Siltation is most often caused by soil erosion or sediment spill. It is sometimes referred to by the ambiguous term "sediment pollution", which can also refer to a chemical contamination of sediments accumulated on the bottom, or to pollutants bound to sediment particles.

How is silt formed?

Silt soil occurs when rock is weathered, or worn away, by water and ice. As flowing water carries tiny rock splinters, they scrape against the bottom and sides of stream beds, working away more rock. The particles mince against each other, getting smaller and smaller until they become silt-size.

What is the cause of the siltation of a river?

Siltation of coastal waters is increased by soil erosion arising from agricultural practices in the Stann Creek and Toledo Districts, deforestation, particularly along river banks, destruction of mangroves and seagrass beds, and marine dredging (McField et al. 1996).