Theoretical basics
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9.3.3 The Brooks and Corey Model
In the Brooks & Corey model the retention and conductivity function
are defined as (Brooks and Corey, 1964):
1
1
for
for
1
)
(
h
h
h
h
S
e
1
2
2/
1
s
for
for
)
(
h
h
K
h
K
h
K
s
[-] and
[-] are two fitting parameters which correspond to the
pore size distribution, respectively with the tortuosity.
9.4 Optimization of the parameter
The
)
(
h
- and
functions are adapted simultaneously to the
data points. This is essential as distinct parameters (i. e.
)
(
h
K
and
n
at van Genuchten/Mualem) influence the shape of both functions.
The adaption is accomplished by a non-linear regression under
minimization of the sum of all assessed squares of the distance
between data points and model forecast. However, the assumption
that the water content is spread out linear over the column is not
always fulfilled in coarse pored or structured soil. Therefore, the so
called “integral fit” is applied for the adaption of the retention function
to avoid an systematic error (Peters and Durner, 2006). For details of
the fitting procedure and data assessment please refer to Peters and
Durner (2007, 2008).
Please find a reference list in the appendix!
