A structured approach for calibrating two-dimensional, steady-state gr
ound-water flow models is developed. The first step of the proposed ap
proach is to replace the heterogeneous aquifer with an equivalent homo
geneous one using the geometric mean of transmissivities. Then, bounda
ry conditions are adjusted with the aid of a scattergram to reduce bia
s of the simulated hydraulic head distribution of the equivalent homog
eneous aquifer. After the bias is removed, the differences between the
simulated mean hydraulic head and the observed hydraulic head, result
ing from small-scale heterogeneities, are then reduced by adjustment o
f local transmissivity values based on hydrological and geological inf
ormation. The validity of the proposed procedure was tested for a hypo
thetical aquifer under idealized conditions and it was then applied to
the Avra Valley in southern Arizona to demonstrate its utility in rea
l world scenarios.