Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
APPENDIX A: STAT~=S OF "E P=TICIP~TS- Outstanding Problems in the Design of Entrances to Ports and Harbors The statements following were developed during workshop sessions by the participants in the meeting recorded in these proceedings. They are presented here to indicate the broad array of specific concerns pertinent to the design of entrances to ports and harbors, and for readers to whom the statements will be of interest. As individual contributions, the statements should not be interpreted as necessarily representing policies or opinions of the participants' organizations, the Marine Board, or the National Research Council. 167
STATEMENTS OF THE SHIPS AND USERS GROUP 1. There are no criteria for the minimum horizontal dimensions of channels, given specific harbor factors such as: · ships (type, size, traffic density), · navigational aids/aids to navigation, · environmental data, · hydraulics, · and others. 2. No rational computer-aided procedure has been developed to evaluate harbor-entrance systems for given ship users. 3. No validated mathematical model exists for predicting ship motion (horizontal and vertical directions) in shallow water, waves, and currents. 4. Systems-analysis techniques {i.e., failure-mode hazards analysis or single failure-point analysis) are not used in the design of harbor . , entrances. 5. The difficulty of locating ships' positions and latitudinal set relative to the harbor entrance and channel under conditions of night, limited visibility, and stressful situations (such as _ . .. ~ _ heavy traffic, cold, and foreign crews) has not been resolved. 6. Regulations, operating limits, and navigational criteria are sometimes established arbitrarily, without a technical basis. 7. There is no integrated approach for including environmental, . . · · . . · . - construction, maintenance, snap, operational, and economic concerns in the design of harbor entrance". 8. The additional requirements of warship accommodation in harbors are unknown. 9. Insufficient attention is paid in the design of harbor entrances to achieving minimum maintenance costs. 10. No catalog exists of generic ship types, including accurate, mathematically modeled hydrodynamic coefficients for predicting the navigability of harbors. 11. No national initiative or investment has been undertaken to develop existing and future harbors for the growth of international trade. 12. Insufficient information exists for predicting bottom clearance in existing harbor entrances- 169
170 Sinkage/trim Wave spectra/swell Vertical ship motion Detailed currents Actual tidal height Knowledge of draft Salinity. 13. Insufficient meteorological forecasts are available for ships operating in harbors. 14. The displacement of floating aids by weather, ice, and traffic should be given attention. 15. Insufficient consideration is given to placing the harbor entrance on the approach chart to provide the mariner with adequate maneuvering references. 16. No accepted standards or guidelines have been developed for validating models. What comparisons and level of agreement are appropriate? 17. No attention is paid to accommodating stricken vessels In ports or harbors. 18. No criteria have been articulated for selecting an optimum entrance as a function of ship type and speed, the environment, or entrance ~ 1menslons . 19. Insufficient information ha" been collected and analyzed to predict the effect on steering of: · Bottom and bottom irregularities due to silting · Complex three-dimensional currents · Currents in turns · Basic suction · Passing ships. 20. No analytical method exists for predicting three-dimensional currents on harbor entrance waterways. 21. Ship designs may not provide a piloting position with adequate perception for safe navigation within the harbor entrance area. 22 Better understanding needs to be gained of the scale effects of physical models (hydraulic and ship hydrodynamics, and the effects of harbor-entrance variables). 23. Tbe specific support services that operate in harbor entrances {tugs, -salvage vessels, dredging operations, vessel traffic services, anchorages) need to be given more attention. 24. There is inadequate detection and verification of the location of obstructions (wrecks and storm-induced shoaling, for example), and an insufficient program of removal. 25. Limited data are available for prediction of sand bar/shoaling migration. 26. Political barriers impede achievement of the maintenance requirement" of existing ports. 27. There are navigational problems incident to the conflicting uses of harbor entrances--commercial traffic vet fishing and pleasure craft, for example.
171 STATEMENTS OF THE NATURE AND ENVIRONMENT GROUP 101. Designate acceptable and economical dredge-disposal areas. 102. Address the following problems in dealing with spills of hazardous materials . ~ ~ do: ~ _ _ _ ~ _~ _ ~ _ ~ 1 Prevention and control Minimizing environmental effects Restoration. 103. Ensure that the new entrance will provide for safe navigation with respect to tides, currents, winds, waves, channel dimensions, and structure design. 104. Determine the accuracy of environmental information, such as waves, winds, tides, currents, and bottom characteristics. 105. Improve prediction of the rate of littoral drift as a function of wave energy. 106. Site harbors in a manner that protects natural-resource values of estuaries and wetlands. 107. Develop a consistent data base of waves and currents for port design. 108. Develop reliable methods for estimating shoaling rates and patterns in harbor interiors. 109. Investigate the effects of mitigation practices, and development of other habitats. 110. Minimize the costs of maintenance dredging through navigational aids, channel siting, control structures, optimum dredging and disposal operations. 111. Provide for accurate prediction of the environmental effects of dredged material placed in the water. 112. Predict siltation rate in a dredged navigation channel seaward of a harbor entrance. 113. Test and validate techniques for habitat restoration. 114. Develop cost-effective models of waves, currents, water levels, tsunamis, storm surges, sedimentation, and other hydrodynamic processes. 115. Develop reliable methods of predicting seiching in harbors. 116. Educate the public to enhance participation in planning. 117. Ensure that changes caused in the physical parameters (tides, currents, salinity, etc.) are not so drastic as to cause major adverse environmental effects. 118. Develop cost-effective technology for measurement of waves, tides, salinity, sediments, etc. 119. Experiment with new techniques for sand bypassing at harbor entrances. 120. Design efficient decision making processes that involve all parties with legitimate environmental concerns. 121. Develop real-time systems to provide data on wind, waves, and currents as aids to navigation. 122. Develop and validate field procedures to establish shoaling rates. 123. Estimate alterations in the biological resource value" of bottoms. 124. Design breakwaters for deep water. 125. Solve wave-current interaction problem.
172 128. 129. 126. Improve communication of findings and implications of research to policy makers. 127. Predict the hydrodynamics of ship-ship interaction in a confined channel. Develop low-energy methods for maintaining navigable channels. Integrate watershed management as a consideration in port planning. 130. Develop a systems approach to integrating all aspects of the natural environment in port planning. 131. Develop techniques for predicting changes in physical and chemical parameters resulting from harbor entrance redesign. STATEMENTS OF THE DESIGN AND MAINTENANCE GROUP 201. There i" not enough basic data on existing harbor entrances with which we can model capability. 202. The needs of the mariner, as they affect harbor-entrance design, need to be defined quantitatively. 203. There is a need to develop better concepts and designs of seagoing cutter-head dredges and discharge pipelines that can operate efficiently in the open sea. 204. Cost-effective methods of quantifying physical environmental parameters in coastal areas should be sought. 205. The state of the art of design and maintenance of rubble-mound harbor entrance structures needs advancement. 206. The full impact of the design on all users of coastal zones needs to be recognized. 207. Harbor-entrance design demands systems analysis. 208. There are unmet needs for reliable quantitative hydraulic (and/or) mathematical models for the prediction of tides, currents, wave", salinity, and sediment changes in harbor entrances as a function of various design configurations. 209. A draft of a national decision making process (replacing that of the National Environmental Protection Act of 1969) that evaluates needs and desires, and avoids adversary processes needs to be submitted to Congress, so that permits are obtained and action started promptly on improvements that are required. 210. A technique should be developed to minimize the conflicts of split governmental responsibility to allow more effective implementation of harbor entrance projects. 211. Standards of safety need to be established to limit the rink of casualties. 212. There is a need for better estimates of shoaling rates in approach channels for different sediments and different waves and currents. 213. A cost-effective instrumentation system is needed with which to measure synoptically vessel excursion and forcing physical function in harbor entrances. 214. A users manual and associated short coursers) on the planning and design of harbor entrances should be produced.
173 215. A mechanism should be developed to identify the operational limitations and constraints that are implicit in basic design. 216. Improved procedures are needed to predict the capabilities of existing harbor entrances to accommodate new systems {of managing vessel-traffic flow, for example) and to identify the minimum improvements needed to accommodate these new systems, as well as constraints. 217. What is the proper design of a bridge across a harbor entrance? Can reliable energy-absorbing systems be developed to withstand ramming by a ship? 218. Research on the processing, treatment, and placement of fine dredged sediments is needed to make them suitable for upland use or deep-sea deposition. 219. With respect to harbor-ent£ance design, there is a need to develop a more effective technique for disseminating information about results of the U. S. Ax my Corps of Engineers' Dredged Materials Research Program. 220. The recent reduction in maintenance dredging and in other related harbor-entrance activities should be reversed. 221. Second- and third-generation mathematical models should be developed to predict the behavior of ships in an approach channel, between the jetties, and in the harbor. These are necessary for (among other important functions): · Checking the design of ship channels, and · Determining the geometry of the channel entrance. 222. There is a need for better quantification of physical environmental parameters in coastal areas (i.e., waves, climate, currents, sediment movement, etc.~. 223. The projected marine traffic mix and density need to be better identified and incorporated into the design of harbor entrances, using improved models. 2 24. A model should be developed to demonstrate effectively the incorporated models. be developed to demonstrate effectively the relationship between optimum port and channel use, and the channel-entrance design. Additional financing resources for entrance improvements are needed to serve national and regional, as well as local interests. 226. Better quantification is needed of the economic benefits realized by improvement of harbor entrances. 227. The development of fixed systems to permit sand bypassing of the harbor entrance should be continued. 228. The feasibility of open-water disposal of dredged materials should be re-evaluated. OMNIBUS STATEMENTS (combined for a single vote by unanimous consent) 105, 108, 122, 212, 25, 112 Need for better estimates of shoaling rates 101, 111, 228, 218, 219 Research on dredged materials to improve disposal Design of breakwaters, improvement of rubble-mound structures 124, 205
174 3, 221, 19, 127 106, lO9t 113 4, 7, 207, 130 20' 114, 131J 208 11 18, 12 211, 103 202, 14, 23, 15 119, 227 222, 201, 104, 107 118, 204 Need for improved second- and tbird-generation mathematical models--ship motion in shallow water, ship-ship interaction, etc.--to determine geometry and check the design of harbor entrances Research, evaluation, and methods for preservation of valuable natural resources, and the restoration of habitats Need for systems analysis and integrated approach to the design of harbor entrances Cost-effective models of hydrodynamic proces~es--waves, currents, water levels, sedimentation, and others Criteria for minimum horizontal dimensions of channels Need for standards of safety Quantitative definition of the needs of mariners Development of sand-bypassing systems Better quantification of physical environmental parameters Cost-effective technologies for the measurement, analysis, and presentation of wave, tide, and other data
