headwall

Headwall is a term used in civil engineering, geomorphology, and mining to describe a wall-like feature that forms the upstream boundary or terminus of a channel, conduit, or excavation. In engineering practice, a headwall is typically a reinforced concrete or masonry end wall at the inlet or outlet of a culvert, storm drain, or natural channel. It often includes wing walls that extend from the main face to confine flow, improve stability, and reduce erosion where the structure meets the surrounding ground.

Function and design: The headwall acts to anchor the end of a pipe or channel, absorb hydrostatic pressures, and direct flow into or away from the conduit. It may be paired with an outlet apron or riprap to dissipate energy and limit scour. Local codes specify materials, thickness, and anchorage, taking into account soil conditions, flood flows, and seismic loads.

Geology and geomorphology: In natural settings, the term describes the steep rock face at the upper end of a canyon, alcove, or slot canyon, produced by headward erosion and fluvial incision. The headwall can delineate the boundary between different rock units or weathering profiles and often presents a cliff or escarpment.

Other uses: In mining and construction contexts, the term may refer to a rock face at the head of an open pit or mine tunnel where stabilization work is required to control rockfall and ensure safe access.

Related terms include culvert, wing wall, erosion control, and escarpment.