38 



NEW YORK STATE MUSEUM 



seemed to be safely drawn that in 1890, due to changes in forest 

 area and in quality of crops grown, the amount of water re- 

 quired in Wyoming county to support vegetation during the 

 growing season would amount to 3.4 inches more than in 1850. 

 Why a mill stream in Wyoming county, which was ample for all 

 demands in 1850, entirely failed in 1890 seemed, therefore, fully 

 explained. 



In order to determine whether such conclusion was in accord 

 with the rainfall records of western New York, a large number 

 of such were tabulated in periods, with December to May, in- 

 clusive, making the storage period; June to August, inclusive, 

 the growing period, and September to November, inclusive, the 

 replenishing period. From a tabulation of the rainfall records 

 kept at Middlebury Academy, in Wyoming county, for certain 

 years — seventeen in all — from 1826 to 1848, inclusive, the mean 

 rainfall for the growing period was determined at 9.52 inches. 

 In 1832 it was only 6.76 inches. The maximum at Middlebury 

 Academy was 14.36 inches in the growing period of 1828. Tabu- 

 lating more recent records it was found that at Arcade, in 

 Wyoming county, from 1891 to 1896, the mean of the growing 

 period was 13.61 inches, the minimum of 9.62 inches occurring 

 in 1894. At Leroy, in the adjoining county of Genesee, the 

 mean of the growing period from 1891 to 1895, inclusive, was 

 10.31 inches, the minimum being 6.61 inches in 1894. At 

 Rochester the records show a mean of the growing period for the 

 years 1871 to 1896, inclusive, of 8.29 inches, the minimum being 

 only 5 inches in 1887. It appeared, therefore, that at the 

 present time, with the catchment areas almost entirely de- 

 forested, streams must necessarily be very low during the sum- 

 mer season of nearly every year. Practical observation in 

 western New York amply confirms this theoretical deduction. 1 



Variation in water yield. The runoff of Niagara river has been 

 commonly assumed on the authority of the Lake Survey at about 



i Abstract from Stream Flow in Relation to Forests, by George W. Rafter, 

 in An. Rept. of Fisheries, Game and Forest Commission for 1S0G. The 

 portion relating to Risler's experiments is from paper on the Data of 

 Stream Flow in Relation to Forests. 



