Since the “Grain for Green”Project (GfGP) was implemented on the Chinese Loess
Plateau in 1999，many farmlands have been changed into grasslands and forests． The vegetation
cover is significantly recovered from crops and bare soil so that the previous severe soil erosion
is largely reduced． However，rapid change of vegetation type from crops to forests leads to less
water supply and more water demand in some forest regions as the trees use more soil water than
crop for evapotranspiration process． To quantitatively investigate effects of large-scale vegetation
restoration on eco-hydrological processes as well as the tendency of the changes in
precipitation，evapotranspiration，and streamflow，we use in-situ observations，PT-JPL
evaporation model，and remotely-sensed vegetation and evaporation data to perform a series of
simulations and analyses． The results show that during 2001 to 2015 period，precipitation
increases at a rate of 5. 16mm·a
－1 ，evapotranspiration increases at a rate of 4. 39mm·a －1 ，and
streamflow in most basins，decreases at a mean rate of － 1. 45mm·a
－1 ． The increased canopy
transpiration is the primary driving factor to the increase of total evapotranspiration． The findings
suggest that it’s necessary to establish a set of scientific and practical strategy and policy by
comprehensively considering the relationship between soil，vegetation，and water． Such a series
of strategies and policies can potentially relieve water shortages caused by revegetation，and
provide scientific guidance for sustainable development of vegetation restoration over the Loess
Plateau and efficient management of water resources in the Yellow Ｒiver basin．
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