Dynamic, forward-looking team player with relevant experience in the field of Environmental Science, Remote sensing and GIS. Combines extensive technical, analytical, and interpretive skills with practical field experience. Possess strong interpersonal skills: experience working with multi-discipline research/scientific teams and professionals. Supervisors: N. Chandrasekar Phone: 9944717646 Address: Centre for Geotechnology Manonmaniam Sundaranar University Tirunelveli Tamilnadu India - 627 012
Trace element concentration in the beach placer mining areas of Kanyakumari coast, South India wa... more Trace element concentration in the beach placer mining areas of Kanyakumari coast, South India was assessed. Sewage and contaminated sediments from mining sites has contaminated the surface sediments. Enrichment factor indicates moderately severe enrichment for Pb, minor enrichment for Mn, Zn, Ni, Fe and no enrichment for Cr and Cu. The Igeo values show higher concentration of Pb ranging in the scale of 3-4, which shows strong contamination due to high anthropogenic activity such as mining and terrestrial influences into the coastal regions. Correlation coefficient shows that most of the elements are associated with each other except Ni and Pb. Factor analysis reveals that Mn, Zn, Fe, Cr, Pb and Cu are having a significant loading and it indicates that these elements are mainly derived from similar origin. The cluster analysis clearly indicated that the mining areas are grouped under cluster 2 and non-mining areas are clustered under group 1.
The present study focused on the elemental distribution of nearshore environment and to understan... more The present study focused on the elemental distribution of nearshore environment and to understand the interrelationship between different parameters such as trace elements, organic matter, calcium carbonate and sediment texture. For this purpose, 24 surface samples were collected from the nearshore environment using a stainless steel Van Veen grab sampler. The above said parameters indicate that nearshore sediment transport, contaminants from estuarine source and anthropogenic activities deteriorates the sediment quality in the nearshore area. The enrichment factor reveals that the sediments are enriched with Pb, Co, Ni and Cr, whereas the geoaccumulation index highlights that the sediments are polluted with Pb, Ni and Co. The elevated concentration of Pb in the nearshore sediments are possibly from the port activities and thermal power plants situated in the north of the study area. Proper management of industrial effluents is needed to curb further metal pollution in the nearshor...
Forty eight surface sediment samples were collected from the vicinity of Van Island in order to a... more Forty eight surface sediment samples were collected from the vicinity of Van Island in order to assess the sediment pollution level and potential ecological risk on coral reef ecosystem. The analytical and correlation results indicate a distribution of elements is chiefly controlled by the CaCO3 and OM. The enrichment factor and geoaccumulation index show the elevated level of Pb in the surface sediments is due to application of lead petrol and coal incinerating power plants. The sediment pollution index reveals that majority of the sediments falling under highly polluted sediment category (35.4%) followed by moderately polluted (25%) and dangerous sediment category (14.58%). The potential ecological risk suggests that nearly 66.6% of the samples falling under the low risk category, moderate risk category (20.8%) followed by considerable risk category (8.33%) and very high risk category (4.1%). The accumulation level of trace elements clearly suggests that the coral reef ecosystem i...
The present study was conducted to assess the trace element concentration in marine surface sedim... more The present study was conducted to assess the trace element concentration in marine surface sediments after major flood event of Chennai metropolis, India. Thirty surface samples were collected from off Chennai coast. Trace elements, organic matter, CaCO3, sand-silt-clay and C/N ratios were studied to understand the accumulation dynamics on sediments. The elemental concentration, calcium carbonate and OM distribution suggest that they are derived from urban runoff and transported through Adyar and Cooum Rivers. The enrichment factor reveals that the sediments are enriched by Pb, Cu, Zn, Cr, Co, Ni followed by Fe. The observed Igeo value shows that the samples are contaminated by Pb, Cu and Zn. The elemental concentration of the surface sediments is low when compared to other coastal region except Pb. The elevated level of Pb in the surface sediments is probably due to migration of contaminated urban soil from industrial and transportation sectors into marine environment.
The present study was carried out on the Porites coral growth bands (1979 to 2014) to measure the... more The present study was carried out on the Porites coral growth bands (1979 to 2014) to measure the metal accumulation for assessing the environmental pollution status. The concentrations of studiedmetals are compared with similar global studies,which indicate that themetals are probably derived fromnatural sources. The identical peaks of Fe and Mn are perfectly matched with Cu, Cr and Ni concentrations. However, the metal profile trend is slightly depressed froma regular trend in Zn, Cd and Pb peaks. Themetal accumulation affinity of the reef skeleton is ranked in the following order Cr N Cd N Pb N Fe N MnN Cu N Ni N Zn. The distribution ofmetal constituents in coral growth bands is primarily controlled by Fe andMn in the reef skeleton. Other reef associatedmetals such as Pb and Cd are derived from other sources like coastal developments and anthropogenic sources.
During the last three decades, remotely sensed data
(both satellite images and aerial photographs... more During the last three decades, remotely sensed data (both satellite images and aerial photographs) have been in-creasingly used in groundwater exploration and management exercises. An integrated approach has been adopted in the present study to delineate groundwater recharge potential zones using RS and GIS techniques. IRS-1C satellite imager-ies and Survey of India toposheets are used to prepare various thematic layers viz. geology, soil, land-use, slope, lineament and drainage. These layers were then transformed in to raster data using feature to raster converter tool in ArcGIS 9.3 soft-ware. The raster maps of these factors are allocated a fixed score and weight computed from Influencing Factor (IF) tech-nique. The weights of factors contributing to the groundwater recharge are derived using aerial photos, geologymaps, a land use database, and field verification. Subjective weights are assigned to the respective thematic layers and overlaid in GIS platform for the identification of potential groundwater recharge zones within the study area. Then these potential zones were categories as‘high’, ‘moderate’, ‘low’, ‘poor’. The resulted map shows that 19 % of the area has highest recharge potential, mainly confined to buried pediplain, agri-culture land-use and river terraces (considerable amount of precipitatedwater percolates into subsurface), 28%of the area hasmoderate groundwater recharge potentiality and rest of the area has low to poor recharge potentiality. The residual hills and linear ridges with steep slopes are not suitable for artificial recharge sites. Finally, 13 % of total average annual precipi-tated water (840 mm) percolates downward and ultimately contributes to recharge theaquifers in the Kovilpatti Municipality area. The paper is an attempt to suggest for maintaining the proper balance between the groundwater quantity and its exploitation.
The south west coast of Kanyakumari district in Tamil Nadu, India, is significantly affected by s... more The south west coast of Kanyakumari district in Tamil Nadu, India, is significantly affected by seawater intrusion and diffusion of pollutants into the aquifers due to unregulated beach placer mining and other anthropogenic activities. The present study investigates the vulnerability of the coastal aquifers using Geographic Information System (GIS)-based DRASTIC model. The seven DRASTIC parameters have been analyzed using the statistical equation of this model to demarcate the vulnerable zones for aquifer contamination. The vulnerability index map is prepared from the weighted spatial parameters, and an accounting of total index value ranged from 85 to 213. Based on the categorization of vulnerability classes, the high vulnerable zones are found near the beach placer mining areas between Manavalakurichi and Kodimanal coastal stretches. The aquifers associated with settlements and agricultural lands in the middle-eastern part have experienced high vulnerability due to contaminated wa...
In the present study, the geochemical characteristics
of groundwater and drinking water quality h... more In the present study, the geochemical characteristics of groundwater and drinking water quality has been studied. 24 groundwater samples were collected and analyzed for pH, electrical conductivity, total dissolved solids, carbonate, bicarbonate, chloride, sulphate, nitrate, calcium, magnesium, sodium, potassium and total hardness. The results were evaluated and compared with WHO and BIS water quality standards. The studied results reveal that the groundwater is fresh to brackish and moderately high to hard in nature. Na and Cl are dominant ions among cations and anions. Chloride, calcium and magnesium ions are within the allowable limit except few samples. According to Gibbs diagram, the predominant samples fall in the rock–water interaction dominance and evaporation dominance field. The piper trilinear diagram shows that groundwater samples are Na–Cl and mixed CaMgCl type. Based on the WQI results majority of the samples are falling under excellent to good category and suitable for drinking water purposes.
ABSTRACT A total of 20 groundwater samples were col-lected from both dug and bore wells of southe... more ABSTRACT A total of 20 groundwater samples were col-lected from both dug and bore wells of southern Tiruchi-rappalli district and analyzed for various hydrogeochemical parameters. The analyzed physicochemical parameters such as pH, electrical conductivity, total dissolved solids, calcium, magnesium, sodium, potassium, bicarbonate, carbonate, sulfate, chloride, nitrate, and fluoride are used to characterize the groundwater quality and its suitability for drinking and irrigational uses. The results of the chemical analysis indicates that the groundwater in the study area is slightly alkaline and mainly contains Na ? , Ca 2? , and Mg 2? cations as well as HCO 3 2-, Cl -, SO 4 2-and NO 3 -anions. The total dissolved solids mainly depend on the concen-tration of major ions such as Ca, Mg, Na, K, HCO 3 , Cl, and SO 4 . Based on TDS, 55 % of the samples are suitable for drinking and rest of the samples are unsuitable for drinking. The total hardness indicates that majority of the ground-water samples are found within the permissible limit of WHO. The dominant hydrochemical facies for groundwater are Ca–Mg–Cl, Ca–HCO 3 , and Ca–Cl type. The USSL graphical geochemical representation of groundwater quality suggests that majority of the water samples belongs to high medium salinity with low alkali hazards. The Gibb's plot indicates that the groundwater chemistry of the study area is mainly controlled by evap-oration and rock–water interaction. Spearman's correlation and factor analysis were used to distinguish the statistical relation between different ions and contamination source in the study area.
Trace elements in the groundwater of Tamiraparani river basin is modeled spatially. Elemental con... more Trace elements in the groundwater of Tamiraparani river basin is modeled spatially. Elemental concentrations were compared with WHO standards. Emprical bayesian kriging was used and prediction errors were quantified. Health risk assessment was done through oral and dermal pathways. Multivariate statistical analysis were used to infer the source. a b s t r a c t This study investigates the concentration of trace elements in the groundwater of Tamiraparani river basin, South India. 124 groundwater samples were collected representing diverse landuse condition over the study area. The results reveal that the mean concentrations of Fe, Mn, Cu, Cr, Pb, Zn and Ni were 0.269, 0.02, 0.007, 0.007, 0.003, 0.066, and 0.004 ppm respectively. The decreasing trend of trace element content shows the following order: Fe > Zn > Mn > Cu > Cr > Ni > Pb. Significant positive correlation (p < 0.05) is found between most of the variables such as water level and Fe, Pb; EC and Ni; Fe and Pb; Mn and Pb; Cu and Zn, Ni; Cr and Pb; Zn and Ni. The studied trace elements are found below the international drinking water guidelines except Fe, Mn, and Pb. The Empirical Bayesian Kriging (EBK) model is used to interpolate the studied metal concentrations in the groundwater of the study area. A health risk assessment was carried out using exposure dose index (CDI) and hazard quotient (HQ). The CDI values of trace elements for oral and dermal pathways shows the following order of Fe > Zn > Mn > Cu > Cr > Ni > Pb and Fe > Zn > Mn > Cr > Cu > Ni > Pb respectively. The Hazard quotients suggest that the risk of contamination through oral and dermal pathways is feeble as all the elements show values less than one. The multivariate statistical analysis reveals that the source of trace elements in the groundwater is through natural origin except copper, chromium and lead as these contaminants are derived from anthropogenic activities.
This study is an approach to better estimate the
groundwater recharge potential zones using geogr... more This study is an approach to better estimate the groundwater recharge potential zones using geographical information system (GIS), influence factor and RS techniques. This concept has been applied in Ottapidaram taluk in Tuticorin district to determine the overall groundwater recharge potentiality. Survey of India toposheets and Indian Remote Sensing-1C satellite imageries are used to prepare various thematic layers such as: lithology, slope, land use, lineament, drainage, soil, and rainfall. These layers were then transformed into raster data using the feature to raster converter tool in ArcGIS 9.3 software. Subjective weights are assigned to the respective thematic layers and overlaid in GIS platform for the identification of potential groundwater zones within the study area. These potential zones were categorized as ‘high’, ‘moderate’, and ‘low’ zones with respect to the assigned weightage of different thematic layers. The results reveal that the areas of good groundwater potential are estimated to cover 260.25 km2 (35 % of the study area), moderate potential 297.43 km2 (40 %), and low potential 185 km2 (25 %). Moreover, only 34 % of the total average annual precipitated water (680 mm) percolates into subsurface and ultimately contributes to recharge the groundwater. These results suggest that the high potential zones will have a key role in future expansion of drinking water and irrigation development in the study area.
Abstract: The present study was carried out to decipher the groundwater potential zones in the co... more Abstract: The present study was carried out to decipher the groundwater potential zones in the coastal terrain of Tuticorin using Indian remote sensing satellite IRS-1C, LlSS-III data on a 1:50,000 scale and Survey of India (SOI) toposheets. The thematic layers such as lithology, slope, land-use, lineament, drainage, soil and rainfall were generated and integrated to prepare the groundwater prospect and recharge map of the study area. These layers were transformed to raster data using feature to raster converter tool in Arc GIS 9.2 software. Subjective weights are assigned to the respective thematic layers and overlaid in GIS platform for the identification of potential groundwater zones within the area. These potential zones were categorized as ‘high’, ‘moderate’, and ‘low’ zones with respect to the assigned weightage of different thematic layers. The resultant map shows that 10% of the area has highest recharge potentials, this is due to the percolation of precipitated water into the sub-surface rocks, followed by 65% of the area with moderate groundwater recharge potentiality, and rest of the area has low recharge potential. The study highlights that the total average annual precipitated water (877 mm) is responsible for natural recharge of the aquifers in the Tuticorin area.
Abstract The present study investigates the groundwater
recharge potential zone and suitable site... more Abstract The present study investigates the groundwater recharge potential zone and suitable sites for artificial recharge structures in the River Vaigai upper basin, Theni district, Tamil Nadu, using GIS-based multi-parameter weighted overlay method. The study area experiences severe groundwater scarcity despite having high rainfall and runoff. Therefore, an integrated remote sensing and GIS technique is used to assess the permeability and infiltration characteristics of the area and demarcate the recharge potential zones. The recharge potential zones and site-specific artificial recharge structures have been demarcated based on the weights of multiple parameters based on their permeability and infiltration capacity to groundwater recharge. The groundwater recharge potential map shows the twenty suitable sites for artificial recharge structures such as percolation ponds, loose rock check dams, and water absorption trench (WAT) in various parts of the study area. The effective recharge practices such as percolation ponds and check dams are highly suitable for gentle-sloped barren and agricultural plains in the northwestern and northeastern parts. Whereas, the barren valley fill, bajada and streams intersecting lineaments along the middle-eastern and central part are suitable for constructing WAT and check dams. These water-harvesting features can improve the groundwater scenario of the study area and groundwater augmentation is possible in future with the help of advanced techniques like remote sensing and GIS.
Abstract The quantitative analysis of the drainage morphometric system is vital to understand the... more Abstract The quantitative analysis of the drainage morphometric system is vital to understand the hydrological and environmental interaction and its processes of an area. The present study deals with quantitative characteristics of morphometry of steep slope and short length sub-basin of R. Thamirabarani in Kanyakumari District, Tamilnadu, India, using geospatial technology. In this study, the digital elevation model data product (ASTER DEM), Landsat ETM? image and Survey of India topographical map were used to delineate slope, relief and drainage system structures such as drainage pattern, stream order, stream network and stream length of the sub-basin using ArcGIS 9.3 software. The morphometric analysis deals with hydrologic processes such as stream frequency, bifurcation ratio, circulatory ratio and length of overland flow of the sub-basin area and their influences on the local morphologic landforms. The quantitative measurement of these characteristics is used to explore the basin’s contribution to the hydrological cycle and the shape, size and formation of the local landscapes in the region. Moreover, the hypsometric analysis and denudation rate were estimated for understanding the quantitative geomorphological characteristics of the sub-basin. The relationship of the morphometric parameters reveals that the drainage network is strongly controlled by geological and geomorphological structures of the area. The geometry of streams exhibits dendritic drainage pattern associated with coarse drainage texture in primary order of streams present on hilly terrain surface and semi-dendritic pattern in higher stream order flow on less elevated surface with gentle slope. The drainage density of the study area ranges from 0.1 to 1.89 km/km2, and the maximum density value was found along the higher stream order. The mean bifurcation ratio of this area is 4.21 and the high ratio was measured between the third and fourth order of stream segments. The morphometry of this area is depicted by the length of the stream segment, drainage pattern and stream flow direction, which are influenced by relief, steep slope and local geological structure. Furthermore, the sub-basin is found to be strongly elongated in shape with a length of 42.78 km, and the circularity ratio of this area is measured as 0.33 and elongation ratio as 0.57. The textural dissection of the landforms shows low drainage density in the high elevated hilly terrain in the north and high level in the plain areas in the southern part. The values of the circulatory ratio, length of overland flow and elongation ratio are relatively close to one another and the relationship among them shows their influences on the process of surface runoff and sediment deposition along the estuary landforms in the study area. Moreover, it is observed that the hypsometric curve of this study area is characterized by convex-up shape in nature and represents the youth stage (inequilibrium) of landscapes. Consequently, the hypsometric integral value 0.49 reflects the distribution of a major volume of the landmass (435.32 km2) at relatively low elevations (\180 m). The morphometric parameters-induced denudation rate of this study area is 65.14 t/km2/year and indicates the occurrence of a wide range of denudation intensities throughout the sub-basin, which is relatively proportional to the suspended sediment yield that is transported in the suspension per unit area. Based on the realistic output, it is proved that remote sensing and GIS are effective tools for morphometric studies of the drainage basin.
The quantitative analysis of the drainage morphometric system is vital to understand the hydrolo... more The quantitative analysis of the drainage morphometric system is vital to understand the hydrological and environmental interaction and its processes of an area. The present study deals with quantitative characteristics of morphometry of steep slope and short length sub-basin of R. Thamirabarani in Kanyakumari District, Tamilnadu, India, using geospatial technology. In this study, the digital elevation model data product (ASTER DEM), Landsat ETM+ image and Survey of India topographical map were used to delineate slope, relief and drainage system structures such as drainage pattern, stream order, stream network and stream length of the sub-basin using ArcGIS 9.3 software. The morphometric analysis deals with hydrologic processes such as stream frequency, bifurcation ratio, circulatory ratio and length of overland flow of the sub-basin area and their influences on the local morphologic landforms. The quantitative measurement of these characteristics is used to explore the basin’s contribution to the hydrological cycle and the shape, size and formation of the local landscapes in the region. Moreover, the hypsometric analysis and denudation rate were estimated for understanding the quantitative geomorphological characteristics of the sub-basin. The relationship of the morphometric parameters reveals that the drainage network is strongly controlled by geological and geomorphological structures of the area. The geometry of streams exhibits dendritic drainage pattern associated with coarse drainage texture in primary order of streams present on hilly terrain surface and semi-dendritic pattern in higher stream order flow on less elevated surface with gentle slope. The drainage density of the study area ranges from 0.1 to 1.89 km/km2, and the maximum density value was found along the higher stream order. The mean bifurcation ratio of this area is 4.21 and the high ratio was measured between the third and fourth order of stream segments. The morphometry of this area is depicted by the length of the stream segment, drainage pattern and stream flow direction, which are influenced by relief, steep slope and local geological structure. Furthermore, the sub-basin is found to be strongly elongated in shape with a length of 42.78 km, and the circularity ratio of this area is measured as 0.33 and elongation ratio as 0.57. The textural dissection of the landforms shows low drainage density in the high elevated hilly terrain in the north and high level in the plain areas in the southern part. The values of the circulatory ratio, length of overland flow and elongation ratio are relatively close to one another and the relationship among them shows their influences on the process of surface runoff and sediment deposition along the estuary landforms in the study area. Moreover, it is observed that the hypsometric curve of this study area is characterized by convex-up shape in nature and represents the youth stage (inequilibrium) of landscapes. Consequently, the hypsometric integral value 0.49 reflects the distribution of a major volume of the landmass (435.32 km2) at relatively low elevations (<180 m). The morphometric parameters-induced denudation rate of this study area is 65.14 t/km2/year and indicates the occurrence of a wide range of denudation intensities throughout the sub-basin, which is relatively proportional to the suspended sediment yield that is transported in the suspension per unit area. Based on the realistic output, it is proved that remote sensing and GIS are effective tools for morphometric studies of the drainage basin.
The present study was carried out to evaluate the groundwater quality and its suitability for dri... more The present study was carried out to evaluate the groundwater quality and its suitability for drinking purposes in the urban coastal aquifers of part of south Chennai, Tamil Nadu, India. Twenty-three groundwater samples were collected during March 2012. The minimum and maximum values of pH (6.3–8 on scale), electrical conductivity (620–12,150 lS/cm), total dissolved solids (399.28–7,824.6 mg/l), carbonate (0–30 mg/l), bicarbonate (0.9–58.9 mg/l), chloride (70.9–4,067.89 mg/l), sulphate (17.4–105 mg/l), nitrate (0.4–6.0 mg/l), calcium (30–200 mg/l), magnesium (1.2–164 mg/l), sodium (69–1,490 mg/l) and potassium (8–340 mg/l) were recorded in the coastal aquifers of Chennai city. The groundwater samples show that the majority of the sampling points clustered on the NaCl and mixed CaMgCl facies of the piper trilinear diagram.
In the Gibbs diagram, the majority of the sampling points fall under rock water and evaporation dominance field. Fuzzy membership classification suggests that the majority of the samples fall under good water type followed by excellent water and poor water categories. Groundwater quality index showing the majority of the
samples falls under excellent to poor category of water. A positive correlation was observed with Cl-, SO4 2-, Ca2+, Na+, K+, EC and TDS. The extracted results of the correlation matrix and geochemical analysis suggest that the dominant ions of groundwater (Na+, Ca2+, K+, Cl- and SO4 2-) were derived from seawater intrusion and gypsum dissolution process. Nitrate concentration is most significantly derived from anthropogenic sources.
Trace element concentration in the beach placer mining areas of Kanyakumari coast, South India wa... more Trace element concentration in the beach placer mining areas of Kanyakumari coast, South India was assessed. Sewage and contaminated sediments from mining sites has contaminated the surface sediments. Enrichment factor indicates moderately severe enrichment for Pb, minor enrichment for Mn, Zn, Ni, Fe and no enrichment for Cr and Cu. The Igeo values show higher concentration of Pb ranging in the scale of 3-4, which shows strong contamination due to high anthropogenic activity such as mining and terrestrial influences into the coastal regions. Correlation coefficient shows that most of the elements are associated with each other except Ni and Pb. Factor analysis reveals that Mn, Zn, Fe, Cr, Pb and Cu are having a significant loading and it indicates that these elements are mainly derived from similar origin. The cluster analysis clearly indicated that the mining areas are grouped under cluster 2 and non-mining areas are clustered under group 1.
The present study focused on the elemental distribution of nearshore environment and to understan... more The present study focused on the elemental distribution of nearshore environment and to understand the interrelationship between different parameters such as trace elements, organic matter, calcium carbonate and sediment texture. For this purpose, 24 surface samples were collected from the nearshore environment using a stainless steel Van Veen grab sampler. The above said parameters indicate that nearshore sediment transport, contaminants from estuarine source and anthropogenic activities deteriorates the sediment quality in the nearshore area. The enrichment factor reveals that the sediments are enriched with Pb, Co, Ni and Cr, whereas the geoaccumulation index highlights that the sediments are polluted with Pb, Ni and Co. The elevated concentration of Pb in the nearshore sediments are possibly from the port activities and thermal power plants situated in the north of the study area. Proper management of industrial effluents is needed to curb further metal pollution in the nearshor...
Forty eight surface sediment samples were collected from the vicinity of Van Island in order to a... more Forty eight surface sediment samples were collected from the vicinity of Van Island in order to assess the sediment pollution level and potential ecological risk on coral reef ecosystem. The analytical and correlation results indicate a distribution of elements is chiefly controlled by the CaCO3 and OM. The enrichment factor and geoaccumulation index show the elevated level of Pb in the surface sediments is due to application of lead petrol and coal incinerating power plants. The sediment pollution index reveals that majority of the sediments falling under highly polluted sediment category (35.4%) followed by moderately polluted (25%) and dangerous sediment category (14.58%). The potential ecological risk suggests that nearly 66.6% of the samples falling under the low risk category, moderate risk category (20.8%) followed by considerable risk category (8.33%) and very high risk category (4.1%). The accumulation level of trace elements clearly suggests that the coral reef ecosystem i...
The present study was conducted to assess the trace element concentration in marine surface sedim... more The present study was conducted to assess the trace element concentration in marine surface sediments after major flood event of Chennai metropolis, India. Thirty surface samples were collected from off Chennai coast. Trace elements, organic matter, CaCO3, sand-silt-clay and C/N ratios were studied to understand the accumulation dynamics on sediments. The elemental concentration, calcium carbonate and OM distribution suggest that they are derived from urban runoff and transported through Adyar and Cooum Rivers. The enrichment factor reveals that the sediments are enriched by Pb, Cu, Zn, Cr, Co, Ni followed by Fe. The observed Igeo value shows that the samples are contaminated by Pb, Cu and Zn. The elemental concentration of the surface sediments is low when compared to other coastal region except Pb. The elevated level of Pb in the surface sediments is probably due to migration of contaminated urban soil from industrial and transportation sectors into marine environment.
The present study was carried out on the Porites coral growth bands (1979 to 2014) to measure the... more The present study was carried out on the Porites coral growth bands (1979 to 2014) to measure the metal accumulation for assessing the environmental pollution status. The concentrations of studiedmetals are compared with similar global studies,which indicate that themetals are probably derived fromnatural sources. The identical peaks of Fe and Mn are perfectly matched with Cu, Cr and Ni concentrations. However, the metal profile trend is slightly depressed froma regular trend in Zn, Cd and Pb peaks. Themetal accumulation affinity of the reef skeleton is ranked in the following order Cr N Cd N Pb N Fe N MnN Cu N Ni N Zn. The distribution ofmetal constituents in coral growth bands is primarily controlled by Fe andMn in the reef skeleton. Other reef associatedmetals such as Pb and Cd are derived from other sources like coastal developments and anthropogenic sources.
During the last three decades, remotely sensed data
(both satellite images and aerial photographs... more During the last three decades, remotely sensed data (both satellite images and aerial photographs) have been in-creasingly used in groundwater exploration and management exercises. An integrated approach has been adopted in the present study to delineate groundwater recharge potential zones using RS and GIS techniques. IRS-1C satellite imager-ies and Survey of India toposheets are used to prepare various thematic layers viz. geology, soil, land-use, slope, lineament and drainage. These layers were then transformed in to raster data using feature to raster converter tool in ArcGIS 9.3 soft-ware. The raster maps of these factors are allocated a fixed score and weight computed from Influencing Factor (IF) tech-nique. The weights of factors contributing to the groundwater recharge are derived using aerial photos, geologymaps, a land use database, and field verification. Subjective weights are assigned to the respective thematic layers and overlaid in GIS platform for the identification of potential groundwater recharge zones within the study area. Then these potential zones were categories as‘high’, ‘moderate’, ‘low’, ‘poor’. The resulted map shows that 19 % of the area has highest recharge potential, mainly confined to buried pediplain, agri-culture land-use and river terraces (considerable amount of precipitatedwater percolates into subsurface), 28%of the area hasmoderate groundwater recharge potentiality and rest of the area has low to poor recharge potentiality. The residual hills and linear ridges with steep slopes are not suitable for artificial recharge sites. Finally, 13 % of total average annual precipi-tated water (840 mm) percolates downward and ultimately contributes to recharge theaquifers in the Kovilpatti Municipality area. The paper is an attempt to suggest for maintaining the proper balance between the groundwater quantity and its exploitation.
The south west coast of Kanyakumari district in Tamil Nadu, India, is significantly affected by s... more The south west coast of Kanyakumari district in Tamil Nadu, India, is significantly affected by seawater intrusion and diffusion of pollutants into the aquifers due to unregulated beach placer mining and other anthropogenic activities. The present study investigates the vulnerability of the coastal aquifers using Geographic Information System (GIS)-based DRASTIC model. The seven DRASTIC parameters have been analyzed using the statistical equation of this model to demarcate the vulnerable zones for aquifer contamination. The vulnerability index map is prepared from the weighted spatial parameters, and an accounting of total index value ranged from 85 to 213. Based on the categorization of vulnerability classes, the high vulnerable zones are found near the beach placer mining areas between Manavalakurichi and Kodimanal coastal stretches. The aquifers associated with settlements and agricultural lands in the middle-eastern part have experienced high vulnerability due to contaminated wa...
In the present study, the geochemical characteristics
of groundwater and drinking water quality h... more In the present study, the geochemical characteristics of groundwater and drinking water quality has been studied. 24 groundwater samples were collected and analyzed for pH, electrical conductivity, total dissolved solids, carbonate, bicarbonate, chloride, sulphate, nitrate, calcium, magnesium, sodium, potassium and total hardness. The results were evaluated and compared with WHO and BIS water quality standards. The studied results reveal that the groundwater is fresh to brackish and moderately high to hard in nature. Na and Cl are dominant ions among cations and anions. Chloride, calcium and magnesium ions are within the allowable limit except few samples. According to Gibbs diagram, the predominant samples fall in the rock–water interaction dominance and evaporation dominance field. The piper trilinear diagram shows that groundwater samples are Na–Cl and mixed CaMgCl type. Based on the WQI results majority of the samples are falling under excellent to good category and suitable for drinking water purposes.
ABSTRACT A total of 20 groundwater samples were col-lected from both dug and bore wells of southe... more ABSTRACT A total of 20 groundwater samples were col-lected from both dug and bore wells of southern Tiruchi-rappalli district and analyzed for various hydrogeochemical parameters. The analyzed physicochemical parameters such as pH, electrical conductivity, total dissolved solids, calcium, magnesium, sodium, potassium, bicarbonate, carbonate, sulfate, chloride, nitrate, and fluoride are used to characterize the groundwater quality and its suitability for drinking and irrigational uses. The results of the chemical analysis indicates that the groundwater in the study area is slightly alkaline and mainly contains Na ? , Ca 2? , and Mg 2? cations as well as HCO 3 2-, Cl -, SO 4 2-and NO 3 -anions. The total dissolved solids mainly depend on the concen-tration of major ions such as Ca, Mg, Na, K, HCO 3 , Cl, and SO 4 . Based on TDS, 55 % of the samples are suitable for drinking and rest of the samples are unsuitable for drinking. The total hardness indicates that majority of the ground-water samples are found within the permissible limit of WHO. The dominant hydrochemical facies for groundwater are Ca–Mg–Cl, Ca–HCO 3 , and Ca–Cl type. The USSL graphical geochemical representation of groundwater quality suggests that majority of the water samples belongs to high medium salinity with low alkali hazards. The Gibb&#39;s plot indicates that the groundwater chemistry of the study area is mainly controlled by evap-oration and rock–water interaction. Spearman&#39;s correlation and factor analysis were used to distinguish the statistical relation between different ions and contamination source in the study area.
Trace elements in the groundwater of Tamiraparani river basin is modeled spatially. Elemental con... more Trace elements in the groundwater of Tamiraparani river basin is modeled spatially. Elemental concentrations were compared with WHO standards. Emprical bayesian kriging was used and prediction errors were quantified. Health risk assessment was done through oral and dermal pathways. Multivariate statistical analysis were used to infer the source. a b s t r a c t This study investigates the concentration of trace elements in the groundwater of Tamiraparani river basin, South India. 124 groundwater samples were collected representing diverse landuse condition over the study area. The results reveal that the mean concentrations of Fe, Mn, Cu, Cr, Pb, Zn and Ni were 0.269, 0.02, 0.007, 0.007, 0.003, 0.066, and 0.004 ppm respectively. The decreasing trend of trace element content shows the following order: Fe > Zn > Mn > Cu > Cr > Ni > Pb. Significant positive correlation (p < 0.05) is found between most of the variables such as water level and Fe, Pb; EC and Ni; Fe and Pb; Mn and Pb; Cu and Zn, Ni; Cr and Pb; Zn and Ni. The studied trace elements are found below the international drinking water guidelines except Fe, Mn, and Pb. The Empirical Bayesian Kriging (EBK) model is used to interpolate the studied metal concentrations in the groundwater of the study area. A health risk assessment was carried out using exposure dose index (CDI) and hazard quotient (HQ). The CDI values of trace elements for oral and dermal pathways shows the following order of Fe > Zn > Mn > Cu > Cr > Ni > Pb and Fe > Zn > Mn > Cr > Cu > Ni > Pb respectively. The Hazard quotients suggest that the risk of contamination through oral and dermal pathways is feeble as all the elements show values less than one. The multivariate statistical analysis reveals that the source of trace elements in the groundwater is through natural origin except copper, chromium and lead as these contaminants are derived from anthropogenic activities.
This study is an approach to better estimate the
groundwater recharge potential zones using geogr... more This study is an approach to better estimate the groundwater recharge potential zones using geographical information system (GIS), influence factor and RS techniques. This concept has been applied in Ottapidaram taluk in Tuticorin district to determine the overall groundwater recharge potentiality. Survey of India toposheets and Indian Remote Sensing-1C satellite imageries are used to prepare various thematic layers such as: lithology, slope, land use, lineament, drainage, soil, and rainfall. These layers were then transformed into raster data using the feature to raster converter tool in ArcGIS 9.3 software. Subjective weights are assigned to the respective thematic layers and overlaid in GIS platform for the identification of potential groundwater zones within the study area. These potential zones were categorized as ‘high’, ‘moderate’, and ‘low’ zones with respect to the assigned weightage of different thematic layers. The results reveal that the areas of good groundwater potential are estimated to cover 260.25 km2 (35 % of the study area), moderate potential 297.43 km2 (40 %), and low potential 185 km2 (25 %). Moreover, only 34 % of the total average annual precipitated water (680 mm) percolates into subsurface and ultimately contributes to recharge the groundwater. These results suggest that the high potential zones will have a key role in future expansion of drinking water and irrigation development in the study area.
Abstract: The present study was carried out to decipher the groundwater potential zones in the co... more Abstract: The present study was carried out to decipher the groundwater potential zones in the coastal terrain of Tuticorin using Indian remote sensing satellite IRS-1C, LlSS-III data on a 1:50,000 scale and Survey of India (SOI) toposheets. The thematic layers such as lithology, slope, land-use, lineament, drainage, soil and rainfall were generated and integrated to prepare the groundwater prospect and recharge map of the study area. These layers were transformed to raster data using feature to raster converter tool in Arc GIS 9.2 software. Subjective weights are assigned to the respective thematic layers and overlaid in GIS platform for the identification of potential groundwater zones within the area. These potential zones were categorized as ‘high’, ‘moderate’, and ‘low’ zones with respect to the assigned weightage of different thematic layers. The resultant map shows that 10% of the area has highest recharge potentials, this is due to the percolation of precipitated water into the sub-surface rocks, followed by 65% of the area with moderate groundwater recharge potentiality, and rest of the area has low recharge potential. The study highlights that the total average annual precipitated water (877 mm) is responsible for natural recharge of the aquifers in the Tuticorin area.
Abstract The present study investigates the groundwater
recharge potential zone and suitable site... more Abstract The present study investigates the groundwater recharge potential zone and suitable sites for artificial recharge structures in the River Vaigai upper basin, Theni district, Tamil Nadu, using GIS-based multi-parameter weighted overlay method. The study area experiences severe groundwater scarcity despite having high rainfall and runoff. Therefore, an integrated remote sensing and GIS technique is used to assess the permeability and infiltration characteristics of the area and demarcate the recharge potential zones. The recharge potential zones and site-specific artificial recharge structures have been demarcated based on the weights of multiple parameters based on their permeability and infiltration capacity to groundwater recharge. The groundwater recharge potential map shows the twenty suitable sites for artificial recharge structures such as percolation ponds, loose rock check dams, and water absorption trench (WAT) in various parts of the study area. The effective recharge practices such as percolation ponds and check dams are highly suitable for gentle-sloped barren and agricultural plains in the northwestern and northeastern parts. Whereas, the barren valley fill, bajada and streams intersecting lineaments along the middle-eastern and central part are suitable for constructing WAT and check dams. These water-harvesting features can improve the groundwater scenario of the study area and groundwater augmentation is possible in future with the help of advanced techniques like remote sensing and GIS.
Abstract The quantitative analysis of the drainage morphometric system is vital to understand the... more Abstract The quantitative analysis of the drainage morphometric system is vital to understand the hydrological and environmental interaction and its processes of an area. The present study deals with quantitative characteristics of morphometry of steep slope and short length sub-basin of R. Thamirabarani in Kanyakumari District, Tamilnadu, India, using geospatial technology. In this study, the digital elevation model data product (ASTER DEM), Landsat ETM? image and Survey of India topographical map were used to delineate slope, relief and drainage system structures such as drainage pattern, stream order, stream network and stream length of the sub-basin using ArcGIS 9.3 software. The morphometric analysis deals with hydrologic processes such as stream frequency, bifurcation ratio, circulatory ratio and length of overland flow of the sub-basin area and their influences on the local morphologic landforms. The quantitative measurement of these characteristics is used to explore the basin’s contribution to the hydrological cycle and the shape, size and formation of the local landscapes in the region. Moreover, the hypsometric analysis and denudation rate were estimated for understanding the quantitative geomorphological characteristics of the sub-basin. The relationship of the morphometric parameters reveals that the drainage network is strongly controlled by geological and geomorphological structures of the area. The geometry of streams exhibits dendritic drainage pattern associated with coarse drainage texture in primary order of streams present on hilly terrain surface and semi-dendritic pattern in higher stream order flow on less elevated surface with gentle slope. The drainage density of the study area ranges from 0.1 to 1.89 km/km2, and the maximum density value was found along the higher stream order. The mean bifurcation ratio of this area is 4.21 and the high ratio was measured between the third and fourth order of stream segments. The morphometry of this area is depicted by the length of the stream segment, drainage pattern and stream flow direction, which are influenced by relief, steep slope and local geological structure. Furthermore, the sub-basin is found to be strongly elongated in shape with a length of 42.78 km, and the circularity ratio of this area is measured as 0.33 and elongation ratio as 0.57. The textural dissection of the landforms shows low drainage density in the high elevated hilly terrain in the north and high level in the plain areas in the southern part. The values of the circulatory ratio, length of overland flow and elongation ratio are relatively close to one another and the relationship among them shows their influences on the process of surface runoff and sediment deposition along the estuary landforms in the study area. Moreover, it is observed that the hypsometric curve of this study area is characterized by convex-up shape in nature and represents the youth stage (inequilibrium) of landscapes. Consequently, the hypsometric integral value 0.49 reflects the distribution of a major volume of the landmass (435.32 km2) at relatively low elevations (\180 m). The morphometric parameters-induced denudation rate of this study area is 65.14 t/km2/year and indicates the occurrence of a wide range of denudation intensities throughout the sub-basin, which is relatively proportional to the suspended sediment yield that is transported in the suspension per unit area. Based on the realistic output, it is proved that remote sensing and GIS are effective tools for morphometric studies of the drainage basin.
The quantitative analysis of the drainage morphometric system is vital to understand the hydrolo... more The quantitative analysis of the drainage morphometric system is vital to understand the hydrological and environmental interaction and its processes of an area. The present study deals with quantitative characteristics of morphometry of steep slope and short length sub-basin of R. Thamirabarani in Kanyakumari District, Tamilnadu, India, using geospatial technology. In this study, the digital elevation model data product (ASTER DEM), Landsat ETM+ image and Survey of India topographical map were used to delineate slope, relief and drainage system structures such as drainage pattern, stream order, stream network and stream length of the sub-basin using ArcGIS 9.3 software. The morphometric analysis deals with hydrologic processes such as stream frequency, bifurcation ratio, circulatory ratio and length of overland flow of the sub-basin area and their influences on the local morphologic landforms. The quantitative measurement of these characteristics is used to explore the basin’s contribution to the hydrological cycle and the shape, size and formation of the local landscapes in the region. Moreover, the hypsometric analysis and denudation rate were estimated for understanding the quantitative geomorphological characteristics of the sub-basin. The relationship of the morphometric parameters reveals that the drainage network is strongly controlled by geological and geomorphological structures of the area. The geometry of streams exhibits dendritic drainage pattern associated with coarse drainage texture in primary order of streams present on hilly terrain surface and semi-dendritic pattern in higher stream order flow on less elevated surface with gentle slope. The drainage density of the study area ranges from 0.1 to 1.89 km/km2, and the maximum density value was found along the higher stream order. The mean bifurcation ratio of this area is 4.21 and the high ratio was measured between the third and fourth order of stream segments. The morphometry of this area is depicted by the length of the stream segment, drainage pattern and stream flow direction, which are influenced by relief, steep slope and local geological structure. Furthermore, the sub-basin is found to be strongly elongated in shape with a length of 42.78 km, and the circularity ratio of this area is measured as 0.33 and elongation ratio as 0.57. The textural dissection of the landforms shows low drainage density in the high elevated hilly terrain in the north and high level in the plain areas in the southern part. The values of the circulatory ratio, length of overland flow and elongation ratio are relatively close to one another and the relationship among them shows their influences on the process of surface runoff and sediment deposition along the estuary landforms in the study area. Moreover, it is observed that the hypsometric curve of this study area is characterized by convex-up shape in nature and represents the youth stage (inequilibrium) of landscapes. Consequently, the hypsometric integral value 0.49 reflects the distribution of a major volume of the landmass (435.32 km2) at relatively low elevations (<180 m). The morphometric parameters-induced denudation rate of this study area is 65.14 t/km2/year and indicates the occurrence of a wide range of denudation intensities throughout the sub-basin, which is relatively proportional to the suspended sediment yield that is transported in the suspension per unit area. Based on the realistic output, it is proved that remote sensing and GIS are effective tools for morphometric studies of the drainage basin.
The present study was carried out to evaluate the groundwater quality and its suitability for dri... more The present study was carried out to evaluate the groundwater quality and its suitability for drinking purposes in the urban coastal aquifers of part of south Chennai, Tamil Nadu, India. Twenty-three groundwater samples were collected during March 2012. The minimum and maximum values of pH (6.3–8 on scale), electrical conductivity (620–12,150 lS/cm), total dissolved solids (399.28–7,824.6 mg/l), carbonate (0–30 mg/l), bicarbonate (0.9–58.9 mg/l), chloride (70.9–4,067.89 mg/l), sulphate (17.4–105 mg/l), nitrate (0.4–6.0 mg/l), calcium (30–200 mg/l), magnesium (1.2–164 mg/l), sodium (69–1,490 mg/l) and potassium (8–340 mg/l) were recorded in the coastal aquifers of Chennai city. The groundwater samples show that the majority of the sampling points clustered on the NaCl and mixed CaMgCl facies of the piper trilinear diagram.
In the Gibbs diagram, the majority of the sampling points fall under rock water and evaporation dominance field. Fuzzy membership classification suggests that the majority of the samples fall under good water type followed by excellent water and poor water categories. Groundwater quality index showing the majority of the
samples falls under excellent to poor category of water. A positive correlation was observed with Cl-, SO4 2-, Ca2+, Na+, K+, EC and TDS. The extracted results of the correlation matrix and geochemical analysis suggest that the dominant ions of groundwater (Na+, Ca2+, K+, Cl- and SO4 2-) were derived from seawater intrusion and gypsum dissolution process. Nitrate concentration is most significantly derived from anthropogenic sources.
Uploads
accumulation for assessing the environmental pollution status. The concentrations of studiedmetals are compared
with similar global studies,which indicate that themetals are probably derived fromnatural sources. The identical
peaks of Fe and Mn are perfectly matched with Cu, Cr and Ni concentrations. However, the metal profile trend is
slightly depressed froma regular trend in Zn, Cd and Pb peaks. Themetal accumulation affinity of the reef skeleton
is ranked in the following order Cr N Cd N Pb N Fe N MnN Cu N Ni N Zn. The distribution ofmetal constituents in coral
growth bands is primarily controlled by Fe andMn in the reef skeleton. Other reef associatedmetals such as Pb and
Cd are derived from other sources like coastal developments and anthropogenic sources.
(both satellite images and aerial photographs) have been in-creasingly used in groundwater exploration and management
exercises. An integrated approach has been adopted in the
present study to delineate groundwater recharge potential
zones using RS and GIS techniques. IRS-1C satellite imager-ies and Survey of India toposheets are used to prepare various
thematic layers viz. geology, soil, land-use, slope, lineament
and drainage. These layers were then transformed in to raster
data using feature to raster converter tool in ArcGIS 9.3 soft-ware. The raster maps of these factors are allocated a fixed
score and weight computed from Influencing Factor (IF) tech-nique. The weights of factors contributing to the groundwater
recharge are derived using aerial photos, geologymaps, a land
use database, and field verification. Subjective weights are
assigned to the respective thematic layers and overlaid in
GIS platform for the identification of potential groundwater
recharge zones within the study area. Then these potential zones were categories as‘high’, ‘moderate’, ‘low’, ‘poor’.
The resulted map shows that 19 % of the area has highest
recharge potential, mainly confined to buried pediplain, agri-culture land-use and river terraces (considerable amount of
precipitatedwater percolates into subsurface), 28%of the area
hasmoderate groundwater recharge potentiality and rest of the
area has low to poor recharge potentiality. The residual hills
and linear ridges with steep slopes are not suitable for artificial
recharge sites. Finally, 13 % of total average annual precipi-tated water (840 mm) percolates downward and ultimately
contributes to recharge theaquifers in the Kovilpatti
Municipality area. The paper is an attempt to suggest for
maintaining the proper balance between the groundwater
quantity and its exploitation.
of groundwater and drinking water quality has
been studied. 24 groundwater samples were collected and
analyzed for pH, electrical conductivity, total dissolved
solids, carbonate, bicarbonate, chloride, sulphate, nitrate,
calcium, magnesium, sodium, potassium and total hardness.
The results were evaluated and compared with WHO
and BIS water quality standards. The studied results reveal
that the groundwater is fresh to brackish and moderately
high to hard in nature. Na and Cl are dominant ions among
cations and anions. Chloride, calcium and magnesium ions
are within the allowable limit except few samples.
According to Gibbs diagram, the predominant samples fall
in the rock–water interaction dominance and evaporation
dominance field. The piper trilinear diagram shows that
groundwater samples are Na–Cl and mixed CaMgCl type.
Based on the WQI results majority of the samples are
falling under excellent to good category and suitable for
drinking water purposes.
groundwater recharge potential zones using geographical
information system (GIS), influence factor and RS techniques.
This concept has been applied in Ottapidaram taluk
in Tuticorin district to determine the overall groundwater
recharge potentiality. Survey of India toposheets and
Indian Remote Sensing-1C satellite imageries are used to
prepare various thematic layers such as: lithology, slope,
land use, lineament, drainage, soil, and rainfall. These
layers were then transformed into raster data using the
feature to raster converter tool in ArcGIS 9.3 software.
Subjective weights are assigned to the respective thematic
layers and overlaid in GIS platform for the identification of
potential groundwater zones within the study area. These
potential zones were categorized as ‘high’, ‘moderate’, and
‘low’ zones with respect to the assigned weightage of
different thematic layers. The results reveal that the areas of good groundwater potential are estimated to cover
260.25 km2 (35 % of the study area), moderate potential
297.43 km2 (40 %), and low potential 185 km2 (25 %).
Moreover, only 34 % of the total average annual precipitated
water (680 mm) percolates into subsurface and ultimately
contributes to recharge the groundwater. These
results suggest that the high potential zones will have a key
role in future expansion of drinking water and irrigation
development in the study area.
using Indian remote sensing satellite IRS-1C, LlSS-III data on a 1:50,000 scale and Survey of India (SOI) toposheets.
The thematic layers such as lithology, slope, land-use, lineament, drainage, soil and rainfall were generated and integrated
to prepare the groundwater prospect and recharge map of the study area. These layers were transformed to raster data
using feature to raster converter tool in Arc GIS 9.2 software. Subjective weights are assigned to the respective thematic
layers and overlaid in GIS platform for the identification of potential groundwater zones within the area. These potential
zones were categorized as ‘high’, ‘moderate’, and ‘low’ zones with respect to the assigned weightage of different thematic
layers. The resultant map shows that 10% of the area has highest recharge potentials, this is due to the percolation of
precipitated water into the sub-surface rocks, followed by 65% of the area with moderate groundwater recharge potentiality,
and rest of the area has low recharge potential. The study highlights that the total average annual precipitated water
(877 mm) is responsible for natural recharge of the aquifers in the Tuticorin area.
recharge potential zone and suitable sites for artificial
recharge structures in the River Vaigai upper basin, Theni
district, Tamil Nadu, using GIS-based multi-parameter
weighted overlay method. The study area experiences
severe groundwater scarcity despite having high rainfall
and runoff. Therefore, an integrated remote sensing and
GIS technique is used to assess the permeability and infiltration characteristics of the area and demarcate the
recharge potential zones. The recharge potential zones and
site-specific artificial recharge structures have been demarcated based on the weights of multiple parameters
based on their permeability and infiltration capacity to
groundwater recharge. The groundwater recharge potential
map shows the twenty suitable sites for artificial recharge
structures such as percolation ponds, loose rock check
dams, and water absorption trench (WAT) in various parts
of the study area. The effective recharge practices such as
percolation ponds and check dams are highly suitable for
gentle-sloped barren and agricultural plains in the northwestern and northeastern parts. Whereas, the barren valley
fill, bajada and streams intersecting lineaments along the
middle-eastern and central part are suitable for constructing
WAT and check dams. These water-harvesting features can
improve the groundwater scenario of the study area and
groundwater augmentation is possible in future with the
help of advanced techniques like remote sensing and GIS.
and environmental interaction and its processes of an area.
The present study deals with quantitative characteristics of
morphometry of steep slope and short length sub-basin of
R. Thamirabarani in Kanyakumari District, Tamilnadu,
India, using geospatial technology. In this study, the digital
elevation model data product (ASTER DEM), Landsat
ETM? image and Survey of India topographical map were
used to delineate slope, relief and drainage system structures such as drainage pattern, stream order, stream network and stream length of the sub-basin using ArcGIS 9.3
software. The morphometric analysis deals with hydrologic
processes such as stream frequency, bifurcation ratio, circulatory ratio and length of overland flow of the sub-basin
area and their influences on the local morphologic landforms. The quantitative measurement of these characteristics is used to explore the basin’s contribution to the
hydrological cycle and the shape, size and formation of the
local landscapes in the region. Moreover, the hypsometric
analysis and denudation rate were estimated for understanding the quantitative geomorphological characteristics
of the sub-basin. The relationship of the morphometric
parameters reveals that the drainage network is strongly
controlled by geological and geomorphological structures
of the area. The geometry of streams exhibits dendritic
drainage pattern associated with coarse drainage texture in
primary order of streams present on hilly terrain surface
and semi-dendritic pattern in higher stream order flow on
less elevated surface with gentle slope. The drainage density of the study area ranges from 0.1 to 1.89 km/km2, and
the maximum density value was found along the higher
stream order. The mean bifurcation ratio of this area is 4.21
and the high ratio was measured between the third and
fourth order of stream segments. The morphometry of this
area is depicted by the length of the stream segment,
drainage pattern and stream flow direction, which are
influenced by relief, steep slope and local geological
structure. Furthermore, the sub-basin is found to be
strongly elongated in shape with a length of 42.78 km, and
the circularity ratio of this area is measured as 0.33 and
elongation ratio as 0.57. The textural dissection of the
landforms shows low drainage density in the high elevated
hilly terrain in the north and high level in the plain areas in
the southern part. The values of the circulatory ratio, length
of overland flow and elongation ratio are relatively close to
one another and the relationship among them shows their
influences on the process of surface runoff and sediment
deposition along the estuary landforms in the study area.
Moreover, it is observed that the hypsometric curve of this
study area is characterized by convex-up shape in nature
and represents the youth stage (inequilibrium) of landscapes. Consequently, the hypsometric integral value 0.49
reflects the distribution of a major volume of the landmass
(435.32 km2) at relatively low elevations (\180 m). The
morphometric parameters-induced denudation rate of this
study area is 65.14 t/km2/year and indicates the occurrence
of a wide range of denudation intensities throughout the
sub-basin, which is relatively proportional to the suspended
sediment yield that is transported in the suspension per unit
area. Based on the realistic output, it is proved that remote sensing and GIS are effective tools for morphometric
studies of the drainage basin.
In the Gibbs diagram, the majority of the sampling points fall under rock water and evaporation dominance field. Fuzzy membership classification suggests that the majority of the samples fall under good water type followed by excellent water and poor water categories. Groundwater quality index showing the majority of the
samples falls under excellent to poor category of water. A positive correlation was observed with Cl-, SO4 2-, Ca2+, Na+, K+, EC and TDS. The extracted results of the correlation matrix and geochemical analysis suggest that the dominant ions of groundwater (Na+, Ca2+, K+, Cl- and SO4 2-) were derived from seawater intrusion and gypsum dissolution process. Nitrate concentration is most significantly derived from anthropogenic sources.
accumulation for assessing the environmental pollution status. The concentrations of studiedmetals are compared
with similar global studies,which indicate that themetals are probably derived fromnatural sources. The identical
peaks of Fe and Mn are perfectly matched with Cu, Cr and Ni concentrations. However, the metal profile trend is
slightly depressed froma regular trend in Zn, Cd and Pb peaks. Themetal accumulation affinity of the reef skeleton
is ranked in the following order Cr N Cd N Pb N Fe N MnN Cu N Ni N Zn. The distribution ofmetal constituents in coral
growth bands is primarily controlled by Fe andMn in the reef skeleton. Other reef associatedmetals such as Pb and
Cd are derived from other sources like coastal developments and anthropogenic sources.
(both satellite images and aerial photographs) have been in-creasingly used in groundwater exploration and management
exercises. An integrated approach has been adopted in the
present study to delineate groundwater recharge potential
zones using RS and GIS techniques. IRS-1C satellite imager-ies and Survey of India toposheets are used to prepare various
thematic layers viz. geology, soil, land-use, slope, lineament
and drainage. These layers were then transformed in to raster
data using feature to raster converter tool in ArcGIS 9.3 soft-ware. The raster maps of these factors are allocated a fixed
score and weight computed from Influencing Factor (IF) tech-nique. The weights of factors contributing to the groundwater
recharge are derived using aerial photos, geologymaps, a land
use database, and field verification. Subjective weights are
assigned to the respective thematic layers and overlaid in
GIS platform for the identification of potential groundwater
recharge zones within the study area. Then these potential zones were categories as‘high’, ‘moderate’, ‘low’, ‘poor’.
The resulted map shows that 19 % of the area has highest
recharge potential, mainly confined to buried pediplain, agri-culture land-use and river terraces (considerable amount of
precipitatedwater percolates into subsurface), 28%of the area
hasmoderate groundwater recharge potentiality and rest of the
area has low to poor recharge potentiality. The residual hills
and linear ridges with steep slopes are not suitable for artificial
recharge sites. Finally, 13 % of total average annual precipi-tated water (840 mm) percolates downward and ultimately
contributes to recharge theaquifers in the Kovilpatti
Municipality area. The paper is an attempt to suggest for
maintaining the proper balance between the groundwater
quantity and its exploitation.
of groundwater and drinking water quality has
been studied. 24 groundwater samples were collected and
analyzed for pH, electrical conductivity, total dissolved
solids, carbonate, bicarbonate, chloride, sulphate, nitrate,
calcium, magnesium, sodium, potassium and total hardness.
The results were evaluated and compared with WHO
and BIS water quality standards. The studied results reveal
that the groundwater is fresh to brackish and moderately
high to hard in nature. Na and Cl are dominant ions among
cations and anions. Chloride, calcium and magnesium ions
are within the allowable limit except few samples.
According to Gibbs diagram, the predominant samples fall
in the rock–water interaction dominance and evaporation
dominance field. The piper trilinear diagram shows that
groundwater samples are Na–Cl and mixed CaMgCl type.
Based on the WQI results majority of the samples are
falling under excellent to good category and suitable for
drinking water purposes.
groundwater recharge potential zones using geographical
information system (GIS), influence factor and RS techniques.
This concept has been applied in Ottapidaram taluk
in Tuticorin district to determine the overall groundwater
recharge potentiality. Survey of India toposheets and
Indian Remote Sensing-1C satellite imageries are used to
prepare various thematic layers such as: lithology, slope,
land use, lineament, drainage, soil, and rainfall. These
layers were then transformed into raster data using the
feature to raster converter tool in ArcGIS 9.3 software.
Subjective weights are assigned to the respective thematic
layers and overlaid in GIS platform for the identification of
potential groundwater zones within the study area. These
potential zones were categorized as ‘high’, ‘moderate’, and
‘low’ zones with respect to the assigned weightage of
different thematic layers. The results reveal that the areas of good groundwater potential are estimated to cover
260.25 km2 (35 % of the study area), moderate potential
297.43 km2 (40 %), and low potential 185 km2 (25 %).
Moreover, only 34 % of the total average annual precipitated
water (680 mm) percolates into subsurface and ultimately
contributes to recharge the groundwater. These
results suggest that the high potential zones will have a key
role in future expansion of drinking water and irrigation
development in the study area.
using Indian remote sensing satellite IRS-1C, LlSS-III data on a 1:50,000 scale and Survey of India (SOI) toposheets.
The thematic layers such as lithology, slope, land-use, lineament, drainage, soil and rainfall were generated and integrated
to prepare the groundwater prospect and recharge map of the study area. These layers were transformed to raster data
using feature to raster converter tool in Arc GIS 9.2 software. Subjective weights are assigned to the respective thematic
layers and overlaid in GIS platform for the identification of potential groundwater zones within the area. These potential
zones were categorized as ‘high’, ‘moderate’, and ‘low’ zones with respect to the assigned weightage of different thematic
layers. The resultant map shows that 10% of the area has highest recharge potentials, this is due to the percolation of
precipitated water into the sub-surface rocks, followed by 65% of the area with moderate groundwater recharge potentiality,
and rest of the area has low recharge potential. The study highlights that the total average annual precipitated water
(877 mm) is responsible for natural recharge of the aquifers in the Tuticorin area.
recharge potential zone and suitable sites for artificial
recharge structures in the River Vaigai upper basin, Theni
district, Tamil Nadu, using GIS-based multi-parameter
weighted overlay method. The study area experiences
severe groundwater scarcity despite having high rainfall
and runoff. Therefore, an integrated remote sensing and
GIS technique is used to assess the permeability and infiltration characteristics of the area and demarcate the
recharge potential zones. The recharge potential zones and
site-specific artificial recharge structures have been demarcated based on the weights of multiple parameters
based on their permeability and infiltration capacity to
groundwater recharge. The groundwater recharge potential
map shows the twenty suitable sites for artificial recharge
structures such as percolation ponds, loose rock check
dams, and water absorption trench (WAT) in various parts
of the study area. The effective recharge practices such as
percolation ponds and check dams are highly suitable for
gentle-sloped barren and agricultural plains in the northwestern and northeastern parts. Whereas, the barren valley
fill, bajada and streams intersecting lineaments along the
middle-eastern and central part are suitable for constructing
WAT and check dams. These water-harvesting features can
improve the groundwater scenario of the study area and
groundwater augmentation is possible in future with the
help of advanced techniques like remote sensing and GIS.
and environmental interaction and its processes of an area.
The present study deals with quantitative characteristics of
morphometry of steep slope and short length sub-basin of
R. Thamirabarani in Kanyakumari District, Tamilnadu,
India, using geospatial technology. In this study, the digital
elevation model data product (ASTER DEM), Landsat
ETM? image and Survey of India topographical map were
used to delineate slope, relief and drainage system structures such as drainage pattern, stream order, stream network and stream length of the sub-basin using ArcGIS 9.3
software. The morphometric analysis deals with hydrologic
processes such as stream frequency, bifurcation ratio, circulatory ratio and length of overland flow of the sub-basin
area and their influences on the local morphologic landforms. The quantitative measurement of these characteristics is used to explore the basin’s contribution to the
hydrological cycle and the shape, size and formation of the
local landscapes in the region. Moreover, the hypsometric
analysis and denudation rate were estimated for understanding the quantitative geomorphological characteristics
of the sub-basin. The relationship of the morphometric
parameters reveals that the drainage network is strongly
controlled by geological and geomorphological structures
of the area. The geometry of streams exhibits dendritic
drainage pattern associated with coarse drainage texture in
primary order of streams present on hilly terrain surface
and semi-dendritic pattern in higher stream order flow on
less elevated surface with gentle slope. The drainage density of the study area ranges from 0.1 to 1.89 km/km2, and
the maximum density value was found along the higher
stream order. The mean bifurcation ratio of this area is 4.21
and the high ratio was measured between the third and
fourth order of stream segments. The morphometry of this
area is depicted by the length of the stream segment,
drainage pattern and stream flow direction, which are
influenced by relief, steep slope and local geological
structure. Furthermore, the sub-basin is found to be
strongly elongated in shape with a length of 42.78 km, and
the circularity ratio of this area is measured as 0.33 and
elongation ratio as 0.57. The textural dissection of the
landforms shows low drainage density in the high elevated
hilly terrain in the north and high level in the plain areas in
the southern part. The values of the circulatory ratio, length
of overland flow and elongation ratio are relatively close to
one another and the relationship among them shows their
influences on the process of surface runoff and sediment
deposition along the estuary landforms in the study area.
Moreover, it is observed that the hypsometric curve of this
study area is characterized by convex-up shape in nature
and represents the youth stage (inequilibrium) of landscapes. Consequently, the hypsometric integral value 0.49
reflects the distribution of a major volume of the landmass
(435.32 km2) at relatively low elevations (\180 m). The
morphometric parameters-induced denudation rate of this
study area is 65.14 t/km2/year and indicates the occurrence
of a wide range of denudation intensities throughout the
sub-basin, which is relatively proportional to the suspended
sediment yield that is transported in the suspension per unit
area. Based on the realistic output, it is proved that remote sensing and GIS are effective tools for morphometric
studies of the drainage basin.
In the Gibbs diagram, the majority of the sampling points fall under rock water and evaporation dominance field. Fuzzy membership classification suggests that the majority of the samples fall under good water type followed by excellent water and poor water categories. Groundwater quality index showing the majority of the
samples falls under excellent to poor category of water. A positive correlation was observed with Cl-, SO4 2-, Ca2+, Na+, K+, EC and TDS. The extracted results of the correlation matrix and geochemical analysis suggest that the dominant ions of groundwater (Na+, Ca2+, K+, Cl- and SO4 2-) were derived from seawater intrusion and gypsum dissolution process. Nitrate concentration is most significantly derived from anthropogenic sources.