The side of a levee in Sacramento, California

Components of a levee:

1. Design high water level (HWL)
2. Low water channel
3. Flood channel
4. Riverside slope
5. Riverside banquette
6. Levee crown
7. Landside slope
8. Landside banquette
9. Berm
10. Low water revetment
11. Riverside land
12. Levee
13. Protected lowland
14. River zone

A levee, or levée, is a raised bank of a river. The levee or dyke is a protection against floods. There are two types of levee: riverdykes and seadykes.

The seadyke was invented in Holland in 1277. Rotterdam is largely below sea level, but is protected by its dykes. It is quite clear now that other coastal cities are going to need protection from the sea.