Beschreibung:
<jats:p>A finite element formulation is developed for the simulation of groundwater flow and solute transport in multilayer systems of several aquifers and aquitards. This formulation is general, flexibile, and capable of taking full advantage of the nature of flow in such multilayer systems. A fully three‐dimensional spatial representation can be performed for certain aquifers or for the entire flow system if needed. Those parts of the system that require three‐dimensional spatial discretization are handled effectively by combining two‐dimensional basis functions in the <jats:italic>x</jats:italic>‐<jats:italic>y</jats:italic> space and one‐dimensional basis functions in the <jats:italic>z</jats:italic> space. Furthermore, the formulation has a desirable option to perform one‐dimensional representation of flow and transport in aquitards and areal representation of flow and transport in certain aquifers that do not require the fully three‐dimensional discretization. When the one‐dimensional representation of an aquitard is used, coupling of adjacent aquifer and aquitard layers is handled using a convolution integral approach. A general solution strategy is also developed to allow systematic time stepping and cost‐effective matrix handling schemes. For those parts of the system that require three‐dimensional discretization, an algorithm referred to as the alternate sublayer and line sweep procedure is presented for decomposing three‐dimensional matrix equations. This algorithm can accomodate several thousand nodal unknowns without requiring excessive core storage and CPU time. Four examples of transient flow and transport problems are provided. These examples show verification of numerical results and demonstrate that the present finite element models are far more cost‐effective than earlier three‐dimensional models that are based on the conventional Galerkin approach and direct matrix solution algorithms.</jats:p>