There are eight main tributaries in the MRYR, including Huangfuchuan (HF) River, Kuye (KY) River, Wuding (WD) River, Yan River (YR), Wei River, and Yiluo (YL) River on the right bank, and Fen River (FR) and Qin River (QR) on the left bank. Among them, the Weihe River is the largest tributary of the Yellow River, with a drainage area of 134,800 km². The larger tributaries of the Weihe River are mostly concentrated on the north bank. Among them, the major tributaries larger than 10,000 km² are the Hulu River, the Jing River (JR), and the Beiluo (BL) River. The FR is the second-largest tributary of the Yellow River and the largest river in Shanxi Province. Many important industrial cities are concentrated in the basins of the FR. The QR and the YL River are one of the main sources of floods in the Yellow River. Because of their proximity to the lower reaches of the Yellow River, the occurrence of floods poses a great threat to the lower reaches. The typical middle reaches selected in this study are HF River, KY River, WD River, YR, FR, JR, BL River, QR, and YL River (Figure 1 and Table 1), which basically cover the entire MRYR.