EXCESSIVE RAINS 



45 



already referred to, based on rainfall records at Chestnut Hill 

 Reservoir at Boston. His equations, in logarithmic form, 



are y ' 687 , for rains of maximum intensity for any period, 



2^.12 



y = ' 687 for rains giving the greatest intensity of pre- 



STORM INTENSITY AT 

 WASHINGTON AND BALTIMORE 

 Washington Storms 



DURATION OF STORM IN HOURS 

 FIG. 9. 



cipitation which it would ordinarily be necessary to consider 

 in engineering design. 



Figs. 8 and 9 show similar diagrams from the report of the 

 Sewerage Commission of the City of Baltimore, 1897. 



Fig. 10, prepared * by Mr. George S. Webster, Chief Engineer, 



* Trans. Am. Soc. C. E., Vol. LIV, p. 210. 



