Where are V-shaped valleys commonly found?

V-shaped valleys are commonly found in the upper course of rivers due to the steep gradient and erosional processes that dominate this part of the river's journey. In these regions, rivers primarily engage in vertical erosion as they cut down into the landscape, effectively carving out valleys that resemble a V shape when viewed in cross-section. This process is driven by the fast-flowing waters, which have a high energy and can erode the landscape significantly.

In contrast, the mouth of rivers is typically characterized by wider, flatter areas where sediment deposition occurs, leading to the formation of features like deltas, rather than V-shaped valleys. Urban areas often have modified landscapes where natural valley shapes have been altered or obscured due to human development. Similarly, river deltas are created at the end of a river's course, where sediment is deposited as the river slows down, again lacking the sharp, steep-sided features characteristic of V-shaped valleys.