[Explanation] Qiantang River is located in Zhejiang Province, China. The tide at its mouth is the Qiantang tide. Every year, many tourists come to watch this wonder.
Every year on the 15th day of the eighth lunar month, the Qiantang River has the largest tide, with the tide head reaching several meters.
A few days ago, the reporter learned at the center of the Qiantang River Basin in Zhejiang Province that the scale of the Qiantang River tide in 2020 will reach the largest in nearly three years.
The Qianjiang tide is affected by the shape of the estuary and other factors: In the "horn"-shaped Hangzhou Bay, the estuary narrows from 100 kilometers to 2.2 kilometers. When a large amount of tide flows in from the estuary, the river surface shrinks rapidly. Produced under the influence of tidal range and wind direction.
Xu Youcheng, chairman of the Qiantang River Tidal Bore Research Association in Zhejiang Province and a professor-level senior engineer, told reporters that from the perspective of landscape, the most admirable tide viewing points are also the most dangerous. Therefore, it is particularly important for various departments to cooperate with each other to do early warning work.
[Concurrent] Xu Youcheng, Professor-level Senior Engineer, Chairman of Zhejiang Qiantang River Tide Research Association
According to what I know, first, from the perspective of viewing, where there is thrilling, there is viewing. Like the resurgence of the old salt warehouses in Qige, Meimeiba, and Haining, including the pockets of the old warehouse in Xincang The tides are very spectacular, so it is very enjoyable from the view point of view, but it is also the most dangerous.
Because these tide forecasting resources are now distributed in different units, relevant departments can understand these situations and strengthen a mutual cooperation mechanism, so that when the tide comes, it is necessary to have a spectacular tide forecast. Landscape, but it must be properly protected and reminded.
[Explanation] Xu Youcheng said that the direction of the Qiantang River tidal bore is greatly affected by topography, but the underwater topography is changeable, which also brings difficulties to early warning.
On September 20th, near the No. 1 dam of Jiuxi, Zhijiang Road, Hangzhou, the tide overflowed the river embankment and washed onto the road. Many cars were hit by the tide. Xu Youcheng was a reporter who explained the tide surge at that time.
[Concurrent] Xu Youcheng, Professor-level Senior Engineer, Chairman of Zhejiang Qiantang River Tide Research Association
After this tidal bore passes from the Qiantang River Bridge, it often depends on the direction and height of the tidal bore. If the height of this year is relatively high, then its momentum will be stronger. Another is the direction of travel. It went in such a direction, and the tide went in this direction. It happened that the terrain was curved and the tide surged up.
(Reporter: What does it mean to go to the tide?) It means that after a body of water has passed, it is difficult for the body of water to spread after hitting this location, and then it directly surges upward.
This direction is mainly determined by the underwater terrain, and it changes every day.
[Explanation] In the 1990s and the beginning of the 21st century, there have been many incidents in Hangzhou and other places where tourists were swept away by the tide on the embankment of the river, causing casualties, leaving a painful lesson.
Xu Youcheng said that in recent years, Hangzhou has adopted a number of measures such as the establishment of a “tide shouting” system to ensure public safety for tide surges, but there is still no unified standard for tide surge data measurement.
[Concurrent] Xu Youcheng, Professor-level Senior Engineer, Chairman of Zhejiang Qiantang River Tide Research Association
We have not explored and studied these laws of Qiantang River tidal wave much. It is a level of basic science and applied basic science, so our understanding of it is not detailed enough.
You are like the tide height, what is the tide height?
In this regard, because the standards are not uniform, it is said that the relevant departments are based on their own understanding when measuring, so he measured such (results), so we often find that the data reported by different departments is different. There may be differences. It may mean that if the standards are unified and reported, there may be differences, but the differences will not be so big.
Therefore, in these aspects, we want to promote all sectors of society to uniformly formulate these standards and promote our own industry standards, our national standards, and even we can formulate world standards.
It is to clarify the scientific definition of tidal wave, which is good for our next early warning and forecasting.
Wang Weichen reports from Hangzhou
Editor in charge: [Li Yuxin]