How high was the flood level in Beibei in 1981?
From July 9 to 14, 1981, a historically rare large-scale heavy rain occurred in the Sichuan Basin in the upper reaches of the Yangtze River for six consecutive days. The rain areas were mainly concentrated in the middle reaches of the main stream of the Jialing River, the middle and lower reaches of the Fujiang River, and the Tuojiang River. The upper and middle reaches of the Yangtze River, as well as the middle reaches of the Minjiang and Qujiang rivers, caused flooding in the Chongqing to Yichang section of the upper reaches of the Yangtze River, which was rare after the founding of the People's Republic of China or in history.
The peak flow rate at Chongqing Cuntan Station was as high as 85,700 cubic meters per second, making it the largest flood since the 20th century. Due to flash floods and flooding, serious losses of life, property, and industrial and agricultural production occurred on both sides of the main and tributary rivers. The affected population reached more than 15 million, 1.5 million people were made homeless, and more than 13 million acres of cultivated land were flooded. Direct economic losses were approximately 2 billion yuan.
The Sichuan Basin has a subtropical climate with abundant rainfall. The annual rainfall is 900-1200 mm. It basically decreases from the basin edge mountains to the basin belly. The rainfall is concentrated in the flood season. The rainfall from May to October accounts for about 10% of the annual rainfall. 80%, with heavy rains mostly occurring in July and August. Emei Mountain in the western Sichuan Basin and the southern foot of Daba Mountain in northeastern Sichuan are the main heavy rain areas in the Yangtze River Basin. Flood disasters are frequent in the Sichuan Basin. The Jialing River and Hechuan County have been flooded 13 times in the past 200 years. Suining County in the lower reaches of the Fujiang River has also been flooded 8 times in the past century. The terrain of Sichuan Province is complex, and local areas such as the Ertiao River System have more chances of major floods. However, the Minjiang, Tuojiang, and Jialing River systems have less chance of simultaneous major floods. The heavy rain flood in July 1981 fell into this type. Historically, it has Similar ones include the floods of 1840 and 1870.
From July 9 to 14, 1981, a large-scale heavy rain occurred in the hinterland of the Sichuan Basin in the upper reaches of the Yangtze River, which lasted for one day. The rainfall was concentrated in the three days from 11th to 13th, with high intensity and wide range. Among them, the rain intensity was the strongest from 11:00 on the 12th to 11:00 on the 13th. The six days of heavy rain consisted of two rainfalls from the 9th to the 11th and the 12th to the 14th. From the 9th to the 11th, east-west shear caused a northeast-southwest heavy rain belt. The rainy areas are mainly distributed in the middle and upper reaches of the Min, Tuo, Fu and Jiajiang Rivers.
There were 4 heavy rain centers with a total rainfall of more than 105 mm in three days, of which Anningqiao Station had the largest rainfall of 206.1 mm. The area covered by three-day rainfall greater than 100 mm is 15,048 square kilometers. From December 12 to 14, the weather situation from the Beicao Nanvortex continued to cause large-scale heavy rains or extremely heavy rains in the upper and middle reaches of the Min, Tuo, Fu, and Jiajiang Rivers. There were five heavy rain centers with a total rainfall of more than 300 millimeters in three days, with Shangsi Station located in the middle reaches of the Jialing River being the largest with 439.7 millimeters. The area covered by heavy rain is much larger than that of the rainfall process from 9 to 11 days. The area covered by three-day rainfall greater than 100 mm is 103,480 square kilometers.