Table 3. — Surface temperature and chemical characteristics of water in Snake River {at Weiser, Idaho), Powder River, and 



Eagle Creek, January 1963 to June 1964 



Year and month 



Total Phenol- 



alkalinity phthalein 

 alkalinity 



C02 



pH 



Tempera- 

 ture 



Oj 



SiOj 



Snake River: 



1963: 



January 



February. _. 



March 



April , 



May 



June , 



July 



August 



September., 



October 



November., 

 December.. 



1964: 



January 



February. . , 



March 



April _, 



May 



June 



Powder River: 



1963: 



January 



February.. 



March 



April 



May 



June 



July 



August 



September. 



October 



November, . 

 December.. 



1964: 



January 



February.., 



March 



April 



May 



June 



Eagle Creek: 



1963: 



January 



February. . 



March 



April 



May _ 



June 



July 



August 



September. 



October 



November. , 

 December.. 



1964: 



January 



February.. 



March 



April 



May 



June.. 



' Computed from Moore (1938). 



their subsequent conversion to hioarbonate by car- 

 bonic acid probably accounted for the higher read- 

 ings. The large local \ariatioii in the concentration 

 was probably caused Ijy currents, algae, and 

 clianges in alkalinity of the inflowing river. 



The samples were also analyzed for normal car- 

 bonate. Concentrations for July 1902 through June 

 1903 ranged from () to 30 p.p.m.: for 1963-64, the 

 range was to 21 p.p.m. Maximum concentrations 



were in the surface layer (0-15.2 m.). The lower 

 depths contained no normal carbonate during July 

 and August, when production of algae was high 

 and stratification complete. This condition was 

 similar to that in lakes described by Welch ( 1952) . 

 Decomposition of algae and other organic material 

 at the lower depths ajiparently liberated enough 

 carbon dioxide to convert all carbonate to bicar- 

 bonate. This assumption is supported by the fact 



314 



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