Effects of parameter uncertainty in a flow routing model / Les effets de l'incertitude des paramètres dans un modèle du calcul du cheminement

Abstract

Abstract A Monte Carlo simulation approach is used to investigate the effects of parameter uncertainty in a ‘nonlinear storage’ flow routing model on downstream flow prediction. The analysis is orientated towards a study of the problem of routing the measured discharge hydrograph at Hughes Bridge on the Murray River, Western Australia, to an ungauged point some 36 km downstream, but implications of the results pertain to broader issues of flow routing in inadequately gauged rivers. The downstream flow predictions are insensitive to N, the number of reaches into which the river segment is divided, and, for small perturbations in inflow, are also relatively insensitive to a and b, the travel time parameters. Peak flow predictions, however, depend strongly on the values of a and b, and consequently accurate flood prediction requires careful determination of these parameters. The estimate of the ‘gain’ in discharge at a downstream station due to lateral inflow in the river segment is also subject to considera...