28 



XXX Have Height (ft) 



H — I — h Water Elevation (ft, MLW) 



• — ■ — ■ Mave Period (s) 



Figure 5. Storm profile for storm of February 1978 



(hr 27) was selected to test the worst recorded conditions, a low water 

 level was selected to allow estimation of the period of the storm in which 

 overtopping could be neglected (approximately hr 13, 18, 25, and 30), and 

 an intermediate water level was selected to represent the rest of the storm 

 (approximately hr 14, 16, 26, and 29). Each of the lower water levels se- 

 lected was tested with wave conditions on the incoming and outgoing 

 tides of both tide cycles. Storm hour, swl, wave height, and wave period 

 are shown in Table 1 after shoaling in SBEACH to the approximate loca- 

 tion of the wave generator in the physical model (approximately 2,000 ft 

 offshore). 



Because of the amount of time involved in changing water levels in the 

 wave flume, it was desired to use a constant water level for each of the 

 four points on each of the two lower water levels. The swl at hr 25 was 

 chosen for the lowest water level (10.8 ft mean low water (mlw)) and the 

 swl at hr 16 was chosen for the higher water level (13.0 ft mlw). Linear 

 interpolation based on water level and two surrounding data points was 

 used to adjust wave conditions to the selected points in the storm profile. 

 For example, the swl at hr 13 was 10.5 ft mlw, and 13.5 ft at hr 14. Linear 

 interpolation determined that the test conditions of 10.8 ft mlw and 13.0 ft 

 mlw occurred at hr 13.27 and hr 13.83, respectively. Using the same inter- 

 polation for wave height and wave period yielded the interpolated results 

 shown in Table 1 . 



Physical model tests were conducted with irregular waves following 

 the Texel Marsen Arsloe (TMA) spectrum (Hughes 1984), which is a 



10 



Chapter 3 Research Tasks A, B, and C 



