In this research with the use of the hydrological convex sub-methods the operation of finding flood routing was done between the Sarghanat and Kelal stations located in Dalki river. the characterstics of 26 flood was extracted as model input and then to evalute model performance and predict the output of hydrographs the Nash–Sutcliffe criteria, RMSE and relative error was used. Results of this study showed that Convex graphical sub-method can predict the outputs of hydrographs with higher precision as compared to other three methods. Moreover another result of this research is the priority of the use of 50% discharge as input discharge in model and results showed that in all sub-methods the predictiong the discharges of lower than 700 cubic meter per second had higher precision compared to discharges more than 700 cubic meter per second.
