Modeling the impacts of climate change on flow and nitrate in the Kor River Southwest of Iran

The catchment of the Kor River, a principal river system in Far province in Southwest of Iran, plays an important role in agro-economy and people’s livehood in the area. The Integrated Catchment Model for Nitrogen (INCA-N) has been applied the Kor River. The model was calibrated from 2003 to 2008 and validated from 2009 to 2012 to simulate impacts of climate change on streamflow and nitrate (NO3-N) concentrations. Global Circulation Model CCSM4.0 for two IPCC AR5 scenarios (RCP 2.6 and RCP 8.5) were statistically downscaled and used in this study as climate change scenarios. Results revealed that streamflow will increase in summer, and winter months and decrease in spring and autumn months In particular, the streamflow increases by 43% and 45% in October and decreases by 13% and 7% in March under RCP 2.6 and 8.5 respectively. The increase in nitrate concentrations occurs in the spring and winter (December–May) then decreases in the summer and fall (Jun–November) under two RCP scenarios. Seasonally, maximum increase in nitrate concentrations are 87% and 57% in the winter under RCP 2.6 and RCP 8.5 respectively. NO3–N reductions in the fall are about 20 percent under two scenarios.