River deposits are sedimentary materials that accumulate in a river and its tributaries. The most common type of river deposit is SILT, which is composed of fine particles of clay, sand, and other materials. DELTA is a term used to describe the landform created when a river splits into multiple channels and deposits sediment at its mouth. Alluvial deposits are sedimentary materials that are deposited by rivers over time. These deposits can include SILT, gravel, and other materials.