ITERATIVE QUASI-3-DIMENSIONAL FINITE-ELEMENT MODEL FOR HETEROGENEOUS MULTI-AQUIFER SYSTEMS

A quasi‐three‐dimensional flow model is developed for the analysis of hydrogeologic systems consisting of several aquifers interconnected by aquitards. Provided only that each layer is continuous within the domain and that a permeability contrast of 2 orders of magnitude or more exists between adjoining layers, a system can be completely heterogeneous. Any of the aquifers can be pumped, and discharge rates can be arbitrary. Flexibility is achieved by utilizing finite element discretizations for aquifers as well as aquitards. The solution is iterative, aquifers and aquitards being solved separately and coupling being provided through the leakage flux. Aquitard storage and interaction between aquifers are rigorously accounted for at all times. Convergence is demonstrated experimentally by comparison with the analytical solution of Neuman and Witherspoon. The multiaquifer model is shown to be much more economical than an equivalent three‐dimensional model. Copyright 1978 by the American Geophysical Union.