Assessment of effects of changes in land use on the water balance components using SWAT (Case study: Doroudzan dam basin)

In this study, to investigate the effects of land use changes on hydrological components of the Doroudzan Dam basin for the three periods of ۱۹۷۹ to ۱۹۹۰, from ۱۹۸۷ to ۱۹۹۹, and from ۱۹۹۷ to ۲۰۰۶, three land use maps for the years ۱۹۸۶, ۱۹۹۶ and ۲۰۰۵ were prepared. Then, using the semi-distributed SWAT model, the basin hydrology processes were simulated. After calibration to validate the model, validation was performed for each period. The Nash-Sutcliffe coefficient in calibration and validation of the first period was ۰.۷۴ and ۰.۵۲, in the second period was ۰.۸۸ and ۰.۶۱, and in the third period was ۰.۸۳ and ۰.۸, respectively. Also, three scenarios were defined to determine the effect of each land use management application in the study time step (۱۹۷۹ to ۲۰۰۶). All the scenarios were simulated under the same conditions for rainfall and temperature and  different land use maps. The impact of land use change under these scenarios is well observed, with the latter having a ۲۷.۷% decrease in surface runoff compared to the control scenario, as rangeland, forest, agricultural cover increased, wasteland decreased. Has found. In the third scenario, surface runoff decreased by ۱۳.۵% compared to the control scenario, but increased compared to the second scenario, as rangeland cover decreased and wasteland increased.

کلیدواژه ها:

Doroudzan basin ، Land use ، Water balance ، SWAT