Alamance County, NC Fence Regulations: Retaining Walls (2026)

6's Other Development provisions reach any retaining wall, sidewalk, or driveway built in a regulated floodway or non-encroachment area that involves placing fill. Under that section, retaining walls in those areas must meet the limitations imposed on encroachments generally. 9 spells out what that means: no fill, new construction, or substantial improvement is permitted within a floodway or non-encroachment area unless the applicant demonstrates, through hydrologic and hydraulic analysis performed to standard engineering practice and presented to the Floodplain Administrator, that the retaining wall will not increase flood levels during the base flood, or unless FEMA has approved a Conditional Letter of Map Revision, followed by a final Letter of Map Revision within six months of completing the wall.

Because floodways carry fast-moving water with erosion potential and debris, the ordinance treats any fill-retaining structure there as an encroachment first and a wall second: the engineering no-rise certification, not a height table, is the operative limit. 2, but the ordinance does not impose a numeric height cap or a stand-alone retaining-wall permit for dry-land walls.