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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
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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-
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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.
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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.
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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.
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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-entŁance 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
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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
Representative terms from entire chapter:
harbor entrance
