M^JLLS /l J-.CJ?pl^'^'^ Ph usical Environment 



Page no : 

 Calculated by: 



Checl ' d by-: 



Date 



(O of /33 

 J. R. -V. 



RM.T 



1 Mar. 73 



Wafer Levels ~ Storm S urate and Astronomical Tides ^ 



Tt)e fol lording calculations establish design 

 \Nater levels at the island site using the methods 

 of Chapter 3 and supple men ted by data for the 

 Delav^ore bai^ Area given in References 5 &,I6. 



Estimate of Storm Surge - Nomopraph Method 



Note: The nomograph method can only provide 

 a rough estimate for the present 

 problem since the island site is in 

 atxjut 40 ft. of ifvater in an estuary 

 entrance. The nomograph method will 

 give peak surge on the open coast 

 (a high estimate for the island site). 



Design Hurricanes For illustrative purposes 

 use hurricanes "A " 6, "b" given by 

 dretschneider in References S&/&. 



Hurricane A 



Radius to maximum winds - ^= 335 n.m. 



Central pressure Ap - 2.2 in. of mercury 



forward speed = )/p= 15 to 25 knots 

 (use Vp'25 knots) 



Maximum gradient wind., ^ 



^m^..= 0.tGb{75(p,-p.f-R (0.575 f)} 



Nhere for latitude 40* hJ, 



f= 0.536 ^ 

 Umax^ OM6l73 (2.2)^' 33.5 (0.575)(0.33b)} 



(102 mph) 

 Maximum sustained wind for lip " 25 knots 

 U„= 0.bG5U„a>c ^O.SVf 



U^ = abGS (S6.3) 1-0.5(25) = 66.9 knots 



(lOZ mph) 



Chapter 3 



Sect.3.&65 

 b(i)(b) 



Refs.S&fC 



£q. 3-35 



£g. 



3-34 



8-10 



