Hierarchy classification:

1. top of the aat hierarchies
2. Objects Facet
3. Built Environment (hierarchy name)
4. Single Built Works (hierarchy name)
5. single built works (built environment)
6. [single built works by specific type]
7. [single built works by function]
8. hydraulic structures
9. [hydraulic structures by function]
10. erosion protection works
11. breakwaters

Anotations

Scope note:

Breakwaters comprising a mound of rubble, having a core of small rocks or rubble to provide the basic stability, with an outer covering of larger boulders, or armoring, to protect it from removal by the sea.