no 



BULLETIN OF THE BITREAU OF FISHERIES 



by melting snow and glaciers, with the result that they are grouped fairly close 

 together in water resistivity and the value is relatively high. 



The resistivity of the sea-water sample from Seaside, Oreg., was so low that it 

 could not be plotted in Figure 8. The resistivity of the sea water at 60° F. was 11.2 

 ohms per inch cube, or 1/880 that of the Clearwater River water at the same 

 temperature. 



Figure 9, a semilogarithmic plot of these temperature-resistivity data for the 

 waters from all of the sources investigated, shows two very interesting relations. 

 First, all of the curves are straight lines; second, all of the curves are parallel. The 

 significance of all of the curves being straight lines when plotted this way is that the 

 temperature-resistivity characteristic within the limits of temperature investigated 

 can be represented by an exponential equation of the form 



where p = the resistivity in ohms per inch cube, 9 = the temperature in degrees 

 Fahrenheit, e = 2.7183 base of Naperian logarithms, A = a, constant, and & = a constant. 

 The significance of all of the curves being parallel is that the slopes are all the same; 

 therefore, the constant term h in the exponent of this equation is the same for sea 

 water and the water from every stream investigated. The numerical value of the 

 constant 6 was calculated and found to be 0.014. The values of the constants A 

 for the various kinds of water were calculated and are tabulated in Table 5. With 

 these values of the constant term A and 0.014 for the constant term 6 in the above 

 equation, the resistivity of any of the waters investigated can be calculated for any 

 temperature from 40 to 100° F., with a maximum error not greater than 3 per cent. 

 Therefore, the temperature-resistivity characteristics for the waters studied can be 

 represented over the range of temperature from 40 to 100° F. by the following 

 equation: 



where ^ is a constant having a different value for the water from each stream and for 

 the waters investigated has a minimum value of 26.9 and a maximum value of 23,100. 



Table 5. — Constants for water temperature-resistivity equation p = At-^Q 



Stream 



Location at which sample was talien 



Sea water (Pacific Ocean) __ 

 Snake River 



Do 



John Day River 



Columbia River 



Do_ 



Deschutes River 



Hood River 



Rogue River 



Willamette River. 



North Fork Umpqua River 



Sandy River _,- 



Clackamas River 



Santiam River 



Tanner Creek 



Clearwater River 



Seaside, Oreg 



Salmon River Falls, Idaho 



Clarkston, Idaho 



Columbia River Highway, Oreg- 



B onnev ille, Oreg 



Priest Rapids, Wash 



Miller. Oreg 



Hood River, Oreg _ 



I Gold Ray Dam, Oreg 



I West Lynn, Oreg 



I Winchester, Oreg 



I Lower Sandy Bridge, Oreg 



Oregon City. Oreg 



Jefferson, Oreg 



Bonneville, Oreg. 



Lewiston, Idaho,. 



