Introduction of Qionghai characteristics

Geographical location: 5 kilometers southeast of Xichang, Liangshan Yi Autonomous Prefecture, Sichuan Province.

Area: 3 1-28.5 square kilometers

Depth: the maximum depth is 34m, and the average depth is10.32m.

Volume: 320 million cubic meters

Genetic type: subsidence lake

Why: How was Qionghai formed? There are different opinions on this issue. For example, oxbow lake theory, ancient bend lake residual theory, Anning River southeast flowing to ancient river course theory, dammed lake theory; However, the most influential is the Qionghai earthquake settlement theory.

The theory of Qionghai earthquake subsidence began in the ancient book "The Biography of Southwest China in the Later Han Dynasty": "Now it is for foreigners, and it was opened by Emperor Wu of the Han Dynasty, thinking that it is a county. Rarely get into siltation, hence the name Qiongchi. Southerners think He Qionghe. " There is no "Qionghai earthquake subsidence theory" in Hanshu and Shiji written by Sima Qian before Hanshu. Tai Shigong only said in the preface of Historical Records: "So I became a doctor and ordered the westward expedition to the south of Bashu. Nan Luqiong and Yu, from Kunming, also reported their birth. " Joan, Xichang, arrived in Xichang, thus having the above records. Sima Qian, who is famous for his rigorous and informative writing style, will certainly not ignore such a big historical fact as "Qionghai Earthquake".

Mars of the Southern Dynasties wrote Yizhou Story, in which there is a story that a snake was bitten by a basking snake in Du Qiong County to avenge it. "At night, Fang Shili and the city people were trapped in a lake for a while, and the natives called it' trapped lake'. Later, the magistrate of Xichang county compiled the Xichang County Records, which recorded that "the initial earthquake caused the county to sink into mud". So later, there were five quotations from the Book of the New Tang Dynasty, and the earthquakes in two states lasted for eighty days and nights. Crushed 100 people, and those who fell to the ground were three miles away. Later, there was a description in the inscription on Lushan Mountain in the Ming Dynasty that "during the period from Lang to Jiajing, the earthquake collapsed and Duan Citian turned into the sea"; So that the book "Diseases of Counties and Countries in the World" later described that "the theory that the water burst its banks and fell four or five feet, and the outer city of the Acropolis just floated ... fell into the river is almost true"; So that there was Zhou Xun's "Shu Hai Cong Shuo", "Ningyuan Fucheng was hit by an earthquake between Xianfeng Tongzhi, all of which fell into the ground and became a huge flood. Today's government city is the builder of another place after the earthquake; Later, there was a narrative in Macau Daily 1987 "Qionghai Vicissitudes" that "1A great earthquake occurred in the middle of the 7th century and Jianchang City fell into the sea".

There are so many consistent theories about the earthquake subsidence in Qionghai, so the cause of Qionghai is undoubtedly "earthquake subsidence". However, some geological and water conservancy experts said that the above records were not credible.

As mentioned above, Sima Qian wrote Historical Records, but there is no record of the Qionghai earthquake in Xichang. Later, Ye Fan, the author of the Book of Later Han Dynasty, has never been to Sichuan, let alone Xichang, and his native place is far away in Yang Shun, Henan. It is not known whether this theory is reliable. At the same time, the Book of the Later Han Dynasty also said that "a handsome man indulges himself and is hard to control", which shows that the rulers of the Han Dynasty at that time had not completely conquered other nationalities. In this case, the government building could not be located outside the city, and the site of the Western Han Dynasty at Dafendui was probably where Du Qiong was at that time. Because of the existence of the old site, Qionghai earthquake subsidence theory is difficult to establish. The poem "Chronology of Xichang Earthquake" written by magistrate Niu describes the situation after the Xichang earthquake in 1850: "Wei Kun walked in the middle of the night, thunder rumbled, the earth shook and the sea ebbed. The couch is like a dancer, and the leaves of Wanjia Cave House are destroyed. " "When you look at the city late in the morning, you can know who knows this street." Here, it is not described that the whole city sank into the lake. A number of Neolithic sites, unearthed pottery and net pendants around Qionghai in the 1980s show that they were formed in prehistoric Qionghai at the latest, and the site of Xichang City and unearthed cultural relics also show that the theory of "subsidence lake" cannot be established.

Earthquakes may "fall into the city", such as the Tangshan earthquake of 1976, but not all of them. Xichang is indeed an earthquake-prone area. There were several recorded large earthquakes of magnitude 7 or above: in 1 16 BC, the magnitude reached 8-9; AD 1536, grade 7.25; A.D. 1850, 7.5. However, just because there were many earthquakes in Xichang in the past, we can't think that Qionghai was formed by earthquake subsidence. So how was Qionghai formed?

As for the theory of oxbow lake, the theory of ancient bend lake, the theory of ancient channel flowing southeast of Anning River, and the theory of dammed lake, all of them have certain basis, but they are not sufficient and cannot be used as conclusive evidence.

In a word, the origin theory of Qionghai cannot be fully established. The origin of Qionghai is still an unsolved mystery, which needs further study and confirmation by experts in geology, cultural relics and archaeology.

Origin of water source: Where does the water source come from in such a large catchment area? According to experts' research, there are four sources of water in Qionghai: one is the atmospheric precipitation of 3 1 square kilometer on the surface of Qionghai; Second, the surface runoff of Qionghai enters the stream and its regional scope; The third is the underground runoff between alluvium in Qionghai; Fourthly, karst and its fissure water supply.

Ecological characteristics: Qionghai is in a middle trophic level and has been in a state of eutrophication, with pollution elements such as sediment, nitrogen and phosphorus; The annual average water temperature is 65438 07.8℃. There are more than 40 kinds of fish in Qionghai, including unique white fish, carp, prawn and crab. In late autumn and early winter, 19 species of migratory birds come here for the winter with their families. Although it is located in the plateau, its fish fauna is all composed of fish in the river plains of China, which is different from the schizothorax and loach endemic to the Qinghai-Tibet Plateau, but similar to the Chenghai fish in the Jinsha River system. Among the existing fishes, Paragonimus rubripes, Misgurnus brachypodi, Spinibarbus sinensis, Leptospira yunnanensis, Carp, and "Fish Center" with white edges are widely distributed in the upper reaches of the Yangtze River, while carp and crucian carp are widely distributed. 13 species are distributed in Chenghai, Yunnan, and 17 species, such as loach and broadfin fish, are widely distributed in the middle and lower reaches of Changting. Among the fish in Qionghai, only a few species, such as white fish, carp and red snapper, have obvious morphological characteristics.

Description: Qionghai Lake, called Qiongchi in ancient times, belongs to the early Pleistocene rift lake, which has been around 6.5438+0.8 million years. The name of Qionghai can be found in Hanshu: "Du Qiong Nanshan produces copper, and there is Qiongchi Ze"; The Book of the Later Han Dynasty: "People in the south of Qiongchi think that the He Qiong River is twenty miles wide and more than a hundred feet deep, with plenty of fish ..." Qionghai, which is shaped like a snail, is 1 1.5km long from north to south, 5.5 km wide from east to west, 35 km in circumference and 3 1 km2 in water area. The average depth of the lake is 14m, and the deepest part is 34m. Water level1507.14-1509.28m; The fluctuation of water level is small, and the catchment area is about 30 square kilometers.

Qionghai is snail-shaped, with its head at the estuary in the northwest. Length 1 1.5km, width 5.5km, average width 2.7km, and coastline 35km long. The lake basin is pot-bottomed, and the depth from the shore to the center of the lake varies greatly. Most of the water depth is above 15m, and the largest area of the lake is 3lkm2. At the lowest water level, the area is 28.5km2 (water surface elevation 1507. 14m), and the catchment area of the basin is 309km2, with a volume of 320 million cubic meters. Lake sediments are reddish-brown fine mud, which is formed by storm runoff scouring the surface soil and depositing in the lake. The larger rivers are Heqiong River, Guanba River and Ezhou River, among which Guanba River has a large catchment area and can retain water all the year round.

Qionghai Lake is the second largest freshwater lake in Sichuan Province, 7 kilometers away from the city center, located at the northern foot of Lushan Mountain and the north side of Luoji Mountain. It is one of the top ten scenic spots in Sichuan Province. Qionghai water is clear and transparent, with an area of about 3 1 km2.

Qionghai, like some plateau lakes in China, is famous for its tranquility and different scenery in four seasons. In spring, the sky is high and the clouds are light, and the blue waves are boundless. "Sailing on the blue waves, people roam in the world of picture scroll", and the shore is full of eyebrows and cheeks, and the face is whispering. In summer, the lake is bright, the rosy clouds are dazzling, and the mountain temples and fishing villages set each other off. In autumn, the sky is crisp, the sunset is lonely, and the autumn water is eternal, which makes people linger. In winter, the lake is clear, and red maple and cypress trees are reflected on the lake. In the afternoon, the wind blows and the waves are urgent, like white geese playing on the waves.

The charming scenery of Qionghai and the bright moon at night in Xichang form a poetic feeling of "the moon rises out of Qiongchi". For example, after visiting Qionghai, Kyle Polo, a famous Italian traveler, was full of praise for its scenery and was very excited, and wrote in his travel notes "Travels of Marco Polo": "The clear water is beautiful, the vegetation is lush, the fish is rich, the pearls are huge and beautiful, and its climate and tranquility are far better than that of the Mediterranean. It is really the Oriental Pearl. "

For another example, Zhu Qi, a former professor at Central University, wrote after visiting Qionghai: "I have been boating on the West Lake, drumming on Dongting Lake, crossing Taihu Lake and boarding Poyang Lake, feeling the vastness of Dongting Lake, the grandeur of Poyang Lake, the beauty of Taihu Lake, the makeup of calligraphy and the faint of Qiongchi, each with its own advantages. Qiongchi is particularly quiet and wins. " The scenery in Qionghai is so general.

Qionghai is not only beautiful, but also has many wonderful folklore, which highlights its mystery and beauty, such as Mars's Gaizhou Ji and Taiping Magnolia, which are recorded in many works. There are more than 40 kinds of fish in Qionghai, including endemic whitefish, carp, prawn and crab. In late autumn and early winter, 19 species of migratory birds come here for the winter with their families. There are Qionghai Park, Qionghai Hotel, Xintan Fishing Village, Lianchi, Moon Bay, Sunshine Resort, Rosa Rose Garden, Qingliu Temple, Laohaiting Site, Walnut Village Ornamental Garden and Provincial Sports Commission Water Sports School.

In May, 2002, Sichuan Qionghai-Luojishan Scenic Spot was approved by the State Council to be included in the fourth batch of national scenic spots.