Yangtze River History – Change of Estuary

Yangtze River History – Brief Introduction of the Estuary

According to some data, the estuary of the Yangtze River was located in today's Yanghzou and Zhenjiang area about 5000 to 6000 years ago. In West Han Dynasty (about 2000 years ago), the estuary of the Yangtze River was still located at Yangzhou and Zhenjiang area. But at that time, the river was about 20 kilometers wide at the estuary part, and the sea tide could come here and formed billowy tide, which was named "Guangling Tide" in history. At that time, the effect of the tide has reached Jiujiang area, which was 200 kilometers away from the tide line. At that time, the whole Yangtze River estuary looked like a triangle bay. The shape looked like today's Hangzhou Bay, near to tuba form. This form kept to middle period of Tang Dynasty (8th century), without great change. At that time, there was a reef located on the south side of Jiao Mountain in Yangtze River area, which was named "Haimen (the Gate of Sea) Mountain. It proved that people at that time regarded there as the estuary of the Yangtze River. Although Yangtze River Basin is one of the ancient culture birthplaces and already planted rice for four or five thousands years, the population in Tang Dynasty was small and which was not effective for the agriculture development. So the plants, water and soil in Yangtze River Basin were well protected, and the inner side of the Yangtze River estuary moved to the sea slowly. After the middle period of Tang Dynasty, as the western population largely moved to Yangtze River Basin which caused the silt in Yangtze River became more, the shape of the Yangtze River estuary changed to today's shape.

Yangtze River History – River Course of the Estuary

The river course at the Yangtze River estuary can be divided into three levels: it was divided into South Branch and North Branch by the Chongming Island; then the South Branch was divided into South Port and North Port by Changxing Island and Hengsha; then the South Port was divided into South Passage and North Passage by Jiuduansha. The islands and beaches in Yangtze River estuary were formed by the silt accumulation in Yangtze River.

Yangtze River History – Runoff of Yangtze River Estuary

Before 18th century, most of Yangtze River runoff flow into the sea by North Branch. After 18th century, the runoff of the Yangtze River was changed to flow into the sea by South Branch. Until early of this century, there was 25 percents runoff flow into the sea by the North Branch. To the middle of this century, the water power condition in Yangtze River estuary changed: the North Branch became a passage which take advantages of tide, and the runoff of Yangtze River almost don't flow into North Branch, except in flood season. It caused the North Branch can't navigate. On the contrary, it also makes the management in the South Branch become harder.

The change of the Yangtze River estuary is an important part of Yangtze River history, which is closely related with the development of the Yangtze River and Yangtze Cruises.