The Impacts of Climate Change on Runoff of Ghareh-Chay Basin in Markazi Province, Iran

Climate change has a critical impact on water resources, especially in arid regions. In the first part of the study, the LARS-WG was used for downscaling of climatic variables including rainfall, solar radiation, minimum and maximum temperature over the Ghareh-Chay basin in Markazi province for a 31 year historical period (1983-2013). Results showed that LARS-WG can be applied successfully to downscale the climatic variables. By using the three emission scenarios, A1B, A2 and B1 in different future horizon, decreasing and increasing trends were seen for rainfall and temperature, respectively. In the second part of study, adaptive inference neuro fuzzy system (ANFIS) was applied for run-off simulation over the basin for three different horizons, 1400, 1435 and 1470. Two different identification methods namely, grid partitioning and subtractive clustering were used for ANFIS model. Performance of the subtractive clustering was slightly better than the grid partitioning in run-off modeling process. The results indicated that in comparison to the baseline period, the maximum discharge will be reduced by14, 27 and 43 percent in 2020, 2055and 2090 horizons, respectively. Based on the occurrence of climate change over the basin and intensification during the next years, it seems necessary to consider some ways for adaptation and coping with climate change for protecting the water resources.