An optimized routing model for flood forecasting

A conceptual flow routing model for flood forecasting is adopted for a reach of river given only historic upstream and downstream stage hydrographs and the associated in-bank rating curves, local rainfall, and minimal additional information. The ungauged lateral inflows are generated by a unit hydrograph rainfall-runoff model. The model is calibrated by optimizing the parameters of the functional form for the average cross section along the reach, the base lateral inflow and the peak of the unit hydrograph, and the rating curve extensions downstream and upstream. The model is confirmed by applying it to a synthetic river reach and then to the forecasting of floods in a reach of the River Wye, UK.