An Empirical Formula for Suspended Sediment Delivery Ratio of Main River after Confluence of Debris flow

In order to calculate the suspended sediment discharge of the flood debris flows into the main river, a small scale flume test was designed to simulate the process of confluence of Jiangjia Ravine and Xiangjiang River in Yunnan province, China. By test observation and data analysis, suspended sediment discharge of Debris flow after its entry into the main river was found to have a close relation with the bulk density, the confluence angle of the Debris flow and the main river, the ratio between per unit width discharge of Debris flow and main river. Based on the measured and simulated results, and statistical analysis, an empirical formula was proposed for the suspended SDR (Sediment Delivery Ratio) of the main river after the confluence of Debris flow. Compared with the observed results of Debris flow in 2009, the error between the data calculated by the empirical formula and the monitored data is only about 10%.