Positive confirmation on the replenishment of groundwater storage at a regional scale has been reported by a research team from IIT Kharagpur in collaboration with NASA scientists. Groundwater rejuvenation in parts of India was influenced by water-policy change implementation, the research suggests.
The research reported by Nature Scientific Report in August 2017 comes as a huge relief considering that India’s groundwater storage had been falling steadily in recent years. At least 54 percent of India was being regarded as highly to extremely water stressed. “India consumes the largest volume of global groundwater resource, higher than the sum of the total groundwater abstraction of United States and China, the second and third countries, respectively, in the country-wise groundwater utilization list,” the study quotes. The groundwater withdrawal to availability ratio was higher than 0.8 in most parts of the country and this has been of great concern in recent years.
While the northern and eastern parts of the country are still undergoing acute usable groundwater depletion and stress, groundwater replenishment was noted in west and south India specifically in parts of Gujarat and Andhra Pradesh as per the study. The study involved long-term (1996-2014) observations by the researchers using more than 19,000 groundwater observation locations, ground-based measurements and decadal-scale (2003-2014) satellite-based groundwater storage measurements all over the country.
In Gujarat and Andhra Pradesh, groundwater storage renewal trends of up to 4 metres rise in groundwater level has been evident in recent years.“In parts of western (Gujarat) and southern (Andhra Pradesh) India, groundwater storage has been decreasing at the rate of -5.81±0.38 km3/year (1996-2001) and -0.92±0.12 km3/year (1996-2002) respectively. But this was reversed to replenish at the rate of 2.04±0.20 km3/year (2002-2014) and 0.76±0.08 km3/year (2003-2014), respectively. We have been able to demonstrate the initial scenarios of rejuvenating groundwater in parts of India, which has the potential to be the largest groundwater replenishment occurrence in human history,” the study states.
The authors point that “both the central and state governments over the years have undertaken several projects to replenish groundwater through efficient groundwater management and utilisation policies.” The study surmises that the increasing trend of groundwater is related to groundwater management strategy adaptation in the detailed study areas. This includes policy and management measures like decreasing power subsidy or increasing artificial recharge by creating surface water bodies.
“While, unregulated abstraction for enhanced irrigation of water-intensive cultivation (e.g. boro rice, including Basmati) is resulting in one of the most rapid and drastic groundwater depletion in human history, recent paradigm shift in Indian central/state government management strategies on groundwater withdrawal and stress (e.g. Pradhan Mantri Krishi Sinchayee Yojana) will likely start to demonstrate its results in near future,” the study presumes.
The conclusions have been made through advanced statistical approaches and simulation of a global-scale hydrological model. “In present knowledge scenario, impacts of some of the water management issues are almost impossible to quantify, for example, the effect of change in farmer management practice on groundwater resources in Andhra Pradesh etc.,” the study says.
Especially in Gujarat, the authors predict that “policies like restriction of subsidized electricity for irrigation, separate electricity distribution for agricultural purpose (Jyotigram Yojana), construction of large-scale, regional enhanced recharge systems in water-stressed crystalline aquifers (Tapti river mega recharge project), artificial recharge of 85 BCM/year in 0.5 million km2 through 10 million structures, enhanced recharge by interlinking of river catchments (e.g. Narmada-Sabarmati interlinking), will probably start replenishing the aquifers by increasing groundwater storage in near future.”
This is for the first time, that a research has given positive confirmation on the replenishment of groundwater storage at a regional scale. The conclusions are too good to believe. The study hopefully will not come under criticism like the recent study linking Indian farmers’ suicides to climate change has, with many accusing it of poor analysis and wrong conclusions.
The study can be accessed here
Image courtesy: Groundwater tubewell irrigation for horticulture in Gujarat, Tesh Tesh, Wikimedia Commons (License: CC BY-SA 4.0)