water level (maximum) water level (maximum) Difference between the elevation of the highest local water mark and the elevation of the sea-level at the time of the tsunami attack. This is different from maximum run-up because the water mark is often not observed at the inundation line, but maybe halfway up the side of a building or on a tree trunk.

wave crest 1. The highest part of a wave. 2. That part of the wave above still water level.

WDC World Data Center.