Infinite leaky aquifer
Assumptions:
✓leaky aquifer system consists of isotropic aquifers interbedded with aquitards;
✓main aquifer: the aquifer that contains pumping well and where the water drawdown is estimated;
✓adjacent aquifer (may be two aquifers) water level drawdown is constant during the test period;
✓initial water levels in aquifers may be different or coincide;
✓boundary: aquifer has infinite areal extent;
✓pumping well is fully penetrating, located in the main aquifer, its storage capacity is neglected;
✓drawdown is estimated in the main aquifer at any distance from the pumping well;
✓crossflow through the aquitard is vertical;
✓storage of the aquitards is neglected;
✓pumping well storage capacity may be taken into account (see complementary solutions below).
a 
b 
c 
d 
e 
f 
Cross-section of the leaky aquifer system with water level in adjacent aquifers constant during the test period.
a – 3-layered confined aquifer system with a leaky roof; b – the same with a leaky bed; c – 3-layered confined aquifer system with different initial levels in aquifers; d – 3-layered unconfined leaky aquifer system; e, f – 5-layered confined (e) and unconfined (f) aquifer systems with leaky roof and bed. Arrows show flow direction within layers.
Fundamental equation:
Laplace transform solution:
Besides the fundamental equation the following complementary solutions are applied:
1) solution for water level drawdown in the fully penetrating observation well in the leaky aquifer with allowance for the pumping well storage capacity
Laplace transform solution:
2) solution for water level drawdown in the pumping well in leaky aquifer with allowance for the pumping well storage capacity
Laplace transform solution:
3) Hantush’s solution for the aquifer anisotropic on the lateral plane
To be analyzed are:
One well pumped at a constant rate
Pumping
Recovery
One or several wells pumped at a variable rate
Pumping
References
Hantush M.S. Analysis of data from pumping tests in anisotropic aquifers // Journal of Geophysical Research. 1966. Vol. 71, N 2. P. 421–426.
Hantush M.S., Jacob C.E. Non-steady radial flow in an infinite leaky aquifer // Transactions, American Geophysical Union. 1955. Vol. 36, N 1. P. 95–100.
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. Radial flow in a leaky artesian aquifer // Transactions, American Geophysical Union. 1946. Vol. 27, N 2. P. 198–205.
Lai R.Y.S., Chen-Wu Su. Nonsteady flow to a large well in a leaky aquifer // Journal of Hydrology. 1974. Vol. 22, N 3/4. P. 333–345.