Revetments

A revetment is a facing, wall, or embankment constructed along coastlines, rivers, or hillsides to absorb and dissipate hydraulic or gravitational forces. The primary purpose is to reduce erosion, stabilize slopes, and protect infrastructure, such as shorelines, levees, roads, and buildings, from wave action, currents, flood flows, or mass wasting. Revetments are designed to blend with surrounding terrain while providing durability.

Common revetment types include rock revetments (riprap) composed of large, interlocked stones; concrete armor units such as tetrapods, dolos, or cubipods; gabion walls made of wire cages filled with stone; sheet-pile or steel armor used in river settings; and timber or soil-geosynthetic systems. Selection depends on energy level, foundation conditions, aesthetics, and maintenance requirements.

Design factors: expected hydraulic energy, wave and current climate, slope stability, crest width, toe protection, drainage and permeability, scour potential, and freeze–thaw resistance. Armor unit size and arrangement, foundation bearing capacity, and potential environmental impacts (habitat disruption) are evaluated. Revets may be combined with drainage, filtration layers, or vegetation to improve performance and reduce maintenance.

Applications span coastal zones, rivers and harbors, flood-control embankments, and hillside stabilization projects. They may replace or complement seawalls or levees, reduce toe erosion, and provide a more natural shoreline appearance where appropriate. In some cases they are designed to permit limited sediment transport and ecological access.

Construction involves preparing a stable foundation, placing armor or gabion units in prescribed patterns, backfilling, and ensuring drainage. Maintenance includes regular inspection, replacement of displaced units, repair of scour at the toe, and monitoring for signs of undermining or settlement. Longevity varies by material, exposure, and maintenance, typically decades for well-designed systems.