Rivers erode and shape the land through a process called hydraulic action, where the force of the flowing water wears away the land's surface. Additionally, rivers use abrasion, where they carry sediments that act like sandpaper, gradually smoothing and shaping the land. The movement of the water also causes erosion by picking up and carrying away loose material. Over time, these erosional processes result in the formation of river valleys, canyons, and other landforms.
