Trough of wave
Lowest part of a waveform between successive crests. Also, that part of a wave below stillwater level. (US Army Corps of Engineers, Low Cost Shore Protection: A Property Owner's Guide, 2004)
Lowest part of a waveform between successive crests. Also, that part of a wave below stillwater level. (US Army Corps of Engineers, Low Cost Shore Protection: A Property Owner's Guide, 2004)