Wave run-up is the height to which waves run up the slope of a revetment, bank or dike, regardless of whether the waves are breaking or not. Conversely, wave run-down is the height to which waves recede. These heights are always measured vertically (and not along the slope). The wave run-up height, denoted by , , or , is a very important parameter in coastal engineering as, together with the design highest still water level, it determines the required crest height of a dike or revetment.
