Multiplicative ARIMA modelling of monthly stream flows of Betwa river

The multiplicative ARIMA (p,d,q)×(P,D,Q)_w models of different orders were tried for modelling of monthly stream flow of Betwa River. The parameters of multiplicative ARIMA models were computed by a seasonal ARMA (P, Q) fitted to the D-th seasonal difference of the data coupled with an ARMA (p, q) model fitted to the d-th difference of the residuals of the former model. The goodness of fit of models was tested by Box-Pierce Portmanteau test and by comparison of historical and forecasted data correlograms. Forecasting performance of the models was evaluated by using the goodness of fit tests. The lower values of integral square error and higher values of correlation coefficient and coefficient of efficiency for multiplicative ARIMA (2,0,0)×(0,1,2)_w model indicated closer agreement between forecasted and historical monthly stream flow series data.