Adaptation strategies of agriculture and water management to climate change in the Upper Tarim River basin, NW China

The Upper Tarim River basin, contributing about 85% of the total inflow to the mainstream Tarim River, is heavily influenced by climate change and human interferences. This study is the first integrated assessment of agriculture and water management under climate change scenarios for this arid river basin in Central Asia. It aims to analyze changes in river discharge of the Upper Tarim under 28 climate projections for 3 representative concentration pathways (RCP) and the A1B scenario and 30 combinations of changes in land use (agricultural area) and water saving measures considered as adaptation strategies. Headwater discharge simulations of two hydrological models (SWIM-G and WASA) are used to drive a hydrological model of the lowland area (SWIM-oasis), taking account irrigation and river transmission losses. The projections show that the river discharge of the Upper Tarim River is likely to increase in a warmer climate if the agricultural area is reduced to the level as in 1998 even without any water saving measures. If the agricultural area increases to the 2010 level, strong water saving measures must be applied to ensure sufficient water inflow to the mainstream Tarim under all climate scenarios. If agricultural area continues to expand, there is a risk of decreasing river discharge at the end of this century under the RCP2.6 scenario. The uncertainty of the projections is large, especially in the far future, and it is mainly related to the climate and hydrological models.