Which feature is most commonly associated with flood events along rivers?

Levees are raised banks built alongside rivers to help contain floodwaters and prevent them from overflowing into surrounding areas. They can be made from natural materials such as sediment or artificially constructed with soil and rock. During flood events, rivers often exceed their normal banks, and levees are crucial to managing these excess waters, thus mitigating potential damage to the adjacent land and communities. The presence of levees indicates a history of flooding and an effort to control such events.

While waterfalls, deltas, and water tables are important features in river systems, they do not have the same direct association with flooding. Waterfalls typically occur in areas where rivers descend abruptly, deltas form at river mouths where sediment is deposited as water slows down when entering a larger body of water, and water tables refer to the underground level where soil and rocks are saturated with water. They do not play a functional role in flood management like levees do.