Ground water exploration aided by drilling is one of the major activities of the Central Ground Water Board (CGWB) with an objective to discover aquifers in different hydrogeological conditions and determination of hydraulic parameters. Large-scale sub-surface exploration programme for ground water was initiated during 1954. In the initial years, exploratory drilling activities were confined to alluvial tracts in major river basins and sub mountainous boundary tracts of Himalayan foothills. In mid eighties, CGWB added 26 new Down The Hole Hammer (DTH) drilling rigs in its fleet with which the exploratory drilling in hard rock regions gained momentum. The major thrust of exploratory drilling programme in nineties was in areas underlain by hard rock. Another important development in first half of nineties was introduction of open hole drilling technology in India. CGWB acquired seven percussion drilling rigs for exploratory drilling in boundary/semi-consolidated formations in Himalayan foothills from Jammu & Kashmir in north-west to Arunachal Pradesh in north-east. These exploration programmes formed the background of scientific evaluation of the water bearing properties of various rock formations.
About 34451 wells have been drilled by CGWB throughout the Country. CGWB has undertaken ground water exploration programme in water deficient areas in the Country, including tribal and drought prone areas. The successful wells have been handed over to the respective State Governments for public water supply. The Board had also come forward in disaster mitigation activities during Latur earthquake during 1993, Bhuj earthquake during 2001, Super cyclone in Orissa during 2000 and Tsunami hit coastal belt of Tamil Nadu & Kerala and Andaman & Nicobar Islands during 2004 by way of construction of tube-wells for water supply and also through conducting surveys and investigation for preparation of short, medium and long term water supply management plan for the latter. Presently, CGWB is also focussing on accelerated exploration in the areas having the problem of water availability and water quality in order to come out with ground water management plan in these areas.
CGWB possesses drilling rigs comprising of direct rotary rigs, percussion/combination rigs and down the hole hammer drilling rigs, which enable CGWB to drill almost in any geological formation of the Country. Groundwater exploration also being reoriented to generate additional data under National Aquifer Mapping programme in order to refine sub-surface disposition for the preparation of aquifer maps.
Annexure-II: State-wise Status of Borehole Drilled by CGWB