150 see 



UOLUME (ACRE-FT) 



Figure 34. Stage volume versus volume relationship for 

 Roughans Point interior 



in the following paragraphs, were made to match the estimated stages. 



78. For existing conditions, overtopping at reach D was not allowed 

 during periods of weir outflow at that wall. Since there would be a contin- 

 uous current flowing outward in this situation, it was reasoned that any over- 

 topping would almost immediately be conveyed back into the ocean. Without 

 this reasoning, reach D would contribute enormous quantities of overtopping at 

 those times when Roughans Point was full to overflowing. This assumption is 

 consistent with the limited information available from the only historic 

 event, in February 1978, during which the water level inside Roughans Point 

 was higher than the elevation of reach D. 



79. Wave heights attacking reach E were reduced by 15 percent. There 

 were several possible adjustments which could have been made to eliminate 

 overprediction of overtopping rates. Among these are (a) reducing the cal- 

 culated overtopping rate, (b) lowering the still-water level, and (c) reducing 

 the wave heights. The wave heights were selected for reduction because they 

 are the least certain of these possibilities (see "Estimating Error in Stage- 

 Frequency Curves" in Part VI). 



80. Wave heights were also lowered for the three northern reaches. At 



62 



