Projected climate change impacts on the availability of blue and green water in a watershed of intensive human water usage

Abstract

Study region: The Dongjiang River Basin (DRB), Southern China. Study focus: Quantifying the impacts of climate change on blue water (BW) and green water (GW) resources is important for the efficient management of water resources and watersheds socio-economic development. This study projects the impacts of climate change on blue and green water availability in DRB, using the multi-water-flux calibrated soil and water assessment tool (SWAT), the future land use simulation model (Geosos-FLUS), and the outputs of 21 global climate models under two Shared Socioeconomic Pathways (SSP126 and SSP585) that were bias-corrected by utilizing the quantile delta mapping method for the near (2030–2064) and far future (2065–2100). New hydrological insights for the region: The results indicate that annual precipitation, temperature, and extreme precipitation are projected to increase in DRB in the future. Future increases in precipitation intensity are projected to result in variations in the partition of precipitation to blue and green water, increases in blue water and green water flow (GWF), and decreases in green water storage (GWS). Climate change is projected to decrease seasonal water availability and exacerbate green water scarcity (GWSC) in DRB. Therefore, it is crucial to consider changes in the precipitation intensity on the regional blue and green water security. Our finding can assist watershed managers in identifying future hydrologic risks and developing appropriate adaptation policies.

Keywords

• Climate change
• Blue and green water
• Water security
• Precipitation changes
• Dongjiang river basin