Why is August 18 tide-watching day?

According to legend, August 18th of the lunar calendar is the day when Wu Zixu, the tide god, was ordered by the prince of Wu to commit suicide and threw himself into the Qiantang River. August 18 is designated as a memorial tide god. Tides are caused by the attraction of the moon and the sun to the sea water on the earth's surface. The sun, the moon and the earth line up in a straight line around the first and fifteenth day of each month in the lunar calendar. The gravity of the sun and the moon combine to attract the sea water on the earth's surface, so the tides on the first and fifteenth day of each month are relatively large. Especially around the Mid-Autumn Festival, it is the time when the earth is closest to the sun in a year, so the autumn tide around the fifteenth day of the eighth lunar month is the biggest in a year.

Matters needing attention in tide watching

1. Watch the tide in a safe area and obey the management and command of the field staff.

2. Don't climb over the retaining wall to watch and play in dangerous areas such as floodplain, groin and apron, don't swim and play in the river, and don't go into the river at night or in flood season.

3. We should fully understand the dangers of tides. When the tidal bore comes, don't compete with others for position, pay more attention to the surrounding environment and avoid secondary injuries such as trampling.

4. In case of distress, don't panic, call for help in time, and retreat to safety quickly and orderly. Don't covet wealth and lose precious time.

Wu Zixu's contribution and influence

Jianshe gusu

The fief of the State of Wu was in the Taihu Lake Basin in Jiangdong (now southern Jiangsu and northern Zhejiang), and the capital was in Meili in the early stage and in Wu (now Suzhou) in the later stage.

Wu Zixu fully investigated the geographical and hydrological conditions of Wuzhong, saying that "Xiangtu tasted water like heaven and earth", and thought that there were lakes and hills in the west between the hills and plains on the east bank of Taihu Lake, which was not conducive to the March of Chu State and could provide a large number of stones for city construction; Wuzhong Plain, with fertile land and land of plenty, is an excellent rear area.

Wu Zixu has built a big city with a perimeter of 47 miles and an ancient city of Gusu with a perimeter of 10. Wu Zixu has also made great contributions to Suzhou's water conservancy construction. The excavation and dredging of Xu Xi and Xupu not only avoided floods in Wuzhong area, but also facilitated local water transportation and irrigation. The new capital includes two cities, a big one and a small one. "He Greentown" is nearly 20 kilometers in circumference, located in Suzhou, Jiangsu Province, nearly 4 kilometers as the Acropolis "He Greentown", on the north bank of Taihu Lake, at the junction of Wuxi and Changzhou in Jiangsu Province.

Water conservancy construction

Wu Zixu led many people to dig the first artificial canal in history-Xujianghe. The emergence of Xujiang not only avoided the flood in Wudi, but also facilitated the local water transportation and irrigation, which was of great significance to the livelihood development of local people. The saying that Xujiang River is dredged by Wu Zixu can be traced back to the Song Dynasty. Qian Gongfu was quoted in the Water Conservancy Records of Wuzhong written by Yixing, a water conservancy scientist in the Song Dynasty, in the fourth year of Yuan Dynasty (1089): "Since the Spring and Autumn Period, He Lv, the king of Wu, used Wu Zixu's plan to cut Chu and open this river in four years (51year ago) to transport grain in spring and summer.

Xu Jianghang was of great significance at that time, and Wu's shipmaster could directly appear in the great river near Wuhu City, Anhui Province. According to legend, in that year, the 60,000 water army of Wu started from Taihu Lake, quietly marched westward along Xu Xi, and suddenly appeared in front of the Chu army in Chaohu Lake. As a result, five wars and five wins, and Chu was defeated.