Historical facts about the Pearl River Delta

The Pearl River in China is a delta formed by alluvial deposits in the middle of Guangdong. It consists of three small deltas: Xijiang River, Beijiang River and Pearl River Delta, covering an area of about 1. 1.3 million square kilometers. The Xijiang River and Beijiang River Delta account for110. There are more than 160 bedrock mounds in the delta, which were originally islands in shallow bay about 6000 ~ 2000 years ago. There is not much sediment in the Pearl River, and the annual total sediment is only 65438+ 100 million tons. Shallow bays with many islands are conducive to sediment stagnation, so the delta has developed rapidly in the past 2000 years. Canqiu is 300 ~ 500 meters above sea level and often becomes a beautiful scenic spot, such as Xiqiao Mountain, Wugui Mountain and Yashan Mountain. Located in the southeast of Guangdong Province, at the lower reaches of the Pearl River, adjacent to Hong Kong and Macao, across the sea from Southeast Asia, with convenient land and water transportation, it is known as the "South Gate" of China. Formerly known as Yuejiang Plain. The Pearl River Delta for short. Located in the eastern coast of Guangdong Province, China, it is a delta complex with radial estuary, which is the general name of the large delta formed by simultaneous alluvial of Xijiang River and Beijiang River and the small delta formed by alluvial of Dongjiang River. It is an inverted triangle, with the bottom line starting from Sanshui City in the west, Guangzhou City in the east, and Shilong, with the apex at Yamenwan. The Pearl River Delta with an area of about 1. 1 10,000 square meters. Alluvium is thin, generally 20 ~ 30 meters. The ground fluctuates greatly, surrounded by hills, mountains and islands, accounting for 30% of the area. The central part is plain, distributed in southern Guangzhou, northern Zhongshan, eastern Jiangmen and western Humen. The annual sediment transport capacity of the Pearl River system is more than 80 million tons, and the delta near the estuary is still extending to the South China Sea. Hekou District can extend 65,438+00 ~ 65,438+020 meters every year, which is one of the key reclamation areas in China. The delta has a subtropical climate, which is warm and humid all year round. The annual average temperature is 2 1 ~ 23℃, with the highest Leng Yue 13 ~ 15℃ and the hottest month above 28℃. There are frequent typhoons from June to 10, with concentrated rainfall and the hottest weather. The annual average precipitation exceeds1500mm. The rainy season is synchronized with the high temperature season, with fertile soil and rivers, which is beneficial to agriculture. The yield per unit area of rice is among the best in China. Tropical and subtropical fruits include litchi, citrus, banana, pineapple, longan, carambola, mango, grapefruit and lemon. Three-dimensional agricultural structures such as mulberry-based fish ponds, fruit-based fish ponds and sugarcane-based fish ponds have been developed, which has become a model of ecological agriculture in China. There are sugar, silk, food, paper, machinery, chemicals, building materials, shipbuilding and other industries, known as the pearl of the South China Sea. At present, there are nearly 100 large waterways in the delta, and there are more smaller ports interwoven into a network. The Pearl River enters the sea through eight gates respectively. There are often residual hills at the sea, and the situation is dangerous, which is called "door". The famous ones are Humen, Modaomen and Yamen. Due to the different separation conditions of water and sediment, the sedimentation rate of each inlet is also different. The Wanqingsha between Jiaomen and Li Hongqi increased by110m annually, the lantern sand in Modaomen increased by 80 ~100m annually, and the areas around Humen and Hutiaomen were less than10m. The Pearl River Delta is located in the south subtropical zone, and local people have created management modes such as "mulberry-based fish ponds", "fruit-based fish ponds" and "sugarcane-based fish ponds", which not only make use of superior natural conditions, but also protect the agricultural ecosystem. In addition, due to the construction of dikes and the establishment of electronic irrigation and drainage systems, floods and tides have been prevented and the development of agriculture has been promoted. Rich in rice, sugar cane, cocoon, jute, banana, pineapple, papaya, litchi, longan, orange, lemon and so on. Freshwater fishery is also called developed.