Social Sciences, asked by Kannusambyal24, 1 year ago

write a short note on groundwater in india at least two pages

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Answered by RishitaSurve
16
Groundwater has played a significant role in the maintenance of India’s economy, environment, and standard of living. India is the largest groundwater user in the world. Through the construction of millions of private wells, there has been a phenomenal growth in the exploitation of groundwater in the last five decades. The factors driving this expansion include poor public irrigation and drinking water delivery, new pump technologies, the flexibility and timeliness of groundwater supply, and government electricity subsidies. As a result, 29 percent of the groundwater assessment blocks in the country are classified in semi-critical, critical, or overexploited categories with the situation deteriorating rapidly.
Overexploitation of groundwater and intensive irrigation in major canal commands has posed serious problems for groundwater managers in India. Depletion of water tables, saltwater encroachment, drying of aquifers, groundwater pollution, water logging and salinity, etc. are major consequences of overexploitation and intensive irrigation. It has been reported that in many parts of the country the water table is declining at the rate of 1-2 m/year. At the same time in some canal commands, the water table rise is as high as 1 m/year. Deterioration in groundwater quality by various causes is another serious issue. Increased arsenic content in shallow aquifers of West Bengal reported recently has created panic among the groundwater users. Summed together, all these issues are expected to reduce the fresh water availability for irrigation, domestic and industrial uses. If this trend continues unchecked, India is going to face a major water crisis in the near future. Realizing this, the Government of India has initiated several protective and legislative measures to overcome the groundwater management-related problems but, due to the lack of awareness and political and administrative will, none of the measures has made any significant impact. This paper highlights the critical issues and examines the various schemes related to groundwater development and management.



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Answered by geniusmen
11
India has vast ground water resources. The average rainfall over the country is about 110 cm as a whole and this rainfall over India's area of 328 million hectares gives a total precipitation of 3700 billion cubic metres. Only 22 per cent of this total rainfall percolates under the ground. Of this total amount about 430 billion cubic metre reaches upto the upper surface of the soil. Remaining 384 billion cubic metre reaches the pervious strata which could be obtained by dugging the well. But only 70 percent of this amount can be exploited economically.

The underground water resources are af­fected by the climatic conditions, relief (topogra­phy), geological structure and hydrological condi­tions of the area. Prof. R.L. Singh (1971) has identi­fied 8 ground water provinces within the country

1. Pre-Cambrian Crystalline Province-this is a deficient ground water province covering about one-half of the country's area. It includes Tamil Nadu, Andhra Pradesh, and Karnataka, Maharashtra, Dandakaranya, Bundelkhand and Aravallis.

2. Pre-Cambrian Sedimentary Province-this area is also not suitable for ground water develop­ment. Here rocks belonging to the Cuddapah and Vindhyan Systems contain less amount of ground water.

3. Gond wana Sedimentary Province-Here the Gondwana sedimentary rocks of the Barakar and Godavari river basins contain good-aquifers for wa­ter.

4. Deccan Trap Province-this region is also deficient in ground water due to a 1, 2(X) metre thick covering of basalt over the surface which obstructs percolation. The only aquifers preserved arc in the fractures where secondary porosity develops in the weathered moorums, at times in the intertrappean beds sandwitched between two impermeable strata as also in the vesicles and the amygdales.

5. Cenozoic Sedimentary Province-this in­cludes coastal areas of Andhra Pradesh, Tamil Nadu, Kerala and Gujarat where Tertiary sandstones and slates provide good aquifers.

6. Cenozoic Fault Basin-the rift zone of the Narmada, Purna and Tapi rivers provides rich re­source of ground water in their 80-160 m thick alluvial cover of sand, silt and clay.

7. Ganga-Brahmaputra Alluvial Province-this forms the richest ground water province of the coun­try. Here Bhabar, Tarai, axial belts and alluviums encourage percolation and contain good storage of ground water

8. Himalayan Province-this complex struc­tural and geographic unit is not very significant with respect to ground water resources. It provides a number of natural springs but the dug wells arc rare feature to be seen. According to the Central Ground Water Commission about 44 per cent of the underground water resources are concentrated in the Ganga- Brahmaputra Basin. Here 100-150 cumic meters per hour water is available at the depth of 600 meters. This is also corroborated by NATMO. it ok
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