The Chao Phraya River basin is a region where cultivated land is concentrated in Thailand. The water quantity of Chao phraya River changes dramatically with the seasons, and the difference between dry season and rainy season is more than ten times. The flow in dry season is only 150 seconds, and it reaches 2000 seconds in rainy season. So rivers flood in the rainy season, bringing a layer of fertile sediment. Paddy field irrigation basically depends on natural flooding.
Northeast Thailand is a mountainous area with towering mountains. From west to east, there are Denglao Mountain, Tanan Taweng Mountain, Kundan Mountain and Luanshan Mountain from north to south in turn. Among these mountains, Binhe River, Wanghe River, Yonghe River and Nanhe River develop, forming the upper reaches of Chao Phraya River.
Four rivers, Bin, Wang, Yong and Nan, pass through the mountains, and many valleys have developed into fertile plains due to the long-term alluvial action of rivers, among which Chiang Mai, Nanbang and Fu Nan are more famous. Because of its gentle terrain, suitable climate and convenient irrigation, this mountain basin has always been the center of economic development in the northern mountainous areas, with dense population and rich products. Chiang Mai, the second largest city in Thailand, is located in the Chiang Mai Basin and is the largest rice distribution center in northern Thailand.
Riverside, Wang, Yong and Nansi rivers flow through most areas with dense forests and rich forest products, especially teak. After the teak was cut down, it was exiled in various rivers and concentrated in Beilanpo before being transported to other places or exported to the south. Therefore, Beilanpo is the largest teak distribution center in the Chao phraya River.
Below the North Lanpo, the Chao Phraya River flows southward for about 40 kilometers, and divides into two tributaries near Chena, of which the east tributary is the main stream, still called Chao Phraya River, and the west tributary is called Tazhen River. Further down, the Chao Phraya River continues to gather many tributaries, but at the same time, many tributaries are constantly divided, among which the main ones are the Basse River, the lopburi River, the Lianhe River and the Segenggang River, forming a dense water network in the downstream area.
The plain in the lower reaches of the Chao Phraya River covers a vast area of about 50,000 square kilometers. Rivers crisscross here, with hot climate, abundant rainfall, regular flooding of rivers and fertile land. Especially through the hard work of the Thai people, it has developed into the most densely populated and economically developed area in Thailand.