a delta is formed by sediment depositing at the mouth of a river by water fanning out
delta is flow_path. delta is geological_formation. river is flowing_body_of_water. mississippi_river_delta is branching_or_bird_foot_delta. stream is small_body_of_flowing_water. river is stream_of_water. stream is body_of_water. stream is narrow_body_of_flowing_water. delta is alluvial_sediment. illinois_river is river.