Groundwater Development in Hard Rocks

Groundwater development in fractured hard rock aquifers has always assumed a secondary role compared with that in unconsolidated alluvial strata or in soluble carbonate rocks. This is because of the nonextensive, irregular, nonisotropic, and inhomogeneous nature of the aquifer and the relatively small yields of water available from dug-wells or drilled bores. However, many of the highly populated areas in the world are underlain by hard, fractured rock aquifers. Whatever small supply of groundwater is available from these aquifers is the only source for millions of people to obtain their drinking water supply and to irrigate their small plots of farms. In India and many other countries, institutional finance at concessional rate of interest has been provided to farmers since the early 1970s for well digging/drilling for irrigational use. This resulted in overdevelopment in some sub-basins, thereby stressing the need to promote recharge augmentation. For sustainable development, it is necessary to adopt soil and water conservation techniques in each watershed, taking a sub-basin as the unit for planning. This article discusses various aspects of groundwater development in hard, fractured rock aquifers including occurrence of water, types of wells, exploration, recharge augmentation, and legal control of pumpage.