Upper course features

Upper-course river features

As the river moves through the upper course it cuts downwards. The gradient here is steep and the river channel is narrow. Vertical erosion in this highland part of the river helps to create steep sided V-shaped valleys, interlocking spurs, rapids, waterfalls and gorges:

Interlocking spurs on a tributary of the Yangtse

• As the river erodes the landscape in the upper course, it winds and bends to avoid areas of hard rock. This creates interlocking spurs, which look a bit like the interlocking parts of a zip.

• When a river runs over alternating layers of hard and soft rock, rapids and waterfalls may form. The graphic shows how waterfalls and rapids are formed.

The formation of waterfalls and rapids