Levee

A levee ( or ),}} is an elevated ridge alongside the banks of a river, often intended to protect against flooding of the area adjoining the river. Alternatively, it is called a dike (American English), dyke (Commonwealth English), floodbank, or stop bank. It is a type of embankment. A levee, natural or artificial, is usually earthen and often runs parallel to the course of a river in its floodplain or along low-lying coastlines.

Naturally occurring levees form on river floodplains following flooding. Sediment and alluvium are deposited on the banks and settle, forming a ridge that increases the river channel's capacity. Alternatively, levees can be artificially constructed from fill, designed to regulate water levels. In some circumstances, artificial levees can be environmentally damaging.

Ancient civilizations in the Indus Valley, ancient Egypt, Mesopotamia and China all built levees. Today, levees can be found around the world, and failures of levees due to erosion or other causes can be major disasters, such as the catastrophic 2005 levee failures in Greater New Orleans that occurred as a result of Hurricane Katrina. Provided by Wikipedia