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In this paper, an attempt has been made at Sweta sub basin, Kallar basin, Tamil Nadu, where sites for groundwater exploration have been demarcated applying geophysics and GIS technique using Arc GIS software. In this paper, the geophysical output was taken to GIS platform, where the point scoring of the individual theme followed by the final map was assessed to predict the water bearing formation. The total work is executed with the weighted rating analysis in GIS environment. Spatial and non-spatial data was analyzed in GIS in a quick and efficient way. The term 'geographic' in GIS refers to the locational attributes which define the spatial positioning of the piece of information on the face of the earth. The advent of digital computers with high data processing speed and the development of analytical tools in GIS have helped in handling geographically referenced data with ease and flexibility. Of late, computer-aided GIS has become a reality. Using of GIS in hydrogeology is only at its inception, but there have been cases of some successful applications. [ABSTRACT FROM AUTHOR]

The study area, upper Gadilam River basin, is located in Vizhupuram district of Tamil Nadu. The number of energized wells in this area has increased manifold due to free supply of electric power until recently by the government of Tamil Nadu, which has resulted in a regional decline in groundwater piezometric heads in this water table aquifer. A hydrogeological study was carried out in the study area. This paper deals with aquifer parameters estimation based on the pumping test data generated in the field. Water level observations in the area indicated that aquifer has undergone less stress condition within the course of time from the yesteryears or early 1995 to June 2004. Transmissivity computed by Theis (1935) method ranges from 301.82 gpd/sq. ft at Ponniyandal to 19,910.14 gpd/sq. ft in Pallavadi towards south central part of the study area. The specific capacity has a range of 0.906 gpm/ft. of dd in Ponniyandal to 121.91 gpm/ft of dd at Kottaiyampalayam in the eastern central part of the study area. Groundwater level in the basin by rainfall recharge and hydrodynamic method is estimated as 69 million cu.m of recharge and 33 million cu. m of groundwater storage. [ABSTRACT FROM AUTHOR]

Land use/land cover mapping serves as a basic inventory of land resources throughout the world. Detecting and analyzing the quantitative changes along the earth's surface has become necessary and advantageous because it can result in proper planning, which would ultimately result in improvement in infrastructure development, and economic and industrial growth. This paper examines the changes in land use/land cover types in Tiruchirappalli city, Tamil Nadu from 1998-2006, using remote sensing technology and Geographic Information Systems (GIS). The spatial and temporal changes of land use/land cover were analyzed through visual interpretation and image classification of IRS remote sensing data collected for years 1998, 2002 and 2006. The results of the study indicated an overall growth in built-up land by 80% over a span of eight years, with an incredible boost (58%) in development from 1998-2002. The area under agricultural wet land was found to have decreased from 3,776 ha to 2,689 ha, with an increase in agricultural dry land from 814 ha to 1,058 ha during this period, suggesting the wastage of land due to excessive use of fertilizers. [ABSTRACT FROM AUTHOR]