Presentations 2016

The Groundwater Constraint: Responses to Falling Water Tables in India

George Washington University

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The objective of this paper is to examine the trends in groundwater depletion in India and analyze their short term consequences by studying their impact on area under irrigation. Indian agriculture continues to employ three out of five people in the labour force and its development is crucial for the growth of the entire economy. Efforts to increase the growth rate of agriculture have relied on increasing the intensity of cropping, use of high-yielding variety of seeds, expansion of irrigation facilities and use of fertilizers. On one hand, the modern seed-fertilizer-water technology, has catalyzed the entire crop production system, but on the other it has led to deleterious environmental consequences (in terms of ground water depletion). An open question in policy circles now is whether the groundwater constraint is binding or not, and if it is then what is the impact of falling water tables. To study this we present results from a new panel dataset that records groundwater levels in 20,166 wells, four times a year, over 1996-2012. We document two results: firstly, overall trends in groundwater depletion mask important regional and temporal heterogeneity. We can identify three distinct phases: (a) in the first phase - the period of concentration - groundwater is declining in the north and west (excluding Maharashtra); (ii) in the second phase - the period of diffusion - there is a remarkable improvement in the second phase as locii of groundwater extraction shifts to east (though in terms of magnitude the problem is not severe); (iii) in the third phase - the period of resurgence - the erstwhile problem areas from phase 1 make a comeback and the problem intensifies in the new areas that were added in phase 2.Secondly, analyzing the impacts of falling water tables, using over 100,000 observations and high resolution spatial data, we find that a 1 meter fall in November’s water table leads to a decline in irrigated area by approximately 0.1 percentage points. To put these numbers in perspective, it is important to remember that gains in area under irrigation are notoriously sluggish and that it has taken India more than 60 years to increase gross irrigated area by 20 percentage points (net irrigated area has increased only by 13 percentage points since independence). Given that the magnitude of the impact we estimate is a third of the average annual gains India has made in irrigation since independence, this implies that the groundwater constraint is strict and binding.