When a stream deposits material due to reduced velocity, what happens to the channel?

When a stream deposits material due to reduced velocity, the channel builds up as sediment settles to the bottom and sides of the watercourse. This process of sedimentation occurs when the energy of the flowing water decreases, often due to changes in slope, terrain, or the presence of obstacles that disrupt the flow. As the flow slows down, it loses the ability to carry sediment, leading to the deposition of particles. Over time, this buildup can alter the channel’s shape and size.

In contrast, when a stream erodes deeper, widens significantly, or becomes stagnant, it indicates different processes at work. Erosion typically involves the removal of sediment rather than its accumulation. Widening may occur under various conditions, such as high energy flows or lateral erosion, while stagnation refers to a complete lack of flow, which is not a direct result of sediment deposition. Thus, the building up of the channel specifically relates to the deposition of material.