Aquifer of infinite lateral extent (Theis’s method)
Assumptions:
üaquifer
is
confined, isotropic, of infinite lateral extent;
üdrawdown
in
the aquifer could be calculated at any distance from the pumping
well;
üdrawdown
develops in two
stages: unsteadystate flow and quasisteadystate flow;
üstorage capacity
of the pumping well as well as skin effect and storage capacity of
the observation well could be taken into account (see corresponding
complimentary solutions below).
Confined aquifer of lateral infinite extent (cross section).
Fundumental equation:
Besides the
fundamental equation the following
complementary solutions are
applied:
1)
Moench’s solution for drawdown in the fully penetrating observation
well in confined aquifer; the solution takes into account storage
capacity of the pumping well, storage capacity of the observation
well and skin effect of the pumping well.
Code of WTAQ3
program is used for calculation (author Moench, 1997). See:
Moench A.F.
Flow to a well of
finite diameter in a homogeneous, anisotropic water table aquifer
// Water Resources Research. 1997. Vol. 33, N 6.
P. 1397–1407.
2)
Moench’s solution for drawdown in the pumping well in confined
aquifer; the solution takes into account the storage capacity and
the skin effect of the pumping well.
Code of WTAQ3
program is used for calculation (author Moench, 1997). See:
Moench A.F.
Flow to a well of
finite diameter in a homogeneous, anisotropic water table aquifer
// Water Resources Research. 1997. Vol. 33, N 6.
P. 1397–1407.
3)
Popadopulos’s solution for
drawdown in the fully penetrating observation well in confined
aquifer; storage capacity of the pumping well is taken into
account
4)
Popadopulos’s solution for
drawdown in the pumping well in confined aquifer; storage capacity
of the pumping well is taken into account
5)
Hantush’s solution for the aquifer anisotropic on the lateral
plane
To be analyzed
are:
One well pumped at a constant
rate
Pumping test
Recovery test
drawdown is counted off from the
beginning of the pumping test
drawdown is counted off from the
beginning of the recovery test
The whole test period including
pumping /injection/ and recovery stages is analyzed
Several wells pumped at a
constant rate
Pumping test (simultaneous start
of all pumping wells)
Recovery test after simultaneous
start and simultaneous shutdown of all pumping wells
drawdown is counted off from the
beginning of the pumping test
drawdown is counted off from the
beginning of the recovery test
The whole test period including
pumping /injection/ and recovery stages is analyzed (simultaneous
start and simultaneous shutdown of all pumping wells)
Pumping test (asynchronous start
of the wells)
One well pumped at a variable
rate
Pumping test
Several wells pumped at a
variable rate
Pumping test
Graphical
methods are displayed only for the basic solution. Parameters
matching /matching the observed data against theoretical curves/
can also be made using complementary solutions. Then the following
additional parameters should be specified such as: casing radius of
the pumping well, skin hydraulic conductivity, skin thickness and,
if needed, shape
factor of the
observation well.
References
Cooper H.H.,
Jacob C.E. A generalized
graphical method for evaluating formation constants and summarizing
wellfield history // Transactions, American Geophysical Union.
1946. Vol. 27, N 4. P. 526–534.
Hantush M.S. Analysis of data
from pumping tests in anisotropic aquifers // Journal of
Geophysical Research. 1966a. Vol. 71, N 2.
P. 421–426.
Hantush M.S.,
Thomas R.G. A method for
analyzing a drawdown test in anisotropic aquifers // Water
Resources Research. 1966. Vol. 2, N 2.
P. 281–285.
Jacob C.E. Effective radius
of drawdown test to determine artesian well // Proceedings of the
American Society of Civil Engineers. 1946. Vol. 72, N 5.
P. 629–646.
Moench A.F. Flow to a well
of finite diameter in a homogeneous, anisotropic water table
aquifer // Water Resources Research. 1997. Vol. 33, N 6.
P. 1397–1407.
Papadopulos I.S.,
Cooper H.H. Drawdown in a
well of large diameter // Water Resources Research. 1967.
Vol. 3, N 1. P. 241–244.
Theis C.V. The relation
between the lowering of the piezometric surface and the rate and
duration of discharge of a well using groundwater storage //
Transactions, American Geophysical Union. 1935. Vol. 35,
pt. 2. P. 519–524.
