Question

Which one of the following statements is TRUE concerning natural levees?

a.They form the high, steep banks of a downcutting stream.
b.They are depositional features formed at times of low discharge.
c.They are mostly fine sand and silt that build up during floods.
d.They are erosional features left behind when meander cutoff occurs.

Answer 1

Natural levees are composed of fine sand and silt that accumulate during floods, creating raised banks along the sides of a river.

Step-by-step explanation:

The true statement concerning natural levees is: c. They are mostly fine sand and silt that build up during floods. Natural levees are formed as a river overflows its banks during flood events. As the water spreads out over the floodplain, it loses energy and deposits the sediments it carries, primarily sand and silt. Over time, these deposited materials build up alongside the river, creating natural levees that are slightly elevated compared to the surrounding floodplain.

Natural levees function as additional barriers that can help contain the river within its channel during low-level floods, though they can be overcome by higher floodwaters. Neglecting levee maintenance or encountering unusually high flood conditions can result in levee failure, thus it's crucial to protect and fortify these natural features.