River channel deposition is primarily influenced by several key factors: the velocity of the river, its sediment load, and the gradient or slope of the riverbed.

The velocity of a river is crucial in determining its deposition characteristics. When a river’s flow slows down, it loses energy and its capacity to transport sediment, resulting in deposition. This deceleration often occurs when the river enters a wider, flatter area or when it encounters a body of still water, such as a lake or the sea. Notably, the slower the river’s speed, the larger the sediment particles it tends to deposit. This phenomenon explains why larger rocks and boulders are frequently found deposited on the inside of meanders, where the flow velocity is at its lowest.

The sediment load of a river also plays a significant role in the deposition process. A river carrying a substantial amount of sediment has more material available for deposition. Various factors can affect this sediment load, including the geology of the river’s catchment area, the extent of erosion occurring upstream, and human activities such as deforestation or agriculture, which can exacerbate soil erosion and increase the sediment supply to the river.

Another critical factor influencing deposition is the gradient or slope of the river channel. A steeper gradient typically results in faster flow and greater energy, enabling the river to carry more sediment. In contrast, a gentler gradient causes the river to slow down and lose energy, leading to deposition. This is particularly evident in the lower course of a river, where the gradient is usually less steep, resulting in significant sediment deposition.

Additionally, the river’s discharge can impact deposition dynamics. High discharge, often a result of heavy rainfall or snowmelt, can increase the river’s velocity and its ability to transport sediment. However, when discharge decreases, the river’s flow slows, leading to increased deposition.

Finally, human interventions, such as the construction of dams and weirs, can significantly influence deposition patterns. These structures reduce the river’s velocity, causing it to lose energy and deposit its sediment load. Such deposition can result in the formation of new landforms, including deltas and alluvial fans.