Groundwater exploitation and Land subsidence

Groundwater exploitation and Land subsidence
 

News: While the scary scenes of Land subsidence and cracks in buildings in Joshimath is not forgotten, A similar phenomenon has been playing out for years in the plains of Punjab, Haryana, Delhi and Faridabad.
 

What is Land Subsidence?
 Land subsidence refers to the gradual sinking or settling of the Earth's surface, usually due to the compaction of underground layers of soil, rock, or other materials.
 It occurs when the support structures beneath the land, such as aquifers, underground mines, or natural gas extraction, are depleted or when certain geological processes take place.
 

How groundwater extraction is connected to sinking land?
 When the underlying aquifers – deep water channels that are stores of percolated water, aren’t recharged, they run dry. Hence, the layers of soil and rock above them start to sink and the issue is not specific to north India alone.
 

What is the magnitude of problem?
 Unlike land movement from landslides or earthquakes, subsidence from groundwater extraction was gradual and barely visible annually.
 Studies utilizing satellite-based analysis of ground movement have identified building deformities resulting from groundwater withdrawals.
 For example, data from the Sentinel-1 satellite shows that the NCR region sank 15 mm per year (on average) between 2011-2017.
 Urbanization and unplanned growth exacerbated groundwater withdrawal and contributed to subsidence in the NCR.
 

What should be done?
 Most important thing is to understand that groundwater exploitation has consequences other than water scarcity.
 Incentivising rainwater harvesting, ensuring strict implementation of laws against illegal mining of groundwater, evaluating building conditions in hazard zones and provisioning of such subsidence in building designs.
 To promote crop diversification and shift to more water-efficient irrigation techniques like drip irrigation and sprinkler systems.
 Leverage technology for real-time monitoring of groundwater levels, such as remote sensing, IoT devices, and data analytics can help in informed decision-making and enable prompt action to mitigate groundwater depletion.
 

Government initiatives:
 Atal Bhujal Yojana is a groundwater management scheme launched in 2019.
 Jal Shakti Abhiyan (2019) - Launched in 256 water-stressed districts to improve groundwater conditions in these areas.
 Pradhan Mantri Krishi Sinchayee Yojana
 The United Nations-Water Summit on Groundwater 2022 - Organised to raise awareness on groundwater conservation.