Evaluating potential impacts of land use changes on water supply–demand under multiple development scenarios in dryland region

Water scarcity greatly hinders sustainable development goal agenda and regional agriculture development in dryland regions. As we know, land use and cover changes are strongly responsible for spatial–temporal evolutions of water resource. However, there is little explicit understanding of how spatial patterns of future dryland use will affect the water supply–demand risk. To answer this question, this study took Yulin city of China, a typical dryland region, as a case study area, and firstly estimated its 2020–2050 land use patterns under three different scenarios, covering Natural Increased Scenario (NIS), Food Security Scenario (FSS) and Economic Development Scenario (EDS), with the help of the path-generating land use simulation (PLUS) model as well as Markov-chain model. Furthermore, this study employed InVEST model to explicitly investigate spatial–temporal evolutions of water supply, water demand and water supply–demand risk in all scenarios. The estimated results indicated that the largest expanding/shrinking land use types were grasslands/croplands in NIS, croplands/grasslands in FSS and built-up lands/croplands in EDS during 2020–2050, respectively. By 2050, all projected land use changes only slightly affected regional water supply (the fluctuation of ∼ 5% compared to that in 2020), but greatly increased by ∼ 57% regional water demand. Particularly, strong land use changes would likely put nearly 90% regions of Yulin city at endangered water supply–demand risk in 2020–2050. Ecological land and built-up land would easier suffer from critically endangered water supply–demand risk. In view of these modeled and analyzed results, some potential mitigation strategies of water resource utilization, such as developing water-efficient eco-agriculture, adjusting agricultural structures and enriching revegetation diversity, were suggested to coordinate future areal human-nature relationships. This study could provide some valuable information for dryland agricultural development, water-environment management and regional policy decision-making.