The use of decision analysis (DA) has been proposed as a technique for sele
cting from among alternative designs for subsurface remediation. To assess
the ability of DA to generate consistent decisions for the widely practiced
pump-and-treat (PAT) strategy, 27 candidate PAT designs were compared for
a case study site. The sensitivity of the alternative selection to various
modeling assumptions was examined, including the complexity of the site-spe
cific numerical models, the assumed degree of aquifer heterogeneity, the ma
nner of defining failure: and the assumed cost of failure. The initial net-
present-worth analysis resulted in the selection of one of two designs that
included injection wells for effluent disposal and hydraulic control. Howe
ver, when the injection wells were excluded from consideration, the selecti
on from a diverse set of alternative PAT designs was highly sensitive to th
e particular modeling assumptions. In general, the practical usefulness of
the DA approach is dependent on the ability to characterize the nature and
probability of system failure.