Why is the middle and lower reaches of the Yangtze River prone to floods?
2. Topographic factors: the rainstorm has a large confluence area, many tributaries, flat terrain, curved rivers and poor drainage, and is sandwiched between the north and south hills and mountains.
3. Human factors:
1) The vegetation in the upper reaches is seriously damaged, soil erosion, sediment deposition in the lower reaches and river bed elevation affect flood discharge.
2) Reclaiming land around the lake reduces the lake area and weakens its flood storage capacity.
Governance measures:
1. Strengthening dike construction, river regulation and reservoir engineering construction are direct measures to avoid flood disasters.
2. Long-term and lasting implementation of soil and water conservation can fundamentally reduce the probability of floods.
3. Scientific flood and weather forecast and reasonable flood storage and detention area planning can reduce the loss of flood disasters.
4. Establishing emergency system for flood control is the last measure to reduce disaster losses.
Extended data
The formation process of the middle and lower reaches of the Yangtze River;
The plain in the middle and lower reaches of the Yangtze River is located in the fold and fault depression zone of the Yangtze River paraplatform. The Yanshan movement produced a series of fault basins, which were cut, connected and alluvial by the Yangtze River, forming the whole plain in the middle and lower reaches of the Yangtze River today.
Under the influence of neotectonic movement, the Cretaceous-Tertiary red beds and Quaternary red beds on the edge of the plain rose slightly and were cut into red mounds with a relative height of 20-30 meters by running water, while the central and coastal areas along the river continued to fall, forming floodplains and coastal plains.
Flood distribution in China:
The main flood areas in China are located in the east of Daxing 'anling-Taihang Mountain-Wuling Mountain.
According to historical waterlogging statistics, the most serious waterlogging areas are mainly the southeast coast, Hunan and Jiangxi provinces and Huaihe River basin, followed by the middle and lower reaches of the Yangtze River, Nanling, Wuyishan, Haihe River and Yellow River, Sichuan Basin, Liaohe River and Songhua River. The areas with the least rainfall and waterlogging in China are Northwest China, Inner Mongolia and Qinghai-Tibet Plateau, followed by Loess Plateau, Yunnan-Guizhou Plateau and Northeast China.
Generally speaking, the distribution of rain and waterlogging is characterized by more in the east and less in the west; There are many coastal areas and few inland areas; There are many lakes in the plain and few mountains in the plateau; There are many slopes in the east and south of the mountain range, but few in the west and north.
Baidu Encyclopedia-Plain in the Middle and Lower Reaches of Yangtze River
Baidu encyclopedia-flood
Edited on 2019/05-30.
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