Tingju Zhu, IFPRI
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This document discusses groundwater use and depletion in Asia and its implications for irrigated agriculture. It notes that Asia accounts for 70% of the world's net irrigated area and half of global groundwater used for irrigation. Regions like Northwestern India and North China Plain are particularly vulnerable to groundwater depletion. The growing population and changing diets in Asia are increasing demand for irrigation water. Sustainable groundwater management policies are needed to address this critical issue for Asian agriculture and food security.
Tingju Zhu, IFPRI
- 1. Groundwater Use and Depletion in Asia Implications for Irrigated Agriculture Tingju Zhu International Food Policy Research Institute Washington, DC Water Policy for Food Security: A Global Conference, Davis, CA, October 5-6 at UC Davis
- 2. The world's most populous continent, with 4.4 billion population in 2014 Accounting for 70 percent of the world’s net irrigated area With 20 million wells, South Asia alone accounts for nearly half of global groundwater used for irrigation Asia is responsible for the largest share of food production from depleting groundwater, especially in northwestern India and North China Plain High vulnerability to climate change – Glacier-fed rivers and major river deltas critical for agriculture are to be affected Growing population and changing to more water- intensive diet Asia – Population, Water, and Agriculture
- 3. Hydro-climatology, Irrigation, and Irrigated Areas Source: 1) Precipitation from GPCC v5. 2) PET and runoff simulated by the IMPACT Global Hydrological Model (IGHM) for 1971-2000. 3) Irrigated area share based on GMIA database by Siebert et al. (2007). • IGP • NCP • Deltas
- 4. 78 80 82 84 86 88 90 1000 1200 1400 1600 1800 2000 2200 2005 2010 2015 2020 2025 2030 2035 2040 2045 2050 2055 Asia - Irrigation consumption World - Irrigation consumption Asia - Share of irrigation water consumption World - Share of irrigation water consumption Irrigation Water Consumption and Share in Total Water Consumption – Asia and World Source: IMPACT3.2 baseline projection Notes: Consumption in km3/yr
- 5. 0 200 400 600 800 1000 1200 2000 2030 2050 ConsumptiveUseinIrrigation(km3/yr) Other Vegetables Cotton Maize Sugarcane Wheat Rice Irrigation Water Consumption by Crop in Asia Source: IMPACT model projections in IFPRI report submitted to ADB (2013)
- 6. 0 50 100 150 200 250 2000 2030 2050 ConsumptiveUseinIrrigation(km3/yr) Other Soybean Cotton Vegetables Maize Wheat Rice 0 50 100 150 200 250 300 350 400 450 500 2000 2030 2050 ConsumptiveUseinIrrigation(km3/yr) Other Sub-tropical fruit Cotton Sugarcane Rice Wheat China India Irrigation Water Consumption by Crop in China and India Source: IMPACT model projections in IFPRI report submitted to ADB (2013)
- 7. Groundwater Irrigated area in Asia Source: Irrigated area share based on GMIA database by Siebert et al. (2007).
- 8. Groundwater Withdrawal in Asia: 1940-2010 Source: Shah et al. (2007)
- 9. Groundwater Abstraction by Region and Crop Australia/Ocean ia 0% Central Asia 2% East Asia 14% Latin America and the Caribbean 2% Near East/North Africa 16% OECD 23% Other European Countries 1% South Asia 41% Sub-Saharan Africa 1% Regions Beverage and spice crops 19% Cereals 43% Leguminous crops 4% NonFood Crops 9% Oilseed Crop 8% Other Crops 0% Roots and Tubers 2% Sugar Crops 7% Vegetables and Fruits 8% Crop Groups Source: IWMI and IFPRI analysis, work in progress
- 10. Groundwater Depletion by Region and Crop Australia/Oceani a 0% Central Asia 2% East Asia 10% Latin America and the Caribbean 1% Near East/North Africa 23% OECD 24%Other European Countries 1% South Asia 38% Sub-Saharan Africa 1% Regions Beverage and spice crops 11% Cereals 49% Leguminous crops 4% NonFood Crops 12% Oilseed Crop 7% Other Crops 0% Roots and Tubers 2% Sugar Crops 6% Vegetables and Fruits 9% Crop Groups Source: IWMI and IFPRI analysis, work in progress
- 11. Groundwater Depletion in Indus and Ganges Basins (GRACE and Reconstructed Depletion in Dry Season) Oct-Apr Oct-Apr Source: IFPRI and UCF, work in progress
- 12. Drought Frequency in the Indus and Ganges and Reconstructed Precipitation Drought frequency (as a percentage) during the Period of 1300-1899 (left) and 1900-2010 (right) Indus basin Ganges basin Source: IFPRI and UCF, in Davtalab et al. (2015)
- 13. Source: Gao et al. (2013) Groundwater Depletion in North China Plain
- 14. Groundwater Management in the Indo-Gangetic Plains Bihar Western IGP: • High investment in infrastructure; • Effective institutions and policy support • Intensive agriculture (e.g. agrochemicals and ground- water irrigation) • Surplus food production responsible for regional food security • Seasonal in-migration of male labor Eastern IGP: • Relatively low productivity and poor infrastructure • Limited capacity for private investment • Prone to flooding and drought • Food deficit region; out-migration of male labor to other regions Food-Water-Energy Nexus Energy Subsidies Groundwater development challenges
- 15. Groundwater irrigation Challenges in Eastern IGP (Vaishali, Bihar) • Irrigation in Vaishali almost entirely depends on groundwater; surface water irrigation infrastructure existing but not functional • Bihar is an electricity-scarce state; irrigation in Vaishali has to rely on diesel pumps • Diesel price is high (~Rs52/l; new pump set Rs25K~30K) • Ownership of tubewells and pump sets • Farmers have little capacity in private investment • Farmers indicate delayed Monsoon can cause ~80% production cost increase (rice + wheat)
- 16. Additional Irrigation for Crop Intensification in China? Source: IFPRI and CAAS, work in progress by Yu et al. Irrigation water use in China remains roughly unchanged for more than two decades. South-to-North Water Transfer Project’s water too expensive for agriculture. Investment in rural water infrastructure has been increased since 2011. Pilot sites for market-based water transfers in 7 provinces, by MWR.
- 17. Is water-saving irrigation technologies a solution?
- 18. Lack of Incentives: Farmers concern economic return and production risks, not necessarily irrigation water- saving Technologies need to be adapted to local settings Technologies need to go hand in hand with agricultural extension Move from water-saving to cost-effectiveness, including labor-saving, energy-saving, higher yield and better crop quality, and reduced production risks Information and institutional development Adoption of Irrigation Technologies for Water- saving in Asia
- 19. Conclusions Groundwater is critical for agricultural production in Asia, with increasing withdrawal trends in many countries. Depletion of groundwater is a growing challenge to sustainable water use and agricultural production, especially in northwestern India and North China Plain. Groundwater will become only more important in the future, with decreasing snowpack (i.e. Himalayas rivers) and increasing hydroclimatic variability. Enhanced monitoring, assessment, and holistic multisector policies are critical for sustainable groundwater use and irrigation in Asia.