What happens to the sediments when the flow of a stream decreases?

When the flow of a stream decreases, the energy of the current diminishes, which affects how sediments are managed within the water system. In flowing water, sediments are typically kept in suspension due to the velocity of the current. When the flow slows down, the capacity of the water to carry sediments decreases. Consequently, larger and heavier particles will settle out of the water and accumulate on the riverbed or surrounding areas. This process is known as deposition, where sediments are laid down in new locations rather than being carried along.

In contrast, erosion occurs when water flow is sufficient to wear away materials from the stream banks or bed, while transportation refers to the movement of sediments carried by the water. Sorting happens as sediments may be separated by size as they are deposited. Therefore, deposition is the primary process that occurs when stream flow decreases, leading to the accumulation of sediment.