Future irrigation expansion outweigh groundwater recharge gains from climate change in semi-arid India

Sishodia, R P and Shukla, S and Wani, S P and Graham, W D and Jones, J W (2018) Future irrigation expansion outweigh groundwater recharge gains from climate change in semi-arid India. Science of The Total Environment (TSI), 635. pp. 725-740. ISSN 00489697

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Abstract

Simultaneous effects of future climate and irrigation intensification on surface and groundwater systems are not well understood. Efforts are needed to understand the future groundwater availability and associated surface flows under business-as-usual management to formulate policy changes to improve water sustainability. We combine measurements with integrated modeling (MIKE SHE/MIKE11) to evaluate the effects of future climate (2040–2069), with and without irrigation expansion, on water levels and flows in an agricultural watershed in low-storage crystalline aquifer region of south India. Demand and supply management changes, including improved efficiency of irrigation water as well as energy uses, were evaluated. Increased future rainfall (7–43%, from 5 Global Climate Models) with no further expansion of irrigation wells increased the groundwater recharge (10–55%); however, most of the recharge moved out of watershed as increased baseflow (17–154%) with a small increase in net recharge (+0.2 mm/year). When increased rainfall was considered with projected increase in irrigation withdrawals, both hydrologic extremes of well drying and flooding were predicted. A 100-year flow event was predicted to be a 5-year event in the future. If irrigation expansion follows the historical trends, earlier and more frequent well drying, a source of farmers' distress in India, was predicted to worsen in the future despite the recharge gains from increased rainfall. Storage and use of excess flows, improved irrigation efficiency with flood to drip conversion in 25% of irrigated area, and reduced energy subsidy (free electricity for 3.5 h compared to 7 h/day; $1 billion savings) provided sufficient water savings to support future expansion in irrigated areas while mitigating well drying as well as flooding. Reductions in energy subsidy to fund the implementation of economically desirable (high benefit-cost ratio) demand (drip irrigation) and supply (water capture and storage) management was recommended to achieve a sustainable food-water-energy nexus in semi-arid regions.

Item Type: Article
Divisions: Research Program : Asia
CRP: UNSPECIFIED
Uncontrolled Keywords: Crystalline aquifer, Demand and supply management, Energy policy, Flooding, Uncertainty, Well drying, Irrigation expansion, groundwater recharge, climate with irrigation expansion
Subjects: Others > Semi-arid tropics
Others > Irrigation
Others > Climate Change
Others > Water Resources
Others > Indian Agriculture
Others > Water Conservation
Depositing User: Mr Ramesh K
Date Deposited: 18 Jul 2018 09:55
Last Modified: 18 Jul 2018 09:55
URI: http://oar.icrisat.org/id/eprint/10802
Official URL: http://dx.doi.org/10.1016/j.scitotenv.2018.04.130
Projects: UNSPECIFIED
Funders: UNSPECIFIED
Acknowledgement: Authorswould like to thank Dr. Alex Ruane, NASA-Goddard Institute for Space Studies, and Dr. Dakshina Murthy Kadiyala, ICRISAT for providing the R source files for development of climate change scenarios. Funding support to Rajendra Sishodiawas provided by IFAS and CoE, UF.
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