36 



SEWER DESIGN 



hurricanes. They are more abundant on the Gulf and South 

 Atlantic coasts than at inland points." 



This report shows for Washington, D. C., 73 storms rain- 

 ing at the rate of i inch per hour or over in fifteen years before 

 January i, 1897. For Savannah, 62 in eight years; for St. 

 Louis, 36 in the same time. To show that the intensity becomes 

 a maximum as the time of the storm becomes less, the table 

 opposite is given. 



Table III from the same Bulletin shows, in another form, 

 the same thing. It gives the maximum intensity of rainfall 

 for periods of five, ten, and sixty minutes at Weather Bureau 

 stations equipped with self-registering gages, and is compiled 

 from all available sources. 



Table IV, abridged from a paper by C. W. Sherman * on 

 " Maximum Rates of Rainfall at Boston," shows again the 

 relation between the intensity and length of the storm. 



TABLE IV 



MAXIMUM RATES OF RAINFALL, AUTHENTICALLY REPORTED 

 FOR THE EASTERN UNITED STATES 



Heavy rains at the Chestnut Hill Reservoir in Boston 

 * Trans. Am. Soc. C. E., Vol. LIV, p. 212. 



