study concerns critical minimum seepage 

 rates, only the laminar flow is dealt with 

 in the laboratory calibration tests de- 

 scribed here. 



Among the factors mentioned by Fair as 

 governing the flow of water through sand 

 are those of velocity and temperature. 

 Girard (1891), Slichter (1905), Christian- 

 sen (1944), and Burmister (1954) also cite 

 the importance of temperature or viscous 

 forces in laminar flow. The viscosity fac- 

 tor is used to transform the velocity at 

 the temperature of the test to the corre- 

 sponding velocity at a standard temperature, 

 In the tests reported in this paper, 50" 

 was taken as standard and the following 

 formula was used: 



o 

 ^ Q Kinematlo viscosity at T F . 



Velocity at 50 ?■- Velocity at T Kinematic viscosity at 50 F. 



Values of kinematic viscosity are given in 

 table 2. 



Another factor considered by Fair is 

 the void space, which is governed by the 



size, shape, and packing of material through 

 which the water flows. Jones (1954) com- 

 pares the influence of gravel sizes; Bur- 

 mister (1954) compares gradation, shape, and 

 compaction of materials; and Mavis and Wil- 

 sey (1937) and Bodman and Harrodine (1938) 

 note clogging of sand in permeability tests. 



Application of Factors Peculiar 

 to the Mill Creek Standpipe 



Other factors requiring correction in 

 laboratory tests stem from the use of a salt 

 Solution and the conductivity bridge. One 

 of these corrections is the temperature 

 influence on resistance readings. The for- 

 mula for the correction is as follows: 



Rs = 



R^ (1 



0.01389 i\) 



Rg = Specific or measured resistance 

 at the standard temperature 



K. = Specific or measured resistance 

 at higher or lower temperature 



Table 1. — Description and Classification of 

 Turbulent and Laminar Flows 



Table 2. — ^ICinematic viscosity values for appropriate 

 teii?)eratures, from King and Brater (195U). 



Temperature 



Kinematic viscosity 



0°F. 



-IT- 

 39.2 

 ^0.0 

 60.0 

 70.0 

 80.0 



Sq. ft. per second 



0.0d0?)l931 

 0.00001687 

 O.OOOOllilO 

 0.00001217 



0.00001059 



0.00000930 



