What primarily causes a river to have a steep gradient?

A river's steep gradient is primarily influenced by elevated terrain and geological features. When a river flows from higher elevations, such as mountains or high plateaus, it experiences a significant drop in altitude over a relatively short horizontal distance. This ensures that the river gains velocity and power as it descends, which contributes to a steep gradient.

Geological features, such as faults, fractures, and the composition of the land through which the river flows, can also play a crucial role in forming steep gradient areas. For instance, rugged landscapes with harder rock formations may lead to swift inclines and declines in the river’s course.

The riverbed's mineral composition, the presence of waterfalls, and the amount of rainfall in the area can influence other aspects like river flow, sediment transport, and overall river morphology, but they do not fundamentally establish the steepness of the gradient as effectively as the combination of elevation and geological context does.