HYDROLOGY OF NEW YORK 



129 



time the net runoff did not exceed under the assumed conditions 

 7.09 inches. The average runoff for 20 months was 0.354 inch and 

 for 7 months 0.110 inch. 



On Genesee river there have been two low-water periods during 

 the time covered by the gagings. The first was from June, 1894, 

 to February, 1896, a period of 21 months, during which time there 

 was a gross runoff of 13.02 inches. Evaporation has been com- 

 puted for a proposed reservoir of 12.1 square miles water-surface 

 area, with allowance for actual hight of water during the differ- 

 ent months. On this basis and with a small allowance for per- 

 colation, leakage, etc. the total evaporation loss for the 21 months 

 becomes 0.65 inch, leaving a net 'runoff of 12.37 inches. The aver- 

 age runoff for 21 months was 0.59 inch, or, if we assume 1.43 

 inches left in reservoir at end of period, the average allowable 

 runoff becomes 0.52 inch. For 10 months, with some allowance, 

 the average runoff is 0.30 inch and for 7 months 0.10 inch. 



The second period was from June, 1896, to December, 1897, a 

 period of 19 months, during which time the net runoff was 13.24 

 inches. The average runoff for 19 months, with 1.24 inches left 

 in reservoir at end of the period, was-0.63 inch; for 8 months, 0.31 

 inch, and for 6 months, 0.17 inch. These figures, without being 

 exhaustive, show that the Genesee river is a somewhat better 

 water yielder than the Muskingum river. The relation of the 

 rainfalls is shown in the tables. 



A large number of other interesting and valuable tabulations 

 could be drawn from these data, specially those relating to 

 storage. In any case, enough has been said to sustain the state- 

 ment that streams vary, not only as regards their total capability 

 of yielding water, but as regards their distribution. In order to 

 develop a stream to its maximum capacity for either water power 

 or municipal purposes, it is absolutely indispensable to have a 

 series of carefully prepared gagings. Lacking these, there should 

 be gathered as long a rainfall record as possible, from which, by 

 comparison, the approximate runoff of the stream may be com- 

 puted. A carefully taken series of gagings is, however, in every 

 way preferable. 



