Geoscience Reference
In-Depth Information
Fig. 19.2
Boundary conditions and calibrated groundwater contours of the model 'Catchment'
for today's climatic conditions. The special case of Neumann boundary condition ('no-flow') was
used along the watershed to outline the catchments area.
Blue
arrows represent the groundwater
flow direction
(
R
0.98) to 20 groundwater measurement points at different depths by variation
of hydraulic conductivity (Darsow
2004
). Groundwater recharge, as one of the key
parameters in this study, is kept as evaluated by Eq. (
5
).
Since sink terms other than discharge are not modelled, the total discharge
equals groundwater recharge,
=
i.e. 56,000 m
3
/day or 146 mm/a. Almost 59%
Table 19.2
Horizontal hydraulic conductivity
K
and effective porosity
n
e
used in the groundwater
flow model 'Catchment'
Layer 1
Upper aquifer
Layer 2
Confining layer
Layer 3
Middle aquifer
Layer 4
Confining layer
Layer 5
Lower aquifer
K
(m/s)
a
10
-4
-7.2
10
-7
-1.2
10
-4
-5.0
10
-8
10
-5
-2.5
1.8
×
3.7
×
3.4
×
2.0
×
3
×
10
-4
10
-5
10
-4
10
-4
×
×
×
×
n
e
0.2
0.1
0.2
0.1
0.2
a
Vertical hydraulic conductivity is assumed to be 1/10 of horizontal hydraulic conductivity
