Geomorphology and hydrogeology of coastal tracts of the Central West Coast of India

Abstract

Dakshina Kannada district which is a coastal district of Karnataka, spreads along the west coast of India covering coastal tract of about 40 km. Dakshina Kannada district is divided into three regions, low land, mid land and high land. The coast line is generally straight and followed the Dharwar rocks trending NNW-SSE.The rocks weathered fractured and jointed granitic gneisses and laterite varies from 10 m to 30 m. The thickness of coastal alluvium varies from 7 to 29 m. There are spits and beach ridges available in coastal tract. The Netravati river flow towards Mangalore where it joins Gurupur River and both the Rivers from common esture discharging into the sea. Gneissic rocks archaean age cover a major part of this region as basement rocks. These are elsewhere overlain by oligomictic quartz conglomerate belonging to Dharwar super group. The recent alluvium and colluvial deposits occur along the river bed and sea coast. The exposure of crystalline rock found as isolated hills along the shore and off shore. The black clay marine sediments with a thickness of 0.30 m to > 1m occur as lenses along the coast and in the deltaic islands. Its occurrence as marked at a depth ranges of 5 to 6 mbgl. The groundwater below the black clay horizons of coastal sediments found with high salinity, which marks the index bed for saline water and fresh water interface. 2013 CAFET-INNOVA TECHNICAL SOCIETY.