Investigating the impact of climatic change on spatio-temporal variation of green and blue water resources in the Neyshabur-Rokh basin, Iran

Sustainable availability of renewable freshwater varies under the influence of different factors such as climate change. Identifying the impact of climate change on different water resources components seems essential for the appropriate management of watersheds. In this study, for the first time, it was attempted to evaluate the spatio-temporal reaction of green and blue waters to climate change in Neyshabur-Rokh watershed using WetSpass-M. In this regard, the water balance components were estimated by WetSpass-M during 1991–2017. The data related to six General Circulation Models under RCP4.5 were downscaled using the Quantile Mapping (QM) and applied as an ensemble to project the near-future climatic conditions of the green and blue water. Results showed that the mean annual precipitation, mean temperature, green water, and blue water would increase by 4.66%, 1.96 °C, 0.55%, and 5.9% in the near-future, respectively. The maximum and minimum rates of green and blue waters were predicted to be observed in 2033 and 2048, respectively. The maximum volume of blue water would occur in the mountain areas with the rangeland land use, and the green water spatial distribution would be reduced in the eastern parts of the plain. This study can contribute to the overall knowledge about the hydrological processes and spatio-temporal changes in green and blue waters caused by global climate change.