The projects were selected for several reasons, including
the variety of navigational-harbor design problems that the simulations addressed,
the different levels of sophistication applied in several of the applications, and
the firsthand knowledge of many of the simulations by the committee.
A summary of each of the six case studies is included in Appendix C. Each was reviewed with particular attention given to specific lessons learned that might be generalized for application to other simulations. These lessons, both technical and administrative, are included in the descriptions in Appendix C and are consolidated into the five findings that follow.
Simulation results were used to reduce costs, increase ship safety, and reduce environmental risks.
In each of the six applications of simulators that were examined, the project sponsors were able to modify the waterway design and/or operation to achieve: significant cost savings, improvements in ship safety, and/or reduction in environmental risk. Cost savings were generally the result of reduced dredging or shifting of dredging activity to less costly sites. In one case, Coatzacoalcos, the cost savings resulted from being able to use larger ships safely without additional dredging.
Increased ship safety was achieved by identifying critical navigational areas during the simulation process. For example, in Oakland, significant safety benefits were derived by widening the bar channel and the entrance channel beyond the width initially proposed. Although this widening required an extra cost for additional dredging, it was offset by reduced dredging in other areas where the simulation had indicated it was not necessary. (Although the simulation was successful, port-sponsored project construction on an accelerated schedule has been discontinued because of legal constraints and the inability of the sponsor to develop a plan for disposal of dredged material that was acceptable to all parties [Appendix C]).
Environmental risks may be reduced by simulations in two ways. Improved ship safety contributes to a reduction in environmental risk because it reduces the probability of spillage of oil or other toxic substance that might result from ship groundings or collisions. Simulation can also reveal channel configurations that have smaller dredging requirements and which therefore minimize the environmental impact.