Safety measures to be paid attention to in watching tide in Qiantang River in senior high school geography

Matters needing attention in watching tide in Qiantang River

Due to the comprehensive factors such as waterway, high riverbed and meteorology, the tide of Qiantang River is coming rapidly this year. For the upcoming tide-watching festival, remind tide watchers that the tidal bore of Qianjiang River can be viewed from a distance, but not from a close distance. According to the characteristics of the tidal bore in Qiantang River, the spectacular tidal scene is often a dangerous place, and the advancing speed and destructive ability of the tidal bore can not be confronted by flesh and blood. When the tidal bore comes, people must not compete with it, lest people be washed away by the tide and cause casualties. In addition, don't go down the dike pond to watch the tide on the river beach and groin. The entrance and exit left on the standard dike pond is necessary for the inspection and maintenance of the dike pond, and the concrete platform on the waterfront side of the dike is a part of the dike pond structure, which is by no means for people to watch the tide and swim. To avoid the tide below the bend, the tide in this place often rushes to the pond and can't dodge. It is necessary to obey the dissuasion and command of the police and observe the order of tide watching.

Brief introduction of tide watching

Tidal bore is also called tide, which is called tidal bore during the day and tidal bore at night. Tidal bore is one of the rare natural phenomena in the world. Abroad, it only occurs in a few estuaries, such as the Seine River in Britain, the Seine River in France and the Amazon River in South America, but it is not as typical and spectacular as the tidal bore of Qiantang River in China.

The spectacular Qian Jiangchao is not only influenced by the gravity of the moon and the sun, but also related to the trumpet-shaped mouth of Qiantang River. When a large number of tides flood in from the mouth of Qiantang River, because the river surface shrinks rapidly, the tides can't rise evenly, so the back waves push the front waves, and the front waves can't run fast, and the back waves catch up and overlap with each other. Secondly, it is related to excessive sediment deposition under the Qiantang River, which plays a role in blocking and rubbing the tidal current, making the front slope of the tidal current steep and gentle, forming a tidal bore with the back wave chasing the front wave, wave after wave, and wave after wave.

Due to the huge energy released by tidal wave breaking, the tidal bore advances very fast, generally reaching 5 to 7 meters per second, 12 meters per second, and the maximum tidal difference is 8.93 meters. According to the calculation, a huge tidal bore can have a pressure of 7 tons per square meter, so pay attention to safety when watching the tidal bore. It is forbidden to watch the tide not only at the dam head, dam crest and cliff, but also far away from the dam root even on the seawall levee. Generally, it is forbidden to watch tides within the range of10m in the south of dam and 40m in the north of dam. If you watch the night tide, stay away to ensure safety. And we must obey the management and command of the public security department.

The tide-watching style of Qianjiang was formed as early as the Tang Dynasty, especially in the Southern Song Dynasty. At that time, the imperial court focused on the eighth day of the eighth lunar month (according to legend, it was the birthday of the tide god), which later became a traditional festival.

Tide watchers should enhance their awareness of self-protection

One is the great power of the tides. The tidal bore in Qiantang River has two climaxes a year, namely the vernal equinox and the autumnal equinox. There are two flood seasons in January, which appear two or three days after the first day and the fifteenth day of the first lunar month. There are two orgasms a day, with an interval of 12 hours. The tidal head of a tidal bore is generally 1-2 meters high and can reach 3 meters, and it advances from downstream to upstream at a speed of about 20 kilometers per hour. Every year, the tides around August 18 of the lunar calendar are the most spectacular, and special tidal bore such as first-line tide and resurgence can be seen. There is also a dark high tide at ordinary times, which is calm and imperceptible in the distance, but it is overwhelming, hidden and dangerous when it is near.

Second, tidal watchers and activists along the river lack understanding of tides, and their safety awareness and vigilance are not high. Many accidents are caused by people's lack of understanding of the danger of tidal bore in Qianjiang, or by people's ignorance of the danger. The outstanding performance is that many foreigners turn a blind eye to the warning signs and signs specially used for the inspection and maintenance of dikes and ponds next to the entrance gate, cross at will, go to the beaches and groins to play, enjoy the cool, and even go swimming and bathing in the river.

Judging from the accidents that have happened over the years, the victims are mostly foreigners and students. Therefore, tide watchers should enhance their awareness of self-protection and pay attention to the following three points:

First, we should fully understand the fluctuation law and habits of tidal water in Qiantang River, especially the harm of tidal water. Water in Qian Jiangchao is not only supplied on the 18th day of the eighth lunar month, but also four days a year. Pay attention to the flood season information of Qiantang River released by the media.

Second, we should choose safe areas and lots for tidal observation and activities, pay attention to warning signs and obey the management of managers. Pay attention to the warning signs on the dams along the river and strictly abide by them. To obey the management command of the management personnel, stop in the designated area to watch the tide. Don't cross the fence to the floodplain, groin and other places. Go to play and enjoy the cool. Don't swim or bathe in the river.

The third is to master the method of self-help. In the face of danger, don't panic, quickly and orderly retreat to safety, and immediately call for help to the surrounding staff or others. When you leave, don't lose the precious opportunity to save yourself in order to save your property. In case of falling into the water or being hit by the tide, try to grasp the fixtures around you to prevent them from being swept away by the tide. In case of emergency, people around should take rescue measures quickly and call 1 10 to call the police.

Seven dangerous tidal observation points in Qianjiang River

The tidal bore of Qiantang River starts from the sea surface of Gaoyang Mountain below Dajianshan, and the initial tidal bore height is about 0.2-0.3 meters. When the tidal wave propagates in the mouth of Qiantang River, it enters the narrow trumpet mouth. Due to topographic factors such as river bed elevation, when the water turns from deep to shallow, tidal waves push to the vicinity of the big gap in Xiaojianshan, and the two tidal waves meet, and the energy increases greatly, which makes the tidal waves deform sharply and form transverse tides. Therefore, the big gap is the first danger point of tide watching. After the cross tides converge, they move upstream, forming a first-line tide in Yan Guan. Qiantang River turns at the old salt warehouse, so a tidal surge hits the seawall and turns back rapidly, forming a turning tide. This is the second danger point. When the tide rushes to the Beauty Dam, there are two dangerous points because the seawall turns. Meinvba has suffered many tidal injuries. Qiantang River turns again at Qige, which is another dangerous point for tide watching. Besides the Three Treasures, Jiuxi should be a very dangerous place. You should be extra careful at these dangerous points, and of course you should be careful when watching tides in other places.

Please ask relevant employees of all departments to study and strengthen ideological safety education to avoid related accidents.