There’s a lot of buzz about mines and mining in India. It was strange that I never came across ‘water mining’ before.
Let’s first see what fossil water is.
Fossil water or paleowater is groundwater that has remained sealed in an aquifer for a long period of time. Water can rest underground in “fossil aquifers” for thousands or even millions of years. When changes in the surrounding geology seal the aquifer off from further replenishing from precipitation, the water becomes trapped within, and is known as fossil water. Fossil water is, by definition, a non-renewable resource. Whereas most aquifers are naturally replenished by infiltration of water from precipitation, fossil aquifers are those that get little or no recharge. – Wikipedia
What is water mining?
The extraction of water from such non-replenishing groundwater reserves (known as low safe-yield reserves) is known in hydrology as water mining. If water is pumped from a well at a withdrawal rate that exceeds the natural recharge rate (which is very low or zero for a fossil aquifer), the water table drops, forming a depression in the water levels around the well. – Wikipedia
Now, let’s look at the water scenario in India:
“Nearly a third of India is suffering from chronic water shortages, and making up for it with “the world’s largest groundwater mining operation,” according to experts…… For about half of the country, their analysis suggests, if people used small-scale “rainwater harvesting”—capturing rain and storing it in tanks and ponds—they would have much of the water they needed, assuming they continued to grow the same types of crops….. In other parts of India, though, rainwater harvesting alone won’t be enough to avoid depleting groundwater further, the study suggests.So the team is studying how farmers could shift the crops they grow to ones that require less water.” – National Geographic
It is not just the depletion of this non-renewable source that is a problem, but some even say that it is raising sea-levels.
“But a new study shows that global warming is not the only cause of swelling seas. Much comes from “water mining” – the pumping of vast amounts of groundwater from beneath the earth, mainly to irrigate crops. This inevitably ends up in the oceans after it evaporates from farmland and comes down as rain.” – The Telegraph
What can we do now?
Here are some of the technologies that people are into:
- In the state of Tamil Nadu, rainwater harvesting was made compulsory for every building to avoid ground water depletion. It proved excellent results within five years, and every other state took it as role model. Since its implementation, Chennai saw a 50 percent rise in water level in five years and the water quality significantly improved.
- In Rajasthan, rainwater harvesting has traditionally been practiced by the people of the Thar Desert. There are many ancient water harvesting systems in Rajasthan, which have now been revived.
- Rainwater harvesting in Kerala
- At present, in Pune (in Maharashtra), rainwater harvesting is compulsory for any new society to be registered.
- An attempt has been made at Dept. of Chemical Engineering, IISc, Bangalore to harvest rainwater using upper surface of a solar still, which was used for water distillation
“Little drops of water make a mighty ocean.”