backshore

Backshore is a coastal geomorphological zone describing the part of the shore that lies landward of the high-water mark and seaward of the landward extent of the beach profile, typically where permanent features such as dunes or vegetation begin. It is normally dry and not regularly wetted by waves; only during storms, exceptionally high tides, or overwash events does water reach this area.

On sandy beaches, the backshore often includes the berm and the inland dune field. It is shaped largely by wind action and sediment transport, with vegetation and dune development stabilizing the area over time. The backshore supports various coastal habitats and is commonly used for recreation, access, and stabilization structures in some locations.

The backshore contrasts with the foreshore, which lies between the high- and low-tide lines and is regularly wetted and actively reshaped by wave swash. The backshore acts as a buffer that absorbs some wave energy and stores sediment through dune migration and overwash processes during storms. Sediment movement from the backshore can contribute to dune growth or inland transport, influencing shoreline evolution and resilience.

Definitions of the backshore can vary by region and discipline, and different coastal surveys may designate the boundary differently (for example, at vegetation lines, dune bases, or man-made features). Nevertheless, it is generally understood as the dry, landward portion of the beach profile that is not regularly affected by normal wave action.