• TABLE OF CONTENTS
HIDE
 Front Cover
 Title Page
 Table of Contents
 List of Tables
 Introduction
 Comments on field and laboratory...
 Some study suggestions
 References






Group Title: Miscellaneous Publication - University of Florida. Coastal and Oceanographic Engineering Program ; 94/04
Title: Comments by the panel on scoping field and laboratory investigations in coastal inlet research
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Permanent Link: http://ufdc.ufl.edu/UF00074654/00001
 Material Information
Title: Comments by the panel on scoping field and laboratory investigations in coastal inlet research
Series Title: Miscellaneous Publication - University of Florida. Coastal and Oceanographic Engineering Program ; 94/04
Physical Description: Book
Creator: Mehta, Ashish J.
Bruun, Per
Dean, Robert
FitzGerald, Duncan
Goodwin, Peter
Komar, Paul
van de Kreeke, Jacobus
Affiliation: University of Florida -- Gainesville -- College of Engineering -- Department of Civil and Coastal Engineering -- Coastal and Oceanographic Program
Publisher: Dept. of Coastal and Oceanographic Engineering, University of Florida
Publication Date: 1994
 Subjects
Subject: Coastal Engineering
Inlets
University of Florida.   ( lcsh )
Spatial Coverage: North America -- United States of America -- Florida
 Notes
Funding: This publication is being made available as part of the report series written by the faculty, staff, and students of the Coastal and Oceanographic Program of the Department of Civil and Coastal Engineering.
 Record Information
Bibliographic ID: UF00074654
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida

Table of Contents
    Front Cover
        Front Cover
    Title Page
        Page 1
    Table of Contents
        Page 2
    List of Tables
        Page 3
    Introduction
        Page 4
        Page 5
    Comments on field and laboratory research within CIRP
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
    Some study suggestions
        Page 19
    References
        Page 20
        Page 21
        Page 22
        Page 23
        Page 24
        Page 25
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
        Page 33
        Page 34
        Page 35
        Page 36
Full Text




UFL/COEL/MP-94/04


COMMENTS BY THE PANEL ON SCOPING FIELD
AND LABORATORY INVESTIGATIONS IN
COASTAL INLET RESEARCH





Contributors:

Ashish Mehta
Per Bruun
Robert Dean
Duncan FitzGerald
Peter Goodwin
Paul Komar
and
Jacobus van de Kreeke


November, 1994









UFL/COELIMP-94/04


COMMENTS BY THE PANEL ON SCOPING FIELD AND LABORATORY
INVESTIGATIONS IN COASTAL INLET RESEARCH






Contributors:

Ashish Mehta
Per Bruun
Robert Dean
Duncan FitzGerald
Peter Goodwin
Paul Komar
and
Jacobus van de Kreeke


November, 1994









TABLE OF CONTENTS






LIST OF TABLES ........... .................... ............................ 3


INTRODUCTION ....................................................... 4


COMMENTS ON FIELD AND LABORATORY RESEARCH WITHIN CIRP ......... 6


SOME STUDY SUGGESTIONS ............................................. 19


ACKNOWLEDGMENT ....................................................20


REFERENCES .........................................................20









LIST OF TABLES


TABLE


International Inlet Studies in Progress ................ ..................... 27
Suggested Historic Case Studies ......................................... 29
Experiments of Opportunity .......................................... 35


PAGE









COMMENTS BY THE PANEL ON SCOPING FIELD AND LABORATORY
INVESTIGATIONS IN COASTAL INLET RESEARCH
Contributors: Ashish Mehta, Per Bruun, Robert Dean, Duncan FitzGerald, Peter Goodwin,
Paul Komar and Jacobus van de Kreeke


INTRODUCTION
Under contract between the University of Florida and the Coastal Engineering Research
Center (CERC) of the U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS a seven-
member technical panel was convened to provide guidance for CERC's agenda for field and
laboratory experimental studies under the Coastal Inlets Research Program (CIRP). CIRP's main
objective is as follows:


CIRP's objective is to provide tools to address present and future needs for
operations management and engineering offederally maintained coastal inlets. This
requirement is being addressed through a program of research and development
focused on understanding inlet physical processes. In addition to the traditional
inlets related hydrodynamic problems, CIRP will address present issues by including
major efforts in sedimentary processes and shore impacts of inlets and structures.
The two major components of the program are field and laboratory investigations
of inlet processes. These investigations must provide the new data necessary to
evolve empirical and semi-empirical models of inlet behavior to physics-based
approaches.


The panel was charged with providing recommendations on the objectives, scope, priorities
and methods of field and laboratory investigations required to accomplish CIRP goals. The panel
was expected to consider the following technical issues:









a) Review of past experience.
b) Review of modeling and measurement techniques in previous studies.
c) Review of current international efforts and their relevance and potential benefits.
d) Review laboratory and field data needs for development and validation of the new research,
process-models and engineering tools required to accomplish CIRP objectives.
e) Review of prototype data requirements for operational use of next generation 3-D numerical
models of inlet behavior.
f) Recommendations on the use or development of new techniques which have the potential
to provide substantial benefits to future studies.

g) Review of existing theoretical relationships which could be tested in field and laboratory
studies.

h) Recommendations for meeting the needs for the development and validation of long-term
geomorphological evolution models.


As a part of the panel's agenda for arriving the comments made in this report, a workshop
on Scoping Field and Laboratory Investigations in Coastal Inlet Research was held during September
13-15, 1994 at Daytona Beach Shores, Florida. The workshop agenda and the list of participants are
given in the Appendix. Based on the presentations and discussions at the workshop, and the
collective experience of the panel members, the panel decided to: 1) issue a set of comments to
CERC based on panel deliberations on September 15, and 2) subsequently publish a monograph
tentatively titled, Coastal Inlets: Bases for Field and Laboratory Research. The monograph will
collectively examine the technical issues required to be addressed by the panel.
This report contains brief comments relative to the various components of CIRP's field and
laboratory research outlined under Technical Areas 1 and 2, and presented and discussed at the
workshop. See Smith et al. (undated) for a description of Technical Area 2. The first set of general
comments is followed by some study suggestions complementing CIRP's agenda.









COMMENTS ON FIELD AND LABORATORY RESEARCH WITHIN CIRP
1. The panel is of the opinion that, as for understanding key physical processes at inlets, the
overall mission of CIRP is well suited to address the nation's problems at coastal inlets. CERC's
effort in fleshing out the components of the mission in terms of study tasks, or work units, is
extensive. The panel also recognizes that CIRP has provided a "once-in-a-life-time" opportunity to
advance the state-of-the-art in understanding inlet processes. Therefore, a great responsibility has
been placed on CERC to meet the challenge posed by the need to advance relevant science and
technology. The panel trusts that this challenge will be met, despite the limited resources and time
constraints inherent in CIRP. Concerning the expected CIRP deliverables the following points
should be noted:
First, while it is understood that, in consonance with the mission of the U.S. Army Corps of
Engineers, CIRP is directed to address inlet problems at federal projects, every appropriate
opportunity to study inlet processes must be seized, irrespectively of inlet location, whether it is a
federal project or otherwise. As a case in point, at several inlets that do not lie within federal
projects, the Intracoastal Waterway in the vicinity influences the processes within the inlet channels
and in the adjacent waters.
Second, in future the Corps of Engineers is likely to be increasingly called upon to address
problems that demand mitigation for ecological impacts. A case in point is the issue that arose
concerning the impact of extending the jetties at Oregon Inlet, North Carolina on larval transport into
the highly productive Pamlico Sound. In such a case, it becomes essential to understand the
transportability of larvae around jetties due to tide and wind driven motions of water masses that may
be stratified with respect to chlorinity and temperature. A review of literature showed that,
hydrodynamic data essential to resolve larval transport issues are inadequate (Mehta and Montague,
1991). Similarly, at some sites, e.g., in California, problems of maintaining inlets for providing
adequate circulation to restore, maintain and enhance coastal wetlands have arisen in recent years.
While in many cases these issues do not pose problems that are typical to federal navigation
channels, their solution often demands challenging new approaches and data to back up the
elucidation of such approaches. Evidently therefore, capabilities to deal with issues related to non-









federal inlets are necessary in situations where the Corps of Engineers acts as a consultant to local
entities.
In some situations, e.g., at Elkhorn Slough in California, massive loss of marsh-habitat has
occurred due to construction of jetties by the Corps of Engineers. In such cases the problem of
shoreline erosion is characteristically different from the traditional one involving a sandy barrier
beach. Yet this problem falls well within the rubric of CIRP's goals dealing with shore impacts of
inlets.
It is essential to understand critical physics that influences water circulation and sediment
transport within the inlet, in the nearfield and along contiguous shorelines backed by barrier islands
or marshes. Note that while much discussion in the workshop was focused on waves, currents,
sediment transport and structures, there seemed little emphasis on field data related to flow
stratification, especially in the nearfield. Stratification can have significant consequences for inlet
dynamics (Luketina and Imberger, 1987). Wind effects can also be important, e.g., at Oregon Inlet.
Similarly, Great Lakes inlets are forced by barotropic effects. Although limited funding may
preclude CIRP field studies which include all such considerations of physical processes, a formal
recognition of the wide ranging oceanic forcing parameters on inlet dynamics must be recognized
when analyzing data, and developing essential caveats for the use of the final products.
CIRP must ensure that its products reflect the present and future needs of the nation
for maintaining harbor channels, federal and others, and for dealing with a variety of critical
problems associated with channel maintenance and inlet impacts.


2. The stewardship of maintaining "healthy" inlets rests with several organizations including
CERC, Corps of Engineers Districts and other federal agencies, state and local agencies, consulting
firms, and academic and other research institutions. Due to this diversity, CIRP must develop a mix
of technologies for understanding inlet processes and problems. It will be most appropriate to
generate deliverables that are useful to a variety of agencies, for present and future anticipated
problems at inlets. These should include methods for data collection and analysis. On the other
hand, overemphasis on any particular approach, e.g., "high-tech" data collection protocols and









complex numerical modeling, will occur only at the cost of other simpler and cost-effective
approaches. This in turn will restrict "public" use of CIRP products.
The development of essential engineering guidelines for design, improvement and
management of inlets is an integral component of CIRP. Therefore, adequate time and effort must
be spent in translating physical principles to such guidelines. The panel considers it necessary that
a significant portion of CIRP effort should be devoted to research for the improvement CERC
engineering manuals for inlet design, improvement and management, in particular the old Shore
Protection Manual, which is still highly useful but outdated.
CIRP must contribute to technology that all those assigned the stewardship of inlets can
use. They include CERC, Corps of Engineers Districts, other federal, state and local agencies,
consulting firms, and academic and research institutions. Thus, "high-tech" data collection
efforts and complex numerical modeling should be balanced by the development of cost-
effective and simpler approaches for studying inlets. Furthermore, CIRP must positively and
significantly influence CERC engineering manuals for inlet design, especially the old Shore
Protection Manual.


3. Reviewing the work units within Technical Areas 1 and 2 the panel got the impression
that the number of projects to be undertaken is excessively large and too ambitious. This will lead
to the situation under which far fewer than anticipated concrete, substantive deliverables will result
at the end of the program.
There are several projects that should be completed under other funding meant for coastal
processes in general, and not through CIRP. This is because the limited CIRP resources must be used
only for carefully planned experiments that will improve an understanding of physics, rather than
numerical modeling, which is just one tool for elucidating inlet physics. As an example, wave-
current-sediment interaction is an important and complex basic research issue relevant to
understanding inlet processes, which however should be perused only after specific expertise to
design the necessary experiments and analyze the data in a scholarly way is identified. It will be
inappropriate to collect data with the main purpose of feeding numerical codes, since such codes in
themselves are incapable of explaining physics.









In designing appropriate number of meaningful experiments a rule-of-thumb, namely that
each "Master's level" topic requires about two years to complete, and "Ph.D. level" topic accordingly
takes three to five years, may be used.
Technical Areas 1 and 2 must be considerably more narrowly focused than at present.
Deliverables must be targeted for completion within the given financial and time constraints,
and should be closely aligned to the CIRP objectives.


4. The previous major effort by the Corps of Engineers on inlets, namely the General
Investigation of Tidal Inlets (GITI), ended in the early eighties. Since then, contributions to inlet
research have been very few. However, some of them have been significant in terms of scientific
advancement. Commonly, this advancement was made through important contributions to
conceptual and analytic understanding of inlet mechanics. Examples include wave-current
interaction, wave-current-structure interaction, beach-inlet interaction, inlet-breaching, stability,
closure, ebb shoal dynamics, natural and artificial sand bypassing, etc. This was achieved by using
available data, rather than through new data collection efforts. Unfortunately, lack of funded projects
meant that very few of the students pursuing graduate studies in the eighties and the early nineties
were exposed to in-depth evaluations of inlet processes. At CERC this pattern is reflected in the
backgrounds and experiences of the investigators involved in CIRP. It will be essential for those
concerned with CIRP work units to thoroughly appraise themselves of the fundamentals of inlet
hydrodynamics, sediment transport and beach/inlet interactions as prerequisites for initiating inlet
research. Recommended treatises include Bruun and Gerritsen (1960), Bruun (1978), Aubrey and
Weishar Editors (1986), Mehta Editor (1993) and Aubrey and Giese Editors (1993).
Attention is also drawn to the large number of inlet management studies in Florida that
collectively represent a variety of problems and data bases. Relevant reports on these studies are
available through the Department of Environmental Protection, Tallahassee. For West Coast studies
governmental sources include the California Coastal Conservancy and the California Coastal
Commission. In addition, individual panel members may be contacted for literature in specific areas
of inlet research.









In recent years new studies have been conducted and new approaches tried elsewhere
including The Netherlands, Denmark, Germany, Spain, Italy, Portugal, Japan, Australia, New
Zealand etc. A partial list of inlet or estuary studies that were ongoing during 1994 is provided in
Table 1.
Key CIRP objectives that can be met by literature review would be: 1) prevention of
duplication of effort, 2) emphasis on rational experimental design and data analysis, and 3)
establishment of active and personal links with other researchers and agencies dealing with inlets.
In these areas the panel believes that considerable benefits will accrue to the CIRP agenda.
Justification for the collection of "new" data, as opposed to the use of available data sets, for several
projects outlined in Technical Areas 1 and 2 must be demonstrated through literature search and a
thorough understanding of the subject before collection effort is approved.
As an initial thrust, CIRP staff must thoroughly review available literature including
state-of-the-art understanding of the inlet hydrodynamic and sedimentary processes, and
beach/inlet interactions. Both U.S. efforts and international experience must be examined.


5. Apart from a few important early contributions to understanding the hydraulic behavior
of inlets, e.g., Brown (1928), O'Brien (1931) and Escoffier (1940), most focused research on inlet
processes dates from the mid-fifties. This research was first summarized in Bruun and Gerritsen
(1960). Comparatively large scale funding for inlet studies occurred mostly in the seventies through
the Geography program of the Office of Naval Research (ONR), the Army Research Office, NOAA
Sea Grant and GITI. Series of model and office studies were also conducted through the Hydraulic
Engineering Laboratory of the University of California, Berkeley, the Coastal Engineering
Laboratory of the University of Florida, Gainesville, and other academic institutions. See Mehta and
Joshi (1988) for a list of references related to hydraulics up to the late eighties.
Of the above study "clusters," GITI is clearly the forerunner of CIRP, and through which
some lasting contributions were made. Perhaps the most quoted work of GITI is Jarrett (1976). In
this work the relationship between the tidal prism and the inlet area was extensively explored for
many natural and stabilized inlets. Similarly, the dependence of ebb delta volume on the tidal prism
was examined by Walton and Adams (1976). For important contributions such as these, the









opportunity exists to reexamine them, and to enhance their utility through refinement by inclusion
of additional data available since the end of GITI. The panel considers this an essential ingredient
of CIRP.
As a part of CIRP and as an early initiated component of research, previous clusters
of investigations on tidal inlets should be examined critically. In particular, the strengths,
weaknesses and especially the lasting contributions made by GITI must be explicitly identified
and extended where possible.


6. Some studies initiated under GITI could not be completed, possibly due to lack of time
and personnel. An example is reanalysis, undertaken as a part of GITI, of the moveable model study
on inlet closure reported earlier in Saville et al. (1957). At the time of that study, excellent data on
the change in inlet morphology during closure were collected but not analyzed within any detailed
analytic framework. Such an analysis was slated for completion under GITI; however, a report on
the subject remains unpublished. Given the interest in closure problems under CIRP, the data in
Saville et al. (1957) can be reexamined within a prescribed physical framework. For a recap of other
likely studies under this category, Clark McNair, Bill Seaburgh and Tom Richardson should be
contacted.
Consideration should be given to completing or reexamining some of the studies that
were deemed important during the GITI investigation but not completed at that time due to
time and cost limitations.


7. A large number of prototype inlet projects have been completed nationwide. Many have
been successful, as defined within a certain specified set of goals, and others with mixed results.
In several cases, post-construction hydrographic information is of sufficiently good quality to warrant
examinations of long-term performances. For example, in many of Florida's inlet management
studies good quality data on pre-project and post-project implementation effects have been compiled.
Also, since numerical modeling is used at CERC to help in design or redesign, the opportunity to
show their advantage over previous efforts without computers exists. Similarly, such examinations
should highlight areas of improvement in models.









Performance testing is required in many areas including navigation safety, water circulation
and flushing, channel maintenance, mitigation of beach erosion, maintenance of marine-habitat and
so on. Therefore, selection of inlet case studies must be based on the understanding that performance
testing needs to be documented in a variety of prototype situations. The panel strongly recommends
such exercises.
Advantage should be taken of extensively available information on completed inlet
projects, especially by way of formally documenting and analyzing the performance of such
projects.


8. Given the ongoing work at several federal projects around the nation, experiments of
opportunity exist in many cases from two perspectives: 1) limited funds from CIRP can be stretched
considerably by taking advantage of additional resources allotted to such federal projects, and 2)
CIRP participation can increase the chances of success for such projects. In the opinion of the panel
there seems little justification for initiating studies in federal project areas where there is no ongoing
work, unless the importance of doing otherwise is a priori demonstrated. At the same time, given
the significance of inlet research to all inlets, irrespective of whether their federal status, ongoing
projects that are not federal should also be sought out, and studies carried out through cooperative
agreements.
Post-implementation monitoring is becoming a requirement for most projects, because the
selection of a management plan for tidal inlets may create environmental impacts either directly, if
the inlet is being managed to achieve ecological objectives, or indirectly as a result of dredging for
navigation channels. CERC could adopt a leadership role in specifying guidelines for post-
construction monitoring, and for the way in which monitoring can be used in "adaptive" management
of inlets, rather than the traditional "prescriptive" approach.
Traditionally, a prescriptive approach has been adopted for inlet management, i.e., guidelines
are developed on the best available data at the time of the design and usually based on threshold
values. For example, threshold values that might initiate dredging include:
* minimum depth in the channel;
* water level in lagoon following closure;









* open the inlet channel during specific seasons of the year.
There is considerable uncertainty when specifying these threshold and increasingly long-term
monitoring plans are being specified as an integral part of management plans. The additional data
acquired from long-term monitoring facilitates the validation of design assumptions and modeling
approaches used in the original design, monitoring for performance, monitoring for design and
implementation improvements and monitoring for general research on inlet processes. It also allows
an adaptive approach to the management of tidal inlets and wetlands whereby management actions
can be optimized with minimum impacts to the ecology of the system.
This type of monitoring program is of interest to CIRP because it provides a source of "free"
field data. Further, if CIRP was to prepare guidelines for monitoring plans of inlets, it may allow the
formation of a nationwide database allowing universal, regional and local comparisons and analyses
to be made. Typical monitoring might include:
M response of the inlet to episodic storm events (e.g., the ecologically catastrophic closure of the
Tijuana Estuary in 1983).
* temporal variations of tidal inlets in response to variations in tides, wave and river flows;
* ecological response to inlet management plans, e.g., habitat changes and changes in fish
populations.
Participation in experiments of opportunity can be extremely beneficial and must be
adopted as an essential policy ingredient of the CIRP effort. Further, CIRP should take a
proactive approach toward developing adaptive, post-project monitoring strategies as an
integral component of inlet management.


9. It is undeniable that, starting with the work of Bruun and Gerritsen (1960), and ending
with Aubrey and Giese Editors (1993), a considerable volume of books, refereed monographs and
articles in well known technical and scientific journals on basic inlet processes has been of academic
origin. While this observation may or may not be correlated to the fact that coastal engineering and
science faculty hiring at the major universities is usually based on demonstrated excellence is
research, it is certain that academically based publications have contributed immensely to the
advancement of understanding inlet processes.









Participation of university personnel and personnel from other research institutions and
consulting firms with research-minded people should be a corer stone of CERC policy for research
under CIRP. A review of ONR, NOAA-Sea Grant and other publications of academic origin should
convince CERC of the desirability of promoting collaborative research efforts with institutions where
inlet expertise exists. Given the nationwide spread of intellectual property stewardship in coastal
engineering and science, funding components of research to institutions that are best geared to deal
with them is essential for optimal benefits. Among others, doctoral level studies have proven to be
most cost-effective.
As an integral component of CIRP, CERC should also increase formal participation through
programs in other laboratories within the Waterways Experiment Station, e.g., the Environmental
Laboratory's wetland program, to increase the effectiveness and generality of CIRP products.
By formally participating in a collaborative way with academic and other research
institutions actively involved in inlet research, CERC should take advantage of the opportunity
to diversify and strengthen the nature and scope of CIRP deliverables.


10. While basis research for sorting out inlet physical mechanisms is clearly very important,
resources within CIRP are too limited for allotting funds and personnel for basic research that is not
strongly related to inlets. The panel considers that CIRP studies dealing with the basics of, for
example, wave-current interaction and wave-current-sediment interaction at the micro-scale level
do not necessarily belong to CIRP, unless planned very carefully to answer inlet-specific issues. At
the same time, it is noted that projects that deal with the characteristic meso-scale processes at inlets
are disappointingly few in Technical Areas 1 and 2. The panel also questions the basis of that
component of CIRP strategy according to which a major role of field and laboratory data in several
cases is as input into numerical models. Instead, a significant role for field and laboratory work
should be internally consistent in terms of the need for such data. In other words, field and
laboratory data should be collected for "Masters level" and "Ph.D. level" projects, with their own
goals/hypotheses/theory, experimental design, tasks for achievement, and anticipated results and
benefits. Only those projects that meet the criteria for quality in these aspects must be funded.









Although the panel did not formally review individual proposals for their funding potential, it found
most of them to be written without rigorous standards.


Basis research that is inlet-related should be funded, preferably on a seed money basis, and
for Ph.D. level work. In the late eighties and the early nineties an effort was made by academic
institutions to fund basic research on inlets. A technical white paper issued to that end is available.
Dr. Linwood Vincent participated in this effort, which was led by Dr. David Aubrey at the Woods
Hole Oceanographic Institution, Dr. Jacobus van de Kreeke at the University of Miami and others.
CIRP must be application oriented and focused on inlets. Basic research on coastal
processes in general should not be a part of CIRP and must not be initiated.


11. Numerical models should be a part of CIRP strategy, since in many situations essential
physics is not amenable to conceptual or analytic treatments for deriving the optimal benefits.
However, CIRP personnel will eventually recognize that insufficient funds are at their disposal for
obtaining data of the scope and extent necessary for numerical model validation. CIRP staff must
thoroughly review modeling capabilities and data availability in wave-current and wave-current-
sediment interactions developed in the United States and elsewhere, for an assessment of CERC's
own needs and capabilities in this area, independent of CIRP. Studies in these areas, unless planned
properly, will remain open-ended at the end of CIRP.
At the end of the workshop the panel came away with the impression that within CIRP there
is an excessive emphasis on the use of complex numerical modeling. A workshop-like meeting with
modelers including some outstanding ones representing the MAST program under the European
Union was held a week before the one held by the panel. The panel considers unified meetings
involving modelers together with field and laboratory groups to be considerably productive to CIRP
in future. It is noteworthy that the Geomorphodynamics (G-8) program of MAST is not inlet-
specific, but is meant to enhance coastal engineering numerical modeling, mostly by using available
data. Thus, its connection to CIRP is only indirect.
The panel believes that the role of complex numerical models in coastal engineering will
remain limited in the foreseeable future for the following reasons:









First, while undoubted advancements have been made in modeling wave-current interaction
and wave-current-structure interaction, certain significant limitations appear to exist in modeling
sediment transport and bottom evolution. Such modeling requires integration of
hydrodynamic/sediment transport model results over time-scales that are seemingly too long for
accurate simulation. The problem is more fundamental than merely one of accurately representing
sediment transport, and is exacerbated when structures are present. In the foreseeable future,
numerical meso-scale evolution models will most likely have to resort to the judicious use of
lumped-parameter, time and space-integrated relationships derived from experimental evidence. The
prism-area relationship is one such formulation. This being the case, effective use of CIRP funds
can be made if useful lumped-parameter relationships are first identified through a rational
framework for meso-scale modeling, and then determined or improved upon under CIRP.
The introductory statement in Smith et al. (undated) refers to "modeling of detailed physical
processes at coastal inlets" using data collected "over comparatively short temporal and spatial
scales." Since inlet processes that are of interest to "engineering guidance" are of longer temporal
and spatial scales, great caution is warranted in pursuing this approach, which is known to result in
unverifiable, sometimes erroneous, predictions concerning meso-scale sediment transport and bottom
evolution.
Second, improving the hydrodynamic code will be of little value, when the difficulty lies with
sediment transport. Thus, for example, using turbulence closure modeling to simulate the complex
scour process near structures is unlikely to improve the results limited by sediment transport
description. Evaluation of sediment transport theories beyond what has already been done by others
must include more than mere testing of different formulas (coupled with hydrodynamics) against
selected data sets. Unless science is advanced in a fundamental way through a major undertaking,
scour prediction is unlikely to improve.
Third, engineering experience will always be the cornerstone in good inlet design. The role
of models has been, and in the foreseeable future will remain, an advisory one in terms of flow
circulation and wave-current-structure interactions. Regarding sediment transport the simulations
are considerably more difficult, although useful advancements have been made in that area in recent
years. However, it is interesting to note that in several cases these advancements have been through









comparatively simple analytic and statistical transport descriptions, as opposed to numerical
solutions of the full transport equations.
Fourth, numerical models change rapidly, with comparatively short lives. This evolution has
resulted from advancements in numerical techniques coupled with computation speed. Heavy
investment in numerical modeling must be tempered by this reality, especially as far CIRP funds are
concerned.
Finally, experience suggests that given limited CIRP resources and the extensive data
requirements for model validation, especially of the 3-D codes, it is unlikely that fully validated
models will become operational by the end CIRP.
Excessive reliance on complex numerical models as tools for solving inlet problems must
be avoided. Instead, there should be a balanced development involving conceptual, analytical,
simple numerical and complex numerical models as deliverables. Modelers and field and
laboratory groups must work together to insure that CIRP deliverables make lasting
contributions.


12. The panel is not in a position to comment on what the role of laboratory modeling should
be in relation to field work, as it is not a matter of balance but needs. Clearly, there is a role for
laboratory investigations where controlled parametric input into theory or empirical understanding
is required. This was clearly shown under GITI. In such cases the demand for state-of-the-art
instrumentation exists. On the other hand, for example, flume studies on wave-current interaction
or wave-sediment interaction should not be undertaken unless justified after a thorough literature
review.
Fixed bed models have been used historically to obtain information on, for example, the
influence of different jetty configurations on navigation safety and beach erosion. Studies of inlet
stability, e.g., by Mayor-Mora (1973), using moveable bed models have very yielded useful
information, and should be candidates for further analyses. It is also a fact that the "art" of hydraulic
modeling has been dying the United States and elsewhere, as more reliance is placed on numerical
modeling and field work. At the Waterways Experiment Station the same trends are apparent. The
panel is however of the opinion that no funds should be allotted to physical hydraulic modeling









merely for keeping the art "alive," and that allotment should be based solely on technical needs of
CIRP.
Those studies that are funded must be primarily related to sediment transport as opposed to
hydrodynamics, for which numerical modeling provides stronger tools. Modeling of sediment
transport should be done through the application of proper scaling laws (LeMehaute, 1990).
The division between allocation of resources for field research, versus laboratory
research, must be based on the appropriateness of each in any particular task. While there are
situations for which hydraulic modeling is the most suitable method, no CIRP funds should
be spent for the sole purpose of keeping the art of hydraulic modeling "alive."


13. The panel believes that the number of studies in Technical Areas 1 and 2 to be initiated
more or less simultaneously is too large, and will prevent the "give-and-take" essential to organized
research. A more phased approach to the work and the deliverables based on fewer tasks than those
proposed is essential. This is particularly so because several staff members are just becoming
involved with inlet work. Funding for projects should be time-staggered and strictly subject to peer-
review at each milestone.
As a part of the future review process for work in progress, the panel strongly feels that
annual workshops should be held, and peer-review extended beyond the Coastal Engineering
Research Board (CERB). This opinion is based in part on the observation that CIRP staff work thus
far, although commendable, could have benefitted sooner from a workshop such as the one which
forms the basis of this report.
The total CIRP effort must be carried out in a phased manner, with timely products.
A mechanism must be set in place for an annual external review of progress outside the U.S.
Army Corps of Engineers, including CERB. All the panel members as a group will be
available for this purpose, if necessary, on an as needed basis. One mechanism for review is
through short-duration workshops such the one that led to these comments.


14. The panel wishes to express its concern at the trend set by the comparatively small
number of GITI publications from the Corps of Engineers which made their way to refereed journals.









The International Conferences on Coastal Engineering remain the traditional avenue for
dissemination of results. Therefore, publication in these and other similar conferences must be
encouraged. However, these proceedings do not substitute peer-reviewed publications, which are
essential for establishing the scientific and technical credentials of the products and the producers.
Important findings of CIRP must be published regularly in scientifically recognized
refereed journals.


15. The panel wishes to note the underutilization of CERC's expertise in inlets. For
example, Tom Richardson and Todd Walton are senior staff members, with established credentials
in inlet research. Richardson's contributions in sand bypassing are well known. Walton has made
seminal contributions to inlet process research, much of it before his joining CERC, including the
works on ebb shoals and inlet stability (Dean and Walton, 1975; Walton and Adams, 1976; Escoffier
and Walton, 1979; Walton and Escoffier, 1981). Also, J. B. Smith is well familiar with inlets. It
will be technically most advantageous to incorporate their involvement in CIRP soon.
CIRP must effectively use all available staff with extensive prior experience in inlet
research.


SOME STUDY SUGGESTIONS
Since the panel's charge did not call for a critical review of the various individual proposals
under Technical Areas 1 and 2, the following suggestions are not tied to any proposals within CIRP.
The first suggestion is to document project performance through case histories at inlets mentioned
in Table 2. Additional inlets may be added to this list. The second suggestion is to participate in
experiments of opportunity at sample inlets listed in Table 3.









ACKNOWLEDGMENT
Oral comments made by the workshop participants are acknowledged. Dr. Cyril Galvin
subsequently provided written comments to the panel. Support through WES Contract DACW39-
94-K-0043 is sincerely acknowledged.


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Hubbard D.K., 1975. Morphology and hydrodynamics of the Merrimack River ebb-tidal delta. In:
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Engineers, Coastal Engineering Research Center, Fort Belvoir, VA, 32p plus appendices.

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Johnson J.A., 1969. Barnegat Inlet: a problem and a solution. Shore and Beach, 37(2), 17-23.

Kana T.W. and Mason J.E., 1988. Evolution of an ebb-tidal delta after an inlet relocation. In: D.G.
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Verlag, New York, 382-411.

Kassner J. and Black J.A., 1982. Efforts to stabilize a coastal inlet: a case study of Moriches Inlet,
New York. Shore and Beach, Vol. 50, No. 2, 21-29.

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and Manthorp P.A., 1994. A sand budget for Saco Bay, Maine. Report to Maine and New Hampshire
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Komar P.D. and Terich T.A., 1976. Changes due to jetties at Tillamook Bay, Oregon. Proceedings
of the 15th Conference on Coastal Engineering, ASCE, 1791-1811.

Komar P.D., Lizarraga-Arciniega J.R. and Terich T.A., 1976. Oregon coast shoreline changes due
to jetties. Journal of the Waterways, Harbor and Coastal Engineering Division, ASCE, 102(WW1),
13-30.

Leatherman S.P., Dean R.G., Everts C.E. and Fulford E., 1987. Shoreline and sediment budget
analysis of north Assateague Island, Maryland. Proceedings of Coastal Sediments'87, ASCE, New
York, 1460-1471.

LeMehaute B., 1990. Similitude. In: LeMehaute B. and Hanes D. M. eds., The Sea, Ocean
Engineering Science, Volume 9, Part B, Wiley, New York, 955-981.

Lockett J.B., 1962. Phenomena affecting improvement of the lower Columbia River estuary.
Proceedings of the 8th Conference on Coastal Engineering, ASCE, 695-755.

Luck G., 1976. Inlet changes of the East Friesian Island. Proceedings of the 15th Conference on
Coastal Engineering, ASCE, 1938-1957.









Luketina D.A. and Imberger J., 1987. Characteristics of a surface buoyant jet. Journal of
Geophysical Research, 92(C5), 5435-5447.

Mariano C.G. and FitzGerald D.M., 1991. Wave-current interaction at Wells Inlet, ME. Proceedings
of Coastal Sediments'91, ASCE, 1356-1374.

Mason C., 1981. Hydraulics and stability of five Texas inlets. Miscellaneous Report No. 81-1,
U.S.Army Corps of Engineers, Coastal Engineering Research Center, Fort Belvoir, VA, 105p.

Mayor-Mora R.E., 1973. Hydraulics of tidal inlets on sandy coasts. Report HEL-24-16, Hydraulic
Engineering Laboratory, University of California, Berkeley, 248p.

MEC Analytical Systems, Inc., 1993. San Dieguito restoration project biological baseline study.
Draft Technical Memorandum submitted to Southern California Edison Company. 620p.

Mehta A.J. Editor, 1993. Beach/Inlet Processes and Management: A Florida Perspective. Journal
of Coastal Research, SI18, 308p.

Mehta A.J., Byrne R.J. and DeAlteris J., 1975. Hydraulic constants of tidal entrances III: bed friction
measurements at John's Pass and Blind Pass. Technical Report No. 26, Coastal and Oceanographic
Engineering Laboratory, University of Florida, Gainesville, 43p.

Mehta A.J., Jones C.P. and Adams Wm.D., 1976. John's Pass and Blind Pass, glossary of inlets
report no. 4. Report Number 18, Florida Sea Grant College, Gainesville, 71p.

Mehta A.J. and Joshi P.B., 1988. Tidal inlet hydraulics. Journal of Hydraulic Engineering, 114(11),
1321-1338.

Mehta A.J. and Montague C.L., 1991. A brief review of flow circulation in the vicinity of natural
and jettied inlets: tentative observations on the implications for larval transport at Oregon Inlet, NC.
Report UFL/COEUIMP-91/3, Coastal and Oceanographic Engineering Department, University of
Florida, Gainesville, 73p.

Moffatt and Nichol Engineers, 1990a. Batiquitos Lagoon enhancement plan, phase I: preliminary
studies survey report. Moffatt and Nichol Report 2803, Prepared for the City of Carlsbad, California,
56p plus appendices.

Moffatt and Nichol Engineers, 1990b. Batiquitos Lagoon enhancement project: summary report.
The shingle question: proposed inlet at Batiquitos Lagoon. Report prepared for the City of Carlsbad,
California, and the Port of Los Angeles, 30p.

Morton R.A., 1977. Nearshore changes at jettied inlets, Texas Coast. Coastal Sediments'77, Fifth
Symposium of the Waterways, Port, Coastal and Ocean Division, ASCE, 267-286.









Nathan R.A., 1993. Recommendations of inlet configuration for the Batiquitos Lagoon enhancement
project. Letter Report from Moffatt and Nichol to Port of Los Angeles, M and N File:3172, 10p.

Nummedal D., Oertel G.F., Hubbard D.K. and Hine A.C., 1977. Tidal inlet variability Cape
Hatteras to Cape Canaveral. Coastal Sediments'77, ASCE, 543-562.

Nummedal D. and Penland S., 1981. Sediment dispersal in Nordemeyer Seegat, West Germany. In:
S.D. Nio, R.T.E. Schuttenhelm and C.E. van Weering Eds., Holocene Marine Sedimentation in the
North Sea Basin. International Association of Sedimentology, Special Pub. #5, 187-210.

O'Brien M.P., 1931. Estuary tidal prisms related to entrance areas. Civil Engineering, ASCE, 1(8),
738-739.

Parchure T.M., 1982. St. Marys Entrance, glossary of inlets report no. 11. Report Number 44, Florida
Sea Grant College, Gainesville, 51p.

Ping S.L., 1990. Sedimentological studies of the ebb-tidal deltas along the West Friesian Islands, the
Netherlands. Geological Ultraiectina, Mededelingen van het Instituut voor Aardwetenschappen der
Rijksuniversiteit te Utrecht #64, 160p.

Rambo G. and Clausner J.E., 1989. Jet pump sand bypassing, Indian River Inlet, Delaware. Dredging
Research, DRP-89-2, U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS, 8p.

Ritter J.R., 1973. Bolinas Lagoon, Marin County, California: summary of sedimentation and
hydrology, 1967-69. U.S. Geological Survey, Water-Resources Investigations 19-73, August, 1983.

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invasion at Bolinas Lagoon, Marin County. Department of Geography, University of California,
Berkeley, 1973.

Saville T., Caldwell J. M. and Simmons H. B., 1957. Preliminary report: laboratory study of the
effect of an uncontrolled inlet on adjacent beaches. Technical Memorandum No. 94, Beach Erosion
Board, U.S. Army Corps of Engineers, Washington, DC, 19p plus photographs and figures.

Scheidegger K.F. and Phipps J.B., 1976. Dispersal patterns of sands in Grays Harbor estuary,
Washington. Journal of Sedimentary Petrology, 46:163-166.

Schmeltz E.J., Sorensen R.M., McCarthy M.J. and Nersesian G., 1982. Beach/Inlet interaction at
Moriches Inlet. Proceedings of 18th ICCE, ASCE, 1062-1077.

Smith J. M. et al., undated. Coastal inlets research program technical area 2. Unpublished paper,
CERC, U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS, 5p.









Terich T.A. and Levenseller T., 1986. The severe erosion of Cape Shoalwater, Washington. Journal
of Coastal Research, 2:465-477.

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reach. Fire Island Inlet to Montauk Point Long Island, New York. Beach Erosion and Hurricane
Project. U.S. Army Corps of Engineers, New York District. 52p plus appendices.

U.S. Army Corps of Engineers. 1969. Supplement No. 1 to general design memorandum no. 1:
Moriches to Shinnecock reach. Fire Island Inlet to Montauk Point Long Island, New York. Beach
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Moriches to Shinnecock reach. Fire Island Inlet to Montauk Point Long Island, New York. Beach
Erosion Control and Hurricane Protection Project. U.S. Army Corps of Engineers, New York
District. 23p plus appendices.

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Island, New York. Final Reformulation Study and Environmental Impact Statement. New York
District, 57p plus appendices.

U.S. Army Corps of Engineers, San Francisco District, 1992. Elkhom Slough tidal hydraulics
erosion study. Prepared by Philip Williams and Associates, Ltd., and Moffatt and Nichol, 33p plus
appendices.

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15th Coastal Engineering Conference, Vol. 2, ASCE, New York, 1919-1937.

Walton T. L. and Escoffier F. F., 1981. Linearized solution to inlet equation with inertia. Journal
of the Waterway, Port, Coastal and Ocean Division, ASCE, 107(3), 191-196.

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Bolinas Lagoon. Shore and Beach, Vol. 62, No. 4, 3-12, October.

Zeh T.A., 1980. Sikes Cut, glossary of inlets report no. 7. Report Number 35, Florida Sea Grant
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Table 1. International Inlet Studies in Progress

Country Kind of Study Sponsoring Agency(ies)


Argentina Parand River and Bahia Blanca Estuaries Government

Brazil Geological history of coastal lagoons Universidade Federal da
Bahia, Salvador

China A number of studies of estuaries including Government
the Pearl River, the Yangtse River, the
Hoang-poo River
Hong Kong Harbor Government, NEDECO and
others

England The Mersey River
The Thames River River Boards
The Humber-Goole Estuary

France The Seine and Gironde River entrances National Hydraulic
Laboratory and others

Germany Nordsee Entrances Governments
Die Elbe, die Weser, die Eems Hydraulische Versuchsanstalt,
Verde

Iceland The entrance at H6fn in Hornafj6rdur Government

India The Haldia River Central Water and Power
The entrance to Mangalore Research Station, Pune and
Ports
The entrance to Neandakara The Mysore State laboratory

Ireland The Malahide Inlet Private and Government

Japan Entrance studies of several port projects University of Tokyo
University of Hokaido
University of Osaka

Malaysia Port Kelang Government
Tanjung Berhala Private
Netherlands Friesean Inlets Rijkswaterstaat
Eems entrance Delft Hydraulics Laboratory
Pakistan Karachi Port entrance NEDECO and others
Fishing Ports










Table 1. International Inlet Studies in Progress
Country Kind of Study Sponsoring Agency(ies)


Portugal The Douro River entrance Government
National Laboratory

Russia Several river entrance studies on the Arctic Government
Sea

Thailand River entrance studies NEDECO and others
Venezuela Entrance to Maracaibo Estuary Government









Table 2. Suggested Historic Case Studies

Location Federal Characteristics Reference(s)
Project

Barnegat Inlet, NJ Yes Long record of shifting channel. New south jetty Johnson (1969); Caccese and
constructed in 1990-91. Good record of problems, Spies (1977); Halsey et al.
bathymetry and modifications. Processes of (1981); Fields (1984)
sediment bypassing.
Batiquitos Lagoon, CA No Subject to closure. Gravel beach. Jetties under Moffatt and Nichol
construction extensively studied, including (1990a,b); Nathan (1993)
movable bed hydraulic model.
Big Marco Pass, FL No New inlet has opened next to it; is gradually taking van de Kreeke (1990)
over. Formation of new inlet fairly well
documented.
Bolinas Bay, CA No Record of gradual sedimentation and dynamic inlet Ritter (1973); Rowntree
channel. Concern about potential closure of inlet. (1973); Williams and Cuffe
(1994)
Captain Sam's Inlet, SC No Site of a unique engineering effort to shift ebb FitzGerald (1982); Kana and
shoal to beach. Mason (1988)
Columbia River Entrance, OR/WA Yes Long history of jetty construction and Lockett (1962)
reconstruction. Large system with extreme wave-
energy level. Substantial freshwater discharge, with
density stratification important.
Corpus Christi Pass, TX Yes Sand trapping causing beach erosion Morton (1977)


Doctor's Pass, FL No Tidal prism enlarged in 1960. Small ebb tidal Hine et al. (1986)
shoal. Drive small, but north to south.









Table 2. Suggested Historic Case Studies

Location Federal Characteristics Reference(s)
Project

Drum Inlet, NC Yes New inlet formed in 1960's through explosion Nummedal et al. (1977)
methods. Large flood tide shoal formed. In its
natural condition, inlet was subject to migration.
Elkhorn Slough, CA, Yes Extensive scour of the inlet channel and gradual US Army Corps of Engineers
erosion of salt marsh habitat. (1992)
Friesian Inlets, Germany/Holland No Extensive historical data base. Luck (1976); Nummedal and
Erosional-depositional shoreline trends governed Penland (1981); FitzGerald
by sediment bypassing processes, et al. (1984);
Ping (1990)
Grays Harbor Entrance, WA Yes Good documentation of bathymetric changes since Scheidegger and Phipps
jetty construction in late 1800's. Recent breach of (1976); Committee on Tidal
barrier south of south jetty. Hydraulics (1971);
Indian River Inlet, DE Yes Interesting channel deepening pattern. Dalrymple et al. (1983);
Successful sand bypassing operation. Rambo and Clausner (1989)
Indications of erosion along channel.
Johns Pass, FL Yes Long term changes in morphology, hydraulic data, Mehta et al. (1975,1976);
bridge scour problem Hine et al. (1986)
Jupiter Inlet, FL ICWW in Extensive hydraulic and sediment transport data, Grella (1993)
the well managed sand bypassing protocol
vicinity










Table 2. Suggested Historic Case Studies

Location Federal Characteristics Reference(s)
Project

Little Lagoon, AL No Small, subject to closure. Sudden effect in 1990 on Coastal Planning and
downdrift beaches due to jetty extension. Now Engineering (1991,1992)
sand deposited in the channel is bypassed. Diurnal
tide; large difference between spring tide and neap
tide range.

Mad River, CA Marked northward migration of the inlet during Jeff Borgeld, study recently
recent decades, which recently has threatened the completed for CalTrans
coastal Highway 101. Small controlling structure through Humboldt State
recently built to protect the highway. Large University
seasonal freshwater flow, with a comparatively
small tidal prism (which, however, has grown as
the inlet has migrated).

Masonboro, NC Yes Weir jetty. Extensive physical and numerical GITI (1977)
modeling.

Merrimack, MA Yes Jettied inlet with well developed ebb tidal delta and Hartwell (1970); Hubbard
documented inlet sediment bypassing processes. (1975); FitzGerald (1993)
Channel shoaling due to sediment coming down
river.

Moriches Inlet, NY Yes Unstable channel. Breached in 1981? Recent jetty U.S. Army Corps of
modification. Engineers (1963,1969,
1980); Kassner and Black
(1982); Schmeltz et al.
(1982);









Table 2. Suggested Historic Case Studies

Location Federal Characteristics Reference(s)
Project

Murrells Inlet, NC Yes Jetties constructed relatively recently. Douglas (1987); Hansen and
Effects of ebb tidal delta shoals migrating onshore Knowles (1988)
after jetty construction

New Inlet, MA No Recent inlet opening.Unstable channel. Aubrey and Giese (1993)
Many major changes to bay area. Many major
changes to downdrift shoreline.
Ocean City Inlet, MD Yes Formed by hurricane in 1933 and stabilized shortly Dean and Perlin (1977);
thereafter. Caused rapid erosion to south on Leatherman et al. (1987)
Assateague Island. South jetty made impermeable
in 1986.
Oregon Inlet, NC Yes Wind-influenced flows, shifting channel, heavy Mehta and Montague (1991)
sedimentation, physical and numerical modeling
results
Price Inlet, SC No Well documented inlet hydraulics, sediment FitzGerald and Nummedal
bypassing processes, and effects to adjacent (1983); FitzGerald (1984)
shorelines.
Rollover Pass, TX No Originally cut to improve water quality. Mason (1981)
Caused severe effect on downdrift shoreline.
Russian River Inlet, CA No An inlet subject to periodic closure. Earlier studies Goodwin and Cuffe (1993)
for COE, now managed by Sonoma County
Department of Planning.
Saco Inlet, ME Yes Sediment infilling harbor and between jetties FitzGerald et al. (1993);
coming down river. Severe beach erosion north of Kelley et al. (1994)
jetties









Table 2. Suggested Historic Case Studies

Location Federal Characteristics Reference(s)
Project

St. Mary's Entrance, FL Yes Deep dredged navigation channel, large ebb delta, Parchure (1982)
flow stratification, wave data
San Dieguito Inlet, CA No Subject to periodic closure due to reduction in tidal Goodwin and Liang (1993);
prism. Under consideration for a major Jenkins and Wasyl (1993);
environmental restoration project.. MEC Analytical Systems
(1993)
Shinnecock Inlet, NY Yes Unstable channel. Significant downdrift erosion. U.S. Army Corps of
Engineers (1963,1969,
1980,1987)
Sikes Cut, FL Yes Manmade channel experiencing sedimentation, Zeh (1980)
hydraulic data
Siuslaw River Entrance, OR Jetties have been recently extended, with the Komar et al. (1976);
addition of flanking ribs to inhibit the development Hartman (1977)
of rip currents adjacent to the jetties which had
carried beach sand into the entrance. Good
documentation both before and after the extension.
Large seasonal freshwater discharge, with an
accompanying seasonal variation in the density
stratification. High wave-energy environment.
Tijuana River Entrance, CA No Natural inlet subject to closure twice in past Florsheim et al. (1990)
century with severe environmental impacts.









Table 2. Suggested Historic Case Studies

Location Federal Characteristics Reference(s)
Project

Tillamook Bay Entrance, OR Yes Of special interest in that originally, in 1917, only a Fisackerly (1974); Komar
single north jetty was constructed. The south jetty and Terich (1976); (Paul
was not built until 1974. Well documented Komar, personal
example of changes in shoals due to a single jetty, communication)
and also the erosion of the adjacent shorelines.
Minimal freshwater input, but a large tidal prism
due to the extensive bay. High wave energy. Jettied
inlet, but major changes are occurring in estuary.
Various dredging plans proposed.
Wells Harbor, ME Yes Harbor shoaling. Bryne and Zeigler (1977);
Severe beach erosion due to sand trapping on both Bottin (1978); Mariano and
sides of jetties. FitzGerald (1991)

Willapa Bay, WA Yes Long beach spit growing from south. Terich and Levenseller
Severe erosion to the north of the inlet documented (1986)
by a number of studies by the Corps (Seattle
office). Minimal freshwater input, but a large tidal
prism due to the extensive bay. High wave energy..










Table 3. Experiments of Opportunity

Location Experimental Goals

East Bay Pass, MA 1. Document reestablishment of ebb-tidal delta and relationship of nearby beach
stability.

Grays Harbor Entrance, WA 1. Predict weather breach would capture channel.
2. Document effectiveness of repairs to south beach.

Longboat Pass and New Pass, FL 1. Document recovery of ebb tidal shoals and possible interrelationship with beach
stability.
2. Consider methods of providing sand flow control at south end of beach
nourishment project.

New Inlet, MA 1. Document bay's adjustment (morphologically, sedimentologically and
hydraulically) to recent inlet opening.
2. Document downdrift effects of recent inlet opening and disruption of sediment
supply.
Ponce de Leon Inlet, FL 1. Document history of required changes.
2. Determine why shoaling occurs from south.
3. Develop approaches to remedying erosion inside north jetty.

St. John's River, FL 1. Document interrelationship between lack of placement of sand on beach south of
jetty with erosion.
San Elijo Lagoon, San Dieguito Lagoon 1. Reduce risk of inlet closure or diminished tidal exchange.
and Tijuana Estuary are a few of several 2. Establish variability of salt marsh habitat on inland side of inlet.
ongoing studies with current monitoring
programs in California. (California
Coastal Conservancy 1993)

Sebastian Inlet, FL 1. Document losses of sand to inlet, identify improved means of bypassing and
downdrift impacts of effects.










Table 3. Experiments of Opportunity

Location Experimental Goals

St. Augustine, FL 1. Document history, with emphasis on time scales of ebb tidal shoal evolution, of
relocating inlet.
2. Investigate causes of spit formation inside inlet.
3. Investigate stability of spit inside inlet.




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