HYDROLOGY OF NEW YORK 



183 



year was 34.66 inches, while in 1844, we have for the storage 

 period, 10.52 inches, and the total for the year of 26.46 inches. At 

 Middlebury Academy, for the storage period of 1845, the rainfall 

 was 12.59 inches; for the growing period, 4.82 inches; for the 

 replenishing period, 8.6 inches, and the total for the year was 

 26.01 kiches. The record for the year 1846 at Middlebury Acad- 

 emy is not given, but it is clear, so far as we have any definite 

 meteorological record, that the gagings made by Mr Marsh were 

 at a time of very low water. 



Gagings made in 1895 show that in the month of July the flow 

 at Eochester may have been as low as 232 cubic feet per second, 

 and in September, 221 cubic feet per second. These results are 

 derived from actual gagings at Mount Morris by comparison of 

 catchment areas. Taking approximate gagings made at Rochester, 

 at the Johnson and Seymour dam, for the same year, we have 220 

 cubic feet per second for the mean of the month of October. 

 Moreover, gagings made at the raceway of the Genesee Paper 

 Compan} 7 during the summer of 1895 indicate that on several 

 occasions the flow was less than 200 cubic feet per second. The 

 canal, however, was low during these years and was drawing 

 some water through the feeder at Rochester — probably, on an 

 average, about 50 cubic feet per second. We have, then, a total 

 low-water flow at Rochester of about 250 cubic feet per second 

 during the period July-October, 1895. This quantity is 162 cubic 

 feet per second less than the low-water flow of 1846, as deter- 

 mined by Mr Marsh. 



The catchment area of the Genesee river at Mount Morris, 

 where the gagings were made, is 1070 square miles, and at Roch- 

 ester, with deductions for the area at Hemlock lake, used as a 

 water supply for Rochester, etc. 2365 square miles. In 1846 the 

 upper Genesee area was still largely in forest — probably for the 

 entire area above Rochester the primeval forest was from 50 per 

 cent to 60 per cent of the whole. 1 We have, here, therefore, a 



l In Allegany county, according: to the State census of 1855, the unim- 

 proved area was GO per cent of the whole, but in Livingston and Monroe 

 counties it was considerably less. Since the rapid removal of the timber 

 did not begin until after the construction of the Erie railroad, it is con- 

 sidered that in 1846, 50 per cent to 60 per cent is not far from right. 



