Arina Khan

Hydrochemical characterization of groundwater in lower Kali watershed, Western Uttar Pradesh

A hydrogeochemical study was carried out to assess the groundwater quality in parts of Kali watershed in Bulandshahr and Aligarh district. 42 groundwater samples each were collected from hand pumps in pre-monsoon and post-monsoon period 2012 respectively and analysed for pH, EC, TDS, Total Hardness, silica, anions (Cl, HCO3, CO3, SO4, F & NO3) and cations (Ca, Mg, Na & K). On the basis of various diagrams and plots, groundwater has been assessed for its hydrochemical characteristics and suitability for irrigation and drinking purposes. Results show dominance of alkalis and bicarbonates. The dominant facies identified from piper diagram is Na-K-HCO3. Four chemical groups of water have been identified on L-L diagram and majority of the samples fall in alkali-bicarbonate type and mixed type groups. Possible aqueous species in the groundwater are Mg(HCO3)2, Ca(HCO3)2, NaHCO3, NaCl, CaSO4, K2SO4 and Na2SO4. The US salinity diagram and Residual Sodium Carbonate (RSC) suggest that the water is suitable for irrigation purpose. Nitrates in groundwater are within permissible limits except in 3 different locations in each season, which show high values due to the contamination from a landfill site and application of fertilizers. High positive correlation was observed between TDS and Na+, Cl-, Mg++ and Total Hardness (TH). Sodium show good correlation with Cl. Correlation of silica with Cl and TDS was done to assess the geogenic or anthropogenic involvement in evolving groundwater quality. Anthropogenic contributions from agricultural and domestic sources and weathering of rock forming minerals control the hydrochemistry of the area.

An integrated approach for aquifer vulnerability mapping using GIS and rough sets: study from an alluvial aquifer in North India

A modified DRASTIC model in a geographic information system (GIS) environment coupled with an information-analytic technique called ‘rough sets’ is used to understand the aquifer vulnerability characteristics of a segment of the lower Kali watershed in western Uttar Pradesh, India. Since the region is a flat plain, topography (T) is removed as a potential control. Other parameters are the same as in DRASTIC, hence the new model is termed as DRASIC. The rough set technique is employed to provide insight into the relative vulnerabilities of different administrative units (blocks) within the study area. Using rough sets, three important factors are computed: strength, certainty and coverage. Strength indicates how the vulnerability characteristics vary in the entire area, certainty gives the relative fractions of low, medium and high vulnerability regions within a particular block, and coverage computes the percentage of a particular vulnerability state in each block. The purpose of the work is to demonstrate the utility of this integrated approach in classifying different administrative blocks in the study area according to their aquifer vulnerability characteristics. This approach is particularly useful for block-level planning and decision making for sustainable management of groundwater resources.RésuméUne approche DRASTIC modifiée intégrée dans un système d’information géographique (SIG), couplé avec une technique d’analyse des données nommée « ensembles approximatifs », est utilisée pour comprendre les caractéristiques de vulnérabilité de l’aquifère sur une partie du bassin versant du Kali inférieur, dans l’Ouest de l’Uttar Pradesh, en Inde. Comme la région est une plaine dénuée de relief, la topographie (T) est retirée des paramètres de contrôle. Les autres paramètres sont identiques à ceux de DRASTIC, de sorte que le la nouvelle approche est désignés sous le nom de DRASIC. La technique des ensembles approximatifs est utilisée pour apporter de la précision aux vulnérabilités relatives des différentes unités administratives (blocs), au sein de la zone d’étude. Utilisant les ensembles approximatifs, trois paramètres importants sont calculés: force, certitude et couverture. La force indique comment les caractéristiques de vulnérabilité varient dans l’ensemble de la zone, la certitude donne les fractions relatives des secteurs de vulnérabilité faible, moyenne et élevée, au sein d’un bloc particulier, et la couverture calcule le pourcentage d’un état de vulnérabilité particulier dans chaque bloc. L’objectif de ce travail est de démontrer l’utilité de cette approche intégrée pour classer les différents blocs administratifs de la zone d’étude, en fonction des caractéristiques de la vulnérabilité des aquifères. Cette approche est particulièrement utile pour une planification à l’échelle de chaque bloc et une prise de décision pour une gestion durable des ressources en eau souterraine.ResumenSe utilizó un modelo DRASTIC modificado en un ambiente de sistema de información geográfica (GIS) acoplado con la técnica de información analítica denominada ‘conjuntos aproximados’ para entender las características de la vulnerabilidad del acuífero de un segmento de la cuenca baja de Kali en el oeste de Uttar Pradesh, India. Puesto que la región es una planicie llana, la topografía (T) fue eliminada como un control potencial. Otros parámetros son los mismos que en el DRASTIC, por lo tanto el nuevo modelo es denominado como DRASIC. Se empleó la técnica de conjunto aproximada para proveer conocimientos más profundos de las vulnerabilidades relativas de las diferentes unidades administrativas (bloques) dentro del área de estudio. Usando conjuntos aproximados, se computaron los tres factores importantes: la solidez, la certeza y la cobertura. La solidez indica como varían las características de vulnerabilidad en el total del área, la certeza da la fracción relativa de las regiones de baja, media y alta vulnerabilidad dentro de un bloque particular, y la cobertura computa el porcentaje de un estado particular de vulnerabilidad en cada bloque. El propósito del trabajo es demostrar la utilidad de este enfoque integrado para clasificar diferentes bloques administrativos en el área de estudio de acuerdo a sus características de vulnerabilidad del acuífero. Este enfoque es particularmente útil para la planificación y la toma de decisión a nivel de bloque para el manejo sustentable de los recursos de agua subterránea.摘要与信息解析技术耦合的地理信息系统环境下改进DRASTIC模型被称为“粗集”,用于了解印度北方邦西部Kali流域下游某段含水层脆弱性特征。本地区是平坦的平原,因此,地形(T)不算做一个潜在的控制因素。其他参数与DRASTIC中的相同,因此,新的模型称为DRASIC。采用粗集技术可深入认识研究区内不同管理单元(区块)的相对脆弱性。采用粗集技术,要计算三个主要因素:强度、确定性和覆盖范围。强度是指脆弱性特征在整个地区是如何变化的,确定性表示特定区块内低、中、高脆弱性地区的相对系数,覆盖范围计算每个区块内特殊脆弱性状态的百分比。研究的目的就是展示这个综合方法在研究区根据含水层脆弱性特征对不同管理区块进行分类的使用性。这个方法对地下水资源可持续管理区块尺度的规划和决策特别有用ResumoUtiliza-se um modelo DRASTIC modificado num ambiente de sistema de informação geográfica (SIG) acoplado com uma técnica de informação analítica designada de “conjuntos irregulares” (“rough sets”) para perceber as caraterísticas de vulnerabilidade aquífera de um segmento da bacia hidrográfica do baixo Kali, no Uttar Pradesh ocidental, Índia. Dado que a região é uma planície, o parâmetro topografia (T) é retirado como controlo potencial. Os restantes parâmetros são os mesmos do DRASTIC, pelo que se designa o novo modelo como DRASIC. Utiliza-se a técnica dos conjuntos irregulares para dar uma visão das vulnerabilidades relativas de diferentes unidades administrativas (blocos) da área de estudo. Utilizando conjuntos irregulares, calculam-se três fatores importantes: força, certeza e cobertura. A força indica como as caraterísticas de vulnerabilidade variam na área inteira, a certeza dá as frações relativas das regiões de vulnerabilidade baixa, média ou alta dentro de um bloco particular, e a cobertura calcula a percentagem de um estado de vulnerabilidade particular em cada bloco. O objetivo do trabalho é demonstrar a utilidade da abordagem integrada na classificação de diferentes blocos administrativos na área de estudo, de acordo com as suas caraterísticas de vulnerabilidade aquífera. Esta abordagem é particularmente útil para planeamento e tomada de decisão, a nível de bloco, na gestão sustentável de recursos hídricos subterrâneos.

Impact of land-use on groundwater quality: GIS-based study from an alluvial aquifer in the western Ganges basin

In this study, groundwater quality of an alluvial aquifer in the western Ganges basin is assessed using a GIS-based groundwater quality index (GQI) concept that uses groundwater quality data from field survey and laboratory analysis. Groundwater samples were collected from 42 wells during pre-monsoon and post-monsoon periods of 2012 and analysed for pH, EC, TDS, Anions (Cl, SO4, NO3), and Cations (Ca, Mg, Na). To generate the index, several parameters were selected based on WHO recommendations. The spatially variable grids of each parameter were modified by normalizing with the WHO standards and finally integrated into a GQI grid. The mean GQI values for both the season suggest good groundwater quality. However, spatial variations exist and are represented by GQI map of both seasons. This spatial variability was compared with the existing land-use, prepared using high-resolution satellite imagery available in Google earth. The GQI grids were compared to the land-use map using an innovative GIS-based method. Results indicate that the spatial variability of groundwater quality in the region is not fully controlled by the land-use pattern. This probably reflects the diffuse nature of land-use classes, especially settlements and plantations.