Poyang Lake I. Geographical location Poyang Lake is located at 28 22 ′ to 29 45 ′ north latitude and 115 47 ′ to 116 45 ′ east longitude. Located in the north of Jiangxi Province, the south bank of the middle and lower reaches of the Yangtze River. Poyang Lake, bounded by Songmen Mountain, is divided into north and south parts. The north part is the river inlet, which is 41 kilometers long, 3 to 5 kilometers wide and about 2.8 kilometers at its narrowest point. The main lake is in the south, with a length of 1.33 kilometers and a widest point of 74 kilometers. 2. Poyang Lake, the largest freshwater lake in China, is 173 kilometers long from north to south, 74 kilometers wide from east to west, with an average width of 16.9 kilometers, a coastline of 1,211 kilometers, a lake body area of 3,283 square kilometers (the water level at the mouth of the lake is 21.71 meters), an average water depth of 8.4 meters, a deepest depth of about 25.1 meters and a volume of about 27.6 billion cubic meters. It accepts five major rivers: Ganjiang, Fuhe, Xinjiang, Raohe and Xiuhe. After storage, it flows into the Yangtze River, the largest river in China, from Hukou, and the amount of water flowing into the Yangtze River exceeds the sum of the water of the Yellow River, Huaihe River and Haihe River every year. It is a seasonal and throughput lake. Poyang Lake drainage system covers an area of 162,211 km2, accounting for 97% of the drainage area in Jiangxi Province and 9% of the drainage area in the Yangtze River. Its annual runoff is 152.5 billion cubic meters, accounting for about 16.3% of the annual runoff in the Yangtze River basin. Third, the natural landscape of "low water line, flood" The average water level of Poyang Lake for many years is 12.86 meters, the highest water level is 22.59 meters on July 31, 1998, and the lowest water level is 5.91 meters on February 6, 1963 (Hukou Hydrological Station, Wusong Base). During the year, the water level varied from 9.79 to 15.36 meters, and the absolute water level varied to 16.69 meters. With the change of water quantity, the water level of Poyang Lake rises and falls greatly, which has the function of natural flood regulation and storage. Because the water level fluctuates greatly, the lake area changes greatly. During the flood season, the water level rises, the lake surface increases sharply and the water surface is vast; During the dry season, the water level drops, the beach is exposed, and the water flows back to the trough, leaving only a few winding waterways on the lake. It has a natural landscape of "a dry line, a flood". Iv. Historical Evolution In ancient times, Poyang Lake was called Peng Lize, Guanting Lake and other names. After a long historical period, Peng Lize expanded to the south under the long-term development of geology, meteorology and hydrology, and the lake crossed Songmen Mountain to reach the vicinity of Boyang County, so it was renamed Poyang Lake. Before the lake invaded south, it was originally a densely populated Xiaoyang Plain to the south of Songmen Mountain. With the continuous invasion of the lake, Xiaoyang County and Haihun County in Poyang Lake Basin were successively submerged in the water. In history, there was a saying that "Shen Xiaoyang started from Duchang and Shen Hai fainted from Wucheng". Poyang Lake, with vast misty waves and vast waters, has undergone a long evolution, forming the embryonic form of modern Poyang Lake about 1,611 years ago, just like a huge treasure gourd tied to the belt of the Yangtze River. V. Poyang Lake, an internationally important wetland, is an important storage lake in the main stream of the Yangtze River. It plays a huge special ecological function such as flood storage and biodiversity protection in the Yangtze River basin of China. It is one of the top ten ecological function protection zones in China and one of the important ecological zones in the world designated by the World Wide Fund for Nature. It plays an important role in maintaining regional and national ecological security. 6. "White Crane World" and "Rare Bird Kingdom" Due to the influence of warm and humid southeast monsoon, Poyang Lake has an average annual rainfall of 1,636 mm, thus forming a humid monsoon climate of "Zeguo Fangcao Bibi, Plum Yellow in Smoke and Rain" and becoming a famous land of fish and rice. The environment and climatic conditions here are suitable for migratory birds to overwinter. Therefore, in late autumn and early winter (October) every year, thousands of migratory birds fly from Siberia, Mongolia, Japan, North Korea, northeast and northwest China, until the next spring (April). Today, there are more than 311 species of birds in the nature reserve, with nearly one million birds, including more than 51 rare birds, making it the largest bird sanctuary in the world. It is especially gratifying that the largest crane colony in the contemporary world has been found here. In 2112, the total wintering population reached more than 4,111, accounting for more than 95% of the total number of cranes in the world. Therefore, Poyang Lake is called "the world of white cranes" and "the kingdom of rare birds". VII. Humanities and History Poyang Lake Basin has been a rich area with relatively developed economy in China since ancient times. Many outstanding figures in Chinese history, such as Xu Zhi, Tao Yuanming, Lin Shihong, Liu Shu, Hong Shi, Jiang Wanli and Zhu Da, once lived in the lake area. There have been many heroic deeds here, such as Zhou Yu's naval training, Zhu Yuanzhang's water war with Poyang Lake in Chen Youliang, and Li Liejun's "second revolution" at Hukou. Poyang Lake is the only waterway that entered Jiangxi from the north in ancient times, and the anecdotes and folklore of scholars on Poyang Lake are even more numerous. Wang Bo, a poet in the Tang Dynasty, wrote a famous sentence in Preface to Tengwang Pavilion: "Fishing boats sing late, ringing on the shores of Peng Li", which describes the happy scene of fishermen returning from fishing on Poyang Lake. Su Shi, a poet in the Song Dynasty, wrote "The mountains are grey, the water is boundless, and the elder sister-in-law and younger sister-in-law are in the middle of the river" in his poem "Li Sixun Painting the Island of the Yangtze River", which describes the scenic spot of Poyang Lake. There are many famous mountains and beautiful islands on Poyang Lake. Shi Zhongshan and Dagushan in Hukou County, Nanshan and Laoye Temple in duchang county, and Luoxingdun in Xingzi County are picturesque and pleasant. Jiujiang Tourism Bureau has connected all the scenic spots on Poyang Lake into a line through cruise ships, that is, Poyang Lake water tourism line. Dongting Lake, one of the five largest freshwater lakes in China, is an important throughput lake in the middle reaches of the Yangtze River. Tectonic lake. The Lake District is located on the south bank of Jingjiang River, across Hunan and Hubei provinces, between 28 □ 31 ′ ~ 31 □ 21 ′ north latitude and 111 □ 41 ′ ~ 113 □ 11 ′ east longitude. The lake area is 8,781 square kilometers, the natural lake area is 2,741 square kilometers, and the inner lake area is 1,211 square kilometers. Geology and geomorphology Dongting Lake was formed by Yanshan movement fault depression. Since the Quaternary, it has been in oscillating negative movement, forming a dish-shaped basin with high periphery and low middle. There are island-like mountain protrusions of about 511 meters, such as Taohua Mountain, Taiyangshan Mountain and Taifushan Mountain. The elevation of hills around the lake is below 251 meters, and those below 121 meters on the lakeside hills are erosion terraces, and those below 61 meters are bases and accumulation terraces. The accumulation plain in the middle part, which consists of lacustrine deposits, alluvial rivers and lakes, estuary deltas and outer lakes, is mostly 25-45 meters, showing the landscape of water network plain. It is divided into west, south and east Dongting Lake. The ground at the bottom of the lake slopes slightly from northwest to southeast. The average annual temperature in the climate and hydrological lake area is 16.4 ~ 17℃, 3.8 ~ 4.5℃ in October, and the absolute lowest temperature is -18.1℃ (Linxiang, October 31, 1969). At around 29℃ in July, the absolute maximum temperature was 43.6℃ (Yiyang). The frost-free period is 258 ~ 275 days. The annual precipitation is 1,111 ~ 1,411 mm, which decreases from the peripheral hills to the inner plains. Rainfall from April to June accounts for more than 51% of the total annual precipitation, mostly heavy rain and rainstorm; If all flood peaks gather together, it is easy to cause floods, waterlogging and waterlogging. There are four ports in Dongting Lake, Songzi, Taiping, Ouchi and Diaoxian (blocked in 1958), which discharge the Yangtze River. In the east, south and west, water from Hunan, Guizhou, Yuan and Li directly pours into the lake, forming an asymmetric centripetal water system with abundant water, large annual runoff variation, uneven annual runoff distribution, long flood season and frequent floods. The average annual runoff of Chenglingji is 312.6 billion cubic meters, the maximum annual runoff is (1945) 526.8 billion cubic meters, and the minimum annual runoff is (1978) 199 billion cubic meters. During the flood season (May to October), the runoff accounts for 75% of the average annual runoff; Among them, four ports have a volume of 116.4 billion cubic meters, accounting for 48.5% of the total runoff in flood season. The water level of Dongting Lake began to rise in April, and reached the highest level in July-August, and the dry season was from October to March of the following year. The maximum water level variation for many years, Yueyang reached 17.76 meters. Known as "a large flood, a few lines of low water", "frost falls in the cave and dries up". In 1954, a severe flood occurred in the middle reaches of the Yangtze River, and Dongting Lake was able to reduce the flood peak, showing the lake's storage function. However, among the lakes where many waters converge, only one mouth of Chenglingji flows out, and the flood has stopped for a long time, and a large amount of sediment is deposited. The average sediment entering the lake for many years is 33.5 million cubic meters, of which 18 million cubic meters comes from the Yangtze River, accounting for 82.1%, and 24.1 million cubic meters comes from Sishui, accounting for 18%. The output of Chenglingji only accounts for 25.1% of the sediment entering the lake, and the sediment deposited in Dongting Lake accounts for 25.1%. The average annual siltation is ten times larger than that of Poyang Lake. Since the 1971s, the siltation at the mouth of the Three Mouths has been high, and the amount of water entering the lake has decreased. However, the natural continental soil of the Yuan and Li spillway has grown tremendously, with the siltation at Muping and Qili lakes reaching 2-4 meters each, and the siltation at the north of South Dongting Lake reaching 2 meters. The mouth of Zhuzi River in East Dongting Lake extends eastward and the floating tail reaches Junshan. Therefore, the flood storage capacity of the West Dongting Lake basically disappeared, the South Dongting Lake moved to the south, and the East Dongting Lake eroded eastward, and the storage function tended to decline. During the pre-Qin-Han-Jin period, due to the uninterrupted extension of the river delta into the lake, the lake surface was divided and narrowed, and there were beaches and separated lakes on the edge of the lake area. From the 4th century to the 9th century, Dongting Lake continued to slowly subside, and the Dongting Lake system was influenced by the diversion of the Yangtze River southward. Dongting Lake has been expanding eastward, and it reached its heyday in the light-year period of the Qing Dynasty (1825), with a circumference of more than 411 kilometers and a flooded lake surface of more than 6,111 square kilometers. Over the past hundred years, the Yangtze River has burst southward several times, forming a situation of four streams. The river carries a lot of sediment into the lake, and the lake is rapidly silted up and shrunk. The existing water area is less than half of its heyday, and it has retired to be the second largest freshwater lake in China. Since 1981s, the west Dongting Lake and the south Dongting Lake (north) have been evolving towards swampiness. Economic Overview Dongting Lake area has become one of the important commercial grain bases and one of the key freshwater fishing areas in China after the three-stage farmland capital construction centered on water control in 1954, 1964 and 1971s. The lake is dominated by sedentary fish, including 114 species of saltwater migratory fish and semi-migratory fish in rivers and lakes, belonging to 12 orders, 23 families and 71 genera, with CYPRINIDAE as the main species, accounting for 55.3%. The main economic fish are grass, silver carp, bighead carp, bighead carp, bream bream and bighead carp. Reed is spread all over Huzhou, covering an area of 61,111 hectares, 91% of which is used for papermaking. There are 147 navigable rivers in Dongting Lake area, with a navigable mileage of 3,276 kilometers, and 75 navigable rivers in normal years, of which 16 are main waterways, accounting for 996 kilometers. In addition, Chenglingji was changed into a foreign trade port in 1981 with a design capacity of 2 million tons. Taihu Lake, formerly known as Zhenze, also known as Lize, is a relic of an ancient coastal lake, located at the junction of Jiangsu and Zhejiang provinces and in the south of the Yangtze River Delta. About 1 million years ago, Taihu Lake was still a big bay, but later it was gradually isolated from the sea and turned into an inland lake in the process of desalination. Taihu Lake, with an area of 2,425 square kilometers and a coastline of 411 kilometers, is the third largest freshwater lake in China. Taihu Lake is a large shallow water lake in the plain water network area. The lake area claims to have 48 islands and 72 peaks, with beautiful lakes and mountains, which set each other off. It has natural beauty without carving and is called "Taihu Lake is the best in the world". Wuxi landscape, Suzhou gardens, Dongshan and Xishan in Dongting, Wuxian, and Dongting World in Yixing are all famous tourist attractions in Taihu Lake area. Taihu Lake is located in the center of the water network in the south of the Yangtze River, with large storage capacity and relatively stable water level, which is beneficial to irrigation and shipping. Taihu Lake Basin has a total area of 36511km2 and a population of 34 million, accounting for about 1/8 of the country's gross national product with less than 1.4% of the country's land area. The level of urbanization ranks first in the country, the township industry is developed, the grain output accounts for 3% of the country, and the output value of freshwater fish industry also accounts for a high proportion. Taihu Plain has a mild and humid climate, dense water network and fertile soil. It is an important commodity grain base and one of the three silkworm bases in China, and is known as the "land of plenty". Taihu Lake is the largest lake in the eastern coastal area of China and the third largest freshwater lake in China. Taihu Lake is famous at home and abroad for its beautiful lakes and mountains and splendid cultural landscape. It is a famous scenic spot in China and attracts a large number of Chinese and foreign tourists to visit here every year. Taihu Lake is located in the center of the fertile triangle of Shanghai, Nanjing and Hangzhou. It is a lake formed by silting up the ancient bay in the lower reaches of the Yangtze River and Qiantang River. Around it, there are stars holding the moon, such as Dianling Lake Group, Yangcheng Lake Group and Taoge Lake Group. The criss-crossing rivers, rivers, streams and blasphemies connect Taihu Lake with the surrounding lakes and lakes, forming a distinctive water town in the south of the Yangtze River. Taihu Lake is known as "36,111 hectares, surrounded by 811 Li", but its actual area is affected by factors such as siltation and artificial reclamation, and it has changed a lot since its formation. Today, Taihu Lake borders Wuxi in the north, Huzhou in the south, Yixing in the west and Suzhou in the east, with a water area of about 2,251 square kilometers. Although the area of Taihu Lake basin is smaller than that of Poyang Lake and Dongting Lake, it has a mild climate and abundant specialties, and has been a famous land of fish and rice since ancient times. Taihu Lake is rich in aquatic products, rich in fish and shrimp, known as "Taihu Lake is 811 miles long, and fish and shrimp are inexhaustible". Taihu County Taihu County is located in the southwest of Anhui Province, at the southern foot of Dabie Mountain and on the north bank of the Yangtze River. It faces Tianzhu Mountain in the east and Lushan Mountain in the south, ranking above the tourist hotline in the middle and lower reaches of the Yangtze River. Hejiu Railway, 115 National Road and Shanghai-Chengdu Expressway pass through the territory, and the traffic is very convenient. It only takes 2 hours to drive to Hefei, Wuhan, Nanchang and other large and medium-sized cities. The county governs 15 townships with a population of 561,111 and a total area of 2,131 square kilometers. Taihu Lake has a long history and outstanding people. Throughout the ages, the folk customs were honest and the style of writing became more and more obvious, and it was known as "four scholars in one door, two champions in ten miles". This is the hometown of Zhao Puchu, the late Vice Chairman Chinese People's Political Consultative Conference, a famous social activist and an outstanding patriotic religious leader. The famous poet Zhu Xiang, the female social activist Liu Wangming, Ye Chunshan, the founder of Ye School of Peking Opera, Ma Lan, a performer of Huangmei Opera, writer Heather and Ma Dapu, an expert in forestry, are all from Taihu Lake. They have made great achievements and gained wide fame, adding luster to their hometown. Today, the hometown of the champion is full of education and students all over the world. Taihu Lake has beautiful mountains and rivers and pleasant scenery. The four scenic spots "Night Rain in Longshan, West Wind on the Road, Bambusa Fahua and Mysterious Gu Song" have been well-known since ancient times. Cultural relics such as Haihui Temple built in the Han Dynasty, Shangge City built in the Three Kingdoms, Fotu Temple built in the Jin Dynasty, Xifeng Temple built on behalf of the Tang Dynasty, and the tomb of Zhao Wenkai, the champion of the Qing Dynasty, are well preserved. The national Buddhist activity place and the birthplace of Zen Buddhism in China are under construction. At that time, Liu Bocheng and Deng Xiaoping hosted the Hushi New Temple, the former site of the Gao Qian Conference, in Liu Fan, which was of great significance. Zhaohe Tangwan Hot Spring has a water temperature of 47℃ all the year round and a sunrise volume of 1,511 tons. The water quality is clear, and it can be drunk, bathed and treated. Huating Lake, located in the hinterland of the county center, is a national key scenic spot with a total area of 251 square kilometers and a magnificent water surface of 1 million mu. The lake is dotted with islands, surrounded by mountains and fruit trees, and is a resort for tourism, recuperation and leisure. Taihu Lake is rich in resources and has many special products. Here is the base county of national commodity grain, commercial cattle and lean pig and the key production county of tea, chestnut and citrus in Anhui Province. Tianhua Gujian tea is a superior product and has been awarded the national green food label. Bambusa orientalis fans and Tianhuajian sealed wine are provincial famous brand products, and special products such as motor, daily-use fine porcelain, tipping paper, woolen sweater, canned chestnut, dried Li Du tea and lycopene are well-known throughout the country and exported overseas. There are more than 21 kinds of mineral resources such as quartz stone, purple sand rock, porcelain clay and iron sand in the territory. Since the reform and opening up, the county's economy and various social undertakings have made unprecedented achievements. Comprehensive county power has been significantly enhanced, infrastructure has been improved day by day, people's lives have been significantly improved, and the city