Over-exploited groundwater block
Also called: Stage of groundwater extraction · Topic: Water Resources of India: Availability, Use and Conservation · NCERT: Beyond NCERT
Meaning
An over-exploited groundwater block is an area where more groundwater is pumped out each year than rain and rivers can put back. Its stage of extraction (yearly extraction ÷ yearly extractable recharge × 100) is above 100%. In the yearly assessment, blocks fall into four classes: safe (up to 70%), semi-critical (70-90%), critical (90-100%) and over-exploited (above 100%). In an over-exploited block the water table keeps falling, so wells go dry and pumping costs rise.
Example
The 2024 assessment put Punjab's stage of extraction at about 156%, with about three-quarters of its blocks over-exploited. Free farm electricity and water-hungry paddy have driven this (verify current).
Don't confuse with
- Critical block: the stage is 90-100%. Pumping is close to recharge but has not yet gone beyond it.
Related concepts
- Groundwater
- Dynamic Ground Water Resource Assessment
- National Aquifer Mapping and Management Programme