EM 1110-2-1100 (Part II)
31 July 2003
Definition sketch for wave runup
Definition of runup as local maximum in elevation
a. Regular waves.
(1) For breaking waves, Hunt (1959) empirically determined runup as a function of beach slope, incident
wave height, and wave steepness based on laboratory data. Hunt's formula, given in nondimensional form
(Battjes 1974), is
for 0.1 < ξo < 2.3
for uniform, smooth, impermeable slopes, where ξo is the surf similarity parameter defined in Equation II-4-1.
Walton et al. (1989) modified Equation II-4-26 to extend the application to steep slopes by replacing tan β
in the surf similarity parameter, which becomes infinite as β approaches π/2, with sin β. The modified Hunt
formula was verified with laboratory data from Saville (1956) and Savage (1958) for slopes of 1/10 to
(2) The nonbreaking upper limit of runup on a uniform slope is given by
Surf Zone Hydrodynamics