Global climate changes due to increased greenhouse gases and changes in land use such as urbanization pose challenges for conservation strategies. In this research to assessment the effects of climate changes in Balighloo Chai basin, during the 2050s, A2 and B1 scenarios were downscaled with LARS-WG and were compared with the 1983-2013 period. Results showed the increase between -0.47 to 3.09 percent in average annual rainfall and the increase between 1.80 to 2.02 °C in average temperature in the 2050s. Two land use scenarios were developed to predict the impact of land use changes on the runoff in the coming decades: in the first scenario the current land use assumed fixed and unchangeable in future and in the second scenario assumed the same trend of changes which has occurred in the past (continuation of the past changes) . Results show a decrease of 41 percent in rangelands area and 21 percent increase in agricultural area to 2050s. In order to simulate the hydrologic system in the coming decades, HEC-HMS model calibrated and validated using real data. Results showed increase of peak flow and flood volume in April and decrease of peak flow and flood volume in March, May, and June. If land use change occurs with climate change, this changes will be intensified.
