Results showed that^ apparently, little change in the chemical 

 characteristics of Deer Creek results from algal decomposition. Dis- 

 solved oxygen decreases in amount as summer progresses, but this change 

 is a function of water temperature. As temperature increases, the 

 saturation point for oxygen in water decreases. 



Deer Creek water becomes increasingly alkaline as the season pro- 

 gresses. This change is probably due to changes in run-off. Large quan- 

 tities of snow water entering the stireara from surface sources tend to 

 reduce the alkalinity. After the snow run-off is completed, the stream 

 is fed chiefly from springs and these springs contribute more alkalinity 

 because of the dissolved salts they usually contain. 



Diurnal changes in pH are evidenced by analyses made at different 

 times on any one day. The pH appears to be lower during darkness and 

 early morning when stream temperatures and oxygen content are lowest. 



The amount of dissolved osqygen in the water of Deer Creek varied 

 from a low of 7.92 p. p.m. at 5 p.m. on May 19, with a water temperature 

 of 80° F. to a high of 11,85 p. p.m. at 11 a.m. on November 18, with a 

 water temperature of U7° F. The pH varied from 7.U to 8,5. 



Hazards Encountered by Adult and Young Salmon 



A substantial part of the seaward-migrant salmon produced in Deer 

 Creek are lost in irrigation diversions which take nearly all of the 

 stream by the end of May each year. Results of periodic fishing in the 

 diversion located at the mouth of the canyon during the 19U5 season are 

 presented in table 7, They give a good example of the potential loss 

 of young fish in such diversions. 



Table 7. — Losses in Deer Creek Irrigation Company Canal, 19hS 



In 19i|6, a fyke net was fished for a brief period (nights of May 31 

 and June 3 and 11) in the south canal of the Stanford-Yina Irrigation 

 Company. A total of 32 young salmon was captured at a point below the 

 fish screens. This catch exceeded that in the creek for the similar 

 period. 



11 



