What is the primary feature of a natural levee?

The primary feature of a natural levee is elevated banks formed by sediment during flooding. Natural levees occur when a river overflows its banks during high water events. As the water spills over, it slows down, causing sediment carried by the river to settle along the edges. This process builds up elevated ridges or banks known as levees. These features help to confine the river within its channel during normal flow conditions and can also influence the surrounding ecosystem by creating a distinct environment on either side of the river. The sediment composition can vary depending on the materials transported by the river, contributing to the fertility of the floodplain.

Other choices describe concepts unrelated to the formation of natural levees. For example, a structure built by humans to control floods refers to engineered levees, which are distinctly different from natural formations. A type of plant found along riverbanks does not relate to the physical characteristics of levees, while a geological fault line near a river pertains to tectonic activity rather than sediment deposition processes.