Iowa State Geology Practice Exam 2025 – The Complete All-in-One Guide for Exam Success!

Natural levees typically form in the context of river meanderings, where the flow of water causes sediment to be deposited alongside the riverbanks. As a river flows, particularly during periods of high water or flooding, it transports sediments that are carried along with the current. When the river overflows its banks, the velocity of the water decreases, resulting in the heaviest sediments being deposited right next to the river's edge. Over time, these repeated deposits build up and create natural levees, which help to channel the river flow and protect the adjacent floodplain from flooding during non-peak water levels.

This process is distinct from other contexts such as streams depositing materials at mountain fronts or the construction of flood walls, both of which do not naturally create levees through sediment deposition along riverbanks. Water level rises can also contribute to flooding but do not directly lead to the development of levees unless accompanied by sediment deposition from the river flow itself.