How can WhAEM produce three-dimensional pathlines?
While WhAEM is a so-called Dupuit-Forchheimer model, which uses two-dimensional flow equations, the third (vertical) component of flow can be estimated from continuity considerations. In case the aquifer has a constant transmissivity and a constant recharge rate the vertical component of flow in WhAEM appears to be the same as found from a truly three-dimensional model. In all other cases the vertical component of flow in WhAEM is approximate. For most cases of regional flow the approximation is very accurate. For further reading on the matter see “Analytic Element Modeling of Groundwater Flow” by H. M. Haitjema, Academic Press, 1995, Section 3.5 (page 140).
