The elevation of the whole delta area is less than 3m, and in many places it is only 1 m or even lower, surrounded by steep forest-covered highlands. This area is often flooded, and the sign of high water level in some places exceeds the surrounding villages 14 meters. For many centuries, flood control has been the main part of the economy and culture of the Red River Delta. A huge dam and canal system has been built to control the Red River and irrigate the fertile rice-growing delta. The ancient system imitated China, which was densely populated, and about half of them were multiple cropping rice. Nishihara, strategically extremely important, is the key to control South Vietnam and even the whole South Indian zhina. After 1975, many people moved from densely populated lowlands to highlands.
Coastal lowlands
Between the Red River Delta in the north and the Mekong River Delta in the south, there is a long, narrow and flat coastal lowland extending from north to south. On the land side, Giai Truong Son rises is very steep, extending along the coast and protruding into the sea in several places. Long and narrow coastal areas are usually very fertile and rice is concentrated. The Mekong Delta covers an area of 40,000 square kilometers, and the terrain is extremely low and flat. All places are below 3 meters above sea level, and countless rivers and canals crisscross. The tributaries of the Mekong River carry a lot of sediments, which makes the Mekong Delta push 60-80 meters to the South China Sea every year. According to an official Vietnamese data, the annual sediment volume is estimated to be about 65.438+0 billion cubic meters, which is nearly 654.38+0.3 times that of the Red River. About 65,438+100,000 square kilometers have been opened up as paddy fields in the delta, which is one of the most important rice growing areas in the world. The southernmost tip of the Mekong Delta, known as the Jin 'ou Peninsula, is covered with dense shrubs and mangrove swamps. The Mekong River, with a total length of 4,220 kilometers, is one of the 12 rivers in the world. Originated in the Qinghai-Tibet Plateau, it flows through Yunnan Province of China, forming the border between Laos and Myanmar and the border between Laos and Thailand, and is divided into two tributaries.