Lower High Water (LHW)

Lower High Water (LHW) is the lower of the two high waters that occur during a tidal day where diurnal inequality is present. It is the smaller high of the day, produced when the diurnal constituents K1 and O1 partly cancel the semidiurnal high. The difference between Lower High Water and Higher High Water is the diurnal inequality in the highs, which grows as the form number rises toward a mixed or diurnal regime. In a semidiurnal regime the two highs are close and this label has little practical weight.