REANALYSIS OF WAVE RUNUP ON STRUCTURES AND BEACHES 



by 

 Philip N. Stoa 



I . INTRODUCTION 



Wave runup, or simply runup, is an important aspect of the inter- 

 action of waves and coastal structures. Runup is the height above still- 

 water level (SWL) to which a wave will rise on a structure or beach, and 

 is analyzed in dimensionless parameters. The runup divided by the wave 

 height is commonly defined as relative runup. 



Summaries of previously published studies on wave runup, using 

 various methods of data presentation, were reported in Koh and 

 Le Mehaute (1966); van Dorn (1966); van Dorn, Le Mehaute, and Hwang 

 (1968); Webber and Bullock (1970); Technical Advisory Committee on 

 Protection Against Inundation (1974); and Raichlen (1975). The pres- 

 entation of data in this study is consistent with that used in the Shore 

 Protection Manual (SPM) (U.S. Army, Corps of Engineers, Coastal Engineer- 

 ing Research Center, 1977). 



Only short-period waves, which are of primary interest to coastal 

 engineers, were considered for this study, although long-period waves 

 such as tsunamis are under extensive study. Wind waves are the major 

 component of the short-period wave group, but other waves such as ship- 

 generated waves are also of interest. An arbitrary definition for 

 short-period waves is that wave periods are less than 20 seconds 

 (Le Mehaute, Koh, and Hwang, 1968). The SPM gives mean periods for 

 visual observations on the U.S. coasts (Fig. 1), and the periods fall 

 well within this classification. 



Monochromatic waves are approximated by nature usually during 

 periods when swell is predominant at the shore. Structural design is 

 usually influenced (or determined) by storm conditions, including a 

 confused sea of irregular waves. Although several reports have dis- 

 cussed this problem, it is not yet clear how to fully evaluate the runup 

 produced by irregular waves. Current development of programable wave 

 generators and improved methods for data acquisition will facilitate 

 future analysis of irregular waves and runup. 



This report uses the results from extensive literature on monochro- 

 matic wave testing, which covers a wide range of variables (i.e., struc- 

 ture types, structure slopes, beach slopes, etc.). Section II discusses 

 the dimensional analysis; Section III discusses empirical equations for 

 breaking wave runup, and includes a flow chart defining the limits for 

 use of various solutions of runup on smooth slopes. Experimental data 

 are also presented for smooth slopes in the form of empirical curves 

 based on a reanalysis of smooth-slope runup data. Rough-slope runup is 

 subsequently developed with emphasis on use of quarrystone and precast- 

 concrete armor units. The rough-slope runup is given, where practical, 



