Research on Runoff Forecasting Method for Data-Scarce Areas Based on Hydrological Similarity

Currently, with the advancement of flood forecasting and warning work for small and medium-sized rivers in China, the research on runoff forecasting methods for data-scarce areas has become an urgent technical bottleneck that needs to be addressed. Based on the traditional unit hydrograph method and the theory of hydrological similarity, a spatial transplantation method for unit hydrographs using watershed runoff velocity as the hydrological similarity element is proposed through dimensional analysis. The method was validated using the Huangchuan and Jiangji watersheds. In the application within the Tuanjie River sluice area in Jiangsu, the nearby Fengshan station was selected as the reference station. A comparison between the spatial transplantation results of the reference station's unit hydrograph and the instantaneous unit hydrograph used in Jiangsu's rainstorm flood atlas showed a good agreement between the two results. The unit hydrograph spatial transplantation method proposed in this paper is scientific, and the results are reasonable and credible, making it applicable for hydrological forecasting in data-scarce areas.