River systems and their sediment flux, Indo-Gangetic plains, Northern Bihar, India

River systems of part of the Himalayan foreland, northern Bihar plains, India, are described in terms of their channel morphology, hydrology and suspended sediment characteristics. A simple classification of the river systems based mainly on the source area characteristics is proposed: (i) mountain-fed, (ii) foothills-fed, (iii) plains-fed and (iv) mixed-fed rivers. Distinct differences are noted between these classes of river systems. Most rivers show evidence of channel movement, mainly by avulsion, but cut-offs also occur locally. The mountain-fed rivers are characterized by very high discharge and low suspended sediment concentration and the plains-fed rivers have relatively low discharge and high suspended sediment concentration. The foothill-fed rivers have moderate values of discharge and suspended sediment concentration. The mountain-fed rivers have built megafans of large extent, whereas the foothills-fed and plains-fed rivers have formed muddy interfan areas. Semi-quantitative estimates of water and sediment flux suggest that about 99·9% of the mass transfer into the plains is water, with the remaining 0·1% being sediment, and that 10% of the latter (0·01% of the total) is retained in the basin, the remainder being transferred to the Bengal Fan.     

Assessment of groundwater quality in the flood plains of upper Palar River, India

Groundwater is generally presumed to be good for human consumption and is used as a main source of drinking water. Although there are numerous reasons for groundwater pollution, anthropogenic sources are consid-ered as the prime ones. In this study, twenty-two groundwater samples were collected from the flood plains of upper Palar River during the pre- and post-monsoon seasons to assess the extent of pollution and effects on human health. Physico-chemical characteristics of groundwater were analyzed and compared with those of drinking water standards recommended by the World Health Organization (WHO) and the Bureau of Indian Standards (BIS). The Piper’s tri-linear diagram shows the nature of alkali earth with the high contents of alkalies and prevailing sulphate in the pre-sent samples. The univariate statistics and correlation analysis were performed to find out the relationships between the variables. The tannery effluents, solid wastes and sewage were suspected to be the predominant sources of pollu-tion in the area.     

Hydrochemical characterization of groundwater in the Accra plains of Ghana

Chemical and isotopic analyses are used to characterize and identify the relevant water-rock interactions, which are responsible for the poor groundwater quality in the Accra Plains. Four main water types are identified. Processes that singly or in combination influence the chemical composition of each water type include halite dissolution carbonate dissolution and precipitation, seawater intrusion, cation exchange, evaporative concentration of solutes and aluminosilicates dissolution. These processes contribute considerably to the concentration of major ions in the groundwater. Stable isotope contents of the groundwater suggest mainly direct integrative recharge. A few samples plot along the meteoric-seawater mix line which is coincidentally the evaporative line. The Cl⁻/Br⁻ ratios of some of these are close to 300 confirming marine origin, others probably concentrated by evaporation have their Cl⁻/Br⁻ ratios significantly lower than 300. Groundwater is qualitatively good for drinking purposes only along the foothills of the Akwapim Togoland ranges.     

丹江口水库老灌河流域地下水水化学特征

作为南水北调中线工程的水源地,丹江口水库地下水的水质是影响南水北调工程建设的重要因素。为了确保丹江口水库一库清水送北京,对水库老灌河流域进行地下水采样、统计和分析,研究地下水的水化学特征,结果表明: 丹江口老灌河流域地下水偏弱碱性,属于低矿化水,Ca²⁺为优势阳离子,$HCO_3^-$为优势阴离子; 除$NO_3^-$外,该区主要离子浓度均符合我国及世界卫生组织推荐的饮用水标准; 丰水期和枯水期地下水的水化学类型均为Ca-Mg-HCO₃型和Ca-HCO₃型,水化学过程以风化-溶滤作用为主; 地下水$NO_3^-$超标13%~17%,丰水期部分区域出现Cl^-型水化学类型。季节变化对老灌河流域地下水的水化学类型空间分布影响较小,地下水水质受农业、养殖业、工业遗留废渣及生活污水等影响。     

丹江口水库老灌河流域地下水水化学特征

作为南水北调中线工程的水源地,丹江口水库地下水的水质是影响南水北调工程建设的重要因素.为了确保丹江口水库一库清水送北京,对水库老灌河流域进行地下水采样、统计和分析,研究地下水的水化学特征,结果表明:丹江口老灌河流域地下水偏弱碱性,属于低矿化水,Ca2+为优势阳离子,HCO3-为优势阴离子;除NO3-外,该区主要离子浓度均符合我国及世界卫生组织推荐的饮用水标准;丰水期和枯水期地下水的水化学类型均为Ca-Mg-HCO3型和Ca-HCO3型,水化学过程以风化-溶滤作用为主;地下水NO3-超标13% ~17%,丰水期部分区域出现Cl-型水化学类型.季节变化对老灌河流域地下水的水化学类型空间分布影响较小,地下水水质受农业、养殖业、工业遗留废渣及生活污水等影响.     

Hydrochemical characteristics and groundwater quality assessment in Tirupur Region, Coimbatore District, Tamil Nadu, India

Groundwater samples from 62 locations have been collected from Tirupur region viz. Avinashi, Tirupur and Palladam taluks of Coimbatore District. The extensive agricultural industrial activities and urbanization resulted in the contamination of the aquifer. To study the contamination of groundwater, water samples were collected in an area of 180 km² and analysed for major cations and anions. Most of the locations are contaminated by higher concentration of EC, TDS, K and NO₃. Major hydro chemical facies were identified using Piper trilinear diagram. Based on US salinity diagram, most of the samples fall in the field of C3S1, indicating high salinity and low sodium water, which can be used for almost all types of soil with little danger of exchangeable sodium. Majority of the samples are not suitable for domestic purposes and far from drinking water standards. However, PI values indicates that groundwater is suitable for irrigation.     

Hydrochemical characteristics of groundwater in the Zhangye Basin, Northwestern China

The Zhangye Basin, located in arid northwest China, is an important agricultural and industrial center. In recent years rapid development has created an increased demand for water, which is increasingly being fulfilled by groundwater abstraction. Detailed knowledge of the geochemical evolution of groundwater and water quality can enhance understanding of the hydrochemical system, promoting sustainable development and effective management of groundwater resources. To this end, a hydrochemical investigation was conducted in the Zhangye Basin. Types of shallow groundwater in the Zhangye Basin were found to be HCO₃ ⁻, HCO₃ ⁻–SO₄ ²⁻, SO₄ ²⁻–HCO₃ ⁻, SO₄ ²⁻–Cl⁻, Cl⁻–SO₄ ²⁻ and Cl⁻ . The deep aquifer groundwater type was found to be HCO₃⁻–SO₄²⁻ throughout the entire area. Ionic ratio and saturation index calculations suggest that silicate rock weathering and evaporation deposition are the main processes that determine the ionic composition in the study area. The suitability of the groundwater for irrigation was assessed based on the US Salinity Laboratory salinity classification and the Wilcox diagram. In the study area, the compositions of the stable isotopes δ¹⁸O and δD in groundwater samples were found to range from −4.00 to −9.28‰ and from −34.0 to −65.0‰, respectively. These values indicate that precipitation is the main recharge source for the groundwater system; some local values indicate high levels of evaporation. Tritium analysis was used to estimate the ages of the different groundwaters; the tritium values of the groundwater samples varied from 3.13 to 36.62 TU. The age of the groundwater at depths of less than 30 m is about 5–10 years. The age of the groundwater at depths of 30–50 m is about 10–23 years. The age of the groundwater at depths of 50–100 m is about 12–29 years. For groundwater samples at depths of greater than 100 m, the renewal time is about 40 years.     

Hydrochemical characteristics of groundwater in the Kingston Basin,Kingston, Jamaica

The Kingston Basin in Jamaica is an important hydrologic basin in terms of both domestic and industrial sector. The Kingston hydrologic basin covers an area of approximately 258 km² of which 111 km² underlain by an alluvium aquifer, 34 km² by a limestone aquifer and the remainder underlain by low permeability rocks with insignificant groundwater resources. Rapid development in recent years has led to an increased demand for water, which is increasingly being fulfilled by groundwater abstraction. A detailed knowledge of the water quality can enhance understanding of the hydrochemical system, promoting sustainable development and effective management of groundwater resources. To achieve this, a hydrochemical investigation was carried out in the Kingston Basin. Results showed that the water is Na–Ca–Cl–HCO₃ and Na–Ca–HCO₃ type with higher concentrations of nitrate, sodium and chloride as the leading causes of contamination in most of the wells. High concentrations of nitrate correlate with wells from areas of high population density and could be attributed to anthropogenic causes, mainly involving improper sewage treatment methodologies or leaking sewer lines. Jamaica, owing to its island nature, has the continuous problem of saline water intrusion, and this is reflected in the higher levels of chloride, sodium and conductivity in the water samples collected from the wells. The wells studied show higher concentrations of chloride ranging from around 10.2 mg/l in wells located approximately (4931.45 m) from the coast to around 234 mg/l in the well located near to the coast. The conductivity values also closely correlate with the chloride levels found in the wells.     

甘肃敦煌地区疏勒河尾闾区地下水化学特征及成因分析

疏勒河尾闾区是护卫敦煌绿洲及文化的生态安全屏障,但是对地下水化学的研究相对较少.本次研究在野外调查及采样测试的基础上,综合运用数理统计、Piper三线图、离子相关性分析、Gibbs图及离子比例系数等方法明确了疏勒河尾闾区的地下水化学特征,并对其成因进行了分析.结果表明:疏勒河尾闾区地下水水质总体呈弱碱性,具有高溶解性总...     

甘肃敦煌地区疏勒河尾闾区地下水化学特征及成因分析

疏勒河尾闾区是护卫敦煌绿洲及文化的生态安全屏障,但是对地下水化学的研究相对较少。本次研究在野外调查及采样测试的基础上,综合运用数理统计、Piper三线图、离子相关性分析、Gibbs图及离子比例系数等方法明确了疏勒河尾闾区的地下水化学特征,并对其成因进行了分析。结果表明：疏勒河尾闾区地下水水质总体呈弱碱性,具有高溶解性总固体及高硬度的特征,水化学类型主要为Cl-·SO2-4-Na+型。地下水水化学演化是由蒸发浓缩作用主导,同时风化溶解和阳离子交换共同作用的结果。地下水中的Ca2+及Mg2+主要来自于蒸发岩及硅酸盐的溶解,Na+主要来源于岩盐溶解。高氟水的形成与片麻岩中普遍存在的黑云母矿物、蒸发浓缩主导的水文地球化学作用以及地势低洼的地形条件有关。成果不仅丰富了疏勒河流域内的地下水化学研究,亦可为敦煌绿洲生态安全屏障区的保护与建设提供科学依据。     

山东省东汶河沂南地区地下水水化学特征及形成机理

地下水作为人类重要的水源之一,已经受到了人类活动的明显影响而造成污染,深入研究地下水化学特征及形成机制,对于地下水资源的合理利用具有重要意义.东汶河沂南地区分布着多种类型的含水层,并且农业、养殖业发达,是进行人类活动影响下的地下水水化学形成研究的理想地区.本文综合利用Piper三线图、离子比值法及数理统计(相关性分析、...     

Hydrochemical characteristics and salinity of groundwater in the Ejina Basin, Northwestern China

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.     

柴达木盆地大柴旦地区地下水水化学特征及演化规律

地下水在干旱/半干旱地区的生态环境保护中起着主导作用.柴达木盆地北缘的大柴旦湖地处西北干旱区,其生态环境较为脆弱,了解该地区的地下水水化学演化特征,对这一生态敏感地区的地下水可持续利用至关重要.本研究通过采集该地区28个具有代表性的水样,运用数理统计、Piper图、Gibbs图、离子比值、饱和指数和反向水文地球化学模拟...     

苏北阜宁县地下水水化学特征及成因分析

为了查明苏北阜宁县潜水和承压水的水化学成因和补给特征,文章采集区域内地表水、潜水、承压水(第Ⅱ、第Ⅲ、第Ⅳ承压水)的水样,结合数理统计分析、Piper三线图、Gibbs模型和水化学特征系数等手段,分析了不同水体的氢氧同位素关系和矿化度分布、主要阴阳离子关系、水化学特征。结果表明:① 阜宁县地下水总体为弱碱性,潜水和承压水中阳离子质量浓度都呈现Na+>Ca2+>Mg2+>K+,潜水中阴离子质量浓度呈现HCO-3>Cl->SO2-4>NO-3,第Ⅱ、第Ⅲ、第Ⅳ承压水中阴离子质量浓度皆呈现出HCO-3>SO2-4>Cl->NO-3;潜水的总溶解固体(TDS)比第Ⅱ、第Ⅲ、第Ⅳ承压水偏高,局部区域的潜水为微咸水和咸水,第Ⅱ、第Ⅲ、第Ⅳ承压水的水质明显优于潜水。② 地下水的补给与大气降水相关,潜水为现代降水补给,第Ⅱ、第Ⅲ、第Ⅳ承压水源于晚更新世或者更早时期的降水补给。③ 地下水水化学特性受降水影响较小,主要受到水岩作用、阳离子交换作用控制,其中第Ⅱ、第Ⅲ、第Ⅳ承压水的盐分主要来源于硅酸盐岩风化,人类活动对地下水化学组分影响相对较弱。     

Chemical characteristics of groundwater in parts of the Gambhir River basin,Bharatpur District,Rajasthan, India

Twenty-nine dug well samples have been collected from the Gambhir River basin in the Bharatpur District of Rajasthan State in India for hydrogeochemical study to understand the sources of dissolved ions and assess the chemical quality of the water. Broadly speaking, the groundwaters have a chemical composition within the permissible limits suggested for drinking water. Nitrate is higher than the acceptable limit in some samples, due to the use of fertilizers. Graphical treatment of the major ion chemistry helps in deciphering the chemical characteristics of groundwaters, which may then be used for grouping the samples to identify the trends of the chemical alteration of the meteoric water. Four groups have been identified in the Gambhir River basin groundwater system: (1) HCO ₃ enriched, (2) mixed type, (3) alkali-rich, high TDS type, and (4) HCO ₃ deficient. Possible aqueous species have been identified for these four groups of samples. In groups I and II, the species are Ca (HCO ₃) ₂, Mg (HCO ₃) ₂, NaCl, Na ₂SO ₄ and NaHCO ₃. Group III, in addition to these species, has abundance of KCl. Group IV has Ca (HCO ₃) ₂, NaCl, CaSO ₄, and rather rare species such as CaCl ₂, MgCl ₂ and MgSO ₄. Interpretation of the data reveals that feldspar and pyrite weathering reactions do not play a significant role in giving groundwaters their observed chemical characteristics. Groups I and II samples have evidently been derived by dissolution of surface salts, whereas groups III and IV groundwaters suggest dissolution of a marine evaporite sequence similar to the one known to exist to the west of the study area, unconformably overlying the rocks of the Delhi Super Group. There are indications that joints play an important role in segregating groundwaters with different chemical characteristics.     

拉萨地区地下水水化学特征及形成机制研究

西藏是我国重要的生态安全屏障,拉萨地区地下水化学特征及形成机制研究,对揭示青藏高原现代表生过程变化机理具有重要作用,对服务国家生态安全建设具有重要意义。本文通过拉萨地区地下水调查、水样采集与分析,综合运用Gibbs模型模拟、水化学分析方法分析了地下水化学特征及水岩作用机理。结果表明:地下水电导率介于38.801 193.00 μS/cm,平均值为123.99 μS/cm,总溶解性固体(total dissolved solids,TDS)含量介于44.051 050.55 mg/L,平均值为150.75 mg/L,pH值大于7,属弱碱性水,地下水化学类型为HCO₃-Ca型和Cl-Na型,其中Cl-Na型水为地下温泉水。地下水形成过程主要是碳酸盐岩和硅酸盐岩的溶解、阳离子交换等作用下的结果,且受到一定程度的人为因素影响;地下水中的Na⁺、K⁺和Cl^-主要来自盐岩矿物的风化溶解,过量的Na⁺、K⁺来源于钠长石和钾长石等硅酸盐矿物的溶解, {\mathrm{HCO}}_3^{-}、Ca²⁺、Mg²⁺和 {\mathrm{SO}}_4^{2-}主要来自方解石、白云石、石膏以及其他含钙镁矿物的溶解。     

Hydrochemical and isotopic characteristics of groundwater in the Souss Upstream Basin, southwestern Morocco

Heterogeneous shallow Plio-Quaternary formations of the Souss Plain represent the most important aquifer in southern High Atlas Mountains in Morocco. The present work was conducted in the Souss Upstream Basin to identify the chemical characteristics and the origin of groundwater in an aquifer under semi-arid climate. Isotopic and hydrochemical compositions combined with geological and hydrogeological data were used for this purpose. The total dissolved solids vary from 239 to 997 mg l⁻¹, and the following groundwater types are recognized: Ca²⁺–Mg²⁺–HCO₃⁻, Ca²⁺–Mg²⁺–SO₄²⁻ and Ca²⁺–Mg²⁺–Cl⁻. The groundwater is saturated and slightly supersaturated with respect to carbonate minerals and undersaturated with respect to evaporite minerals, which means that the groundwater composition is largely controlled by the dissolution of carbonate rocks known in the basin. The isotopic contents of groundwaters ranged from −8‰ to −5.2‰ for δ¹⁸O, from −52‰ to −34‰ for δD, and from 0 to 5.5 TU for tritium. The hydrogen (δD) and oxygen (δ¹⁸O) isotope signatures reveal a significant infiltration before evaporation takes place, indicating a major recharge directly from fractures in the crystalline and limestone formations of Atlas Mountains (above 800 m a.s.l.) and infiltration of surface water in the alluvial cones at the border of the Atlas basins. The very low tritium values suggest that the groundwater recharge follows a long flow path and a mixing between old and modern water is shown. However, a slight evaporation effect is noted in the southern part of the basin close to the Anti-Atlas Mountains.     

Hydrochemical and isotopic characteristics of groundwater in the northeastern Tennger Desert,northern China

Groundwater is typically the only water source in arid regions, and its circulation processes should be better understood for rational resource exploitation. Stable isotopes and major ions were investigated in the northeastern Tengger Desert, northern China, to gain insights into groundwater recharge and evolution. In the northern mountains, Quaternary unconsolidated sediments, exposed only in valleys between hills, form the main aquifer, which is mainly made of aeolian sand and gravel. Most of the mountain groundwater samples plot along the local meteoric water line (LMWL), with a more depleted signature compared to summer precipitation, suggesting that mountain groundwater was recharged by local precipitation during winter. Most of the groundwater was fresh, with total dissolved solids less than 1 g/L; dominant ions are Na⁺, SO₄ ^2? and Cl^?, and all mineral saturation indices are less than zero. Evaporation, dissolution and cation exchange are the major hydrogeochemical processes. In the southern plains, however, the main aquifers are sandstone. The linear regression line of δD and δ ¹⁸O of groundwater parallels the LMWL but the intercept is lower, indicating that groundwater in the plains has been recharged by ancient precipitation rather than modern. Both calcite and dolomite phases in the plains groundwater are close to saturation, while gypsum and halite can still be dissolved into the groundwater. Different recharge mechanisms occur in the northern mountains and the southern plains, and the hydraulic connection between them is weak. Because of the limited recharge, groundwater exploitation should be limited as much as possible.     

南宁市区地下水水化学特征及形成机制

为了深入研究南宁市区地下水水化学特征、水质情况及地下水质量演变的主要水化学过程,文章采集南宁市区22组孔隙水和7组岩溶水,检测pH值、阴阳离子、溶解性总固体（TDS）和总硬度等化学指标,探讨地下水水化学特征和形成机制。结果表明:研究区孔隙水和岩溶水pH平均值均小于7,两种水TDS和总硬度基本一致,主要的阴离子（HCO3-、Cl-、SO42-）中含量最高的是HCO3-,平均分别为68.08 mg/L和106.68 mg/L;对于阳离子（Ca2+、Mg2+、K+、Na+）,研究区孔隙水和岩溶水均表现为Ca2+≥Na+>Mg2+>K+,其中Ca2+的平均含量分别为24.04 mg/L和31.34 mg/L;地下水化学成分主要通过风化-溶滤作用与混合作用形成,地下水水化学类型为HCO3--Ca2+型水;地质环境背景是地下水pH值普遍偏低的主要原因,人类活动对地下水的影响越来越重要,pH值和水化学类型改变均与经济发展、人口增加、工矿企业增加等人类活动密切相关。      

珠江三角洲地下咸水形成的水化学证据

珠江三角洲地下咸水分布广泛。迄今仅在珠江三角洲局部地段进行了地下咸水有关的研究,因而对区域性地下咸水成因的认识缺乏。利用近10年来有关水工环地质调查项目获得的67个水文地质钻孔的水化学分析资料,进行了珠江三角洲平原地下咸水水化学的总体特征、水文地球化学参数及特征指标关系研究,探讨了区域性地下咸水成因与影响因素。研究结果表明,地下咸水水化学特征总体上与海水较为一致;地下咸水起源于古海水,主要形成于中全新世海侵期,与退积作用关系密切;地下咸水形成过程中,水循环交替慢,水动力条件不良;地下咸水中的盐分主要来源于古海水及海相沉积物,沉积压实、矿物溶解与离子交换等作用可能造成盐分的富集。