40 



SEWER DESIGN 



with judgment, and it may be necessary to omit two or three 

 uncommon and rarely severe storms. 



Several years ago Prof. A. N. Talbot of the University of 

 Illinois made use of the U. S. Weather Bureau records for the 

 group of States considered, in making a study of the maximum 



W 



I 4 



3 3 



3 

 *; 



? 



c 



tt 



H 



0123 

 DURATION OF STORM IN HOURS. 



FIG. 5. 



intensity of storms, and published his results in the Technograph* 

 The records of these stations range from i to 50 years and include 

 those from 499 stations. After the storms were plotted as 

 indicated above (see Fig. 5), two enveloping curves were drawn, 

 one giving what might be called the very rare rainfalls, and the 

 other the ordinary maximum. The curves drawn were in 



* Technograph, 1891-1892, pp. 103-117. 



