By Ruchika Thakur:
If a recent NASA report titled “NASA Satellites Unlock Secret to Northern India’s Vanishing Water” is to be believed, 114 million residents of Jaipur and Delhi stand to lose access to potable water. Data provided by NASA’s Gravity Recovery and Climate Experiment (GRACE) satellites that observe and monitor changes in critical areas of the world suggests that Earth’s groundwater basins are rapidly getting depleted due to human consumption. GRACE measures dip and bump in Earth’s gravity which is affected by the mass of water. This takes us to three important questions: What is groundwater and why is this water getting depleted even though it is beneath the ground? What is the significance of this groundwater in our lives? And if it is really important then what are the measures that we can take up to preserve this water?
Groundwater, the water used for drinking and irrigation purposes comes from the natural percolation of surface water through cracks in the soil and is accumulated in aquifers which are made of gravel, sand and sandstone or fractured rock.
These aquifers in India are “overstressed” in the regions of Rajasthan, Gujarat, Tamil Nadu and Andhra Pradesh while they are in a semi-critical condition in Maharashtra and Karnataka. The stress on groundwater resources is majorly due to irrigation. The use of resources escalated after the green revolution with the utilisation of fertilizers, low electricity tariffs and technology. The water table in the south is the most affected with 30 % of its groundwater table lower than 60 metres below the ground.
So how will the reduction of groundwater affect us?
More than 60% of irrigated farming depends on mining groundwater, so a drastic reduction in the levels of groundwater will lead to a severe food shortage in the country. To put things in perspective, Tamil Nadu has one of the overstressed aquifers in the country because of which there has been a sharp drop in the overall percentage of irrigated land. This stressful situation was accelerated when states began to cultivate crops, not suited for their geographical conditions; for example sugarcane crop requires a lot of water but it is cultivated in the state of Maharashtra and Uttar Pradesh which only gets moderate rainfall. To provide the required amount of water, farmers then began to make extensive use of technology to drill groundwater.
However, the Eastern states have not shown any sharp decline in groundwater resources. Erratic electricity supply deterred farmers from using the available subsidies to irrigate their lands to the fullest and has helped in maintaining the optimum level of groundwater. If the power distribution was uniform then these states, that naturally receive a good rainfall, can cultivate crops which require large quantities of water rather than pressuring the resources of other states.
The frightening thing is that this rapid depletion of groundwater is a man-made disaster.
Overuse of bore well technology, contamination of water bodies and unawareness about preserving water is taking India to the fresh water crisis. Not only the quantity but the quality is also taking a major setback leading to waterborne diseases.
In the olden days, tank system was heavily relied upon to save water resources which helped in replenishing groundwater. But the importance of tank irrigation declined due to the advancement of the green revolution and pumping technologies. Solar could have been a good alternative, but it may result in overkill of the already depleting groundwater during the day time due to the availability of abundant sunlight.
Positive steps have to be taken to ensure availability of at least drinking water. Going back to the tank system and rainwater harvesting seem to be the two options available according to many scholars on the subject. But the unpredictable nature of the Indian monsoon leaves a huge doubt on workability of these solutions, except that these solutions can be relied upon during the years with normal rainfall. Prevention is the only key here because once the water bodies are redundant our technologies will be worth nothing.