The terrain of the whole South Vietnam region is quite flat, the West borders the Gulf of Thailand, the East and Southeast borders the East Sea, the North and Northwest borders Cambodia and a part of the Northwest borders the South Central Coast.
The Southeast has an altitude of 100 - 200m, with geological structure mainly basalt red soil and ancient alluvial soil. The river delta area here occupies an area of about 6,130,000 ha and over 4,000 canals with a total length of up to 5,700km.
The Southwest has an average altitude of nearly 2m, mainly in new alluvial land. There are some low mountains in the area bordering the Central Highlands, western Kien Giang and Cambodia.
The two largest river systems in the region are the Dong Nai River and the Mekong River. In contrast to the Dong Nai River with low alluvium content, the Mekong River has an average water discharge of about 4,000 billion cubic meters and transports about 100 million tons of alluvium annually, playing a very important role for the delta. The Mekong River covers an area of 39,734 km². Until now, the Mekong Delta is still a lowland, the average altitude is only about 5 meters above sea level. Some areas such as the Long Xuyen quadrangle, Dong Thap Muoi and the west of the Hau river exist at a level below the sea level, so every year up to 1 million hectares of salt water suffers from 2 to 4 month. Historians of this land said that, millions of years ago, this place was originally a large bay but was gradually accreted by alluvium of the Mekong River.
The mountainous areas are mainly concentrated in the Southeast such as Ba Ra mountain (Binh Phuoc) 736m high, Chua Chan mountain (Dong Nai) 839m high, Bao Quan mountain (Ba Ria - Vung Tau), 529m high, Thi Vai mountain (Ba Ria - Vung Tau) 461m high, 986m high Ba Den mountain (Tay Ninh) ... The western region has the That Son mountain range (An Giang) and the Ham Ninh mountain (Kien Giang).
The South is located in the typical region of tropical monsoon and sub-equatorial climate, rich humid background, abundant sunshine, long radiation time, high temperature and total temperate. Amplitude of day and night temperatures between months of the year is low and mild. The annual average humidity ranges from 80 to 82%. The climate is formed in two main seasons all year round, the dry and the rainy seasons. The rainy season is from May to November, the dry season is from December to April. Production season differs from the Northern Delta region.
The annual rainfall ranges from 966 - 1325mm and contributes over 70 - 82% of the total rainfall throughout the year. The rain is unevenly distributed, gradually decreasing from the adjacent area from Ho Chi Minh City to the West and South West. Rainfall is lowest in the Southeast region. When heavy rainfall occurs in some areas in the region, it often causes erosion in high mounds. When rain is combined with high tides and floods, it will cause flooding, affecting production and life of people in the area.
Due to the general climate change phenomenon, the Southern Delta in the coming time may be greatly affected by the exhaustion of water resources in rivers, especially the Mekong River. According to scientists, by 2070, weather changes in the region will affect the water resources of the Mekong Delta, mainly through small and medium rivers, which will be reduced [4 ]
Southern cuisine, which is heavily influenced by Chinese, Cambodian, and Thai cuisines, is characterized by often adding sugar and often using coconut milk (coconut milk and juice). This culinary background also produces a myriad of dried fish sauce (such as fish sauce, snakehead fish sauce, three notch fish sauce, etc.). Southern cuisine also uses more saltwater and brackish water seafood than the North (fish, shrimp, crabs, sea snails), and is very special with the rustic dishes, typical of a time of opening. Nowadays, many times have become specialties: hamster with coconut water, steamed crow bats, cobra with green bean porridge, coconut weevils, earth weevils or date weevils, cramps, grilled snakehead fish etc.