SR-5/98-99 : Hydrological problems of hard rock region (A State - of - Art Report)

Abstract

During last three to four decades, there have been considerable developments in different fields of the hydrological sciences. Physiographically, India as a whole can be divided into three distinct features; (i) The mountainous region of the Himalayas the extra- peninsula, (ii) The great Indus-Ganga-Brahmaputra plains and (iii) The triangular plateau of the peninsula. The hydrogeological framework of India has been divided into three major categories, namely; the areas underlain by unconsolidated formation, the areas underlain by semiconsolidated formation and the areas underlain by the consolidated formations. Almost the entire peninsular region is occupied by the consolidated formations ranging in age from Archean to Tertiary. The Archeans generally include the schistose formations of the Dharwar systems, gneiss, charnockites etc., while the Precambrians include the Cuddapahs and the Vindhya,ns,Consolidated formation involves the hard rock terrain also. Eventhough, there is no exact definition what does hard rock mean, it is generally understood by all geologists that hard rock are crystaline, i.e. igneous and metamorphic rocks. Hard rocks (crystalline rocks) such as granites, gneisses, basalt, and indurated pre-Cambrian sediments cover approximately 75 per cent of the total area of the India. Considering the wide distribution of hard rock in Southern parts of the country and the erratic hydrological behaviour of the hard rock terrain, National Institute of Hydrology established a regional centre to tackle the hydrological problems associated with the hard rock areas of the country. During various meeting of the Regional Co-ordination Committee, which comprises of the field engineers from different State/Central Government organisations within the region, an urgent need has been felt to discuss about the various hydrological problems on the suitable platform, which leads to identification of thrust areas for research, Keeping, this view, it is decided to prepare the status report on the hydrological problems such as Hydrological Network Design, Groundwater Quality, Failure of the Open and Bore Wells, Regional Flood Formulae, groundwater balance studies, tank studies, Reservoir Sedimentation, Hydrological aspects of drought, Forest hydrology and Drainage problems of Black soil of the hard rock terrain etc. In this report, the literature related with the problems were collected from various States and Central Government organisations as well as Universities. This report has been

prepared by Mr. Dilip G. Durbude, Scientist 'B, Regional Centre National Institiute of Hydrology, Belgaum. I am sure that this document would prove to be very good reference source for academic community as well as field engineers dealing the above problems in the hard rock region.