32 Conservation Department 



(Fig. 5) shows the dissolved oxygen content of the Genesee river 

 between the New York-Pennsylvania border and Lake Ontario. 

 Resnlts are expressed as percentage of saturation, based upon the 

 values given by Whipple." This puts upon a common basis varia- 

 tions in temperature, and compensation has been made for the 

 barometric pressure of the regions. As may be seen, entrance of 

 decomposible material into the river is usually marked by a 

 depression in the dissolved oxygen line, and the recovery of the 

 stream is indicated by a corresponding rise in the curve. The 

 data show that beyond a point slightly north of Mt. Morris, the 

 stream never again succeeds in restoring itself to its full satura- 

 tion capacity. 



Figure 6 is a profile of the methyl orange alkalinity of the river, 

 expressed as parts per million of calcium carbonate. Except for 

 that section of its length, where, between Portageville and Mount 

 ]\Iorris, the river flows through a gorge approximately twenty 

 miles in length, this profile shows a progressive increase in alka- 

 linity to Rochester, most pronounced where the river's volume 

 is augmented by highly alkaline streams draining regions of lime- 

 stone. The decrease in alkalinity throughout the length of the 

 gorge is marked, and the entire cause or causes not known Avith 

 certainty. Part of it might be attributed to dilution of the river 

 water by rains. When we consider tributary streams, w^e find the 

 only ones of note at this section are the outlet from Silver lake, 

 and Wolf creek. The lake waters are considerably lower in alka- 

 linity (Apps. Ill, IV) than the river waters which they join. 

 Wolf creek, to be discussed more fully later, is heavily charged 

 with salt refinery wastes. Usually associated in the earth with 

 common salt, sodium chloride, is the chloride of magnesium, wdiich 

 is rejected in the refining of the table product. At elevated 

 temperatures this salt readily hydrolyzes with production of hydro - 

 gen ions, the cause of acidity, and the neutralizer of alkalinity. 

 Increase of tem])erature is chiefly an accelerator of a chemical 

 i-eaction which takes place more slowly in the cold, so it is not im- 

 in'obabh' tliat the drop in the curve may be partly attributable 

 to this cause. 



Regarding carbon dioxide it might be mentioned that tlie same 

 methods whicli serve for aeration likewise serve for deaeration 

 or degassification in general, so although those processes which 

 consume oxygen also ])roduce carbon dioxide, the turbulent stream 

 conditions ])reviously described do not tend toward an a])]n-eciable 

 accumidation of carbon dioxide in water in ecjuilibrium Avith air, 

 and under its ])artial ])ressure which exists in an atmosphere 

 containing normally and at sea level a])])roximately .04 ])er cent 

 of carbon dioxide, c()iii|)ai'('d with 1^0.!) per cent of oxygen. 



Importtince of Character of Stream. — It is hoped that the 

 foregoing will iinpi-css the readei* witli the importance of taking 

 into consideration the nature of a stream and other influencing 

 factors for a i)ro])('r interpretation of results. A specific instance 



3 Standard Methods of Water Analysis, 02, 1925. 



