What are the key features of a river's upper course?

The upper course of a river is characterised by steep gradients, narrow valleys, and features like waterfalls and rapids.

In the upper course, a river is typically closer to its source and is often found in mountainous or hilly terrain. This results in a steep gradient, causing the river to flow quickly and with a lot of energy. This energy is used to erode the river bed and banks, a process known as vertical erosion. This type of erosion deepens the river channel and creates a narrow, V-shaped valley.

One of the most distinctive features of a river's upper course are waterfalls and rapids. These are formed when the river flows over different types of rock with varying resistance to erosion. The less resistant rock erodes faster, creating a step in the river. Over time, this step becomes more pronounced, leading to the formation of a waterfall or rapid.

Another key feature of the upper course is the presence of interlocking spurs. These are ridges of high land that the river winds around, creating a zigzag pattern. This occurs because the river does not have enough energy to erode through the spurs, so it takes the path of least resistance and flows around them.

The river's load (the material it carries) in the upper course is typically large in size, but small in quantity. This is because the river has not yet had the opportunity to erode and transport a large amount of material. The load is also very coarse, consisting of large boulders and rocks. These are transported by the river through a process called traction, where the material rolls along the river bed.

In summary, the upper course of a river is a dynamic and energetic environment, characterised by steep gradients, narrow valleys, and features like waterfalls, rapids, and interlocking spurs. The river's load is also distinctive, being large in size but small in quantity, and consisting of coarse material.