The process or action of depositing sediment. Sediment is composed of solid material, mineral or organic, and can be of any texture. The material has been moved from its site of origin by the forces of air, water, gravity, or ice and has come to rest on the earth's surface. The term siltation does not imply the deposition of silt separates, although the sediment deposited from erosion of agricultural land is often high in silt because of the sorting action into soil separates during the erosion process.