What is it about?
In Delhi NCR there is a huge gap between water demand and water supply due to which extracting underground water has become a usual practice. We are going deeper and deeper in the quest for water. At some places where there is no piped water supply, underground water is the only source. Looks fine, isn't it? Wait there's a problem : The underground water exists deep in the earth surface, where it occupies the void left by soil pores or rock cracks. At those depths, water is pressurised and it pushes the earth up. The weight of the earth is shared by both the water and the matter underneath. When the underground water is drawn out excessively, the matter underneath becomes the sole entity for managing the load.
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Photo by Jeremy Bezanger on Unsplash
Why is it important?
When we extract water the land goes down (pl see the animation below), and when land goes down it damages underground utilities, such as sewage pipes, water mains supply, etc., and increases chances of waterlogging and flooding. Roads, buildings, and highways are also affected, and most importantly it puts human lives in danger.
Perspectives
Read the Original
This page is a summary of: Tracking hidden crisis in India’s capital from space: implications of unsustainable groundwater use, Scientific Reports, January 2022, Springer Science + Business Media,
DOI: 10.1038/s41598-021-04193-9.
You can read the full text:
Resources
Hidden crisis in India's capital unveiled using satellite data
Using satellite data, researchers have found that around 100 sq km in and around Delhi has high risk of land subsidence. Groundwater extraction is causing parts of the city to sink, with the largest area experiencing subsidence just 800m away from Delhi international airport.
Delhi is sinking - AAJ Tak with Shagun
This is an interview with AAJ TAK in Hindi.
[Explainer] How falling groundwater levels compact the land above
The underground water exists deep in the earth surface, where it occupies the void left by soil pores or rock cracks. At those depths, water is pressurised and it pushes the earth up. “The weight of the earth is shared by both the water and the matter underneath,” says Shagun Garg, a civil engineer and researcher at University of Cambridge. “When the underground water is drawn out excessively, the matter underneath becomes the sole entity for managing the load.”
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