FISHERIES, GAME AND FORESTS. 51I 



area above the point of gauging on the Oatka Greek is 27.5 square miles, but this 

 area is so located that its run-off may be fairly considered typical of that of the entire 

 Upper Genesee drainage area, and hence the figures given are fairly applicable to the 

 whole. The drainage area of the main river itself above the point of the gauging 

 is 1,070 square miles. These drainage areas are rolling, somewhat mountainous 

 country, with deep valleys and high hills. The average elevation of the Oatka Creek 

 drainage area is about 1,500 feet above tide water, while the Upper Genesee area 

 above the point of gauging will average perhaps 1,700 to 1,800 feet above tide water. 

 For the year 1890 the rainfall of the Oatka Creek drainage area is taken at 47.54 

 inches. The gaugings are not complete for that year, but so far as available give the 

 following: For the growing period, June to August, inclusive, a run-oflf of 2.51 inches; 

 for the replenishing period, September to November, inclusive, 5.75 inches. For the 

 year 1891, the total rainfall was 38.12 inches, with a run-off of 14.05 inches and an 

 evaporation of 24.07 inches. In 1892, the rainfall was 41.69 inches, the run-off 15.42 

 inches, and the evaporation 26.27 inches. These figures are exceedingly interesting. 

 Although the rainfall for 1892 was 3.57 inches greater than in 1891, still the run-off 

 was only 1.37 inches greater, the evaporation in 1892 being 2.20 inches in excess of 

 1 89 1, or a total of 26.27. The mean temperatures of the years 1 891 and 1892 were 

 practically the same, being 45.70" F. for 1891, and 45.40° F. for 1892. 



Taking the run-off of the entire Upper Genesee drainage area of 1,070 square 

 miles, we have the following : 



RAINFALL. 



'894^ 47-79 



189s. 3I-0O 



1896, 41.68 



The foregoing figures are again interesting as illustrating the persistency of the 

 evaporation element without regard to temperature ; thus in 1894, with a rainfall of 

 47.79 inches, the evaporation from the Upper Genesee area was 28.41 inches. Again, 

 in 1896, when the rainfall was 41.68 inches, the evaporation was 28.88 inches; but in 

 1895, with a rainfall down to the probable extreme minimum of only 31 inches, the 

 evaporation fell to 24.33 inches. Taking into account, then, that three years is not a 

 sufficient lengtli of time to give final conclusions, we may say, as a tentative proposi- 

 tion purely, that, on the Upper Genesee area, with full or nearly full rainfall, we may 

 expect a yearly evaporation of something like 26 to 28 inches, but when the yearly 

 rainfall is at or about its minimum the evaporation will probably fall to about 24 

 inches. Comparing these figures with those already given for the Upper Hudson 

 area, we may draw the further tentative conclusion that the difference in evaporation 

 between the Upper Hudson area and the Upper Genesee area is something like 5 or 6 



