000031946 001__ 31946
000031946 037__ $$aARTICLE--2016-029
000031946 041__ $$aEnglish
000031946 100__ $$aBiemans, H.
000031946 100__ $$aSiderius, C.
000031946 100__ $$aMishra, A.
000031946 100__ $$aAhmad, B.
000031946 245__ $$aCrop-Specific Seasonal Estimates of Irrigation-Water Demand in South Asia
000031946 260__ $$c2016
000031946 300__ $$a1971–1982
000031946 507__ $$aHiAware
000031946 520__ $$aEspecially in the Himalayan headwaters of the main rivers in South Asia, shifts in runoff are expected as a result of a rapidly changing climate. In recent years, our insight into these shifts and their impact on water availability has increased. However, a similar detailed understanding of the seasonal pattern in water demand is surprisingly absent. This hampers a proper assessment of water stress and ways to cope and adapt. In this study, the seasonal pattern of irrigation-water demand resulting from the typical practice of multiple cropping in South Asia was accounted for by introducing double cropping with monsoon-dependent planting dates in a hydrology and vegetation model. Crop yields were calibrated to the latest state-level statistics of India, Pakistan, Bangladesh and Nepal. The improvements in seasonal land use and cropping periods lead to lower estimates of irrigation-water demand compared to previous model-based studies, despite the net irrigated area being higher. Crop irrigation-water demand differs sharply between seasons and regions; in Pakistan, winter (rabi) and monsoon summer (kharif) irrigation demands are almost equal, whereas in Bangladesh the rabi demand is  ∼  100 times higher. Moreover, the relative importance of irrigation supply versus rain decreases sharply from west to east. Given the size and importance of South Asia improved regional estimates of food production and its irrigation-water demand will also affect global estimates. In models used for global water resources and food-security assessments, processes like multiple cropping and monsoon-dependent planting dates should not be ignored.
000031946 653__ $$aheadwaters
000031946 653__ $$arunoff
000031946 653__ $$airrigation
000031946 653__ $$awater demand
000031946 653__ $$awater stress
000031946 650__ $$aAdaptation
000031946 650__ $$aClimate change
000031946 650__ $$aWater availability and demand
000031946 773__ $$pHydrology and Earth System Sciences (HESS)
000031946 773__ $$v20
000031946 773__ $$n5
000031946 8564_ $$uhttp://www.hydrol-earth-syst-sci.net/20/1971/2016/$$yExternal link (open access)
000031946 8560_ $$fanil.jha@icimod.org
000031946 8564_ $$uhttp://lib.icimod.org/record/31946/files/hess-20-1971-2016.pdf
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000031946 980__ $$aARTICLE