A combined deterministic and self-adaptive stochastic algorithm for streamflow forecasting with application to catchments of the Upper Murray Basin, Australia

This paper describes the results of runoff modelling for nine catchments of the Upper Murray Basin (Basin 401) of the Murray-Darling Drainage Division (MDDD), Australia. The work aimed firstly to provide adequate models for long-term streamflow prediction in nine catchments of this Basin feeding the Hume and Dartmouth reservoirs. The development and testing of flow forecasting algorithms for operational management by the Murray-Darling Basin Commission was another purpose of the work reported here. The conceptual lumped parameter rainfall-runoff model IHACRES (Jakeman et al., 1990, 1993; Jakeman and Hornberger, 1993) was selected as the modelling tool for streamflow prediction in the catchments. The conceptual rainfall-runoff model IHACRES (with a snow melt/formation module in snow-affected catchments) and a selfadaptive linear filtering approach for the IHACRES residuals were combined and applied for forecasting daily streamflow in the Upper Murray Basin catchments. Different orders of AutoRegressive Integrated Moving Average (ARIMA) models for the residuals were considered in order to select the most appropriate forecasting algorithm. Linear filtering of the conceptual model residuals provides considerable improvement in forecasting for both low and high values of streamflow for developing the operational streamflow forecast system.