||An embankment of sediment, bordering one or both sides of a submarine canyon, fan
valley, deep-sea channel, river, or other feature. A natural levee has a long, broad,
low shape and is composed of sand and coarse silt, which was built by a stream on
its flood plain and along both sides of its channel—especially in time of flood when
water overflowing the normal banks is forced to deposit the coarsest part of its load.
It has a gentle slope away from the river and toward the surrounding floodplain, and
its highest elevation is closest to the river bank.