## 5 Conclusions  
Based on the large-scale physical modeling experiment, landslide surge caused by the Meilishi H\({}_{3}\) landslide was investigated. The experiment adopted a water level of 1.38 m, designed five test groups of different volumes and chose the test volume of 1.00 m\({}^{3}\) for the reference group. The other tests acted as the comparative test groups. The leading area of the landslide was 4.00 m \(\times\) 0.20 m. The study combined with the river course characteristics and volume analyzed the wave height test data of the spatial and temporal distribution characteristics of the landslide surge waves. The main research objective was to find the relationships between the head wave velocity, surge waveform, and head wave crest along the river course. Based on the findings, the conclusions can be summarized as follows:  
1. By analyzing the time of head wave occurrence, the fitting curve of the time of head occurrence was plotted, and the fitting curve was approximated as a straight line, indicating that the wave velocity of the head wave propagation is unchanged in the river course. Additionally, the wave velocity of the head wave of the MLSH\({}_{3}\) landslide was about 2.65 m/s. 2. The waveforms of surges are greatly influenced by the river course characteristics. In the first 20 s, when the surges are less influenced by the reflected waves, the number of wave crests of the surge in the topographically similar area is basically the same, while the number of wave crests of the surge in the diversion area and the bending area have a large change. Comparing the maximum wave height and the head wave crest, it can be found that the maximum wave height does not necessarily occur at the head wave crest. Under the condition of small volume, the head wave crest is the maximum wave height for the topographically similar area. In contrast, for the diversion area and the curved area, the maximum wave height of the surges may occur in the secondary wave or even the subsequent waves. Under the condition of large volume, the head wave crest may not be the maximum wave height. Therefore, when studying the effect of landslide surge wave height on the river course in the reservoir area, the effect of the head wave is not the main factor to be analyzed; instead, the effect of the subsequent wave column needs to be considered. 3. For the analysis of the head wave height data of along-stream landslide surges, it can be seen that the river course characteristics have a greater influence on the head wave crest compared to that in the two-dimensional experiments. The main factor changes from the water depth to the cross-sectional area. In the river without diversion areas and curved areas, the head wave crest is negatively correlated with the cross-sectional area of the river course. Moreover, the head wave crest decreases after passing through diversion areas and curved areas in the river course; but the head wave crest increases in the middle of the curved area. The cross-sectional area of the river channel has a significant influence on the crest of the first broadcast wave in the process of propagation of landslide surges when the landslide volume is relatively large. Therefore, the cross-sectional area of the river course is a major factor that affects the head wave crest of the landslide surge. 4. There is a possibility of instability of the accumulations on both sides of the curved area near the dam, and the wave height in the middle section of the curved area increases. Thus, the surge climb on the accumulations in the curved area also increases. Since high surge climb affects the stability of the accumulations, it can cause secondary landslides to occur in the surge disaster chain. Therefore, when studying the disaster risk analysis of H\({}_{3}\) landslide surge on the reservoir area, it is crucial to carry out the research on the influence of landslide surge on the stability of the accumulations on both sides. **Author Contributions:** Conceptualization, Y.Z., Q.H. and W.X. ; methodology, Y.Z.