34 



BULLETIN 101*7, U. S. DEPARTMENT OF AGRICULTURE. 



48 hours. The run-off from this storm raised the water in Lake 

 Traverse approximately 2 feet but did not materially increase the 

 discharge from the lake. 



The effect of the two storms of June 10-13 and June 26-28, 1915 

 (fig. 14), is quite marked in the run-off records of Red River at 

 Fargo, Grand Forks, and Emerson. The monthly precipitation for 

 June of that year was maximum. Apparently this was largely due 

 to these two storms which covered large areas in the central portion 



Fig. 11. — Maximum Q-ds.y storm rainfall on watershed of Red River of the North, 



July 17-22, 1897. 



of the watershed above Grand Forks. The run-off for the following 

 month was very close to maximum at that station. Investigation 

 of the monthly and storm precipitation data (see Table 8, Summary) 

 showed that one or more storms occurred during each month March 

 to September, inclusive, and that the excessive monthly precipitation 

 of this period was due largely to excessive storms. 



In the period 1891—1919 excessive storm precipitation, causing 

 maximum or nearly maximum monthly precipitation, occurred dur- 

 ing each month just prior to the months from May to October for 

 which the run-off was maximum above Grand Forks. Thus May, 



