What is created by the uneven distribution of material during flooding?

Natural levees form as a result of the uneven distribution of sediment and other materials during flooding. When a river overflows its banks, the fast-moving water carries sediments away from the main channel. As the water slows down upon leaving the river, it loses its capacity to transport those sediments, causing them to settle near the riverbank. This accumulation creates raised embankments or levees along the edges of the river, which can serve to contain future floodwaters and change the river's flow dynamics.

In contrast, smooth valleys can be formed by various geological processes, such as erosion and sedimentation, but are not specifically a result of flooding. Steep cliffs typically result from erosion processes or tectonic activity, not from the distribution of materials during a flood. Flat floodplains do develop from sediment deposition, but they don't represent the raised features that characterize natural levees; instead, they are the broader, flat areas adjacent to rivers that are affected by overflow events. Thus, natural levees are distinctly associated with how materials are deposited during and after flooding events.