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THE WORKSHOPS Eugene H. Harlow and John B. Herbich The purpose of this meeting was to gain a clearer picture of the principal factors affecting the design of entrances to ports and harbors, and their interaction. To further this purpose, the workshops were structured by the panel to elicit as much of the experience, training, and informed opinion represented by the assembled participants as possible in identifying outstanding problems requiring solution. From a full list of these problems, the consensus of the group would be sought on the ten most important, and their order of significance or urgency. Nominal Groups The structure selected by the panel for the workshops was that of nominal groups. In nominal groups, the members work in one anotber's presence, but without interaction. It teas been demonstrated that in the critical phase of program planning reserved for speculative consideration of all aspects of a problem, or of the range of alternative directions and objectives a program might follow, interacting groups tend to generate and pursue far fewer ideas than nominal groups. 2 The nominal group technique allows a period for the silent generation of ideas. Each member then presents an idea in turn, continuing until all ideas are recorded or the alloted time expires. The ideas are not discussed: questions may be asked for clarification of statements. First Workshop Participants were divided by expertise and interest into three nominal groups to develop statements of the problems faced in the design of entrances to ports and harbors in the areas of: nature and the environment, the concerns of ship owners and operators, and design and maintenance. Their statements were recorded and numbered on large sheets that were then brought to plenary session. (These statements are listed in Appendix A.) 157
158 Second Workshop The participants were assembled to read all the statements, and each was asked to list bis ten selections, in order of the ten most important problems. To avoid spreading the votes too thinly, essentially similar statements were combined for a single vote. (These omnibus statements are also listed in Appendix A.) The votes were tallied, and the statements were announced. Owing to a tie vote, eleven statements were selected. Each statement was given to a small working group for a title, final articulation, and the statement of preliminary objectives for research and other actions addressing the problems identified. These were reviewed and refined by the assembled participants, and the meeting adjourned. The product of the workshops is given in the succeeding section. The Most Urgent Problems in the Design of Entrances to Ports and Harbors 1. PREDICTION OF SHIP MOTIONS Improved and validated models are needed for the prediction of ship motions, vertical and horizontal, in the environmental and operational situations found in harbor entrances. These models are needed in the development of channel design geometry (depth, cross-section, shape, and planform), in the assessment of operating limits and traffic capacity, and to support the training of operators (simulators). Specific areas of weakness in existing models that should be addressed by research programs are: --Lack of data on a wide range of ship types; --Inability to predict the effects of Restricted water conditions {shallow water, banks), Complex, three-dimensional currents, Waves on lateral and vertical motions in restricted waters, Passing ships, Tugs and other auxiliary devices; --Scale effects associated with physical models. Research Objectives Addressing the weaknesses of existing models, as listed above in approximately their order of importance, constitutes a preliminary re~earob program. In all cases, research efforts abould be directed by a balanced program of: --Physical model testing, both captive and free- running, to develop data bases;
159 --Development of analytical predictions; and --Selected full-scale tests for validation or data generation, or both. 2. USE OF SYSTEMS - =YSIS IN To DESIGN OF FOR ENTICES The design, construction, and operation of harbor entrances involve the interaction of various government and non-government entities--ship operators and owners, the U. S. Army Corps of Engineers, the U. S. Coast Guard, National Ocean Survey (of the National Oceanic and Atmospheric Administration), Environmental Protection Agency, local port authorities, pilots and other state interests, local populace and governments--and interactions with other modes of transport, recreational boating, shoreside industries, and national and local economic interests. These interests are not all given adequate consideration in an integrated or systems-analytic manner in the design of harbor entrances. Research Objectives --Develop a detailed systems analysis procedure for use in harbor-entrance design --Test the design procedure for one or more sample ports, and modify as necessary --Sponsor interdisciplinary seminars to disseminate the systems-analysis approach, and to discuss major technical issues. 3. ENVIRONMENTAL DATA There is a need for reliable, economical measurement, reduction, presentation, and storage of environmental data, including: tides, currents, waves, sediments, bathymetry, geometry, salinity, wind", fog, ice, and water samples (chemical analysis). Research Objectives The research program conducted to address these needs should determine what improvements are needed in: --Accuracy, --Automatic analysis techniques, --Storage and retrieval techniques and procedures, --Display, and --Instrumentation
160 to meet the requirements of users. Some of the basic questions that will arise in the course of answering needs for environmental data are: --Length of measurement for a single run, --Interval between runs, --Spacing, and --Distinguishing interactions. 4. MODELS OF THE p~rsIcAL ENVIRONMENT Cost-effective model. for predicting the environmental conditions affecting harbor-entrance design need to be evaluated, improved, and validated. These should provide typical and extreme values of waves, currents, winds, water levels, salinity, sedimentation, water quality, and other environmental parameters as a result of both natural conditions and changes caused by human activity. The information to be provided is critical to the rational design of safe and efficient harbor entrances; for example, the basic forcing functions for ship-motion modeling, determination of maintenance dredging requirements, and ability to evaluate alternative designs and assess environmental effects. Researab Obi ectives The general needs to be addressed are tbose leading to improvements in the test data, numerical techniques, "caring techniques, physical processes, and forcing functions for each parameter and the interactions between parameters. Some examples of specific problems are: --Cost effective two- and three-dimensional matbematical models of all hydrodynamic processes, --Mbvable-bed modeling, "caring, and operational procedures, --Dispersive transport scaling in physical models, --Two- and three-dimensional models of transport, deposition and erosion of cohesive and noncohesive sediments, --Mathematical and physical models of water-quality parameters, --Two- and tbree-dimensional models of short waves and wave-current interaction in port entrances. This list is neither inclusive, exhaustive, nor ordered by priority.
161 5. DISPOSAL AND USES OF DOMED INTERIMS The questions to be answered in this area include: --Accumulation in the food chain of the toxic substances in dredged materials, and the possible effects on human health; --Alteration of the biological-resource value of subtidal bottoms owing to dredging and disposal operations; --Dynamics of dredged materials in open water: Where does it go after disposal? Does it stay put or move? --Relationships between dredge-disposal islands, the alteration of traditional flow patterns, and consequential biological effects on estuarine organisms; --Effects of deep-water disposal on benthic communities and biochemical cycles; --Potential methods of increasing the productivity of bottoms through the controlled use of dredged materials; --Alternative uses of dredged materials--for example, beach nourishment, and fill acquisition; --Use of dredged materials for the development of needed habitats; --New methods for reducing dredging costs; --Effective dissemination of the results of the Dredged Materials Researab Program carried out by the Waterways Experiment Station; and --Processing and treatment of dredged materials for disposal. Research Objectives The research program addressing these questions should determine the susceptibility of various levels in the food chain to the toxicants present in some dredged materials, and develop: --Predictive models for the fate of various components of placed materials, --Productive uses of dredged material for recreational islands, habitat-replacement projects, development of marshes, and nourishment of beaches; and --Methods for reducing dredging costs. The program should seek wider dissemination of the results of the Dredged Materials Research Program of the U. S. Army Corps of Engineers.
162 6. EPt)STON, TRANSPORTATION, "D DEPOSITION GRANULAR SEDIMENTS Improved procedures are needed for the prediction of shoaling rates and patterns near harbor entrances. The methods offered to answer this need should be based on wave, wind, and current characteristics. The results should include the development and verification of appropriate field methodologies. Research Objectives The researob program directed to these procedures and methods should seek improvements in: --Measurement of the quantities and characteristics of littoral materials; --Measurement and quantification of longshore energy-- waves, currents, and winds; and --Understanding of the mechanics of waves and sediments, and of the interactions of waves, sediments, and structures. A principal objective of the research program should be the improvement of predictive models. 7 . ENTRANCE-CHANNEL DES IGN AND OPERATING CRITERIA Improved criteria are required for the siting and design of harbor entrances. Such criteria must include: --Ship types, sizer, and traffic densities, --Appropriate aids to navigation, and --Expected operating equipment, in terms of wave", currents, winds, and tidal range. Data for existing and projected entrance channels are insufficient to predict: --Waves, swells, and sea conditions, --Currents, --Tidal heights, --Salinity, --Sinkage and trim, --Vertical ship motions, --Vessel draft, and --Bank effects.
163 Researab Objectives To develop improved criteria, the following needs for research and development must be met: --Determination of the sophistication necessary for adequate simulation of harbor-entry maneuvers to set harbor-design parameters; --Further development and validation of mathematical models of ship-maneuvering motions for use in simulations of harbor-entrance transits. Such models must adequately account for effects on ship motions on waves, currents, wind, water-depth irregularities, and irregularities in the proximity of the banks; --Establishment of mathematical expressions for the horizontal dimensions and siting of channels in simple harbor entrances as a function of design ship characteristics; --For more complex harbor entrances; e.g., with shear currents,* selection of the best methods and procedures for studies directed to fixing the horizontal dimensions; --Development of a mathematical formula to enable prediction of acceptable ship sizes and load conditions for given wind, tidal, sea/swell measurements, based on the horizontal dimensions of the entrance; and --Similarly, development of statistical formulae to enable prediction of acceptable drafts. 8. STANDARDS OF SAFETY There do not exist accepted standards, analytical techniques, or data for systematic evaluation of the navigability of harbor entrances. Research Objectives --A historical analysis should be performed to determine the safety records of each existing major port. Those with the best and worst safety records should be identified and studied further. *A shear current varies locally for example, sweeping across the mouth of a harbor faster than its uniform speed elsewhere. If a ship intersects a lateral shear current, the bow will feel the current most, with a tendency to turn the ship.
164 --A careful examination of these ports should be conducted, using modern port-design techniques, to determine the characteristics that enhance safety and those that lead to safety problems. --Techniques for measuring these characteristics by reference to a common base need to be developed by experts in various disciplines (perhaps constituting an advisory board). A set of standards should be developed from these efforts to support adequate evaluation of the safe navigability of an arbitrarily selected port, and should be cast in a form that can be used in systems design. --The standards should be promulgated by an independent, authoritative source. 9. MARINER NEEDS The needs of the mariner should be defined in quantitative terms. These needs include (but are not limited to): --Dependability and usefulness of aids to navigation, --Accuracy and usefulness of charting services, --Vessel-maneuvering requirements, and --Vessel support services. Research Objectives The research program designed to investigate and quantify the needs of the mariner should: --Develop and validate mathematical models of vessel behavior characteristics and the effectiveness of aids to navigation; --Conduct studies of the human-factors aspects of vessel control, and of the use of charts and aid; and --Combine the results of these and other studies to develop simulator and physical models of existing and projected harbor entrances. 10. DECISION MAKING PROCESS - The decision making proce"s for harbor entrances should be reviewed to enable evaluation of proposed improvements to harbor entrances, and if these improvements are indeed needed, to enable permits to be obtained and work initiated promptly.
165 Research Objectives --Research case histories of delays in proposals for changes, or for new entrances to harbors, to assess the part played by the decision making process; --Develop and test alternative decision making methods, including non-adversary methods; and --Develop a plan for effectuating legislative action through more effective processes. 11. EVALUATION OF COASTAL-RESOURCE VALUES IN HARBOR SITING, AND RESTORATION OF HAB ITATS Natural-resource values should be evaluated to ensure their proper consideration in siting and design of harbors: their determination, evaluation of their significance, and assessment is essential to achieving proper balance among environmental, economic, and other social values in decision making. Research Objectives --Determine why wetlands and coasts are productive, --Investigate the origins and evolution of wetlands and coasts; and --Establish the ecosystem response to natural events and human activities. REFERENCES 1. Van de yen, Andrew H., and Andre L. Delbecq, "Nominal versus Interacting Groups for Committee Decision-Making Effectiveness, Journal of the Academy of Management, 14 (June 1971~. 2. , A group process model for problem identification and program planning," Journal of Applied Behavioral Science, 7 (1971~: 466-492.
