Can improved agricultural water use efficiency save India’s groundwater?

Irrigated agriculture is placing increasing pressure onfinite freshwater resources, especially in developing countries, wherewater extraction is often unregulated, un-priced and even subsidized.To shift agriculture to amore sustainable use ofwaterwithout harming the food security and livelihoods of hundreds ofmillions of smallholders, substantial improvements ofwater use efficiencywill be required. Here,weuse detailed hydroclimatic and agricultural data to estimate the potential for thewidespread adoption of efficient irrigation technologies to halt the depletionof India’s groundwater resources. Even thoughwefind substantial technical potential for reversingwater table declines,we show that the impacts are highly sensitive to assumptions about farmers’water use decisions. For example,wefind thatwidespread adoptionof proven technologies that include drip and sprinkler irrigationhas the potential to reduce the amount of excessive extractionof groundwater by two thirds.However, under more realistic assumptions about farmers’ irrigation choices, half of these reductions are lost due to the expansionof irrigated area.Our results suggest thatwithout the introductionof incentives for conservation,muchof the potential impact of technology adoption on aquifersmaybe lost. The analysis provides quantitative input to the debate of incentive versus technology basedwater policies.