(5) Unusually high tides are likely to occur in advance 

 of a hurricane surge, as they did in September 1938, causing some 

 inflow and a snail rise of the bay in advance of the hurricane 

 surge. 



(6) Inflow of hurricane waters through the navigation 

 openings was based on model tests. Further testing would be 

 desirable to deterndjie the most effective shape of the openings 

 and distance across the sill normal to the opening, 



(7) Design streamflqw of 8it,000 cubic feet per second 

 (fresh-water runoff) would res\alt in an increase of approximately 

 0.3 foot in the level of the bay. 



(6) The rise in water level from Newport to Providence 

 (wind setup) as a result of design wind blowing across the 25-mile 

 fetch is estimated at 3«1 feet but would vary widely with wind 

 direction and intensity. 



(9) Emptying of the bay to normal levels would occur 

 r^id]y after a hurricane has passed. The northwest winds which 

 follow after passage of the storm center would very likely speed 

 this up. Since the waters of the bay would be tipped vpwards 

 to the north it is likely that the water will rock back towards 

 the barriers at the mouth. The rise in water level likely to 

 occur in the Lower Bay would be small because of the damping 

 action of the islands and the deep water in the lower end of the 

 bay above the barriers. 



g. Navigation openings . These are a key to effective design 

 of the Lower Bay barriers. The navigation openings were selected 

 with a view to: 



(1) Fixing the openings small enough to effectively 

 restrict the entrance of hurricane surges and provide a reasonable 

 degree of protection in the bay as a whole. 



(2) Provide openings of large enough width and depth 

 for the passage of commercial and Naval vessels, without creating 

 excessively fast currents under normal conditions. 



17 



