How does channel erosion typically occur?

Channel erosion typically occurs as a result of the action of flowing water, which can be significantly intensified by human activities. When water flows through a channel, it possesses energy that can cut into the banks and bed of the channel, leading to the removal of soil and sediment. This process is often exacerbated by factors such as urbanization, land clearing, and other alterations to the landscape that increase water runoff and speed. For example, constructing roads or developments can redirect natural water flow, increasing intensity and leading to more severe erosion.

While natural weathering processes play a role in shaping the landscape over time, and heavy machinery can contribute to soil disturbance, the direct interaction of flowing water—with its increased capacity for mobilizing soil—stands out as the primary driver of channel erosion, especially when human actions modify natural drainage patterns. The buildup of sediment often pertains to sediment transport and deposition rather than direct erosion, thus it does not explain how channel erosion occurs.