Simulation and modeling of monthly discharge using time series analysis (case study: Firouzabad River, Iran)

Analysis of hydrologic phenomena due to their stochastic nature has always been paid attention by investigators. Therefore, the use of time series plays an important role in this domain. In this study, the time series relating the monthly average of flow rate of Tangab Station of Firouzabad River was examined. It is located in the Firouzabad watershed at the west part of Fars province. The first stage in the time series analysis was drawing the data diagram and finding the statistical parameters. In the second stage, stabilization of data was carried out by deleting the process and periodic components from the time series. Then, the auto correlation and the partial auto correlation functions of the data were drawn and the appropriate model was chosen from auto regressive (AR), moving average (MA) models and a combination of them, (ARIMA) or (ARMA). The result of this study, in addition to simulation and modeling the river flow, is data generation for the future condition that requires correct management and decision making. Using these data, one can predict the river´s floodwater flow rate in the future.