B-18. STORM SURGE IN NARHAGANSETT BAY 



The storm surge analyses provided by Texas A & M Research 

 Foundation were the basis for surge determination in the bay 

 using the hydraulic model. The results of the model tests, 

 without wind effects, conducted by the Waterways E3cperiraent Station, 

 are tabulated below: 



The determination of wind effect to be added to the model 

 results is complicated by the irregularities of configuration 

 and hydrography in the 2$. 5-mile fetch of the bay and the wind 

 pattern that might apply between the mouth and head. Calculations 

 using a steady wind of 76 miles per hour gave a wind set-up of 

 approxiinately 3.0 feet. More detailed analytical studies by 

 Texas A <§c M Research Foundation are in progress. These indicate 

 that the transient winds of a hurricane might possibly increase 

 the wind effect to 5 feet. 



B-19. SELECTION OF DESIGN STORM SURGE 



The 20-knot storm speed was adopted for the tidal design 

 flood because of its higher elevation and greater volume at the 

 mouth of the bay, making it a more severe test of barrier 

 structures. Recognizing the desirability of continuing research, 

 storm surges of 10. li feet and 15.6 feet, respectively, were 

 selected for Newport and Providence. These adopted surges, 

 when applied upon spring tide elevations of 2.6 feet above m.s.l. 

 at Newport, and 3.1 feet above m.s.l. at Providence, are as follows: 



Design Hurricane Elevations 

 Newport, R.I. Providence , R.I . 



Adopted Storm Surge (feet) IO.I4 15.6 



Spring Tide Elevation(m,s.l.) 2.6 3.1 



Design Hurricane Elevation 13.0 18 •? 



• (m.s.l.) 



B-21 



