公园和规划中的东北部生态回廊绿地。本文利用美国地质调查局(USGS)颁布的三维地下水数值模型(MODFLOW),模拟不同湖底防渗措施和机井开采方案下龙湖周围地下水位变化以及龙湖入渗量,对龙湖周边布井方案可行性和降低地下水效果加以分析和比较。  相似文献   

19.
近20a来西藏朋曲流域冰湖变化及潜在溃决冰湖分析   总被引:19,自引:11,他引:19  
车涛  晋锐  李新  吴立宗 《冰川冻土》2004,26(4):397-402
全球气候变暖,青藏高原冰川普遍处于退缩趋势,由此引发的冰湖溃决洪水的灾害也随之增加.通过对2000/2001年度卫星遥感数据解译结果和1987年国际联合考察的朋曲流域冰湖溃决洪水结果的分析,研究了近20a来朋曲流域内冰湖的变化.结果显示,该流域中的冰湖数量有减少,但冰湖的面积却在增加,这是同期全球气候变暖的结果.在提供了冰湖编目数据的基础上,识别了有潜在危险的冰湖,为冰湖溃决洪水早期预警系统提供了科学依据.  相似文献   

20.
Changes in water chemistry along the High Arctic fluvial–lacustrine system located in Wedel Jarlsberg Land in the SW Spitsbergen (Svalbard) were investigated during the summer season of 2010 and 2011. The newly formed river–lake system consists of three lakes connected with the Brattegg River. The first bathymetric measurements of these lakes were made by the authors in 2010. The Brattegg River catchment represents a partly glaciered Arctic water system. The studied lakes are characterized by low mineralization and temperature of water. The value of the electrolytic conductivity (EC) ranges from 30.2 to 50.5 μS cm?1 and the temperature of surface water from 1.5 to 7.8 °C. The temperature increase takes place downstream starting from Upper Lake to the outflow from Myrktjørna Lake. The waters of lakes have higher temperatures than the stream. The predominant ions are HCO3 ? (up to 16.5 mg L?1), Cl? (6.66–8.53 mg L?1), Ca2+ (2.40–4.45 mg L?1) and Na+ (2.65–3.36 mg L?1). The highest values of ammonium and DOC found in the lowest Myrktjørna Lake seem to be related to the presence of aquatic organisms and also birds. From the group of 10 analyzed microelements, increased concentrations of aluminum, up to almost 500 μg L?1, are present in the lakes’ water. Water isotopic composition ranges for δ18O and δ2H, from ?10.6 to ?10.9‰ and from ?70.8 to ?72.3‰, respectively. The vertical zonality of lake waters is manifested in a decrease in the temperature and increase in EC and chemical elements concentrations.  相似文献   

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