Large rivers have many interesting features, including: Group of answer choices The natural levees, formed when water rushing back into the river channel after floods erodes troughs away from the river. The flood plain, that flat area above where any floods reach. The natural levees, high regions left behind when compaction of mud occurs beneath the river. The flood plain, the flat region left behind when the river cuts downward to make a valley and leave uplands. The natural levees, formed when flood waters leaving the channel slow down and drop much of their load near the channel; beyond the natural levees is the flood plain, where much of the rest of the mud in a flood is deposited in a thin layer.