1998 What was the big flood in the Yangtze River?

1. 1998, the Yangtze River flood occurred in 29 provinces, cities and autonomous regions such as Jiangxi, Hunan, Hubei and Heilongjiang. They all suffered the accident. Hundreds of millions of people were affected, nearly 5 million houses collapsed, more than 20 million hectares of land were flooded, and economic losses amounted to more than 654.38+06 billion yuan.

2. 1998 Analysis of the main causes of Changjiang River flood;

1998 Summer, it was unusually rainy in the south of China. The continuous rainstorm pressed the Yangtze River with overwhelming momentum, which made the Yangtze River experience the biggest flood since 1954, and there was no chance to breathe for a moment. Floods spread thousands of miles, and almost the whole basin flooded. The flood in the Yangtze River is the direct result of soil erosion caused by deforestation and land reclamation in the Yangtze River basin and excessive occupation of rivers in the middle and lower reaches.

There are 400 million people living on both sides of the Yangtze River. In the mid-1950s, the forest coverage rate in the upper reaches of the Yangtze River was 22%. Due to continuous land reclamation, factory construction and urbanization, 80% of the forests on both sides of the Yangtze River have been cut down. Of the 193 counties in Sichuan Province, only 12 counties have forest coverage rate over 30%, and some counties have forest coverage rate less than 3%. Because of this, 20% of the 6.5438+0.8 million square kilometers of land in the Yangtze River Basin is subject to soil erosion, and 2.4 billion tons of topsoil is lost every year. Every year, more than 500 million tons of soil and sand are carried from the upstream and flow into the East China Sea along the Yangtze River. Due to the accumulation of sediment year after year, the riverbed of the Yangtze River has been above the ground many years ago, becoming another "suspended river" after the Yellow River. The "clear water" of the Yangtze River is long gone, and its "muddy yellow" degree can be "comparable" to that of the Yellow River. On the other hand, lakes with flood storage function in the middle and lower reaches of the Yangtze River are rapidly shrinking. The water area of Dongting Lake decreased from 4,350 square kilometers in 1949 to 2 145 square kilometers, and Poyang Lake decreased by15 in 40 years, and hundreds of small and medium-sized lakes disappeared from the map forever. These are the reasons for the flood of the Yangtze River. In addition, this flood is also closely related to the strongest El Ni? o phenomenon in a century that broke out in 1997. El Nino's strong warm and humid airflow brought heavy precipitation and caused continuous flood peaks in the Yangtze River basin. La Nina, followed by El Nino, suddenly killed the subtropical high that should have moved northward as scheduled, making the flood situation in the main stream of the Yangtze River, which was once relatively relieved, tense again, so that the whole Yangtze River was in a state of emergency. The close relationship between the Yangtze River flood and global warming worries experts-if the concentration of carbon dioxide (CO2) in the atmosphere doubles, the precipitation on the earth will increase by 3%- 15%, and the increase of rainstorm and flood will go hand in hand with global warming.

1998 the Yangtze river flood is undoubtedly warning people that the ecological environment in the Yangtze river basin is in danger and may bring people new great disasters at any time.