Geology Reference
In-Depth Information
Thus a trend line was fitted on recorded values of water level and
corresponding shift was made so that the water level at the end of the
experiment reaches its original value. Figure 4 shows this correction
graphically for a typical test.
18.6
18.4
18.2
18
17.8
17.6
17.4
17.2
0.00
1000.00
2000.00
3000.00
4000.00
5000.00
6000.00
Tim e (se cond s)
Water depth (413)
Trend Line
Corrected Water Depth (413)
Figure 4.
Recorded and corrected water level data.
Data recorded by Madofil are water depths (from well head) with time.
Data processing consists of determining
y
(vertical distance between water
level and static water level) for every recorded value. The plot of field data
as ln
y
t
=
f
(
t
) is fitted by a straight line (Fig. 5). According to the equation
of Bouwer & Rice (equation 1), hydraulic conductivity is calculated from
the slope of this straight line and the geometry of the well.
For each test, two
K
's are determined: one average
K
injection and one
average
K
pumping (respectively averages of all
K
's of injection pulses and
all
K
's of pumping pulses) are distinguished. A geometrical average of all
these
K
's gives a representative hydraulic conductivity in the well.
Figure 5.
Plot of ln (
y
) versus
t
for OB 1-2 well.
