Middle course of a river - Info sheet

In the middle course of a river, one can observe a significant transformation from the upper course. As the river flows downstream, its energy and volume grow, while the gradient levels out into a gentler slope. This stage is characterized by lateral erosion, which serves to widen the river channel, and as a result, the river deepens. A distinct feature of the middle course is the formation of meanders—sweeping bends and curves that snake across the landscape. These meanders form due to the river's lateral erosion, which gradually shapes the riverbanks, coupled with deposition that occurs on the adjacent floodplain.

Another key aspect of the middle course is the presence of tributaries—smaller streams or rivers that join the main river at a junction known as the confluence. These tributaries can vary in size, ranging from minor streams to substantial rivers in their own right, such as the Missouri River, which is a major tributary to the Mississippi River. The Missouri River itself spans an impressive 2,500 miles and has numerous smaller tributaries feeding into it. Understanding the dynamics of tributaries and their role in the river system is crucial for comprehending the complexity and the growth of rivers as they progress from their source towards the sea.