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Hydrogeomorphological studies in the Trichirappalli environs,Tamil Nadu, India using Remote Sensing technology
Sankar K
Centre for Remote Sensing, Bharathidasan University
Khajamalai Campus, Trichirappalli-620 023. Tamil Nadu, India
Email: sanmena_2001@rediffmail.com
Introduction:
The growth of the population is increases year by year more stress on agriculture sector for increasing the food grain production, which consequently increased deforestation and demand for more water. Trochirappalli environs, Tamil Nadir, are chronically drought prone and faces acute water scarcity not only drinking purposes but also agriculture purposes. The available surface water resources are inadequate to meet the entire water requirement for different purposes. So the demand for under ground water has increased each and every year.
In general, surface water are more pollution when compare to groundwater. Hence, groundwater serves as a very important source of water for various purposes not only urban development but also rural habitations improvements. In the hard rock terrain exploration groundwater studies are carried out using various conventional methods. In recent years extensive use of satellite remote sensing has made it easier to define the spatial distribution of different groundwater potential zones based on the geomorphology and it's associated features (Prithvi Raju, 1980; Sankar et.al. 1993). In numerous earlier investigations (Bedi and Bhan, 1978; Karanth and Seshu Babu, 1978; Moore, 1978; Bhattacharya et.al 1979; Raju et.al 1985; Sinha et.al 1990; Satyanarayana 1991; Rao, 1991; Prakash and Mishra, 1991; Tiwari and Rai 1996; Palanivel et.al 1996; Ravidran and Jeyaram , 1997; Pradeep, 1998; Kumar et.al 1999 have been applied for remote sensing techniques for groundwater studies. The interpretation of satellite data in conjunction with sufficient ground truth information makes it possible to identify and outline various ground features such as geological structures, geomorphic features and their hydraulic characters (Das et.al 1997), that may serve as direct or indirect indicators of the presence of groundwater ( Ravindran and Jeyaram (1997).
Study area:
The area under study Trichirappalli environs central part of Tamil Nadu State. It lies between north latitudes of 9° 45' to 11° 15' and east longitudes 78° 15' to 80° 30' covers an areas about 9000 sq.km. The major river Cauvery is ephemeral nature through the area from east to west. The average annual rainfall in the area is 95 cm. In the study area, falls under the rocks age group of Achaeans, Cretaceous groups, Tertiary sedimentary formations and an isolated pockets of Gondwanas. More than sixty percentage of area covered by hard rocks while the sedimentary formations occupy the rest.
Physiography and hydrogeology:
In this study area is plain but gently sloping towards the east and southeast. The elevation of the area is in general ranges from 300 - 500 m above MSL. The area is drained by Cauvery River and its tributaries as well as Amaravathi and Bhavani rivers. Groundwater occurs underwater table conditions especially in the weathered and fractured portions of the crystalline formations. The depth of groundwater table ranges from a few m to thirty m below ground level. In the sedimentary areas groundwater occurs under semi-confined conditions, water level ranges from a few m to 20 m below ground level.
Drainage is mostly dendritic to sub-dendritic patterns controlled by fracture and joints are exists in the hard rock areas where as sedimentary areas, parallel to sub parallel pattern is well developed in the east, northeast and southeastern part of the study area.
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