Water-Stage Forecasting in a Multitributary Tidal River Using a Bidirectional Muskingum Method

Abstract

The Muskingum flow routing method has been successfully used in many hydrologic applications due to its simplicity in concept and calculation. This paper presents a bidirectional Muskingum water-stage routing model (BDMWSRM) for water-stage forecasting in a tidal river with consideration of flood and tidal influences. The BDMWSRM separates the hydrologic processes of the tidal river into upper reach flood and downstream tidal waves, respectively. Muskingum water-stage routing method was first used to calculate the propagation of the flood and tidal waves; for the case of multitributary upper reaches, a first routing-second combining approach is used and then routed streamflows are summed up by using different weight factors for two water-stages based on the water-stage threshold. All the parameters used in the model can be adjusted automatically or determined manually. The BDMWSRM was applied in the Jiaojiang River, China for evaluating the tidal effect on the streamflow in this study. The simulated streamflows at the basin outlet capture the seasonal trends which compare realistically well with the observed in both temporal variation and intensities. The results indicate that the BDMWSRM can be applied successfully with high accuracy and reliability on the water-stage forecasting in a tidal river and fewer parameters may be required for model calibration, displaying the relative advantage of the model.