Geology Reference
In-Depth Information
15
Reconstruction of Water Level
Time Series in an Aquifer Using
Geostatistical Technique
Dewashish Kumar and Shakeel Ahmed
Indo-French Centre for Groundwater Research
National Geophysical Research Institute, Hyderabad-500007, India
INTRODUCTION
Water level is the only parameter that is measured from the aquifer directly
and also depicts the dynamics of the aquifer. It is measured normally in
static condition but in spite of all precautions taken while measuring the
water level there are data gaps. In aquifer modelling, particularly in the
calibration of the model in transient condition, a sufficiently long time series
of water level is required on all the wells that are used as control points. So
to deal with two different situations that are to have a sufficiently long time
series of water level at any well, geostatistics was applied to fill the data gap,
at the time when the water level could not be measured. With this we
obtained a mixed time series of water level at any well containing measured
water levels without any error term and the estimated water level with
estimation errors at uniform frequency.
A geostatistical technique from the theory of regionalized variables was
first documented by Matheron (1963). The theory of regionalized variables
very well applied to groundwater hydrology are by Delhomme (1978),
Gambolati and Volpi (1979), Marsily (1986), Isaaks and Srivastava (1989)
and Kitanidis (1997) and many others. This theory of regionalized variables
has been applied here in analyzing time variant parameter, the water level
data. As this parameter is very important in understanding the dynamics as
well as stress-strain behaviour of the aquifer, it is of utmost importance that
it should be available in adequate interval of time. This was used during
calibration of the aquifer model.
In the present study, water level data from IFP wells (Fig. 1) was used
from November 2000 to August 2003. The water level was monitored from
