Prediction and Analysis of Flood Zones under Climate Change Conditions based on CanESM2 Model’s Scenarios

This study aimed to predict flood zone in climate change conditions based on the fifth assessment report of the intergovernmental panel on climate change (IPCC) scenarios in the Talar watershed (Zirab city). To investigate the effect of climate change from six synoptic stations were used. Among the general circulation models (GCM), CanESM2 based on RCP 2.6, RCP4.5, and RCP8.5 scenarios were applied for statistical downscaling of the maximum daily rainfall. To hydrologic and hydraulic simulation of flood were used from HEC- HMS and HEC- RAS models in the recent decades and the future. The results indicated that maximum daily rainfall will increase in the watershed. The results also showed that the increase in maximum daily rainfall in humid climate (the North) is more than dry climate (the South). In general, maximum daily rainfall will increase the minimum and maximum 8 and 33 mm, respectively in the watershed. The simulation results in terms of flood hydrograph indicate that flood increase in the all periods. The RCP 4.5 scenario will produce at minimum and maximum flood discharge in 2020-2040 (374 m3/s) and 2020-2100 (1209 m3/s), respectively. Flood zoning map showed that floodplain area is the base period in the river basin, but climate change will increase the flood zone in this region. Besides, the results showed that at least 0.18 percent and at most 8.7 percent of the total Zirab city will effect on flood under climate change conditions.