PART VI: CONTROL STRUCTURES IMPACT 



53. The Oregon Inlet control structures would consist of two parallel 

 jetties extending seaward from the ends of Bodie and Pea Islands. Jetty 

 spacings of 2,500, 3,500, and 5,000 ft (Figure 12) were evaluated in both the 

 nearshore and shore processes model. In the nearshore model, both normal 

 astronomical tides and an extreme meteorological event represented by Hurricane 

 Donna (September 1960) were simulated. The shore processes model was used to 

 develop much finer flow detail around Oregon Inlet for eventual input to the 

 sediment transport simulations. In order to determine the maximum influence 

 changes at Oregon Inlet could have on bay-side storm tides, tests were run 

 with Oregon Inlet closed. These numerical simulations provided good estimates 

 of how the proposed structures at Oregon Inlet would affect surrounding areas 

 durino both normal and storm generated tides. 



V. 



PAMLICO SOUND 



-V 



ATLANTIC 



A 





v^^ 





< 



A-A 



- 2500- 



\ 



B-B 



- 5000' 



\\ 



C-C 



~ 3500' 



\ 



OCEAN 



Figure 12. Proposed alternate jetty configurations 

 for Oregon Inlet 



Preliminary Tests 



54. The eastern edges of the offshore and nearshore grids (Figure 2) 

 were originally placed far enough from Oregon Inlet so that any changes to the 

 inlet would not disturb the boundary values of the models. This assumption 

 was checked with the offshore model by closing the inlet (the severest change) 

 and then simulating Hurricane Donna (the severest surges). Results of this 

 run were then compared with a similar run with the inlet open. The marigrams 



36 



..AilllE-i .. r I ,f> 



— ' •• '"^ '"""'*^''-i"V ■rr iii p t f i V iiii r ii K 



