Problem: How does the formation of a natural levee impact flooding? Need Assignment Help? Natural levees raise the height of the stream channel, increasing the amount of flooding that will occur on the floodplain. Natural levees lower the height of the stream channel, reducing the amount of flooding that will occur on the floodplain. Natural levees raise the height of the stream channel, reducing the amount of flooding that will occur on the floodplain. Natural levees lower the height of the stream channel, increasing the amount of flooding that will occur on the floodplain. Request Answer