‘Soaking up’ what and where?

M. Dinesh Kumar and Niranjan Vedantam

One doesn’t expect newspaper reports to be scientifically accurate, or for that matter, even the Editorials. But they should not be devoid of any substance and completely-misleading. However, the piece in the editorial column of Times of India (14th January, 2025) belied all those expectations. The column titled Soak It Up makes a clarion call for artificial recharge of groundwater in India. The reason given is that the recharge during the last year’s monsoon was slightly less (447 billion ton or 447 billion cubic metres), than that of the previous year (449 billion cubic metres), in spite of having a slightly higher rainfall.

The Editorial seems to assume that the entire country receives the same quantum of rainfall and therefore if the average rainfall is slightly higher (as reported), it should result in higher recharge. The reality is that the average rainfall varies from 200mm to 11000mm, and while there are regions in India where nearly 20-25 per cent of the annual rainfall goes underground, there are also many regions where the recharge is less than even 0.1 per cent of the annual rainfall (like the mountainous areas of the NE and western Ghats). The article also seems to assume that the formations bearing groundwater have infinite storage space and that any increase in rainfall would result in increased infiltration and recharge.

The misinformation being thrown by the article doesn’t stop at this. It says: “Our cities have spread horizontally and by swallowing tanks, ponds and local streams and their vertical rise depends on the water underground”. Actually, this is a complete divergence from the reality. When the cities spread horizontally (like what has happened to cities like Bangalore and Hyderabad), they are able to meet at least a small portion of their requirements from local groundwater and the rest comes from surface water. But when they grow vertically, the dependence on groundwater becomes too little and 90 to 95% of the water demand has to be met by imported surface water. The water that we get in our taps can come from Sutlej or Narmada or Godavari or Krishna or Cauvery, depending on which city one lives in.

The article gets it completely wrong when it says: “In fact, 2024’s reduced groundwater recharge largely resulted from increased groundwater extraction for agriculture in Punjab, Haryana and western UP”. This is a bizzare argument and it makes a mockery of science. One wonders how increased abstraction resulted in reduced recharge in these areas. There is no scientific data provided to explain this phenomenon, nor do we have any reliable data on groundwater abstraction in our country. In places such as Punjab, Haryana and western UP that are underlain by alluvial soils, reduced surface irrigation can result in reduced annual groundwater replenishment as irrigation return flows from gravity systems constitute a significant share of the annual groundwater replenishment in this region.

The article goes on to blame ‘climate change’ for reducing recharge in the country. It says: “Old timers remember the monsoon as a time of long, steady and frequent wet spells. Now there are fewer wet spells and more bouts of very heavy rains. The scientists blame it on global warming”. The statement is too shallow, to say the least. Is the article referring to ‘old timers’ from western Rajasthan or from Meghalaya? One doesn’t know. If it is the former, then that region is known for extremely erratic monsoon (for centuries) with monsoon limited to 10-12 wet spells in 2-3 months. If it is Meghalaya, the rains last for 8-9 months of the year, with 80-100 rainy days.?

The article laments: “Rainfall alone does not recharge groundwater but it takes care of about two third of the replenishment”. The editorial was kind enough to give some credit to rainfall. But it doesn’t say from where the rest one third of the recharge comes! It comes mostly from surface irrigation (return flows) and some from the natural wetlands. Only a miniscule of the total annual replenishment is from artificial recharge structures. This is not because we have not built enough number of water harvesting and recharge structures, but because there are serious structural constraints to recharging groundwater due to the limits induced by the natural setting (geology and geohydrology). Most of the areas where groundwater is over-exploited has hard rock aquifers with very limited storage space. That space gets filled during monsoon and wells in such areas overflow if the monsoon is good! There are very few pockets in India where the aquifer has large empty space and the aquifer is depleting on a secular basis. In such areas, artificial recharge can happen during monsoon, provided there is runoff water.

Then comes the question of availability of water for recharging. Unfortunately, we are obsessed with recharging using local runoff water. The fallacy of this approach at the macro level is that if there is sufficient runoff available for recharging, then why can’t we use it directly (after storing it on the surface) rather than putting it underground using complex structures with no certainty? This is where we need to apply common sense or rationality. Unfortunately that is becoming very rare when it comes to water management. We are getting carried away by fancy words. The point is that most of the places where groundwater is over-exploited and where additional storage of water is possible, there is too little surface runoff that is uncommitted that can be tapped from the locality.

But one is caught completely off-guard after reading the final message from the Editorial: “So, increasing rainwater harvesting should be a national priority. Dams are costly, ecologically destructive and controversial”. So what have we been doing since the early 90s? Exactly what the Editorial wanted. Every small stream in the dry areas has been blocked by structures, with no water from such streams joining the higher order streams. Our small and medium dams are getting dried up because of intensive water harvesting being carried out upstream that not only blocks the inflows but also evaporates it.? It is only recently we woke up to the reality that this won’t save the country.

Recharge is a good concept and no one should be against it. It has been successfully tried in many developed countries that experienced similar problems many decades ago. But the tragedy is with the approach that we follow, i.e., artificial recharge using local runoff. It is like “catching the crane using butter”. In the hard rock areas, the best way to recharge our over-exploited aquifers is to bring water from regions (where it is in surplus) and use it for recharging the aquifers when the water table lowers (during the summer months). In alluvial areas, recharging of over-exploited aquifers using imported water would be possible even during the monsoon. But to do all that we need big reservoirs, diversion systems and canals to transfer water from ‘water surplus’ areas to water-scarce areas for irrigation, municipal uses, etc. This is exactly what large irrigation systems and multipurpose projects do. Sadly, most people do not realize the fact that building dams in water-rich catchments to create large reservoirs that store runoff water is also ‘rainwater harvesting’! ???

To conclude, as the Editorial started, if we are going to use more and more groundwater, we need to put more rainwater underground. But the method of doing it is what makes all the difference. So we need to recharge our brain cells.

About the authors: M. Dinesh Kumar is the Executive Director of Institute for Resource Analysis and Policy, Hyderabad. Niranjan Vedantam works as a Senior Researcher with IRAP. The views expressed in the article are personal. Email ID: [email protected]