Valleys pass through various stages from the formation stage to reach the final stage. In this, the process of erosion and the position of slope vary.
On this basis, the valleys are classified into the following types:
1. Youth Valley
2. Mature Valley
3. Old Valley
1. Youth Valley: Slope of valley is steep in the youth stage, thus, deep valley is formed due to more of vertical erosion.
2. Mature Valley: Slope of valley gets gentle in the mature stage, thus, valley becomes broad due to more of lateral erosion.
3. Old Valley: This is the last stage of valley. The slope of valley gets extremely gentle in this stage and the valley starts becoming flat.