Interbedding of aquifers and semipervious layers (aquitards)
Types of aquifer systems to be analyzed:
1) three-layer system consists of aquifer overlain and underlain by aquitards;
2) two-layer system consists of aquifer overlain or underlain by aquitards.
a 
b 
Stratified aquifer system: a – three-layer; b – two-layer.
Two sets of solutions are considered in this section: those developed by M.S. Hantush and those developed by A.F. Moench. Hantush’s solutions being simple and based on well-known hydrological functions, however have a time limitation: they can be applied only for certain periods of time. Moench’s solutions are more universal: time-drawdown graph is plotted for the entire time period, drawdown is calculated for the main aquifer and for adjacent aquitards as well, storage capacity of the pumping well and skin effect are taken into account.
References
Hantush M.S. Modification of the theory of leaky aquifers // Journal of Geophysical Research. 1960. Vol. 65, N 11. P. 3713–3725.
Moench A.F. Transient flow to a large-diameter well in an aquifer with storative semiconfining layers // Water Resources Research. 1985. Vol. 21, N 8. P. 1121–1131.