MODELING SNOWMELT-RUNOFF UNDER CLIMATE CHANGE SCENARIOS IN THE BEHESHTABAD WATERSHED

The aim of this study was to evaluate the variability of time distribution and contribution of runoff from snowmelt under the influence of climate change in the Beheshtabad Watershed, Iran using the Snowmelt-Runoff Model (SRM) and Long Ashton Research Station Weather Generator Model (LARS-WG). The LARS-WG model accuracy in downscaling of GCMHadCM3 output with A1B emissions scenario was evaluated based on data for the base period (1986-2010) and climatic data for the future periods (2011-2030 and 2046-2065) were obtained. The SRM variables and parameters were prepared from the Shahrkord station and Snow Cover Areas (SCAs) were obtained by MODIS satellite images. After the calibration and validation of SRM model, then the SRM model was run with the future data and revealed the effects of climate change on snowmelt runoff. The results show the displacement of the peak flow from April to March, and reducing the contribution of snowmelt runoff from 27.2 to 24.5 and 22.3 percent for two future periods. The present study confirmed the effects of climate change on future climate data and discharge and temporal pattern of snowmeltrunoff.