at Re = 3.75 x lo 5 by Saville (1958). Hudson, Jackson, and Cuckler 

 (1957) tested a 1 on 6 slope at a larger scale (Rg = 2.12 x 10 5 ) using 

 a beach-slope length, Z, relatively longer than used in tests at 

 either Re = 9.0 x io*+ or Re = 3.75 x 10 6 , yet the relative runup is 

 higher at R e = 2.12 x io 5 than for either smaller or larger scales. 

 Thus, the data of Hudson, Jackson, and Cuckler give mixed results which 

 are certainly a result of the limited data available, the beach-slope 

 effects, and the different experimental equipment and techniques. 



To better model slope roughness, Saville (1958, 1960) also conducted 

 large-scale testing in addition to that given in Table 20. The small- 

 scale (Re = 1.19 x io 5 ) test structures had plywood surfaces like the 

 large-scale tests (Re = 3.75 x IO 6 ). The large-scale plywood slope was 

 coated with one layer of 0.. 4-millimeter sand, which was expected to more 

 closely model the roughness of the small-scale tests, and was considered 

 to be more representative of prototype situations. Because of time 

 limitations, only three wave conditions were tested on the 1 on 3 slope: 

 Hi * 1.65 meters (5.4 feet) and T = 7.87 seconds; Hi «0.58 meter (1.9 

 feet) and T = 16.0 seconds; H<J, «1.16 meters (3.8 feet) and T = 3.75 

 seconds. Results are given in Table 21. 



Table 21. Large-scale tests of runup on smooth slope roughened with one layer 

 of 0.4 -millimeter sand; 1 on 3 structure slope. 



VS 1-2 



H^/gT 2 



Small scale, smooth 

 d 8 = 0.12 m CO. 4 ft) 



Large scale, roughened 

 d e = 1.2 m (4.0 ft) 



R/HJ 



( R / H o) large 

 W%\mall 



0.000485 



0.00201 



0.0088 



0.00023 

 0.00270 

 0.00845 



6.20 

 2.33 

 1.44 



6.067, 



2.49 



1.70 



0.98 

 1.07 

 1.18 



Correction curves for runup scale effects applicable to a range of 

 structure slopes were developed by Saville (see U.S. Army, Corps of 

 Engineers, Coastal Engineering Research Center, 1977). A similar 

 development is given here with some modifications, but runup data used 

 are restricted to that of Saville (1958, 1960) because of the similar 

 test conditions. 



Basic scale-effect correction factors may be obtained from Table 

 20 for smooth slopes, without considering the roughness test results 

 given in Table 21. Thus, for H^/gT 2 > 0.003, the average ratios of 

 large-scale runup to small-scale runup, k, are 1.25 and 1.155 for 

 the 1 on 3 and 1 on 6 slopes, respectively (i.e., increases of 25 and 

 15.5 percent). These two values are reduced by applying the results 

 from the 1 on 3 roughened slope in Table 21 as follows. After the 

 1 on 3 slope was roughened with a sand layer, large-scale runup for 

 two wave conditions (H^/gT 2 > 0.0027) was larger than small-scale runup 

 by the factors 1.07 and 1.18 (7 and 18 percent). When compared with 

 the runup results for the same wave conditions in Table 20, the per- 

 centage increase of large-scale runup on the roughened slope is shown 

 to be approximately one-half (0.48 or 48 percent) of that for large- 

 scale runup on a smooth slope (i.e., 7 versus 15 percent, and 18 versus 



