Impact of Climate Change on Organic Carbon Removal Efficiency in Jajrood Catchment: From Dam to Water Treatment Plant

Background and purpose: Jajrood River is one of the major drinking water supply rivers in Tehran, so, the effects of climate change on its quantitative and qualitative resources are highly important. This study aimed at investigating the effect of climate change on organic carbon removal in Jajrood basin. Materials and methods: In this descriptive cross-sectional study, CanESM2 general circulation model and SDSM (version 5.3) downscaling model were used for simulating climatic data and HYMOD model was used to simulate runoff in Jajrood catchment. Climate change scenarios RCP2.6, RCP4.5, and RCP8.5 were simulated for 2006-2050. Stepwise regression and linear regression were used in MATLAB R2017a to model the qualitative data. Results: According to findings, the temperature of this basin will be about 2.25°C warmer than the base period. Rainfall and runoff in the whole catchment will increase by about 10% and 93% and the concentrations of total organic carbon of the inlet to the treatment plant will be about three times higher than the base period which will increase the load on carbon in different units of the treatment plant. Conclusion: Increased rainfall caused by washing the upstream agricultural lands and temperature increase due to elevated rate of bioactivity lead to deterioration of the quality of water entering the dam and increase the organic carbon entering the treatment plant. On the other hand, Tehranpars water treatment plant with its current capacity and efficiency will not meet the standards of drinking water in terms of organic carbon.