علی آذره

Water scarcity is a serious problem across many nations. In recent years, water scarcity has increased due to landuse and climate change, particularly in areas that are arid or semi-arid, like, for instance, Iran. While land-use changes influence hydrological processes at the basin scale, the impacts caused by climate change are reflected by dynamics of temperature, precipitation and evapotranspiration (ET) at the regional to global scale. However, the respective impacts of land-use change and climate change, acting in concert, on water yield, water supply and water consumption, are still poorly understood. The present study aims at shedding further light into these effects by taking as example the Halil River basin in Iran. To this end, the Integrated Valuation of Ecosystem Service and Tradeoffs (InVEST) modelling tool is applied to simulate water yield, water supply and water consumption in the study area, by adopting a range of scenarios of land-use and climate change until 2040. Specifically, this study applies the HadGEM2-ES Earth System model under RCP 2.6, 4.5 and 8.5 to assess the effects of future climate change on water scarcity, and the Land Change Modeller (LCM) in TerrSet Geospatial Monitoring and Modeling Software to estimate land-use maps in the next two decades. Our results indicate that water yield and water supply in the study area are more strongly influenced by climate change than by land-use change. By contrast, change in land-use provides the more significant impact on water consumption. However, while water scarcity in Halil River Basin is controlled mainly by climate change and precipitation, the scenarios that combine land-use and climate changes yield the most significant impact on water yield and water supply. Our findings provide, thus, insights for improving strategies of sustainable development in arid to semi-arid regions threatened by land-use and climate change driven water scarcity.