Transporting clastic particles with various sizes and shapes involves a process called sorting. The degree of sorting depends on the flow force. For example, rivers can transport particles of all sizes when flowing rapidly, through the mountains or during flash floods. But when a river flows gently, the size of particles is kept relatively constant.
Sand transport takes place in coastal areas under the combined influence of currents and waves. Wave-induced currents move sand in longshore and cross-shore directions. Longshore transport is commonly known as longshore drift. This process stirs large quantities of sand, and it is also influenced by net currents. These currents can be tide-driven, wind-driven, or density-driven.
To estimate the transport rates of sand, a detailed TR2004 model was used. This model included both suspended and bed loads. The wave heights were varied from 0 to 3 m, and the waves were assumed to be parallel to the coast.
Sand grain sizes are generally smaller than those of other sediment grains. This means that sand is more easily transported and deposited. Small particles tend to be chemically attracted to each other and stick to the underlying sediment. Under higher flow rates, small grains tend to stay in place, while large grains get picked up and moved around.
The distance from the source of silt determines the degree of sorting that can be achieved. Large clasts are the most difficult to transport, while the smaller ones are the easiest to transport. As a result, the degree of sorting increases with distance from the source.
The amount of sediment carried by a river varies greatly based on the amount and type of rainfall that occurs each year. Heavy rainfall and flooding can increase the amount of sediment carried by a river. Anthropogenic land use is one of the leading contributors to excessive sedimentation. Changing land uses, such as building roads, altering vegetation, and deforestation increase the amount of sediment in a river.