Sedimentation characteristics of the reach from Bayangaole to Toudaoguai of the Yellow River

The analysis shows the various sand sources and characteristics of sedimentation in the reach from Bayangaole to Toudaoguai part of Ningmeng reaches of the Yellow River: for a long time (1952—2012), the proportion of fine sands (sediment diameter d≤0.025 mm) of the in-coming sediment is 52.7%, which is dominant. The fine and medium sands (0.025<d≤0.050 mm) and coarse sands (0.050<d≤0.100 mm) all come from the upper reaches of Bayangaole. The proportion of extra coarse sands (d>0.100 mm) in deposition is 56.2%, which is dominant. And the extra coarse sands come from the upper reaches of Bayangaole, tributaries and aeolian sand evenly. The erosion and deposition law of various grain sands is: the erosion and deposition of the fine and medium and coarse sands occur due to flow and sediment conditions, and the extra coarse sands deposit continuously. Therefore, the adjustment characteristics of various grain sands are quite different in each period. In the flood season, the extra coarse sands are the largest part in deposition before 1986, the fine and medium sands are eroded before 1986 and deposit after 1986, and the fine sands are the largest part of deposition. In non-flood season, all the sands are eroded before 1986 and deposit after 1986 mainly due to the fact that fine and medium sands are eroded before 1986 and deposit after 1986, and the deposition of coarse sands increases. The preliminary analysis shows that the sediment erosion and deposition adjustment in the reach from Bayangaole to Toudaoguai in each period depends on the runoff and sediment of the mainstream and flow processes, and is also affected by tributary sand volume. The research results provide a basic support for the control of the susperded river in Ningmeng reaches of the Yellow River.