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The study aims to demarcate groundwater potential zones in the Coimbatore district of South India using geographic information system (GIS), remote sensing (RS), and multi-criteria decision analysis (MCDA) methods. A total of 10 thematic layers such as geomorphology, geology, lineament density, land use/land cover (LULC), soil, drainage density, rainfall, slope, curvature and topographic wetness index (TWI) were created and analysed for groundwater potential zone delineation. The analytical hierarchal process (AHP) was employed to assign suitable weights to various thematic maps. The Weighted sum overlay analysis tool of ArcGIS 10.5 was used to overlay the thematic layers to generate the study area's groundwater potential zone (GWPZ) map. The resulting map was categorised into excellent, good, moderate, and poor. The findings indicate that about 16% and 37% of the study area is classified as poor and moderate groundwater potential zones, respectively, while approximately 26% and 21% fall under the good and excellent potential zones. The obtained results were validated using pre-and post-monsoon groundwater fluctuation data, which demonstrated consistency with the methodology adopted. Overall results prove the efficacy of using geospatial technology in combination with AHP in delineating groundwater potential zones. Hence, the results obtained can be helpful for decision-makers in the planning and management of groundwater resources and for locating the sites for new borewells in the study area.

Groundwater is the only freshwater in the region, as textile industry effluents pollute the Noyyal river. Therefore, a hydrogeochemical investigation was conducted in the western Coimbatore district of Tamil Nadu to examine the groundwater chemistry and its appropriateness for drinking and irrigation. For this purpose, 25 groundwater samples from a borewell were obtained in precleaned 1-L polythene bottles within the study area. The study found that almost all the analysed groundwater samples contained total hardness (TH), total dissolved solids (TDS), sodium (Na+), potassium (K+), calcium Ca2+, bicarbonate HCO3-, and chloride (Cl-) above the World Health Organization and the Bureau of Indian Standards recommendations for drinking water. In the investigated area, the groundwater chemistry is predominantly of Ca2+-HCO3-type, as shown in the Piper Trilinear diagram. Gibbs plot shows that groundwater chemistry is controlled by rock–water interaction. A geographic information system (GIS) platform was used to create a spatial distribution map of all the physical and chemical parameters. About 60% of the groundwater sample fall in the poor water class according to the Water Quality Index (WQI) assessment. In contrast, most groundwater samples are found suitable for irrigation purposes by computing sodium percentage, sodium adsorption ratio, salinity hazard, Kelly ratio, residual sodium carbonate and permeability index. These hydrogeochemical results could benefit stakeholders and farmers by managing the water resources in the study area.

The main purpose of this study was to determine the hydrogeological conditions and to identify the groundwater potential zone in Kodavanar sub-basin using vertical electrical sounding (VES). IGIS DDR3 instrument was used in the present study to achieve the target. GIS plays a powerful tool which is used in the current study to detect the favorable groundwater potential zone and suitable sites for artificial recharge. Basically, the subsurface investigation was carried out through the geophysical surveys (Schlumberger method). To achieve the aim, 50 VES survey was carried out in distinctive parts of the study area. The field data were interpreted by IPI2Win software, which is used to determine the resistivity and thickness of the different layers. Finally, the deciphered information was approved with the bore well information at the recommended site. It demonstrates that the outcome found from IPI2Win programming was observed to be 100% right in the field check. The spatial distribution maps for weathered zone resistivity and its thickness were prepared using conventional GIS method. All the themes were integrated into the GIS platform.

Ennore river mouth is the largest estuary and it's located in Thiruvallur, Tamil Nadu, southeastern part of India. The creek covers an area of 2.25 km2where located 20 km north of the city centre and 2.6 km south of the Ennore port. The studies are carried out using remote sensing and Geospatial technologies. The Landsat images acquired from 2013 to 2016 were used to demarcate the rate of shoreline dynamics using GIS – based digital shoreline analysis system. The succeeding short term river mouth dynamics, coastal erosion, and accretion rates have been considered for the years 2013–2016. The statistical analysis such as linear regression and end point rate were determined from the shoreline layers. The physical parameters are played the main role in the dynamic activities of erosion and accretion. The study area shows during last four years (2013–2016) erosion are more than the accretion of the shoreline occurred over the years.

The purpose of this study was to assess the drinking and irrigation groundwater quality in Kodavanar sub-basin, Dindigul and Karur region, Tamil Nadu, India. Water samples were measured according to the geological and hydrogeological aspects. Geographically, the study area is situated in 10°11′37″–10°27′30″N and 77°37′46″–78°01′10″E with an entire area of 2255 km2. Overall, 82 groundwater samples were taken from bore wells and various physicochemical parameters and major ion chemistry like pH, electrical conductivity, total dissolved solids, calcium, magnesium, sodium, potassium, bicarbonate, chloride, sulfate, nitrate, and phosphate were analyzed. According to the groundwater quality, Gibbs, United States Salinity Laboratory and Wilcox’s diagrams were plotted; and groundwater quality has been illustrated for domestic and agricultural purposes. Gibbs plot results showed that 87% of the sample falls under the rock dominance. Sodium absorption ratio 100%, sodium percentage 85%, and Kelly’s ratio 51% recommends that majority of the sample falls under the acceptable border of irrigation and drinking utility. Using geospatial analysis, the water-quality index was calculated. The result shows that most of the area comes under excellent (402 km2) and good (1297 km2) groundwater categories. Based on the studies, the quality of groundwater is safe for drinking purposes, but in a limited sample, which exceed the limit, due to anthropogenic activities.

A morphometric analysis of Sarabanga watershed in Salem district has been chosen for the present study. Geospatial tools, such as remote sensing and GIS, are utilized for the extraction of river basin and its drainage networks. The Shuttle Radar Topographic Mission (SRTM-30 m resolution) data have been used for morphometric analysis and evaluating various morphometric parameters. The morphometric parameters of Sarabanga watershed have been analyzed and evaluated by pioneer methods, such as Horton and Strahler. The dendritic type of drainage pattern is draining the Sarabanga watershed, which indicates that lithology and gentle slope category is controlling the study area. The Sarabanga watershed is covered an area of 1208 km2. The slope of the watershed is various from 10 to 40% and which is controlled by lithology of the watershed. The bifurcation ratio ranges from 3 to 4.66 indicating the influence of geological structure and suffered more structural disturbances. The form factor indicates elongated shape of the study area. The total stream length and area of watershed indicate that mean annual rainfall runoff is relatively moderate. The basin relief expressed that watershed has relatively high denudation rates. The drainage density of the watershed is low indicating that infiltration is more dominant. The ruggedness number shows the peak discharges that are likely to be relatively higher. The present study is very useful to plan the watershed management.

The water quality study of Salem district, Tamil Nadu has been carried out to assess the water quality for domestic and irrigation purposes. For this purpose, 59 groundwater samples were collected and analyzed for pH, electrical conductivity (EC), total dissolved solids (TDS), major anions (HCO3−, CO3−, F−, Cl−, NO2−+ NO3−, and SO42−), major cations (Ca2+Mg2+, Na+, and K+), alkalinity (ALK), and hardness (HAR). To assess the water quality, the following chemical parameters were calculated based on the analytical results, such as Piper plot, water quality index (WQI), sodium adsorption ratio (SAR), magnesium hazard (MH), Kelly index (KI), and residual sodium carbonate (RSC). Wilcox diagram represents that 23% of the samples are excellent to good, 40% of the samples are good to permissible, 10% of the samples are permissible to doubtful, 24% of the samples are doubtful unsuitable, and only 3% of the samples are unsuitable for irrigation. SAR values shows that 52% of the samples indicate high-to-very high and low-to-medium alkali water. KI values indicate good quality (30%) and not suitable (70%) for irrigation purposes. RSC values indicate that 89% of samples are suitable for irrigation purposes. MH reveals that 17% suitable and 83% samples are not suitable for irrigation purposes and for domestic purposes the excellent (8%), good (48%), and poor (44%). The agricultural waste, fertilizer used, soil leaching, urban runoff, livestock waste, and sewages are the sources of poor water quality. Some samples are not suitable for irrigation purposes due to high salinity, hardness, and magnesium concentration. In general, the groundwater of the Salem district was polluted by agricultural activities, anthropogenic activities, ion exchange, and weathering.

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Abstract: In the present study, the chemical characteristics of groundwater with respect to drinking and Irrigation water quality in upper Thirumanimuthar sub-basin, Cauvery River, have been studied. 51 groundwater samples were collected and analysed for pH, conductance, total dissolved solids, total hardness, calcium, magnesium, carbonate, bicarbonate, total alkalinity, chloride, sodium, potassium, sulphate etc. The values analyzed were evaluated in detail and compared with WHO water quality standards. It is observed that, for most of the groundwater quality parameters, the values are not potable for drinking and irrigational use. To understand the spatial distribution of unsuitable zones, ArcGIS was employed. Attributes were linked and spatial interpolation mapping was done. Inverse distance weighted interpolation technique was followed for raster and vector mapping. Finally the overlay analyses were also carried out to locate the worst quality zone.

The December 26, 2004 tsunami has caused extensive damage in the Union Territory of Andaman & Nicobar Islands, India, affecting 115.36 km of coastline. In order to identify the impacts of tsunami in South Andaman of the Andaman Islands, the study has been carried out using satellite data for pre-tsunami (Feb. 2003) and post-tsunami (March 2005). This paper provides an assessment of damages caused by tsunami and suitable resettlement places for the people using remote sensing and GIS technology. Assessment of tsunami inflicted damage to island ecosystems assumes greater importance owing to their life-sustaining and livelihood support abilities. Apart from the reparation caused to life and property, significant damage has afflicted the ecosystem, which will have long lasting effects. The tsunami-induced damage to coastal ecosystems was studied based on coastal landuse, geomorphology and coastal critical habitat for South Andaman Island using remote sensing and GIS. An area of 3,366 ha of land area was affected by tsunami. Within the coastal ecosystem, coral reef and mangrove were also severely affected. The study of landforms shows that the land is submerged. The severity of damages and their consequences suggest the need for a definite restoration ecology programme.