Specific related data of floods in the Yellow River in recent years

On the night of September 2 1 65438,990, a rainstorm and flood with rare history broke out in Mao Jing, Chedao and Lujiawan Township, west of Huan County, Qingyang City, Gansu Province, which is located in the headwaters of Malianhe River and Puhe River, the third tributaries of the Yellow River. The maximum precipitation in the rainstorm center is 255 mm, and the precipitation lasts for 7 hours (including high-intensity precipitation of about 1 hour, hail for 26 minutes, maximum hail thickness of 18 cm), maximum flood peak discharge modulus of 5 1.8m 3/s/km2, and maximum runoff depth of177.4. It not only caused serious floods and hail disasters, but also caused serious soil erosion. Especially in the valley palm area upstream of the modern ditch head in the middle and lower reaches of the small palm watershed (as shown in figure 1), the gravity erosion (commonly known as palm ditch erosion, as shown in figure 2) caused by the centralized discharge of a large amount of rainwater and flood on the slope is extremely serious. I remember that at that time, the flat palm land in the lower reaches of Liganzhang small watershed (as shown in Figure 3), where the township government of Mao Jing was located, suddenly turned into a 6.7-mu gully within three hours, and the scene was shocking.