How does the Mekong River change as it flows through Cambodia?

The Mekong River undergoes significant physical changes as it traverses Cambodia, covering a distance of approximately 315 miles (510 km) from the Khone Falls to the Vietnamese border.1

Key characteristics of its journey through the country include:

• Topography and Gradient: Entering Cambodia at Khone Falls, the river initially features rapids interspersed with alluvial plains until it reaches Krâchéh. Below Kâmpóng Cham, the river's gradient becomes gentle as it flows through wide floodplains.2
• Hydrological Interaction: Near Phnom Penh, the Mekong connects to the Tonle Sap via the Sab River. This creates a unique seasonal phenomenon: during the rainy season, the Mekong's high volume forces water up the Sab River into the Tonle Sap, significantly expanding the lake's surface area. As water levels fall during the dry season, the flow reverses, and the lake drains back into the Mekong.12
• Distributaries: Below Phnom Penh, the river divides into two main branches: the Mekong proper and the Bassac River, marking the beginning of the river's delta system.2