Switch thirsty crops, water by drip
Where most water goes to fields, moving from paddy and sugarcane to millets, pulses or maize, and from flood to drip or sprinkler irrigation, saves more than any recharge can add.
This area pumps out more water than rain puts back. That is the 2025 stage of groundwater extraction: water pumped out in a year as a share of what rain and other sources safely put back. Down 19 points since 2017.
Each point is one CGWB assessment. Over-exploited means more water leaves the ground than comes back, so the water table keeps falling. Hover over or tap a point to see why it moved.
| Year | Stage | Pumped out | Safe limit | Category | What changed |
|---|---|---|---|---|---|
| 2009 | 86.0% | 409 million m³ | 476 million m³ | Semi-critical | First assessment in this series. |
| 2013 | 127.0% | 461 million m³ | 364 million m³ | Over-exploited | Pumping up 13% (409 → 461 million m³). Safe limit down 24% (476 → 364 million m³). Main reason: less water soaked back in, from weaker rain, less canal seepage or more paved ground. |
| 2017 | 135.2% | – | – | Over-exploited | CGWB changed its method in 2017 (GEC-97 to GEC-2015), so part of this change comes from the new method. |
| 2020 | 135.5% | 523 million m³ | 386 million m³ | Over-exploited | Little change since 2017 (+0.3 points). |
| 2022 | 116.2% | 613 million m³ | 528 million m³ | Over-exploited | Pumping up 17% (523 → 613 million m³). Safe limit up 37% (386 → 528 million m³). Main reason: more water soaked back into the ground, from better rain, canals or recharge structures. A swing this large usually comes partly from revised estimates (a new well count or changed district boundaries), not only from changes on the ground. |
| 2023 | 119.2% | 598 million m³ | 502 million m³ | Over-exploited | Pumping down 2% (613 → 598 million m³). Safe limit down 5% (528 → 502 million m³). Main reason: less water soaked back in, from weaker rain, less canal seepage or more paved ground. |
| 2024 | 112.4% | 609 million m³ | 542 million m³ | Over-exploited | Pumping up 2% (598 → 609 million m³). Safe limit up 8% (502 → 542 million m³). Main reason: more water soaked back into the ground, from better rain, canals or recharge structures. |
| 2025 | 115.9% | 608 million m³ | 524 million m³ | Over-exploited | Pumping down 0% (609 → 608 million m³). Safe limit down 3% (542 → 524 million m³). Main reason: less water soaked back in, from weaker rain, less canal seepage or more paved ground. |
Million m³: 1 million m³ = 100 crore litres. 2009 and 2013 used the older GEC-97 method.
Loading 20 years of rainfall…
711 of 1,061 water bodies (67%) are not in use: dried up, silted, built over or polluted. Bringing them back is one of the cheapest ways to recharge groundwater.
Loading the map of water bodies in Namakkal…
Source: 1st Census of Water Bodies, Ministry of Jal Shakti (counted in 2018-19, published 2023).
Most of the water here goes to farming, so using less on fields matters as much as recharge.
Where most water goes to fields, moving from paddy and sugarcane to millets, pulses or maize, and from flood to drip or sprinkler irrigation, saves more than any recharge can add.
Parks, campuses, warehouse yards and road sides can take recharge shafts that reach past the clay layer, so runoff that floods streets goes down to the aquifer instead.
Desilting old ponds and opening their feeder channels restores natural recharge. A one-hectare pond that soaks in a metre of water over the monsoon puts back about a crore litres.
Pipe roof water through a silt trap and filter into a recharge pit or an old borewell. Every 100 m² of roof puts back tens of thousands of litres a year, right where the pumping happens.
On sloping or rocky land, small dams on seasonal streams and trenches along contours slow water down long enough for it to sink in.
Treated water from a sewage treatment plant can run flushing, gardens, cooling towers and construction, which today often draw on borewells.
In the 2025 Central Ground Water Board assessment, Namakkal (Tamil Nadu) pumped out 116% of the groundwater that can be safely taken out each year, which puts it in the "over-exploited" category. That is 19 points lower than in 2017.
Yes. Namakkal takes out more groundwater than rain and other sources put back, so the water table keeps falling.
Rooftop rainwater harvesting into recharge pits or old borewells, recharge shafts in open land, reviving ponds, check dams, treating and reusing wastewater, and moving farms to drip irrigation and less thirsty crops.
The first Census of Water Bodies counted 1,061 water bodies in Namakkal, including 657 ponds. 711 of them were not in use.
Yearly rain at Namakkal, 2006–2025, from NASA satellite data. Lighter bars are dry years (20% or more below average), when wells are drawn hardest.
To stop the water table falling, Namakkal has to put back or save 83.2 million m³ a year. At 824 mm of rain, here is what that looks like:
In practice it is a mix: recharge in towns, ponds and check dams in villages, and saving water on farms and in factories.
1 mm of rain on 1 m² is 1 litre. The surface factor allows for water lost to splash, evaporation and first-flush.