The varied climatic, geomorphic, geological and hydrological conditions have helped the delineation of the country into 8 ground water provinces.
Image Source: geopostings.com
(i) Pre-Cambrian Crystalline Province:
Occupying about half the area of the country comprising greater parts of Tamil Nadu, Karnataka, Andhra Pradesh, Maharashtra, Dandakaranya, Bundelkhand, and Aravallis, extends discontinuously from the Cape Comorin to the North-West in Ganganagar district.
ADVERTISEMENTS:
The ground water occurs in the weathered parts of the pre-Cambrian granite, gneiss, metamorphic etc. within 80 m from the surface. Quartzites and marbles are poorest in water resource.
(ii) Pre-Cambrian Sedimentary Province:
It is patchy, confined to the Cuddapah and Vindhyan basins of sandstone, conglomerate, limestone and slate. Well-compacted and non porous sedimentary strata are least favourable for ground water resource.
(iii) Gondwana Sedimentary Province:
Isolated basins of the Barakar and the Godavari, surrounded by crystalline rocks, have good aquifers in sandstone, but poor in shales. The wells often show good yields.
(iv) Deccan Trap Province:
Occupied by somewhat 1200 m thick, non-porous and impermeable basalt layers, constitutes a poor ground water province. The only aquifers preserved are in the fractures where secondary porosity develops in the weathered moorums, at time in the intertrappean beds sandwiched between two impermeable strata as also in the vesicles and the amygdales.
(v) Cenozoic Sedimentary Province:
ADVERTISEMENTS:
The Andhra Pradesh, Tamil Nadu, Kerala and Gujarat coasts of Tertiary sandstone and states have good aquifers,
(vi) Cenozoic Fault Basin:
The rift zone of the Narmada, the Purna and the Tapti provides good resource of ground water in their 80-160 m thick alluvial cover of sand, silt and clay.
(vii) Ganga-Brahmaputra Alluvial Province:
By and large, this forms the richest ground water province of the country. The bhabar, tarai and the axial belts are well defined. The streams disappearing in the unassorted materials of the bhabar zone seep out in the terai belt. Moreover, the ground water table is also high.
(viii) Himalayan Province:
This complex structural and geographic unit is not very significant with respect to ground water resource. Local springs are common but wells are a rare feature.