When will the Yangtze River Basin’s main branches and tributaries enter the main flood season?

The flood season of the Yangtze River is consistent with precipitation. There are three relatively concentrated periods of rainfall: spring flood season (April to May), summer flood season (June to August) and autumn flood season (August to October).

The southeast monsoon and southwest monsoon, which carry large amounts of water vapor from the Pacific and Indian Ocean respectively, prevail in the Yangtze River Basin in summer and around summer. When the monsoon advances and retreats and the cold and warm air currents collide, precipitation is formed. In mid-June, the ridge line of the subtropical high jumps to 20° to 25° north latitude, and the middle and lower reaches enter the plum rain season.

In mid-July, plum blossoms bloom in the area and drought weather begins. In and around winter, cold and dry cold air originating from the polar regions and high latitudes in Asia prevails in the basin, resulting in very little precipitation. The average annual precipitation in the Yangtze River Basin is nearly 1100mm.

The rainy season is from April to October, and its precipitation can account for 85% of the annual precipitation. In the basin, except for the Jinsha River above Baiyu and the tributary Yalong River above Luhuo, heavy rains occur from time to time in the rest of the vast area of ??1.5 million km2. Extended information

The Yangtze River is the richest river in China, with a total water resource of 961.6 billion cubic meters, accounting for approximately 36% of the country's total river runoff, which is 20 times that of the Yellow River. It ranks third in the world after the Amazon River and the Congo River (Zaire River) in the equatorial rainforest zone.

The Paraná-La Plata River in South America and the Mississippi River in North America, which are located in similar latitude zones as the Yangtze River Basin, have basin areas larger than those of the Yangtze River, but the water volume is much less than that of the Yangtze River. The former It is about 70% of the Yangtze River, and the latter is about 60% of the Yangtze River. ?

The total water resources in the Yangtze River Basin are 961.6 billion cubic meters, including 951.3 billion cubic meters of surface water resources, 246.3 billion cubic meters of groundwater resources, and 236 billion cubic meters of duplicate water. Due to the large population in the basin, the per capita water volume is 2760m3, which is only 1/4 of the world's per capita water volume. The water resources characteristics of the Yangtze River are mainly reflected in the spatial and temporal distribution of river runoff. The surface water resources in the basin account for 99% of the total water resources.

In surface water resources, river runoff accounts for more than 96%. River runoff during the flood season generally accounts for 70% to 75% of the annual runoff. The distribution of runoff areas is also very uneven. The water production per unit area is the smallest in the Jinsha River and Han River systems, and the largest in the Poyang Lake and Dongting Lake systems. By administrative region, Qinghai and Henan are the smallest, and Hunan is the largest.

Reference: Baidu Encyclopedia-Yangtze River