This study has been largely qualitative in na-
operation at navigation locks and dams is going
ture. Future efforts could further develop the
to become common, whether in the near or dis-
study in a quantitative direction. In particular, it
tant future, an essential step toward that end is
was hoped that this study would develop meth-
to adopt the requirement that all control func-
odologies for evaluating automation costs and
tions be accomplished by programmable logic
effectiveness, but this objective proved too elu-
controllers (PLCs). In other words, electrome-
chanical relays should be phased out in existing
sive, given the level of generalization that had to
facilities and not specified for new facilities or
be maintained. This objective may never be
for rehabilitation projects. Even without any sig-
achievable on a general scale, and may be practi-
nificant level of automation, PLCs offer suffi-
cal only on a project-specific basis.
cient advantages over relay-based controls to
It is important to add the final comment that,
warrant this policy.
if any degree of automation and programmed
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