revetment

"As far as I'm aware, those train tracks were built in 1973 to support the building of the coast protection structures - the timber revetments which go along the cliffs, but also the groynes," he said.

Crews removed about 3,000 feet of levee and revetment — a barrier that slows erosion — built in the 1960s and 1970s.

Other measures include timber revetments or seawalls to slow erosion.

The first, found medieval timber structures thought to represent waterfront revetments, with a wall that runs alongside the medieval location of the riverside.

As part of efforts to defend the castle 5,000 tonnes of granite boulders have been put in place to form a barrier, or "revetment".