to evaporate any moisture. The soil was placed in an 1-

liter graduated cylinder and the height of the soil was

marked. Then water was added by such that the water level

just coincided with the original soil level. Mixing was

provided to eliminate air pockets.

 Porosity = [amount of water added] / 200 (4-1)


 Hydraulic conductivity determination. Hydraulic

conductivity of the soil columns was determined by a

constant head permeameter shown in Figure 4-1. Soil

retention screens made of a few layers of glass fiber

supported with a stainless steel mesh were placed both on

top and at the bottom of the soil column. A piece of 3/4

inch tygon tubing was used to feed water from the constant

head reservoir. The frictional head losses from the tubing

and the fixtures were negligible compared to that caused by

the soil column. The hydraulic conductivity (K) was

calculated according to the formula:

 K = Q L / dh A (4-2)

where K is the hydraulic conductivity (cm/sec), Q is the

measured flow rate (ml/sec), L is the length of the soil

column (cm), dh is the total head loss through the

permeameter (cm) (which is the difference in elevation

between the inflow and outflow water levels), and A is the

cross sectional area of the soil column (cm2) (McWhorter and

Sunada, 1977).