What are the hazards of the Yellow River?
Floods in the upper reaches of the Yellow River mostly occur in September, mainly from above Lanzhou, and the floods in Lanzhou mainly come from above Guide. Due to the long duration and low intensity of rainfall, and the good vegetation above Lanzhou, grasslands and swamps have a strong stagnation effect on rainfall. The flood fluctuation in the upper reaches of the Yellow River is gentle, the flood duration is long, the flood peak is low, and the flood hydrograph is short and fat.
The average duration of a flood at Lanzhou Station is 40 days, with the longest 66 days and the shortest 22 days. The measured peak flow is generally 4000 ~ 6000 cubic meters per second.
Most of the upper reaches of the Yellow River are canyons. Regardless of the size of the flood, the general propagation time does not change much. It takes about 1.5 days from Guide to Lanzhou, and about1.5 days from Lanzhou to Hekou Town. The flood in the upper reaches of the Yellow River reaches the middle and lower reaches and generally becomes the base flow.
The measured flood data in the upper reaches of the Yellow River began after the flood in 1933, when hydrological stations were set up in Lanzhou and Baotou. The measured maximum flood occurred at 1946, and the peak flow at Lanzhou Station reached 5900 cubic meters per second, with a total flood volume of 6.5 billion cubic meters in 15 days.
Although the peak flow of Lanzhou Station in 198 1 year is only 5600 cubic meters per second, the peak flow of Lanzhou Station can reach 7090 cubic meters per second without the cofferdam construction of Longyangxia Reservoir and the water storage of Liujiaxia Reservoir. According to the survey, the largest flood in the upstream occurred at 1904, and the peak flow of Lanzhou Station reached 8600 cubic meters per second.
Extended data:
irrigation project
Yellow River Irrigation District in Inner Mongolia 1
One of the famous large-scale irrigation areas in China. Its scope starts from the eastern edge of Wulanbuhe Desert in the west, reaches the eastern suburb of Hohhot in the east, borders on Langshan, Wulashan and Daqingshan in the north, and borders on Ordos platform in the south, including Hetao, Tumochuan and irrigation areas on the south bank of the Yellow River. 19 flags (counties, districts) crossing Yikezhao League, Bayannaoer League and Hohhot, Baotou and Wuhai.
2. Ningxia Yellow River Diversion Irrigation Area
One of the four ancient irrigation areas in China has a history of more than 2,000 years. Known as "Jiangnan", it is the main grain, cotton and oil producing area in Ningxia and one of the national 12 commodity grain bases.
The irrigation area involves irrigation from the Yellow River in Qingtongxia City, Yongning County, Yinchuan City, Helan County, Pingluo County, Tao Le County, Huinong County, Shizuishan City, Zhongwei County, Zhongning County, wuzhong and lingwu city, covering 12 counties (cities) and more than 20 state-owned agricultural and forestry pastures.
3. Fenhe Irrigation District
This area is located in Taiyuan Basin in the middle of Shanxi Province, distributed on both sides of Fenhe River, starting from Shanglan Village in the northern suburb of Taiyuan City in the north and reaching Hongxiang Village in Jiexiu County of Jinzhong District in the south, with a length of about 140km and a width of about 20km from east to west. It is bounded by Fenyang Highway and Ciyao River in the west, Sanmenxia Highway in the east and Tongpu Railway in the south.
The irrigation area spans Taiyuan, Jinzhong and Lvliang, covering 488 villages and 56 beneficiary townships in 12 counties (cities, districts). The whole irrigation area controls 2,055,500 mu of land, including cultivated land/kloc-0 1.5684 million mu. The designed irrigation area is1495,500 mu, and the benefit area accounts for nearly one tenth of the water area of Shanxi Province. It is one of the largest gravity irrigation areas in Shanxi Province.
Baidu Encyclopedia-Yellow River