Protocol for the Derivation of Environmental and Human ... - CCME

Appendix D
Table D.1
Parameters Used in Estimation of Dilution Factor
Parameter Distribution Min Max Mode Correlations
B, effective
mixing depth in
aquifer
K. saturated
hydraulic
conductivity of
aquifer
i, hydraulic
gradient
Triangular 1 m 5 m 2 m
Triangular 31.5 m yr -1 315000 m yr -1 3150 m yr -1 i, r =-0.5*
Triangular 0.005 0.05 0.028 K, r =-0.5
R, recharge Triangular 0.005 0.5 0.2
L, site
length
Triangular 15 m 200 m 50 m i, r = -0.8
* the combination of high conductivity and gradient is infrequent (Trudell 1994, pers. comm.)
† due to constraints governing control of run-on and runoff, long sites are rarely found on steep slopes
Results
The cumulative frequency distribution for the dilution factor is shown in Fig. D.4. All simulated values of
contaminant dilution were less than 3 500 while about half of all simulations produced a dilution factor
less than 300. Form a perspective of controlling environmental risks and associated liabilities the lower
quantiles of the distribution are of interest (Table D.2).
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