India is a vast country having diversified geological, climatologically and topographic set-up giving rise to divergent ground water situation in different parts of the country the prevalent rock formations, ranging in age from Archaean to Recent, which control occurrence and movement of groundwater, are widely varied in composition and structure. Similarly, not too insignificant are the variations of landforms from the rugged mountainous terrains of the Himalayas.
Eastern and Western Ghats to the flat alluvial plains of the river valleys and coastal tracts, and the Aeolian deserts of Rajasthan the rainfall patterns too show similar region-wide variations. The topography and rainfall virtually control run-off and groundwater recharge.
The groundwater resources have two components, viz., static and dynamic. The static fresh groundwater reserves (aquifer zones below the zone of groundwater table fluctuation) of the country have been estimated as 10812 b. cu.m. The dynamic component is replenished annually, which has been assessed as 432 b.cu.m.
According to the National Water Policy (2002), development of groundwater resources is to be limited to utilization of the dynamic component of groundwater. The available groundwater resources and replenish able resources are given in Table 4.5. The total annual replenish able groundwater resource is about 432 b.cu.m.