Draught risk rises in north-east India: IIT Study

NEW DELHI: The eastern and the northern states of India saw a rapid decline in usable groundwater between the year 2005 to 2013. Researchers also found an impending risk of food crisis, severe droughts and drinking water scarcity for millions of people.

A team of Indian Institute of Technology (IIT) Kharagpur and Athabasa University of Canada put together the first approximates of usable ground water storage (UGWS) at the state level across India using in-situ and satellite measurements.

The study estimates show a rapid deficiency in UGWS in Punjab, Assam, Haryana, Bihar, Uttar Pradesh and West Bengal. In these states, growth in agriculture have resulted in non-renewable loss in groundwater volume at a warning rate. On the other hand, the western and the southern states of India like Maharashtra, Andhra Pradesh, Chattisgarh, and Gujarat show a restore in usable ground water trends.

Abhijeet Mukharjee, a lead researcher from IIT Kharagpur and associate professor of hydrogeology said, “The earlier works done by government agencies, have only been able to approximate the total ground water, is only a part of which is usable for human purposes. The study shows a rapid deficiency in usable ground water mostly in northern regions, losing 8.5 cubic km per year of the total groundwater and in eastern regions five cubic km per year of the total groundwater.” “More than 85 per cent of the groundwater usage in India is linked with irrigation abstraction practices”, he emphasised.

Abhijeet also said that, rapid deficiency in UGWS would boost the decline in production of food and availability of drinking water which is two of the vital goals under SDGs. He further said that, more than 120 million people will get affected only in Gangetic states. “There is a need to develop a robust quantitative approach, with the help of advanced data science and hydro science techniques to know the conjunctive water demands and usage”, he added.

India is the largest country to use ground water in the world by using 230 cubic km of ground per year as an average which is a quarter of the global total.

Dr N C Ghosh, former head of Hydrology, NIH, agreed that the ground water of Rajasthan is definitely declining faster, there are also pockets in Uttar Pradesh where the dip in ground water have been seen. “Around 85 per cent of rural drinking water needs and 65 per cent of irrigation needs and 50 per cent of urban drinking water and industrial needs are fulfilled from the underground water.” he added.

Researchers claimed that the north-eastern states like Assam, which was always known as water affluent, saw a decline of two per cent to its usable groundwater resource, and Assam is at the edge of suffering drought in impending years.  

Himachal Pradesh which gets an annual precipitation of 1,147 mm per year has the lowest UGWS at 520 cm whereas, Haryana holds the highest levels of usable groundwater with an annual precipitation of 689 mm. Assam and some other parts of eastern India seems to be losing the usable groundwater storage at a higher rate, said the researchers.

The depletion trends and practices have not only affected the storage groundwater but also it is affecting the rivers such as Ganga. Dr Ghosh said that definitely there is a huge pressure on underground water and flow of several rivers has also decreased. As a result, river aquifer interaction has been influenced. Wherever there is lack of organised water supply, the dependence on groundwater is high.