5.6 Hydraulic Conductivity


 The purpose of this experiment was to investigate

whether or not the bacterial growth during the aquifer

reclamation period changes hydraulic conductivity. Todd

(1959) indicated some decrease in infiltration rate resulted

from microbial growths clogging the soil pores. Hydraulic

conductivity values of all three columns were evaluated

before and after the first set of column biodegradation

studies using the method described in Chapter 4. The

results are listed in Table 5-25. The apparent hydraulic

conductivity after the biodegradation study was corrected

with the shrinkage of soil column depth (L).


Table 5-25. Column hydraulic conductivity results.


 Parameter #1 #2 #3

 L (cm) 22.5 22.0 23.0
 Before Q (ml/min) 66.3 54.6 60.6
 dh (cm) 48.3 48.6 48.6
 K (cm/sec) 1.13x10 9.03x10- 1.05x10

 L (cm) 20.5 20.5 20.8
 After Q (ml/sec) 66.1 52.5 57.7
 dh (cm) 48.3 48.6 48.6
 -2 -3 -3
 K (cm/sec) 1.03x10 8.09x10 9.02x10

 Corrected K 1.13x10-2 8.68x10-3 9.97x10-3

 A (area) = 45.6 sq.cm.
 K = (Q /60) x L / (dh x A)


 Based on this experiment, the magnitudes of bacterial

growth did not result in significant change in the hydraulic

conductivity, or at least not significant enough to be

measured by the experimental setups used in this experiment.