The second form is simplified and is used for results of tests which 

 had more limited slope and wave conditions. This form can also be used 

 to estimate runup for wave conditions for which runup data are not avail- 

 able. Runup on a rough slope is expressed as a function of the runup on 

 a smooth slope, where 



rough slope _ \ o /rough slope ^^ I ojrs 



smooth slope \ 0} smooth slope \ oi 



The values of r given in this report were determined by comparisons 

 of rough-slope runup with the smooth-slope runup curves given in Stoa 

 (1978a) . These smooth- slope arunup curves differ in some respects from 

 those given in the SPM; the revised curves are also given in Stoa (1978b) 

 which should be used to determine the appropriate smooth-slope runup for 

 use with the value of r. Smooth-slope runup values should not be cor- 

 rected for scale effect as required in Stoa (1978b) if the runup values 

 are being used with r values . 



The tabulated values of r used here were selected for armor-unit 

 relative sizes, H^/k2>, corresponding to design conditions (i.e., the 

 necessary armor weight for an incident wave) as determined from design 

 procedures given in the SPM. Larger armor units (smaller values of 

 H^/kp') should produce a more stable structure. This would also have the 

 effect of reducing runup because of the increased roughness; smaller 

 armor units may be unstable for the design wave conditions. 



IV. DETERMINATION OF RUNUP 



Rough-slope runup is determined by means of flow charts (Figs. 2, 3, 

 and 4) . Figure 2 shows the selection process for determining runup on 

 embankments (i.e., revetment or a similar type of impermeable structure); 

 Figures 3 and 4 show the selection process for determining runup on 

 rubble-mound structures. Results are given in Appendixes A to F. 



Each value of r, as originally given in Stoa (1978a), was an aver- 

 age for several wave steepness parameters (H^/gT^) at specific dg/H^ 

 and H^/k^ . values. Thus, they did not reflect the data extremes and 

 should be considered approximate. Values of r given in this report 

 were selected for the higher values of Hp/kpt approaching the limits 

 of armor-unit stability, or for values of H^/kj, as noted. 



The r values must be considered only as approximate solutions; the 

 design curves in Appendixes B and E should be used if possible. However, 

 comparisons of runup for different wave conditions should use the same 

 method of rxinup determination; i.e., either the curves or r values. 



Scale-effect corrections, as given in the flow charts (Figs. 2, 3, 

 and 4), are from Stoa (1978a). If runups from a range of wave conditions 

 are being compared, it is preferable to make the comparison before appli- 

 cation of scale-effect corrections. 



