Functions as the past participle of the verb "berm" when used attributively.
Definitions
Having been provided with a berm; supplied or surrounded by an earth bank. The campsite was bermed to keep floodwaters out.
Least-common but attested use meaning ‘to build or provide with a berm’.
Definitions
To construct or heap up a berm around or along something for support or protection. The engineers bermed the road to prevent drifting snow.