a, September 1938 Flood . From the 12th to the l6th of 

 September mar^ sections of New England had been saturated by as much 

 as four inches of rainfall, with comparatively little surface runoff. 

 Precipitation commenced again on the 17th and increased in intensity 

 until the 21st when the heavy hurricane rainfall arrived. Although 

 Providence recorded only 3.1 inches of rain during this period, a 

 peak of about 17 inches fell in both Connecticut and Massachusetts 

 (Plate C-2), Had this storm been centered over the Narragansett Bay 

 area, major river flooding wovild have occurred and added more damage 

 and destruction to that already caused by the wind and tidal flooding, 



b, September 11, 19^h Flood (Edna). The rainfall associ- 

 ated with this hurricane amounted to about i;,U inches at Providence 

 and 6,3 inches at Woonsocket, A total of 8,7 inches fell in about 



15 hours at Quonset Point, Rhode Island, There was little antecedent 

 precipitation, but the high concentration of rainfall in a short 

 period of time produced serious flooding on many streams in Rhode 

 Island, This flood was the maxiraxira of record for the Woonasquatucket 

 River and the second highest for the Pawtuxet River (see Table G-1;), 



c» August 19, 1955 Flood (Diane) , Torrential rains ac- 

 companied this hurricane, falling on gro\md already saturated by the 

 heavy precipitation which accompanied Hurricane Connie during the 

 previovis week (August 11-15). In a two-day period over six inches 

 of rain fell in Providence and lOcU inches in Woonsocket, This 

 rainfall caused a devastating flood in Woonsocket and the maximum 

 flood of record on the Blackstone and Taunton Rivers (see Table 

 G-1;). 



C-6. DESIGN STORM 



The September 1938 storm, which produced the highest amoTont of 

 rainfall associated with a damaging hurricane from tidal flooding 

 in southern New England, was adopted as the design storm. The hurri- 

 cane of August 31> I95I4., which was a rapidly moving storm, did not 

 bring extremely heavy precipitation to southern New England but 

 caused excessive tidal flooding in the Narragansett Bay area. Hurri- 

 cane Diane of August I9, 1955j which was a slow moving storm, pro- 

 duced record rainfall in parts of Connecticut and Massachusetts 

 near the Narragansett Bay area, although the winds were not of 

 hurricane intensity coincident with the record rainfall. It has, 

 therefore, been determined that it would not be consistent with 

 design based on probable occurrence to combine the maiximum rain- 

 fall associated with the August 19, 1955 storm and the tidal 

 flooding associated with the September 21, 1938 storm. Therefore, 

 the September 1938 storm was adopted for use in determining the 



c-5 



