In this study, SWAT hydrological model was used to differentiate the effects of drought and changes in land use on hydrological balance of the system in Eskandari Watershed area. To this end, The SWAT model was implemented separately using other user maps to investigate the impact of land use changes on the hydrological cycle of the watershed. Additionally, Van Loon model was used to investigate the effects of drought and water scarcity on discharge. The results showed that the watershed area could meet its environmental needs due to an 11% decrease in rainfall and droughts in 2008 and 2009. Additionally, the average monthly simulated flows were 2.4 m3/s and 2.9 m3/s in the natural and turbulent periods, respectively, indicating a decrease of nearly 18%, which is related to the 11% decrease in rainfall in this Watershed. Furthermore, the average observational flow in the turbulent period was 4 mm, which showed a growth of nearly 13% in comparison to the observational flow in the turbulent period. Decreased rainfall and increased discharge in this period indicated the effect of land use change and human activities on the catchment.
Keywords: Eskandari Watershed; Hydrological cycle; Land use change; SUFI2 algorithm; SWAT model; Van Loon model.