“…Therefore, some well-known formulas for steady flow can be directly employed to wave or wave-current conditions, such as the Einstain-Brown formula ( Einstein, 1950;Tanaka and Shuto, 1984;Shibayama et al, 1989), Meyer Peter-Müeller formula ( Meyer-Peter and Müller, 1948;Perrier et al, 1994;Ribberink, 1998), and Bagnold equation ( Bagnold, 1977;Keen and Glenn, 2002). Recently, van Rijn's…”