A group of researchers have concluded that the gravest threat to groundwater in India is not over-exploitation but arsenic and salt contamination.
The study titled Groundwater quality and depletion in the Indo-Gangetic Basin mapped from in situ observations was published on 29 August 2016 in the journal Nature Geoscience.
The study was concluded after analysing groundwater levels from 3429 wells and spatial data in India, Pakistan, Nepal and Bangladesh.
The study also highlights the fact that unsustainable levels of groundwater extraction are largely limited to urban agglomerations in Punjab, Haryana and Uttar Pradesh.
Key highlights of the study
• About 23% of the 300 Billion Cubic Metre (BCM) is extremely saline about 40% is contaminated by arsenic.
• Compiled water-table records indicate substantial spatial variability.
• Canals built in the 19 and 20 centuries significantly influenced groundwater trends. Water accumulated at the origins of the canal tended to leak out. The leakage led to high recharge and sometimes floods.
• The largest water depletion occurred in Punjab, Haryana, Uttar Pradesh and Pakistan’s Punjab.
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