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THE
ANNUAL

BULLETIN

OF THE

BEACH EROSION BOARD

OFFICE, CHIEF OF ENGINEERS
WASHINGTON, D.C.

PB WOODS HOLE
OCEANOGRAPHIC INSTITUTION
FEB 1 7 1964
WOODS HOLE, MASS.
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VOLUME 17 . JULY (1963

MwA <> |4 S$ DEPARTMENT OF THE ARMY
oy 8 CORPS OF ENGINEERS

THE
ANNUAL

BULLETIN

OF THE

BEACH EROSION BOARD

OFFICE, CHIEF OF ENGINEERS
WASHINGTON, D.C.

WOODS HOLE
OCEANOGRAPHIC INSTITUTION
FEB 1 7 1964

WOODS HOLE, MASS. |

VOLUME 17 JULY 1963

|

TABLE OF CONTENTS

A Geological Process-Response Model for Analysis of Beach Phenomena.

Coastal Engineering Structures

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Review of German Experience on Coastal Protection by Groins

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Model Study of Offshore Wave Tripper

Nomograph for Determining Product of Shoaling and Refraction
Coefficients for Use in Wave Analysis

Progress Reports on Research Sponsored by the Beach Erosion Board

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Beach Erosion Board Publications

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Beach Erosion Studies

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Summaries of Reports Transmitted to Congress:

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Fort Macon-Atlantic Beach & Vicinity, .North.Carolina
Virginia and Biscayne Keys, Florida
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San Gabriel River to Newport Bay, Orange County, California

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Recomputation of Federal Share of Construction Costs under Provisions
of Public Law 87-874

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A GEOLOGICAL PROCESS-RESPONSE MODEL FOR
ANALYSIS OF BEACH PHENOMENA

by
W. C. Krumbein

Northwestern University
Evanston, Illinois

This paper is based on material presented before the ASCE
Water Resources Engineering Conference, Milwaukee, Wisconsin,
May 15,.1963. As presented in Milwaukee, this was the first of
two papers that considered the topic of beach engineering within
the geological framework of shore processes, The second paper,

by J. V. Hall, Jr., immediately follows this in publication
sequence. Research on which this paper is based was supported
in part by the Beach Erosion Board, Corps of Engineers, and by
the Office of Naval Research under Contract Number Nonr-1228(26),
Task Number NR 389-135.

SYNOPSIS

This paper describes beach processes and deposits in terms of a con-
ceptual process-response model that considers the processes and deposits
as separate though closely related aspects of shoreline phenomena. The
model provides a formal framework for analysis of natural beaches as they
may be modified or controlled by the beach engineer.

INTRODUCTION

Engineers and geologists look at beaches from somewhat different
points of view. To the geologist the beach is the result of natural
forces operating on natural materials within the geometric framework of
a particular stretch of shore. To the engineer the beach is a buffer
zone that protects private or public property along the shore from ero-
sive action by waves, currents, and tides. The engineer is thus con-
cerned with the stability of the beach, and even with its enlargement,
in terms either of protective action, or of the use of the beach for
recreational purposes, This latter aspect of beach engineering has
grown rapidly in the past several decades.

The beach engineer must have a clear understanding of natural pro-
cesses along shorelines in order to develop enlarged beaches or to design
protective shore structures. The geologist needs to understand these same
processes in order to evaluate relations among source areas of natural

beach material, movement of this material by waves and currents, and its
ultimate accumulation as a beach deposit. The balance between erosion and
deposition, and the natural forces that control dominance of one or the
other, are also of concern to the geologist,

In his study of beaches the geologist relies mainly on field observa-
tions, complicated as they may be by multitudinous events that take place
simultaneously along the shore. These include the interplay among waves,
currents, and tides, and the corresponding responses shown by beach deposits
under these controlling conditions. The geologist evaluates this complex
situation in terms of relatively long spans of time, viewing the phenomena
of a given instant as the momentary end product of a succession of events
that start with the inception of a beach deposit, and end with a mature
beach that represents some balanced state between erosion and deposition.

The engineer is concerned with those aspects of shore processes that
control erosion and deposition at a given time and place. He seeks for
principles that permit an enlargement of beaches and design of shore pro-
tective structures appropriate to relatively well-defined needs. The
engineer thus supplements the largely qualitative field observations of
the geologist with quantitative study of shore processes in controlled
wave tank experimentation. These experiments yield much basic data on
factors that control beach slopes, movement of sand by waves and currents,
formation of offshore bars, and other specific aspects of shore processes.

Wave tank experimentation involves scale model theory, and requires
simplification of natural shore processes to those features that can
ultimately be expressed as a physico-mathematical model. Extension of
these experimental findings to their natural scale, combined with field
measurement of wave forces on coastal structures, furnish data necessary
for installing protective structures or enlarged beaches which are them-
selves not destroyed or removed by the very forces that they are designed
to control,

In recent decades the geologist has increasingly quantified his field
observations, and the beach engineer has increasingly taken the framework
of geologic observation into account in his own work. Moreover, advent of
the high-speed computer has made readily available a variety of ways in
which the complexly interlocked variables of beach processes and deposits
can be analyzed in greater detail than was feasible by hand calculation.
The way has thus been opened for more fundamental field studies on the one
hand, and for more comprehensive wave tank experimentation on the other,
as the variety of models applicable to the study of shore processes and
deposits is enlarged.

The purpose of this paper is to examine the geological framework
of beach processes and deposits in which the beach engineer operates.
The approach is to set up a conceptual model of the beach deposit as a

response to waves and currents acting within the geometric form of a

given shoreline. This conceptual model is first considered in terms of
unmodified natural beach phenomena, and is then examined to discern those
features of the model that are of particular interest to the beach engineer.

DEVELOPMENT OF A CONCEPTUAL BEACH MODEL

Figure 1 shows a cross-section of a beach with its foreshore rising
to the berm, a relatively flat backshore, and dunes in the hinterland. The
beach deposit is a three-dimensional body of sediment that lies on some
foundation, indicated as bedrock in the figure. There may also be some
interfingering of beach and dune sand, as well as of beach sand and near-
shore bottom silts, as indicated by the dashed beach limits in Figure 1.

The elements from which the conceptual beach model is constructed are
shown in the cross-section of Figure 2. The hinterland is arbitrarily
separated from the beach proper, and may consist of dunes, a cliff or bank,
or a lagoon such as occurs behind barrier beaches. The backshore portion
of the beach is composed of dry sand at its surface. This sand is shifted
about by blowing winds, and under suitable conditions the blown sand ac-
cumulates as dunes piled up in part on and behind the backshore, as shown
in Figure 1. Dune sand is generally finer than beach sand, and has some-
what rounder particles, as a result of selective wind transportation in
terms of grain size, shape, and density. Thus the dune sand is a deriva-
tive deposit from the beach sand, and is properly considered as part of the
hinterland.

The foreshore and nearshore bottom in Figure 2 represent zones of
active hydraulic forces along the shore. The crest of the berm marks the
limit of maximum uprush of waves during any given state of the sea. More
than one berm height may be preserved, some representing seasonal or storm
uprush levels. The uprush-backwash zone, essentially coincident with the
foreshore, lies between the berm and the plunge point where the waves
break. This zone is subjected to a succession of highly turbulent up-
rushing tongues of water that come momentarily to rest on the foreshore,
and then return downslope as backwash less turbulent in its flow. The
effect of this continuous to-and-fro motion is to sort out and arrange the
foreshore material selectively according to its particle size, shape, and
density; and to produce the geometrical form of the foreshore as expressed
by slope, width, and height of berm.

The plunge point is a relatively narrow zone of considerable activity,
in which the breaking waves generate a high degree of turbulence that
carries bottom material into suspension. Part of this material is swept
beachward by the turbulent surge, and part of it, usually the finer material
is moved seaward by turbulence diffusion. Normally the plunge zone is
marked by a shallow trough in the nearshore bottom, composed of somewhat

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coarser material than that on either side. This is a lag deposit of
material large enough in particle size so that, if lifted by turbulent
forces, it drops back into the trough without being carried beachward by
the uprushing tongue of water, or seaward by diffusion.

The cross-section of Figure 2 is properly supplemented by the beach
map of Figure 3, in which waves approach a straight shore at an angle.
The refracted wave crests, the surf zone, and the momentary water edge
are shown schematically. The breaking waves, with their resulting uprush
surge, give rise to swash marks that indicate limits of uprush, normally
on the seaward side of the berm crest. For completeness, a backshore of
moderate width, with dunes in the hinterland, is included in this map,

Waves that approach at an angle to the shore develop a longshore
current as indicated by the arrow in Figure 3. This current normally
transports sand, and introduces a component of movement parallel to the
shoreline. On the other hand, the uprush-backwash zone represents a
component of movement essentially normal to the shoreline. Thus two
phenomena occur simultaneously: a downbeach movement of material from
left to right on the map, and a crossbeach movement of material between
the plunge point and the berm, For any stretch of shore some miles in
length, the downbeach movement results in a gradual but systematic change
in the average size, shape, and density of the beach particles. For any
one cross-section normal to the shore, the nearly continuous uprush and
backwash tends to develop a pattern of relatively rapid change in beach
particle properties across the foreshore. Thus, the rates of change in
beach particle properties are much greater along a traverse normal to the
shoreline than in a direction parallel to the shoreline.

The tide, in essence, moves the water's edge to and fro across the
foreshore, allowing the uprush to extend to greater or lesser distances
from the normal position of the berm. The plunge point, for a given
state of the waves, also moves with the water edge, resulting in con-
siderable reworking of the foreshore material as the tide rises and falls.
The tide also contributes a component to the shore current that may act
with or in opposition to the shore current generated by the waves.

Where the amount of sand moving along a shore is relatively large,
the foreshore may be aggraded, with the result that the berm moves seaward.
This movement of the berm produces a wider backshore, and thus adds sand
to the backshore "storage bin", free from subsequent wave work as long as
the beach foreshore remains stable, or continues to aggrade. The backshore
sand, removed from the zone of hydraulic forces, becomes subject to the
geologic work of wind. The combination of shifting wind directions, and
the selective transport of materials from backshore to dunes, tends to
blur any gradients or trends that may have been inherited from the hy-
draulic conditions operative as the berm moves seaward.

HINTERLAND BERM

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FORESHORE
WATER LEVEL

FIGURE |. SKETCH OF BEACH CROSS-SECTION, SHOWING
GENERAL GEOMETRY OF BEACH DEPOSIT

ERE OND HYDRAULIC FORCES
|
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LAGOON I. oN BACKWASH

FIGURE 2.SKETCH OF BEACH CROSS-SECTION, SHOWING AREAS
OF HYDRAULIC AND WIND FORCES. COMPARE WITH FIGURE I.

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FIGURE 3. SKETCH MAP OF BEACH WITH WAVES APPROACHING
AT AN ANGLE, TO ILLUSTRATE SIMULTANEOUS CROSS-BEACH
AND ALONG-BEACH COMPONENTS OF MOTION

BEACH FIRMNESS
lO= FIRM; O= SOFT

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FIGURE 4. GENERALIZED CONTOUR-TYPE MAP OF BEACH FIRMNESS,
SHOWING SYSTEMATIC CHANGES FROM SOFT TO FIRM SAND

6

It may be anticipated that if various properties of the beach are
measured at a number of points on the beach, the measurements should show
an areal pattern that reflects the processes taking place. Some beach
properties, such as average grain size, sand firmness, and others, show
fairly strong gradients between the plunge point and the berm, and a less
marked but still systematic gradient on the backshore, with a transition
to the hinterland dunes.

Figure 4 is a schematic map of beach firmness constructed by measuring
the sand penetrability at a number of points, and drawing contours through
the resulting field of numbers. The softest part of the beach is commonly
along the berm crest, and firmness increases rapidly across the foreshore
toward the water edge. On aggrading beaches a reversal in firmness may
occur near the water line, though the situation shown in Figure 4 is not
uncommon on sand beaches along the western shore of Lake Michigan. On
the backshore the pattern of contours becomes less regular, though some
zonation may be preserved. The dry, relatively fine wind-blown sand may
show a decrease in firmness in the transition zone between backshore and
dunes.

A BEACH PROCESS-RESPONSE MODEL

Consideration of Figure 2, 3, and 4 furnishes a basis for constructing
a conceptual process-response model of a natural beach. Figure 5 shows
this model schematically, with the process elements on the left, and an
arrow pointing to the response elements on the right.

The process elements include three major items. The first is the
energy factor, expressed in terms of wave height, period, and angle of
approach; by tidal range and related features; by the velocity and direc-
tion of the shore current; and by the velocity and direction of winds that
operate on the backshore. The material factor on the process side includes
all natural materials - pebbles, sand, silt, shells, etc. - which initially
are present in the beach area and are available for movement or shifting
about by the energy factors. The last element on the process side is the
overall geometry of the shoreline. This represents the "boundary conditions"
in which the beach processes operate. Thus, the distribution of wave energy |
along the shore is related to the form of the shoreline and to the nearshore
bottom slope, which influence the pattern of wave refraction.

The response elements in the model include two main items as shown on
the right-hand side of Figure 5. The first is the geometry of the beach
deposit, which includes foreshore slope and width, height of berm, and
width of backshore. In a three-dimensional sense, the geometric element
also includes the volume and shape of the beach deposit as a whole.

The properties of the beach materials on the response side of the
model are controlled by the kinds of material originally available at the

beach site or brought in by currents and tides. The average grain dia-
meter of the foreshore sand, for example, is controlled by the particular
combination of process elements that have recently occurred or are going
on at some given time.

Although the same attributes of the shore and beach materials are
listed on the process and response sides of the model in Figure 5, those
on the left represent initial properties, whereas those on the right are
response properties. Thus, by winnowing action on the original material,
or by inflow of new materials along the shore, the response properties
of the beach material may be significantly different from the initial
materials.

A feature common to all elements in the conceptual model, though not
explicitly stated in Figure 5, is the pattern of areal variation shown by
the grain size, the angle of foreshore slope, and by other attributes, over
the beach area as a whole, as was developed in Figure 4. Beach firmness,
selected as an example for that map, represents a complexly interlocked
response related to grain size, moisture content, and porosity or degree
of packing of the grains.

Until relatively few years ago, limitations both in instrumentation
and in methods of data analysis have hindered quantitative expression of
conceptual beach models. As more quantitative data become available,
additional implications of these models can be examined in terms of data
interlock and feedback on natural beaches. As previous paragraphs indi-
cate, close relations occur among the process elements themselves, in that
the geometry of the beach site as expressed by nearshore bottom slope,
influences the pattern of energy distribution on the shore. This is an
example of interlock in that these two process elements are not wholly
independent. A beach deposit, formed by wave and current energy, may
involve changes in the configuration of the bottom slope with time. These
changes in turn modify the pattern of wave approach, so that a response
element may exert a feedback control on one or more process elements.
These complexities are relatively common in process-response models, and
a generalized feedback arrow is included in Figure 5.

Figure 6 shows a few data-interlock and feedback relationships that
occur in natural beach processes. These have a strong bearing on engin-
eering design. For example, a shore structure may produce unexpected
results, if data interlock and feedback are not taken into consideration.
As Figure 6 shows, wave energy exerts a controlling influence on the grain
size of particles on the beach; it influences the foreshore slope and
nearshore bottom slope; and (if waves approach at an angle) it controls
in part the velocity and direction of the shore current. The shore cur-
rent influences average grain size, and may also modify the nearshore
bottom slope. Hence, the dashed arrow along the top of Figure 6, from
bottom slope to wave energy, represents feedback.

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FIGURE 6. DIAGRAM ILLUSTRATING SOME INTER-RELATIONS AMONG
PROCESS AND RESPONSE ELEMENTS OF THE MODEL IN
FIGURE 5. SEE TEXT FOR DETAILS

ENERGY FACTORS

SHORE CONTROLS (AGENTS) BEACH RESPONSES
WAVES
TIDES
SHORE CURRENTS BEACH
GEOMETRY GEOMETRY
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SHORE BEACH
MATERIAL MATERIAL
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FIGURE 7. PROCESS-RESPONSE MODEL OF BEACH FORESHORE,
ADAPTED FROM FIGURE 5 TO SHOW ENERGY FACTORS
SEPARATE FROM GEOMETRY AND MATERIALS FACTORS

In terms of foreshore slope as a response element, the diagram
indicates that this is influenced by wave energy, by shore currents, by
the average size of the grains present on the foreshore, and very likely
by the nearshore bottom slope. A response produced by the simultaneous
effect of several factors (some of which may themselves be response
elements), raises an important question in the evaluation of the relative
effects played by each of the contributing factors. The engineer who
replenishes a beach with imported sand needs to ask himself whether the
mean grain size of the imported sand is the most important slope control
in the area concerned, or whether other factors such as wave energy and
shore currents are more important.

Until relatively recently, quantitative field data for analysis of
these interlocking situations were not available; moreover, until the
high-speed computer became generally available these complex regression
problems could not be handled without a severe drain on man-hours avail-
able for hand computation.

It is evident from earlier remarks that the continued refinement of
quantitative beach models involves analysis of field interrelations be-
tween process and response elements, as well as scale model experiments
involving these same elements treated perhaps on a more analytical level.
These interrelations can be studied in terms of a large variety of con-
ceptual, physical, mathematical, and statistical models of beach behavior,
In part the identification of an optimum model requires a search for under-
lying principles of data interlock and feedback, such that these may ulti-
mately be expressed as functional relationships. The concept of energy
acting upon material furnishes a basic approach, as is illustrated in the
following paragraphs.

Figure 7 represents a rearrangement of elements in the process-
response model of Figure 5, to indicate an alternative way of expressing
the model as it applies to the foreshore, with explicit treatment of the
energy factor. The model is now divided into three parts. On the left
are two elements that may be called shore controls, which include the
shore geometry and shore material as shown on the left-hand side of
Figure 5, The right-hand block, showing the beach responses, contains
the elements of foreshore beach geometry and beach material from the
right-hand side of Figure 5. The central block in Figure 7 contains the
energy factors - the operative geological agents - that produce the fore-
shore effects indicated by the main arrow pointing to the right.

In this variant of the model the energy factors - waves, tides, and
currents - are those acting on the foreshore. A corresponding model for
the backshore and dunes would have the geometry and materials of the back-
shore in the left-hand block, with a new central energy block having the
term "wind work", and with a new response block on the right representing
the geometric form and material composition of the hinterland dunes.

The form of the model in Figure 7 is more flexible than that in
Figure 5, in that it can separate the influence of different energy
sources that may operate successively on essentially the same materials.
Thus, the response elements of the foreshore processes produce a set of

backshore controls whose responses under wind work are sand dunes.

In all models of the form shown in Figure 7 at least one major feed-
back loop is present, although additional feedback loops extend from the
response block to the central energy block.

Two implications of the model in Figure 7 deserve comment. The first
is that the blocks can be expressed as matrices of numbers, and the model
may be manipulated by the procedures of matrix algebra, conveniently
treated with high-speed computers. For this sort of analysis the central
matrix is a transformation matrix, as pointed out by Griffiths (1962) in
his discussion of a general petrogenetic model.

A second feature of the conceptual beach model is that it permits
examination of those aspects of beach processes that can be controlled by
the engineer. The engineer enters from outside the natural beach model,
and thus introduces an element different either from data interlock or
feedback.

SHORE PROCESSES AND THE BEACH ENGINEER

The role of the engineer may be seen by referring back to the process-
response models in Figures 5 and 7. Though the engineer cannot directly
control the height, period, or angle of approach of the waves, he can
design structures such as offshore breakwaters to modify the pattern of
energy flow to the beach, as is illustrated by Halil (1963) - Figures 13
and 15.

The engineer can exert direct control on the material factor of the
process elements. This may be accomplished by introducing imported sand
onto a beach in the form of stock piles or a sand fill placed along the
foreshore. By this introduction of selected material, the engineer
strongly influences such response elements as the foreshore slope and
average grain size of the resulting modified beach deposit, as well as
the width of the backshore.

Another important way in which the beach engineer can modify the
response side of the beach model is by building structures that introduce
special boundary conditions into the geometry of the shoreline. Among
the commonest of these is the groin, built normal to the shoreline.
Introduction of a groin produces an accumulation of sand (if beach drift
is present) on the upbeach side. Entrapment of sand on the upbeach side
of the groin lessens the amount of sand moving downbeach from the groin.
During this time of downbeach impoverishment, erosion may occur immediately
downbeach of the groin. If this is severe, the structure may be flanked,

Obviously, groin design is important here, as is also developed by Hall
(1963).

Erosion and deposition along shorelines play an important part in the
selection and effectiveness of beach engineering structures. This can be
illustrated by the two diagrams in Figure 8. As mentioned earlier, ag-
gradation along the foreshore moves the berm seaward, and adds sand to the
natural “storage bin" represented by the backshore. With adequate back-
shore width, the bank in the upper cross-section of Figure 8 is effectively
protected from wave action. Thus, in terms of the model of Figure 5, the
geometric response of the beach with aggradation is such that a natural
buffer zone is developed between wave uprush and the bank in the hinterland.

If shore drift is so lean that waves and currents strip material from
the foreshore, the landward movement of the berm narrows the protective
backshore, resulting in the loss of sand from the natural storage bin. In
the extreme case shown in the lower diagram of Figure 8 erosion has con-
tinued until the bin is empty, and the foreshore extends directly to the
bank, In these circumstances the bank is subject to nearly continuous
wave action, and the final erosional response of beach geometry has been
that no backshore remains.

The beach engineer, faced with the problem in the lower diagram of
Figure 8, has several choices for remedial action. One may be to build
groins along the shore, perhaps with a fill of imported sand, to establish
a berm some distance from the bank. If erosion is very severe, and if
costs of beach restoration are prohibitive, the engineer may recommend a
seawall to protect the bank, even at the risk of losing the remaining sand.
Decisions of this sort require not only judgment regarding the kinds of
structures to use, but involve cost factors as well. Thus, the beach
engineer, in taking the conceptual beach model into account, superimposes
upon it a cost factor, and accordingly introduces man-made components
into the model. By introduction of the economic factor and other re-
straints, the conceptual model becomes adaptable to various kinds of
operational research studies.

CONCLUDING REMARKS

The treatment of shore processes in this paper is expository in
terms of a conceptual beach model, and it does not include information
on rates of erosion, quantities of shore drift, or related items. Much
data are available on these quantitative aspects, and for applied use of
the conceptual model such information is used to convert the expository
treatment into a more formal quantitative treatment for analysis of data
matrices, aS was mentioned in connection with Figure 7.

There seems little doubt that improvements in instrumentation and
better understanding of interrelations between process and response
elements have made it possible to design field experiments on beaches

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that parallel the kinds of experiments carried on in wave tanks. In both
cases it is possible to work with many more variables than has formerly
been the rule. As long as computational facilities are limited to thase
of a desk calculator, the treatment of multivariate problems is very
tedious, and indeed is largely impractical. The advent of the high-speed
computer has changed this picture markedly.

During this decade both the geologist and the engineer can gain
greater insight into beach processes and responses than has been possible
heretofore. The more closely that experimentation and field work are
coordinated, the greater will be the opportunity for discerning those
aspects of beach process and response that are of basic importance in the
design of protective shore structures.

The concept of a beach model, in the degree that it provides a
framework for this closer understanding, can become the point of entry
for development of an enlarged and in some respects a more fundamental
approach to the problem of protecting shorelines from severe erosion.

SELECTED REFERENCES

Three of the following papers are pertinent to geological models,
and they are offered as an introduction to the growing literature on the
subject.

Griffiths, J. C., 1962. Uses of computers and statistics in exploration
and development of mineral resources: Univ. Arizona, College of
Mines Symposium, Vol. 1, pp. El 1-19.

Hall, J. V., Jr., 1963. Coastal Engineering Structures: paper presented
before ASCE Water Resources Engineering Conference, Milwaukee, Wisc. ,
15 May 1963.

Krumbein, W. C., 1961. The analysis of observational data from natural
beaches: Beach Erosion Board, U. S. Army Corps of Engineers, Tech-
nical Memorandum No. 130.

Miller, R. L., and Zeigler, J. M., 1958. A model relating dynamics and
sediment pattern in equilibrium in the region of shoaling waves,
breaker zone, and foreshore: Journal of Geology, Vol. 66,
pp. 417-441.

COASTAL ENGINEERING STRUCTURES

by

Jay V. Hall, Jr.
Chief, Engineering Division
Beach Erosion Board, U.S. Army Corps of Engineers

SYNOPSIS

This paper describes the physical characteristics of basic coastal
engineering structures in general use; the behavior of individual struc-
tures and their behavior when grouped as a system. Also described is a
typical example of planning for coastal engineering works.

INTRODUCTION

The foregoing paper by Krumbein has covered beach processes and
deposits in terms of a conceptual process-response model, This paper
parallels Krumbein’s presentation with emphasis on how these natural
forces are controlled or modified to suit man’s purposes by means of
engineering structures.

During the early years of this nation, shore protection was a
relatively unimportant problem since the shores were sparsely settled.
As our economy developed and the value of shore front property in-
creased a line was established beyond which for economic reasons the
shoreline could not be permitted to erode. The science of shore pro-
tection, like others, developed first as an art as the need arose and
continued on that plane until research and development placed it ona
scientific basis. Although some work has been done throughout the years,
the first major concerted effort to increase the knowledge started
shortly after World War I. The next great advance was made in World
War II, due to its amphibious nature.

The science of shore protection covers numerous fields of endeavor
in which geology has and is playing an important role in developing a
fuller understanding of beach processes, so essential to the solution
of shore protection problems. In other words, it is the accumulation
of this knowledge that has enabled the engineer to design structures,
which modify or control the natural forces to suit man’s purposes.

Numerous types of structures have been developed, each having its
mission in shore protection work. These are the working tools of the
engineer and he employs them after a complete engineering study to
provide protection at the least cost.

BASIC TYPES OF STRUCTURES

Numerous types of structures are seen in the coastal areas but all
are variations of a few basic types of which the seawall is possibly the
oldest type used today. It is defined as a structure separating land and
water areas, primarily designed to prevent erosion of the backshore and
other damage due to wave action. Seawalls are generally massive and ex-
pensive, and are used only where economics dictate their use. Most sea-
walls are built of masonry or reinforced concrete (Figure 1). They are
normally designed as gravity structures to resist a frontal attack by the
waves. Their dimensions, height and length, are generally dictated by the
natural features of the area to be protected. In some instances the top
is set at a superelevation to prevent overtopping and flooding of inland
areas due to storm wave run-up on a superelevated tide. Except in special
cases the seawall is rarely recommended for use since more economical means
of protection have been devised.

A bulkhead is defined as a structure which separates land and water
areas, primarily designed to resist earth pressures (Figure 2). By defini-
tion it is not designed for dissipating or absorbing high wave energy. It
is generally built high on the beach as a delimiting boundary between the
shore area and the developed upland. Like a seawall the dimensions of
the bulkhead are determined by the natural features of the area to be
protected. In some instances, the bulkhead, as a secondary line of defense
to the beach, is superelevated to prevent overtopping and flooding during
storm conditions. However, if the beach erodes, the waterline approaches
the bulkhead with the result that the bulkhead must act as a seawall.

Revetments are structures related to seawalls or bulkheads, They are
defined as a facing of stone or concrete shapes built to protect a scarp,
embankment, or shore structure against erosion or damage by wave action or
currents (Figure 3). Revetments have evolved from the simple rubble facing
to the more esthetic structure built of interlocking blocks. The structure
in a sense replaces the buikhead and its height is designed in a manner
similar to that of the bulkhead, but due to its ability to absorb wave
energy, a lesser run-up is experienced, thus resulting in a lower design
height. The cover or armor stone of the rubble type revetment is designed
to be stable under prevailing wave action.

Unlike the preceding structures, which serve essentially as barriers
between land and sea, other structures have been developed and are used to
furnish protection by modifying the natural regimen of the area. A jetty
is classed as a structure extending from the shore into a body of water
and designed to prevent shoaling of a channel by littoral materials, and
to direct and confine the stream or tidal flow (Figure 4). It is usually
built with a trapezoidal section of heavy rubble designed to be stable when
subjected to wave forces extant in the area. The structure may vary in
length from a few hundred to several thousand feet, depending of the dis-
tance from the shore to a water depth equivalent to the depth of channel

7 Steps 2 high

FIGURE I. CONCRETE SEAWALL

NOTE: Dimensions and details to be determined by
particular site conditions

Top elevation of bulkhead = Average height of highest
yearly storm tides plus wave heights

—= =

a 2:

Zab WAR

SECTION PLAN

Water Level Datum

FIGURE 2. TIMBER BULKHEAD

18

20

Riprap (1000 Ibs. to 6000
. Ibs. averaging 4000 Ibs.),
EL.+ 15.0 chinked with one man stone.

Low dunes graded
to + 15.0 ft. Natural beach

Crushed stone unscreened
2 Ye inches and under.

Crest EL. 14.9'

mS '
SSS MLW EL.OO

W Wto W/2 Rh
W/200 to W/6000
W/10 to W/15 3

12" Min. Thickness

Stone Weight Total Layer Thickness |

Ww 4.7 tons plus 7.8 ft.

W to W/2 2.to 5 tons 7.8 ft.

W/10 to W/15 600 to 2000 Ibs. 4.0 ft. (min.) (larger stone on outer surface)
W/200 to W/6000 600 Ibs. to chips — (larger stone on outer surface )

FIGURE 4. RUBBLE MOUND JETTY OR BREAKWATER

to be maintained, A jetty is normally a high structure to insure that
sand will not be carried over it into the navigation channel.

Possibly the most common shore protection structure is the groin.
It is built usually perpendicular to the shoreline to trap littoral drift
or to retard erosion of the shore (Figure 5). It is narrow in width
(measured parallel to the shoreline) and its length may vary from less
than one hundred to several hundred feet (extending from a point landward
of the shoreline out into the water). It is constructed of timber, con-
crete, steel or rubble. Groins may be classified as permeable or im-
permeable, An impermeable groin is a solid or nearly solid structure,
whereas a permeable groin has openings through it of sufficient size to
permit passage of appreciable quantities of littoral drift. The top pro-
file of groins generally parallels the slope of the beach out to about 1
foot above MLW, and thence is horizontal to the outer end; An impermeable
groin is normally designed with low profile to build a beach by impounding
the drift to its top elevation, and then permitting the drift to pass over
its top to nourish the downdrift beaches. A high groin is normally used
only as a barrier at the ends of littoral zones, such as limiting groins
of a bayhead beach or at a harbor entrance.

Breakwaters may be either shore connected or detached (offshore).
Both are used to modify the littoral processes as well as provide shelter
for shipping.

The shore-connected breakwater usually leaves the shore as a jetty
but then changes alignment to roughly parallel to shore. It is generally
built of heavy rubble, and designed to be stable under attack of storm
waves extant in the area. Other construction materials are also used for
breakwater construction, such as precast concrete shapes and, when sited
on hard bottom, concrete, timber or steel caissons loaded with ballast.
The length of the structure is dependent upon the required harbor area to
be protected, Shore-connected breakwaters may be used singly or in pairs
to totally enclose a harbor area.

An offshore breakwater is normally set parallel to the shore. It is
generally built with a trapezoidal section of heavy rubble similar to the
jetty, and designed to be stable when attacked by the waves extant in the
area. The length of the structure is approximately equivalent to the dis-
tance the structure is sited from the shore, From an engineering point of
view, the length is determined by the wave diffraction patterns around the
ends of the structure. In other words, the length of the structure is so
designed that a calm area of required size is created shoreward opposite
the center of the structure.

Undoubtedly the most widely used shore protection device at present,
is the artificially constructed and nourished beach. It is included here

20

Variable

Variable

Variable

Water Level Datum

a
=
=
<s
rn)
©
fe
w
o
a
{3
| aoe

PROFILE

Planks Staggered

NOTE: Dimensions and details to be determined

by particular site conditions.

Round Piles

Planks Staggered

Round Pile

SSS

Timber Wale

Timber Sheet Piling

VIEW-AA

FIGURE 5. TIMBER GROIN

2

as a structure because it is built by man. It has long been recognized
that a beach of proper proportions, including an adequate berm backed by
dunes, is man’s and nature's best solution to the erosion problem. Where
possible, an eroded natural beach is rebuilt to the exact characteristics
of the original beach. In other words, the borrow material is selected to
conform as nearly as possible with material comprising the natural beach.
The dimensions of the beach, such as slope, height, and breadth of berm
are adhered to as closely as possible where similar beach materials are
available. Where the characteristics of the borrow and native beach ma-
terials are not the same, the constructed beach is placed to such dimen-
sions that the material available will be stable under prevailing coastal
processes as is illustrated by Krumbein's Figures 5 and 7 (foregoing paper).

The widespread use of constructed beaches has to a large degree been
brought about by the increasing construction costs of other types of struc-
tures and the need of beaches for recreational use. The beach at Harrison
County, Mississippi, illustrated in Figure 6, is a classic example of this
type of structure.

BEHAVIOR OF INDIVIDUAL STRUCTURES

The structures enumerated all have specific functions to perform and
all react differently in use. The mission of the seawall is to protect the
upland area and is not expected to protect and preserve the beach (Figure
7). It is a massive structure designed to take the full impact of the wave
and is not designed to modify the littoral forcés in the area to preserve
or enlarge the beach. When a wave breaks on a vertical seawall the energy
which throws water high into the air also permits it to move downward with
an equal force, thus eroding the sand at the toe of the wall and carrying
it seaward. Erosion usually continues until the bottom material ceases to
be affected by the downward velocities. A great deal of effort has been
expended in seawall modification to reduce this erosive feature associated
with it. Modification has helped to some extent, but a seawall should never
be used alone as protection if the retention of the beach is desirable.

Bulkheads behave in the same manner as seawalls but are not used
directly as a bulwark against the sea (Figure 8). They are usually placed
well back of the waterline to retain low bluffs or dunes and to serve as a
secondary line of defense during storms - the first line of defense is the
beach. However, if the beach erodes to a point where the wave strikes the
structure the bulkhead becomes a seawall and rapid toe erosion normally
takes place. Since the bulkhead is not designed as a bulwark against the
sea, the structure generally fails by falling seaward after damaging scour
or erosion at the base of the structure has occurred.

A revetment is an alternative to seawalls and bulkheads. Like sea-
walls and bulkheads, revetments protect the shore area from direct attack
but they do not modify the littoral regimen of the area to protect or
preserve the beach (Figure 9). Revetments are generally sloping permeable

22

FIGURE 6, BEFORE AND AFTER BEACH FILL - HARRISON COUNTY, MISSISSIPPI

23

FIGURE 7, CONCRETE SEAWALL - WINTROP BBACH, MASSACHUSETTS

FIGURE 8, TIMBER BULKHEAD AND GROINS - LONG BRANCH, NEW JERSEY

FIGURE 9, STONE REVETMENT - FORT STORY, VIRGINIA

structures constructed of rubble stone or concrete shapes. When a wave
impinges on the structure, its energy is absorbed in the interstices of
the surface units, resulting in a greatly reduced run-up and backwash.
The downward eroding effect of vertical seawalls and bulkheads is greatly
reduced by use of this type of structure.

It is to be emphasized that the above-mentioned structures are used
only to establish a delimiting line between land and sea, and they do not
modify the littoral regimen either to preserve or build a beach. Conse-
quently material transported in the littoral zone is not obstructed, and
So moves past the seawall, bulkhead, or revetment.

Jetties are used at harbor entrances to maintain the channel through
the littoral zone (Figure 10). In addition to providing shelter to the
channel from incident waves they also provide protection by preventing
sand carried alongshore as littoral drift from entering the channel. In
order to serve this latter function they must be impermeable and high,
Since they are high they present a complete obstruction to the- littoral
drift, and thus deprive the downdrift shore of sand supply. This un-
desirable feature has long been recognized, but only in the last decade
has it been possible to develop a satisfactory means of transporting the
impounded material downdrift to re-establish the natural processes. At
the present time systems have been devised whereby material is moved across
harbor entrances by a fixed pumping plant mounted on the updrift jetty.
This system, while helpful, has not been shown to be entirely satisfactory,
Another type now being used will be discussed in subsequent paragraphs.

A groin is the most important shore structure for the enlargement or
stabilization of beaches (Figure 11). It is almost always built perpen-
dicular to the shore to impound the available littoral drift or to reduce
the rate of loss of sand from the area by littoral forces. This structure
has been developed in a variety of forms. It may be long or short; high or
low; and permeable or impermeable. The length of an impermeable groin is
usually determined by measuring the distance from the inner edge of the
berm to the 6-foot depth, on the usual assumption that most of the material
movement along the beach takes place shoreward of the 6-foot depth. The
height of the groin depends on its function. If the structure is designed
to impound all available drift except that which moves around its outer end,
it is built high. It is pointed out, however, that complete obstruction
of the drift creates serious erosion downdrift and may cause flanking of
the structure on the inner end of the downdrift side.

If a groin is required to hold or build a beach at its original pro-
file, a low groin is used, with its top coinciding with the existing or
desired beach profile. The advantage of this type of groin is that when
full, it permits material to pass over its top and nourish downdrift
beaches, thus eliminating shore starvation and possible flanking at the
inner end.

25

FIGURE 10. RUBBLB MOUND JETTIBS-COLD SPRING INLET, NEW JBRSEY

FIGURE 11, GROIN SYSTEM - WILLOUGHBY SPIT, VIRGINIA

Permeable groins are usually built high, the top serving as a recrea-
tion facility such as a fishing platform or sun deck. This kind of groin
has openings through it from top to bottom over its entire length to permit
beach material to pass through. The effectiveness of this structure com-
pared to the low impermeable groin has not been fully demonstrated to the
satisfaction of most coastal engineers, and it is interesting to note that
the Beach Erosion Board has never recommended construction of permeable
groins in its 33-year history.

Breakwaters both shore-connected and detached (offshore) are used to
provide shelter for anchorages and harbor entrances.

The inner end of the shore-connected breakwater acts in the same
manner as a jetty (Figure 12). It impounds the littoral material on the
updrift side and thus excludes these materials from the harbor area. A
structure of this nature, high and sand-tight, is a total littoral barrier,
and its construction will result in accretion updrift and erosion downdrift.
Eventually the impounded material will move along the seaward face of the
structure and accumulate in the harbor area. Through harbor maintenance
by pipeline dredge the material can be spoiled downdrift to nourish the
eroding shore, effecting a sand-bypassing system. The seaward portion of
the structure or that part roughly paralleling the shore acts essentially
as an offshore breakwater absorbing the wave energy to create a calm anchor-
age or harbor area in its lee.

Offshore breakwaters have been designed more recently for the dual
purposes of providing shelter to a harbor entrance and to provide a pro-
tected littoral reservoir from which sand-bypassing operations can be
conducted (Figure 13). In this application the offshore breakwater is
installed seaward and updrift of the harbor entrance to intercept wave
action which would normally strike the shore in the area. This arrange-
ment provides a relatively calm approach for ships entering the harbor.
By intercepting the wave action, it also results in arresting the flow of
littoral material which impounds in the form of a bulge on the shore op-
posite the center of the structure. Thus it can be seen that this struc-
tural arrangement improves conditions by stilling the sea and preventing
littoral material from moving into the navigation channel.

It has long been recognized that littoral barriers are detrimental to
the downdrift shores and that where they exist some sort of sand-bypassing
system should be used. The floating hydraulic pipeline dredge is ideal
equipment for moving sand from one location to another, but it cannot be
safely used near shore in an exposed location. In other words it would be
impracticable to dredge material impounded by a jetty. Dredging behind an
offshore breakwater is another matter. The shelter afforded by such a
structure is conducive to bypassing by pipeline or hopper dredge. It is
considered that this type of bypassing system is superior to others now in
service.

28

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jaodsudi| [o10}}177 40 Uoljoe.iq

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{DIO} 41) ayejdwod DO eq jjlm SIU, :3LON

FIGURE 13, OFFSHORE BREAKWATER = VENTURA COUNTY HARBOR, CALIFORNIA

FIGURE 14, BEFORE AND AFTER BEACH FILL - OCEAN CITY, NEW JBRSEY

31

Artificially nourished and constructed beaches are used extensively
at present to restore required conditions suitable for recreational areas
(Figure 14). The installation of this type of structure involves replacing
a beach using the criteria derived from the natural beach. That is, the
grain size of the material and its gradation; beach slopes (both foreshore
and backshore); and elevation of berm are adhered to as strictly as possible.
In the event that a different beach material, such as sand of different
grain size, need be used, the reconstructed beach will possess different
characteristics even when nourishment is supplied at a rate equal to past
natural losses. This type of constructed beach, however, behaves as did
the natural beach with respect to adjacent shores and is normally bene-
ficial to the downdrift shores.

BEHAVIOR OF SYSTEMS OF STRUCTURES

Structures used singly or in systems have a marked effect on the land
forms in the immediate and contiguous areas through accretion and erosion.
Groin fields are designed to build and hold a beach usually of appreciable
size. Numerous factors must be considered in design, namely, the magnitude
and direction of littoral drift and the resultant direction and magnitude
of natural forces in the area. In an area of abundant littoral drift, or
where natural sand supply approaches the capacity of littoral forces to
transport it, a system of groins can be designed to increase the dimen-
sions of the natural beaches (Figure 11). In constructing a groin field,
construction should proceed updrift. In other words, the downdrift groin
should be constructed first so that the adjacent updrift embayments can
be filling as construction proceeds updrift. Occasionally extended periods
of time are required between the construction of each groin to achieve the
best results. If the groins are built to a low profile, with top at the
elevation of the natural beach, the littoral material passes over their
tops, nourishing the entire system. The process continues until all groins
are full. An undesirable feature of this procedure may be, that while the
groins are filling, the beach downdrift from the groin system may be
eroded, Almost without exception, groin systems are now filled artifici-
ally to allow immediate movement of the littoral material through the
groin field,

For beaches in areas of little or no drift (or relatively little
natural supply of beach sand), two or more high groins in combination with
beach fill can be used to accomplish this same purpose. In this type of
arrangement, the high groins are used at the downdrift ends of the com-
parmented areas to form pockets or bayheads that restrain the material
from being moved out of the area by the littoral forces. Since there was
little or no natural drift in such an area to start with, accelerated
erosion of the downdrift shore should not be induced in important degree.

In locations where a field of low groins is installed adjacent to the
end of a littoral compartment with appreciable natural drift, terminating

32

at a submarine canyon or deep water at the foot of a headland, a high
terminal groin is used on the downdrift end to prevent the loss of sand
from the littoral zone. Such a system is beneficial in conserving sand
under these circumstances since an erosion problem immediately downdrift
would not exist.

Groin systems are the most universally used structures for beach re-
tention and enlargement. Frequently it is found desirable, when building
and maintaining a protective beach, to supply additional protection to
highly valuable property behind the beach berm and dune line. To accom-
plish this, a seawall, bulkhead or revetment is installed to protect the
backshore during storm periods (Figure 8). Although an adequately wide
beach affords excellent protection, it may be overtopped during major
storms, resulting in dune deterioration and major interior flooding.
Occasionally a breach through the beach may occur forming an inlet from
the ocean. In this case the secondary defense structures prevent severe
changes in the land forms.

Harbor jetties, either alone or with an offshore breakwater, accom-
plish the purpose of protecting an entrance through a barrier beach, but
will result in a considerable change in the land form unless a sand by-
passing operation is effected. The offshore breakwater creates a calm
area shoreward of its center, resulting in the deposition of littoral
material at that point. As the point builds, it acts as a natural groin
and a great expanse of beach is built updrift. Further, as this wide
expanse of sand dries, it is frequently moved by the wind into a sub-
stantial dune system. This change in land form can create other problems.
Instances are recorded where sand movement by wind from impounded areas
has built dunes around and completely over shore installations, including
buildings, When this occurs, beach or dune stabilization measures such as
sand fences and vegetal plantings are indicated. The storage of such large
quantities of littoral material upsets the natural regimen of the area by
removing the downdrift shores from the system of natural nourishment.
Erosion is thus accelerated in this downdrift area. In order to reduce
or eliminate this type of change in land form, the material can be moved
downdrift by a hydraulic dredge working in the lee of the breakwater to
re-establish natural conditions. To date sand-bypassing operations at
jettied entrances which do not include an offshore breakwater have not
been completely satisfactory.

Where natural features permit, it is frequently more economical to
supply sand to the beach than to build groins. The artificially nourished
beach is the most satisfactory shore protection system (Figure 14). It
is the one system that maintains the balance of nature, and is relatively
free of the undesirable features of other systems.

33

ENGINEERING PLANNING AND DES IGN

In planning a shore protection project all factors pertinent to the
problem must be considered to produce criteria necessary for a sound design.
These factors are:

1. Geomorphology of the beach area.
2. Littoral materials.

3. Littoral forces.

4. Shoreline history

Study of these factors permits further analysis as follows:
1. Shore processes involved in the problem.

a. The direction, average rate, and variability of littoral
transport.

b. Present and prospective rates of supply and loss, and
quantitative deficiency or surplus in cubic yards.

c. Manner of movement of littoral materials that produced
the problem conditions.

d. Predicted or estimated future shore conditions if no
remedial measures are undertaken.

2. Methods of correcting problem conditions. This includes
the selection of structures by which the objectives can be attained, and
considers their effects within the problem area and adjoining shore.

3. Selection of design criteria for structures under con-
sideration.

As an example; consider the following proposed harbor area (Figure
tS)

1. Examination of the land form and a study of wind, wave,
tides, and current directions indicate a seasonal reversal in drift, but
a net dominance of the eastward component. Further, the resultant of the
natural forces is found to strike the shore from a southwesterly direction.

2. Present supply and loss are in balance, with a net volume of
about 500,000 cubic yards per year passing the area in the dominant direc-
tion of transport (eastward). In the recent past the flow of material has
been uninterrupted eastward past the inlet. The problem arises from fixation
of the inlet, which will cause accretion on the updrift side and equivalent
erosion downdrift.

34

Proposed Harbor Area

Winter Drift Summer Drift

LMG ES

Predominant (Net) Drift 500,000 Cubic Yards / Year

/mproved Harbor Area

Sand Fences

VILLA ARLE

Predominant Drift Groin Field to Reduce
Zs Rate of Loss
Winter Drift f Summer Drift

eee

Rubble -Mound Breakwater

FIGURE 15. SHORE PROTECTION-HARBOR STABILIZATION

35

3. If remedial measures are not taken following fixation of
the inlet, erosion downdrift thereof will be serious with a loss of about
500,000 cubic yards per year.

4, In order to correct the conditions created by fixation of the
inlet, all facets of the problem must be considered and a properly designed
system selected to cover all foreseeable events. In other words, a struc-
ture system must be selected to combat the adverse forces created by the
proposed improvement.

An important phase of present day design is that the natural flow of
littoral material across an inlet should be restored after construction of
jetties. A long updrift jetty preserves the channel to the limit of its
impounding capacity; when it is filled the material will move around its
end, A second disadvantage of this type of structure is that the material
in the impounded area is exposed to wave action and thus difficult to trans-
port downdrift by mechanical means. In view of these factors, it appears
that the most satisfactory method of inlet fixation consists of two short
jetties and an offshore breakwater. With this arrangement jetty length is
not a major problem since the impounded area forms a short distance updrift
from the structure. A further advantage lies in the shelter afforded by
the breakwater, which facilitates sand bypassing by hydraulic pipeline
dredge.

The resulting land form includes impounded material updrift from the
jetties in the lee of the breakwater which is adjacent to the improved
harbor area. It thus appears that some form of sand fixation in the dry
area will be required since the prevailing winds and the direction of
natural forces will undoubtedly carry Some sand from the impounded area
into the harbor. Fixation by vegetation and plantings is not entirely
satisfactory since the impounded area will be removed periodically by
dredging. In view of the above, it is considered that sand fences will be
more satisfactory for the purpose,

On the downdrift side of the jetties it is estimated that a loss rate
of 500,000 cubic yards per year will occur. Since bypassing will be accom-
plished every other year, with consequent removal of 1,000,000 cubic yards
in that interval, some provision may be desirable to protect the downdrift
shores during this period.

Downdrift the land form is a low narrow sand spit separating the ocean
from the harbor area. Since the loss rate from this area will be about
500,000 cubic yards per year, groins will be required to reduce this rate
of loss if found to be more economical than advance nourishment or periodic
bypassing. Further, since the spit is low and could be breached during
storm tide periods, the need for a second line of defense is apparent if
groins are employed. A bulkhead or revetment, whichever has the least cost,
may be used, The extent of the groin system is determined by the worth of

36

the land to be protected. It must certainly cover the low spit area and
extend to a point where some shore recession can be tolerated between sand
bypassing or groin filling operations. The groin field should be of the
low profile type. In the event that a beach is not necessary for recrea-
tional purposes in the area, the bulkhead and groins may be replaced with

a substantial seawall, preferably a rubble mound to reduce wave run-up and
overtopping. In the event that large rock is not available in the area,
concrete shapes, tetrapods, quadripods or others may be used,

Structural design today is a straightforward process. Having selected
a design wave (usually defined as the average of the highest one-third
of the waves in the spectrum), together with a design tide (taken as the
astronomical tide plus selected storm surge), construction material charac-
teristics and foundation conditions, the final design becomes a matter of
adjusting natural forces to man's need, with recognition that these forces
are to be controlled by structures compatible with the natural situation.

SELECTED REFERENCES

Beach Erosion Board, U.S. Army Corps of Engineers, 1961, "Shore Protection
Planning and Design", Technical Report No. 4 (available from Super-
intendent of Documents, U.S. Government Printing Office, Washington
2 DEC Ep IICemss KOO) Ee

Krumbein, W. C., 1963. "A Geological Process-Response Model for Analysis

of Beach Phenomena'' : Paper presented before ASCE Water Resources
Engineering Conference, Milwaukee, Wisconsin, 15 May 1963.

SiG

REVIEW OF GERMAN EXPERIENCE ON COASTAL PROTECTION BY GROINS

by

Dr. Marcus Petersen

Dr. Marcus Petersen, renowned German coastal engineer
and scientist, Director of Water Management and Economy of
Schleswig-Holstein in Kiel, Germany, published in the periodical
"Die Kuste" of 1961, under the title 'Das Deutsche Schrifttum
uber Seebuhnen en Sandigen Kusten", a survey on experience with
groin construction. The 57-page article evaluates the experi-
ence accumulated by 120 prominent German coastal engineers and
scientists as published in 210 bibliographic items which extend
over a period of 140 years. It offers an interesting insight
on the opinion and attitude of German engineers toward the his-
torically controversial and highly disputed subject of coastal
protection by means of groins, in which not only engineering
and scientific, but to a great extent economic elements, have
an important role. The paper by Dr. Petersen has six sections:
I - Introduction; II - Collection and Evaluation of German
Documentation on Groins; III - Chronologic Survey of German
Documentation on Groins; IV - Experience on Seagroin Effect;
V - Conclusions; and VI - Bibliography. Essentially the en-
tire article was translated by Otakar W. Kabelac, Engineering
Division, Beach Erosion Board. The following is an abstract,
prepared by Mr. Kabelac, of each section of the article.

I - INTRODUCTION

The function of sea groins, as a means of protecting sandy shores, re-
mains even to the present time a controversial problem. The coasts of the
earth are perpetually changing, the rocky coasts changing to a lesser degree
than sandy coasts. Natural changes fluctuate in short time intervals around
a certain base, and vary with location and time. Coastal regions exist,
which when viewed with regard to long-term prospects, have a tendency to
silt up, while others tend toward erosion. At the time of observation, the
tendency for long-term coastal recession may coincide with an equally di-
rected tendency for temporary fluctuation (as for example, the conditions
following storm tides); then it is difficult to forecast what development
of the beach will take place in a long period of time,

The engineers responsible for coastal construction are confronted with
this problem more and more. Human interference with the labile equilibrium
of nature, sandy coasts in particular, became more extensive because of the
growing demands for coastal developments and protection. Often it cannot

38

be determined, whether the gain or loss of land in a coastal region is
due to:

a. natural, cyclical and local fluctuation from a basic
average position,

b. natural long-term trends, or
c. human interference.

It is therefore quite understandable that opinions in professional circles
on the effect of sea groins havealways been controversial and even at
present are widely disputed,

In view of the considerable cost of coastal construction it was found
necesSary to examine the German literature on the subject to determine
which publications on the effect of sea groins are of importance and also
which results can be accepted without reservation. The survey is limited
to papers which are generally easy to obtain and can be perused, examined
and evaluated. Unpublished papers in official or private arehives are
not considered, The very extensive foreign literature such as Abecasis
(Portugal), Bruun (U.S.A. and Denmark), Minikin (England), De Rouville
(France), Schijf (Holland), Zenkovich (U.S.S.R.) is not used and only
occasionally referred to. Even in foreign countries opinions vary con-
siderably on this subject.

II - COLLECTION AND EVALUATION OF GERMAN DOCUMENTATION ON GROINS

The first sea groins in Germany were constructed in the period 1818
to 1821. The first publications dealing with them are about one hundred
years old. They may be found in manuals and in approximately forty dif-
ferent periodicals. In addition to engineering papers, there are numerous
publications by geographers, geologists, oceanographers and local his-
torians, in which are described certain conditions and events useful for
the groin investigation, or in which pertinent relationships and develop-
ments are revealed,

All of these papers, together with the treatises of those German
engineers engaged in coastal research, offer material for a new science of
coastal morphology. Coastal engineering and coastal morphology are there-
fore in close relationship. Remarkable surveys on morphological studies
are given in the book by Valentin (1952) "The Coasts of the Earth''. How-
ever, only a few of the essays in that book deal with coastal engineering
problems and groins.

Petersen's classification of German documentation on groins is divided
according to coastal subjects, regions involved, and also chronologically.

39

The geographic location of Germany accounts for the regional distinc-
tion necessitated by dissimilar conditions on the Baltic Sea (a tideless
inland sea), and the North Sea (a marginal sea characterized by its high
and low tides). In the Baltic Sea the coastal currents generally are
unimportant, while the tidal currents of the North Sea create a periodic
movement of water masses. In addition, the currents there are augmented,
when the filling and emptying of tidal flat areas (Wattenraum) occurs
through submarine canyons (Strom gaten), tidal flat streams and river
outlets.

Distinctions exist also between beaches with strong tidal or drift
currents parallel to the coast with or without surge and those beaches with
surge but without strong tide or drift currents. The surge itself often
produces "a surge current" (Brandungstromung) parallel to the coast and
of an intensity exceeding considerably that of the tide or drift current.

Prior to 1860 only a few reporters were writing on the construction
and effect of sea groins because not many such structures were in existence
then, and consequently only a few observations were made and data collected.

Gothilf Hagen was the first German coastal engineer to write on his
experimentations with the sea groins on the Baltic Sea (1863). He traveled
extensively in Holland, Belgium, England and other countries and presented
his observations and the results of his investigations and experiences in
a manual on coastal structures. A substantial part of his manual is valid
up to this day.

At the XVth International Navigation Congress of 1931 in Venice,
considerable attention was given to the defense against the sea on shores
with and without major sediment movement. German papers, by Coen Cagli,
R. Schmidt and H. Heiser, presented there, played an important role during
the discussion. German authors found then that a thorough and systematic
investigation of the coastal zone is paramount for coastal protection and
coastal structural planning. They found that up to this day no generally
applied rule for sea groin construction is apparent, indicating the diffi-
culties associated with the clarification of this complex problem.

Often the most informative documents were simple published statements
describing how the groin or group of groins were built, the construction
material used, the dimensions selected and the experience gained from the
construction. Occasionally we find that these data indicate the purpose
and reason for the construction and also give information on the effective-
ness of the installation. Of course, data on the effectiveness of groins
are of limited value if collected immediately or soon after the completion
of the structure. Usually a minimum period of 10 to 20 years is required
for an objective evaluation of the groin effectiveness. Valuable informa-
tion and experience was accumulated by manufacturers of building material;
the bituminous material industry in particular. Recommendation regarding
groin effectiveness made without a sufficient period of observation should
be considered with some reservation.

40

A description of structural coastal protection is considerably more
valuable if morphological data regarding coastal changes above and below
sea level, sea stages, storm tides, wind observations and other information
are added. Such descriptions are of greater value if based on data and
measurements, measurements in nature as well as on models, systematically
arranged, carried out, and presented with a view to the entire regional
development.

A positive contribution to the knowledge of the functions and effect-
iveness of groins can be made only after a long period of observation. The
unexpected malfunctions of groin systems sometimes are concealed to avoid
adverse publicity and to protect the designer. However, we can learn from
failures, and the sooner they are made known the sooner they can be elimi-
nated by structural changes. The survey of available German publications
on groins indicates that great attention was given to coastal morphology
as the structures were analyzed.

In general, considerable effort was made to achieve close cooperation
between the engineers and natural scientists.

III - CHRONOLOGIC SURVEY OF GERMAN DOCUMENTATION ON GROINS

Contributions to the knowledge of groin construction (starting in
1818) which were based on significant events in the German coastal zone
and led to their use and development, are discussed in this part of the
review by Dr. Petersen. The chronologic progress of German groin con-
struction with regard to distinct scientific, engineering and economic
trends is surveyed in five steps.

a. Construction period prior to 1900 - By 1900 several basic
Papers on coastal morphology, coastal engineering and a treatise on the big
Baltic Sea storm tide of 1872 were already published in which the authors
tried to find the causes and effects of coastal changes. They were good
observers of natural phenomena on beaches. The groins constructed during
this period have a special experimental value, and for this reason re-
searchers in subsequent years draw often on the ideas of older authors.
They compare the old construction methods with the observations of a later
period to see how the older design ideas materialized relative to their
effectiveness.

b. Construction Period 1900 to 1920 - In this period a distinc-
tion between sea groins and stream or river groins can be noted. However,
full definition relative to functional limitation and structural forms
involved is not made clear.

c. Construction Period 1920 to 1930 - The German Harbor Engin-
eering Society entered into the discussion on questions dealing with groin
construction. Of great significance to the German coastal problems was

4\

the XVth International Navigation Congress of 1931 in Venice. The recom-
mendation made at the Congress by Coen Cagli clarifies the German attitude
as follows: "Each plan for coastal protection must be preceded by a
thorough study of the locality and all factors acting on the formation of
the coast and how much it is exposed; the action set up by waves, currents
of various kinds, atmospheric precipitation, and by floating ice; the
origin and nature of material constituting beaches and the regimen of river
deltas; the situation and regimen of the aquiferous sheets of fresh water
flowing toward the sea; the influence on the sea by new scructures when
they project from the coast." It was further stated at the Congress that
the causes of the effect of the sea on coasts should be substantiated. The
German model experiments during this period were successful, and their con-
tinuance under natural conditions was recommended,

d. Construction Period 1931 to 1945 - A general reversal of
coastal construction method took place during this period as nearly all of
the groins on the North Sea as well as the Baltic Sea were built of steel
sheet piling. The economic life of this type of groin structure is very
short (10 to 20 years), particularly when single steel sheet piling is
considered, The result of a series of investigations in coastal morphology
carried out in this period opened wide vistas into coastal zone phenomena
and brought out that the knowledge of forces involved in those processes
is very limited. The demands for more intensive and systematic investiga-
tions were thus substantiated. Differences were increasing between the
practical builders, who believed in progressive success of groins, and the
research engineers and natural scientists. Also, contradictory experiences
and opinions were noticeable among the practicing professionals.

e. Construction Period 1945 to 1960 - Dr. Petersen's survey
covers both parts of Germany, East and West, with considerable reference
to East German scientists and engineers, including governmental agencies
and institutes of higher learning. Following World War II, the incoming
information was at first very scanty, consisting mostly of reports on the
use of asphalt for construction of groins. Ideas on the role of sea groins
continued to be very controversial. They have to serve for current de-
flection, beach protection and sand collection. It is confirmed by several
authors that the groins fulfilled their role as coastal current deflectors.
The groins failed as beach protectors and sand collectors, particularly on
coasts with a deficient balance of sand. Following systematic experimental
observation, it was found that the sand deficit could be balanced by arti-
ficial sand replenishment.

IV - EXPERIENCE ON SEAGROIN EFFECT

The overall survey of experiences on the effectiveness of sea groins
in Germany with special regard to engineering and economics is evaluated,
indicating that controversy on the value of groins continues. Great
progress in the structural strength of groins relative to stability and
material does not prove their functional effectiveness which requires long
periods of time for proper evaluation.

42

a. Motive for Seagroin Construction - In most cases, seagroin
construction was motivated by damages caused by storm tides and the dy-
namic forces of the surge. Damages appearing at the foot of dunes and
seawalls, as well as on longitudinal structures and on groins themselves,
resulted from lee-erosion and the effect of currents moving progressively
beachward.

b. Current Groins and Beach Groins - Seagroins are of ‘two types;

current groins and beach groins - each type having a different function.
Current groins are current-deflecting structures and it has been proved
that they are capable of fulfilling this role. Beach groins are expected
to maintain the surge-exposed beach and improve it as much as possible.
On certain beaches it is considered, with some reservation, that groins do
retard the shore recession. The opinion on the role of beach groins varies
from that on the unverified extent of the reduced recession rate (Success =
1% to 99%), to that on maintenance (success = 100%), up to that on improve-
ment of the beach (success > 100%).

On transitional reaches which are influenced by rivers and inlets from
the sea, and on surge beaches, groins may serve both the functions of cur-
rent deflection and beach protection. Here the success can be assessed only
when the beach groin performance is clarified. The German technical litera-
ture does not yet provide a satisfactory clarification. Current-deflecting
structures were constructed to an equal degree with those which would serve
for beach conservation and improvement.

c. Groin Types - Beach groins have been tested in nature in
an unusual number of cases. From the original procedure on constructing
groins as permeable structures, in the form of single or double-row pile
groins or stone cribs and fascine groins, progress was made toward im-
permeable massive stone groins, sheet pile groins of steel or reinforced
concrete, and recently toward flat stone pitch asphalt grouted structures.
Permeable and impermeable groins are found side by side in the same coastal
reaches, The design of steel sheet-pile and reinforced concrete pile
structures was apparently governed almost entirely by limitations imposed
by structural engineering practices.

d. Groin Length - Initially the length of the groins was deter-
mined by structural engineering limitations. Only after the introduction
of the steam pile driver did the groins advance into deep water. Already
Germelman in 1881 (mentioned by Franzius) had used the jetting procedure,
which was found very suitable for long piles (also sheet piling). The
water jet was applied by appropriate equipment. Current-deflecting groins
were constructed with good results, seaward up to and beyond the MTLW*,
and also through stream channels.

*Mean Tide Low Water - Symbol in use in German Hydrographic Service,

43

With regard to beach groins, opinions as to their proper length were
far apart. Groins of limited length were considered adequate on dry as
well as on wet beaches, while groins reaching beyond the first sand reef
were proposed when sand movement was the main problem involved. In the
Baltic Sea this reef is located approximately 100 meters, and on the North
Sea (Sylt Island) 300 meters, from the shore line. Only economic reasons
account for the fact that such proposals regarding groin length were not,
or only in part, accomplished. The construction as well as maintenance
cost increased considerably with the length of the structure.

e. Elevation of Groin Crest - With regard to the most efficient
elevation of the groin crest, a variety of ideas were found to exist. Some
authors had the attitude that a horizontal position of the crest was cor-
rect, others held that a certain minimum margin above the beach elevation
was necessary; still others constructed groins high above the beach, to
the final elevation which they desired to achieve when the sand-catching
capacity of the structure would be reached. New proposals point toward
structures built so that they would follow the profile of the beach. This
is possible only in the downward direction. During periods of heavy sand
movement these groins would be buried.

f. Groin Groups - Lee Erosion and Groin Spacing - Wherever groins
were erected, it was found that single groins never met the requirements
and that more of them were always needed to provide protection or mainten-
ance of beaches or to retard shore degradation. Always in the lee of surf
currents (adjacent downdrift areas) new damages were found, requiring the
expansion of groin groups. This development logically led to a "Totality
System", meaning that the entire coast had to be protected by groins.
However, Hansen (1938), considering the natural conditions of sand behavior,
believed such a limitless procedure should be rejected not only for func-
tional but also for financial reasons.

In a series of investigations regarding methods to alleviate the lee
erosion problem, no satisfactory solution had yet been found. This problem
played a considerable role in deciding the terminal limits of a group of
current groins as well as for all beach groins in general.

Within a group of groins, spacing of the structures was determined
in many ways; it varied from one to three times the length of the groins,
without any distinct recognized system. As during the course of de-
velopment, lengths of the groins were considerably increased in com-
parison to original concepts, a definite length-spacing relationship could
not be derived on the basis of available engineering experience.

g. Direction of Attack (Groin Alignment) - A number of authors
have held it appropriate to place the heads (outer ends) of a group of
groins in a line conforming to the direction of current flow. In dealing
with current-deflecting groins, this attitude is unamimously accepted as

44

correct. However, in observing the underwater groins between Borkum and
Norderney, a difference in this attitude can be noticed which has not
created disadvantages of a functional nature.

Some modern authors consider the line of attack in design of groins;
some attribute no meaning to the line of attack while other authors do
not present the subject at all.

The reason that a pliant line of attack is required in river engin-
eering is the effort to achieve a regulated flow, particularly for the
purpose of navigation. On beaches we deal with one shore only. The
currents change direction and intensity, and even though of low velocity,
they develop, in combination with the surf, a considerable transport
Capacity, as the surf action provides the suspended sand.

The importance of the line of attack is doubtful with regard to short
groins which do not reach the offshore sand bars where the sand transport
usually takes place. ;

h, Construction Material - A variety of construction materials
used in building seagroins is listed below:

Wood: piles, spars, timber of available beach types, and brushwork
(endangered by marine borers).

Natural stone.

Steel: gingle or multiple wall groins built of steel sheet piling;
connecting elements of structural parts (endangered by rusting and
corrosion).

Concrete: used experimentally at the beginning of the 20th Century,
since then systematically.

Asphalt: for several years used for seagroin construction.

When one construction material is being replaced progressively by
another, it is usually because of its economic life. This is influenced
by changes of wetness, solar radiation, temperatures, surge impact (wave
action), surge currents, elevation changes of the shore, sand abrasion,
ice drift and sea bottom composition.

The economic life of steel and reinforced concrete for seagroins is
generally only 10 to 20 years.

Wood can be destroyed in two to three years, when used in regions

subject to marine borers or other wood-damaging phenomena. Without this
deteriorating effect, the durability can extend several centuries.

45

Stone has an unlimited durability. It is being used as loading ele-
ment in connection with brushworks or for bracing of steep banks or slopes.

As to the use of asphalt for coastal groins it is still too early
to express a conclusive opinion in view of existing experience and dis-
appointments with other construction materials.

The economic life of a structure fixes its maintenance cost.

i, Artificial Sand Addition - The artificial addition of sand
in regions with a deficient balance of natural sand supply, is the most
recent method of coastal protection, despite the fact that several decades
earlier dredged material was discharged for such purpose on beaches of the
Baltic and North Seas with good results. The time is too short to report
on the results of this method of protection. The basic cause of the natural
sand deficiency will not be alleviated by abundant sand importation, and
this operation would have to be periodically repeated. However, sand has
the advantage when compared with other construction materals because of
its natural behavior in places where sand was located before. It is a
question of economics whether or not artificial importation of sand should
be recommended, The volume required and the transportation distances
figure decisively in such calculations.

j. Costs - We find only one article on the cost of construction
and maintenance of coastal structures in the entire German literature. This
was written by Hibben (1935) and deals with the installation at Borkum.

Up to 1916 the cost for the maintenance of protective installation and for
repair of storm damages amounted to 42% of the total expenditures for new
and additional construction. However, it is pointed out that "the latter
mentioned additional construction has to be included in maintenance cost".
This proved to be right, as according to another unpublished statement,
the ratio of maintenance to new construction costs up to 1957 was 5 to 4.
The costs for Borkum cannot be generalized, yet it offers an insight into
the range of costs which may apply also to seagroins.

Initial construction cost for a beach groin is so high that the im-
portation of sand by pipeline dredging proves to be entirely competitive.
Comparison of costs requires the consideration of the limits of restora-
tion. Fulscher, as a responsible referent in the Central Administration,
proposed as early as 1905 to analyze the problem of cost.

V. CONCLUSION

Up to the present, it has not been possible, from available informa-
tion, to clarify the complex problems occurring on sandy beaches and to
interpret all cases properly. It is generally admitted, in view of the
fact that the literature on the effect of beach groins is encumbered with
so many statements and hypotheses, that it is necessary to either sub-
stantiate or invalidate those statements analytically by measurements

46

and figures. In view of the high cost of construction and maintenance,
this procedure should be given primary importance, It has become obvious
that only through such methodical measurement and systematic investigation,
patterned after G. Hagen's ideas, would conclusive judgment be possible

to some degree. Besides the necessary measurements in nature, theoretical
hydrodynamic investigations, measurements and observations on model tests
should be promoted. New measuring instruments will have to be developed
and a good start has already been made.

Systematic observation of coastal development trends, carried out
over a period of decades, may help to avoid obviously unsound investments.
It was shown in some cases that seawalls and other protective structures
should not have been built because the pattern of natural behavior of the
coast indicates that they will be destroyed. Also the construction of
beach protective installations on the East Friesian Islands should have
been postponed, as the current observations would have indicated a natural
tendency toward ultimate silting of protective structures. Generally,
disappointments can be avoided at the construction stage if reports are
critically drafted and failures made known.

Observing development outside of Germany, we can verify that in
general the same problems are encountered in places where surge exists in
front of a sandy beach, and that all pertinent coastal countries are work-
ing on the development of a satisfactory procedure for coastal protection.
Opinions on the effectiveness of seagroins also differ considerably in
other countries, indicated by the new Dutch studies which attribute beach
stabilizing effect to the groins on one side while denying them any effect
on the other, The trend toward artificial beach nourishment is increasing.

Close and substantial cooperation between scientists and practical
men seems to be needed more than ever before in order to avoid duplication
of work and to recognize problems and the proper approach to their solu-
tion. The Coastal Commissions of the Baltic Sea and North Sea represent
an established arrangement which offers the possibility for exchange of
ideas for the purpose of promoting coordinated investigation.

Furthermore, it should be required that all available literature on
coastal regions, both domestic and foreign, be collected at the Coastal
Commissions of the Baltic Sea and North Sea and be publicized. A re-
searcher of a coastal problem, in most cases, due to lack of time to
undertake a survey of information sources, has not sufficient knowledge
of previous achievements in a particular field.

The present status of coastal research and coastal engineering make
combined action of all participating disciplines mandatory; only then can
the physical, technological and economic fundamentals be found for cre-
ating functionally correct and structurally acceptable coastal protective
structures.

47

IV - BIBLIOGRAPHY

a- Index of Documentation of Seagroins

AGATZ, A. (1949) Sea Transportation Structures, III-B. Sea Structures,
Land Conservation, pp. 1080-1083.

BAHR, M. (1955) Helgoland, History of its Origin and Maintenance of its
Harbor Relative to Navigation. "Yearbook of North Friesian
Society" 30, pp. 203-218.

BLAU, E. (1954) Model Tests with Movable Floor in Sea and Sea Harbor
Construction. "Wasserwirtschaft-Wassertechnik" 4, No. 4,
pp. 244-251.

seer (1959) Model Investigations of Harbor Inlet Silting. "Wasser-
wirtschaft-Wassertechnik" 9, No. 6, pp. 244-251.

BOMAS, P. (1952) Underwater Longitudinal Works for Coastal Protection.
"Wasserwirtschaft-Wassertechnik" 2, No. 5.

BRAUN, W. (1957) Construction of a Heavy Dune Cover by Asphalt-Basalt
Method on the Island of Borkum. "Bitumen" 8/9, pp. 176-182.

BRUNS, E. (1956) Some Ideas on the Problem of Research in Coastal Dy-
manics and Model Tests of Coastal Protection. "Wasserwirtschaft-—
Wassertechnik" No. 12, pp. 387-390.

BULOW, K. (1954) Actual Problems of Coastal Protection. "Wasserwirtschaft-
Wassertechnik" 2, No. 9.

Ae ve (1954) General Coastal Dynamics and Coastal Protection of the
South Baltic Sea between Trave and Swine. "Geologie" 10.

Bie ctb (1958) Biological Help in Coastal Protection. "Wasserwirtschaft-
Wassertechnik" 8, No. 2, pp. 54-63.

BURHORN, E. (1951) Seagroins on Coasts with Weak Tides and Strong Sand
Drift. "Planning and Building" 5, No. 3, pp. 57-62.

HANSEN, W. (1954) Model Tests of Wave Run-up on Sea Dykes in Watt Region.
"Proceedings of the Testing Institute of Hannover" No. 5,
pp. 123-165.

Seas (1957) Model Tests of Beach Break at the End of Stabilized Coastal

Reaches (Lee-Erosion). "Proceedings of the Testing Institute of
Hannover" No. 10, pp. 86-119.

48

Index to Documentation of Seagroins (Cont.)

HUNDT, C. (1957) Breaking Reasons on the Northwest Part of Syilt. "Die
Kuste™ 6, No. 2, pp. 3-38.

JANSEN, T. (1956) Island Protection on Eastfriesian Coast, "Hansa" 93,
No. 44/45, pp. 2108-2110.

aenailes (1959) Groins with Asphalt Grout in Eastfriesian Coast Region.
"Bitumen" No. 3.

JANSEN, T. and W, HANSEN (1957) Provisions for Stabilization and Main-
tenance of Floating Islands of the South Coast of German North
Seve 0-06 "German Report of XIXth PIANC, London".

KANNENBERT, E. G. (1958-59) Protection and Drainage of Depressed Areas
of the Schleswig-Holstein Baltic Sea Coast. "Die Kuste" 7,
pp. 47-106.

KLOSS (1952) Asphalt Constructions in Groin Building. "Wasser und Boden"
4, No. 3, pp. 52-56.

KOLP, O. (1956) What Happened to Protection of our Baltic Sea Coast.
"Wasserwirtschaft-Wassertechnik" 6, No. 8, pp. 229-231,

ete ire (1957) The North Heath of Mecklenburg, Berlin.

KRAMER, J. (1945) Problems of Island and Coast Protection. "Report of
West Germany Water Economy Association" pp. 115-133.

Bears (1957) Artificial Restoration of Beaches with Special Regard for
Beach Flushing, Norderney 1951-52. "Annual Report of Research
Institute, Nordeney" Vol IX, pp. 107-139.

KRAMER, J. and H. HOMEIER (1955) The Effect of Island Protective Structures
on Beach Development in West Part of Norderney. "Norderney Annual
Report, Vol. VI, pp. 15-38.

COASTAL COMMISSION OF NORTH SEA AND BALTIC SEA (1952) Experts Report on
Investigation Concerning Reasons for Coastal Breaking Phenomena
on West and North Part of Norderney...... "Die Kuste" 1, No. 1,
pp. 27-42.

COASTAL COMMISSION OF NORTH SEA AND BALTIC SEA (1955) General Recommenda-
tions for German Coastal Protection. "Die Kuste" 4, pp. 52-61.

LAMPRECHT, H. (1955) Surge and Shore Changes on the West Coast of Sylit.
"Proceedings of the Testing Inst. of Hannover" No. 8, pp. 80-136.

49

Index to Documentation of Seagroins (Cont. )

LAMPRECHT, H. (1957) Coastal Changes and Coastal Protection on Sylt. "Die

Kusite?”) 6, No. 2) pp) 39-93"

(1957) Effects of Coastal Protective Structures on Sylt.
"Wasserwirtschaft" 47, No. 5.

(1958) Dunes Protective Works on Sylt. "Bautechnik" 35, No. 1
pp. 16-20.

LEOPOLD, E. (1956) Flood Protection and Coast Stabilization. "Hutte"

Vol. III, 28th Edition, pp. 1076-1082. Berlin.

LORENZEN, J. M. (1954) Hundred Years of Coastal Protection on the North

Sea. "Die Kuste” 3, No. 1/2, pp. 18-32.

LUDERS, K. (1952) The Effect of Groin H in Wangerooge-West.......... "Die

Kuste” 1, No. 1, pp. 21-26.

MAGENS, C. (1957) Coastal Researches in the Area of Fehmarn-Nordwagrien.

OTTMAN,

"Die Kuste” 6, No. 1, pp. 4-39.

(1957) Surge Investigations on the Coast of Fehmarn and
Nordwagrien. "Die Kuste" 6, No. 1, pp. 40-63.

(1958) Swell and Surge as Basis for Planning and Design in Sea
Structures and Coastal Protection. "Proceedings of the Testing
Institute of Hannover" No. 14.

(1953) Steep Shore of Brodten - Cause of Breaking .........
Transactions of Museum of Geography and Natural History” Lubeck.
No. 44, pp. 145-195.

PEPER, G. (1955/56) Origin and Development of Island Protective Works on

Norderney. "Archives Nieders" 8, No. 3, pp. 175-196.

PETERS, A. G. (1946) Report on the Use of Asphalt at Groin Construction

eeceee

in Delftland (Holland). "Transactions of Polytechnic Institute"
No. 49/50.

(1956) Asphalt Groins in U.S.A, "Baumasch und Bautechnik" 3,
Nowe idpe ssi

PETERSEN, M. (1952) Breaking and Protection of Steep Shores of the Baltic

Say Coasitererecieiae "Die Kuste" 1, no. 2.

PRESS, H. (1958) Manual of Water Economy, Hamburg.

eeecee

(1959) Cultivated Land Conservation and Reclamation, Berlin and
Hamburg.

50

Index to Documentation of Seagroins (Cont. )

REINEKE, H. (1955) What Water Economy Expects from Coastal Research
"Wasserwirtschaft-Wassertechnik" 8, pp. 249-250.

(1956) Works of the Coastal Commission - East, "Die Kuste" 5,
pp. 1-8.

REINHARD, H, (1956) Coastal Changes and Coastal Protection of the Island
Hiddensee. Berlin.

RIEDER, K. (1957) Coastal Changes and Coastal Protection Problems of the
Island Sylt. "Die Kuste" 6, No. 2.

RIEDER, K, and H. SUHR, (1958) Water Economy between North Sea and Baltic
Sea, 1948-58. Kiel.

ROHNISH, (1953) Hydraulic Structures (Groins, Dams, Dykes and Canal
Embankments) of Bitumen Type. "Bitumen" 15, No. 9/10.

SCHMITZ, H. P. (1957) Coastal Protection and Scientific Basis of Research.
"Wasserwirtschaft-Wassertechnik" 7, No. 2, pp. 64-74; No. 3,
pp. 103-107.

THILO, R. and G. KURZAK (1952) Origin of Breaking Phenomena on West and
Northwest Beach of the Island of Norderney. "Die Kuste™ 1, No.1.

VOLLBRECHT, K. (1953) Theoretical Observations for Installation of Coastal
Protective Structures on Tideless Shores. '"Wasserwirtschaft-
Wassertechnik" 3, No. 6.

(1955) Beach Abrasion by Waves - Reflection on Steep Wall Type of
Coastal Protective Structures. "Wasserwirtschaft-Wassertechnik"
No. 8, pp. 251-257; 333-339.

WEINNOLDT, E. and H. SUHR, (1951) Water Economy between North and Baltic
Sea, Kiel.

WOHLEBERG, E. (1950) Origin and Decline of the Island Trischen. "Trans-—
actions of Geographic Society, Hamburg" Vol. XLIX, pp. 158-187.

ZISCHER, F. F, (1957) Possibilities and Limits for Application of Asphalt
Types of Constructions for Coastal Protection. ''Proceedings of
the Testing Institute of Hannover" No. 12.

aidhicnsis (1960) Protection of the West Beach of Sylt Island by Flat
Groans. "Bitumen" No. 8/9, p. 190.

ZSCHIESCHE, O. (1956) Suitability of Model Tests in Maritime Engineering
in Harbors, Seaways and Coastal Protection. 'Wasserwirtschaft-
Wassertechnik" No. 12, pp. 383-386.

5|

b - Index of Documentation of Coastal Morphology
AKKERMANN, M, (1956) Rearrangement of Sand in Sea Region of Norderney,
"Annual Report Forschungstation Norderney", Vol. VII.

BRAND, G, (1955a) Sediment Petrographical Investigations to Observe Sand
Shifting Phenomena on Beaches. "Meyniana" 4, pp. 86-110.

Lo ayers (1955b) Recent Changes of Baltic Sea Coast near Kolberg Heath,
"Meyniana™ 4, pp. 112-116.

BRESSAU, S. (1957) Abrasion: Transport and Sedimentation in the Beltsea,
"Die Kuste™" 6, No. 1, pp. 64-102.

CHRISTIANSEN, W, and H. PURPS, Plants of Brodtener Shore, "Die Kuste" 1,
No. 2, pp. 95-99.

DILLO, H. G, (1960) Sand Migration in Tidal Rivers, "Proceedings of the
Testing Institute of Hannover", No. 17, pp. 135-253.

GRIESSEIER, H. (1959) On the Use of Luminofors for Study of Littoral
Drift Movement, "Acta Hydrophysica™, VI, no. 1.

GRIESSEIER, H. and K, VOLLBRECHT (1955) Varieties of Attitude in Coastal
Research, "Forschung and Fortshritt" 29, No. 1/2, pp. 5-12.

ryeeenes (1956) Impossibility of Model Similarity Presentation of Coastal
Wave Phenomena, "Wasserwirtschaft-Wassertechnik" No. 8,

pp. 247-257.

Bcohan as (1957) Problematics of Model Presentation of Littoral Processes,
"Proceedings of the Testing Institute of Hannover" No. 11.
pp. 234-261.

HINTZ, R. A. (1955) The Development of the Delta of Schlei, "Meyniana" 4,
p. 66.

Sites (1955) Sediment Petrographical and Diluvial Geological Investi-

gations in Coastal Region of Angel (Schleswig-Holstein),
"Meyniana"™ 6,

Buttes (1958) Beach Walls in the Region of Kolberg Heath, "Meyniana" 6,
Ro MAY o

HOMEIER, H. (1956) The Development of West Part of Langoog Beginning 18th

Century, "Annual Report Forschungstation Norderney" Vol. VII,
pp. 38-68.

52

b - Index of Documentation of Coastal Morphology (Cont. )

KANNENBERG, E. G. (1951) The Steep Cliff of Schleswig-Holstein Baltic Sea
Coast, "Dissertation of Geographic Institute of University, Kiel"

KORNER, P. (1955) Sediment Material in Suspension in Coastal Zone, "Die
Kuste" 4, pp. 5-51.

KOSTER, R. (1955) Morphology of the Beach Landscape and Geophysical De-
velopment of Oswagrien Coast, "Meyniana™ 4, pp. 52-65.

KRAMER, J. (195 ) Research Station Norderney, "Wasser und Boden", 12
pp. 401-406.

KRAUSE, R. (1952) Meaning and Application of Biologic Research in Coastal
Engineering, ."Wasserwirtschaft" 42, No. 11, pp. 348-349.

LINKE, O. (1952) The Biological Basis for the Protection of Dunes on East
Friesian Islands, "Wasserwirtschaft" 42, No. 11, pp. 350-353.

Ms (1952) Report on Ridge and Sand Migration Investigations of
North Beach of Norderney, "Annual Report Forschung Station
Norderney", Vol. IV.

LUDERS, K. (1953) Origin of East Friesian Islands .......... "Problems of
Coastal Research in North Sea Region”, Vol. 5.

Bees (1954) Remarks on the Balance Report - Coastal Engineering
Hydrometry, "Die Kuste" 3, No. 1/2, pp. 67-69.

NIEBUHR, W. (1952) On the Recent Development of Ems River Outlet "Die
Kuste"™ 1, No. 1, pp. 43-62.

San (1953) Noteworthy Changes on Gross Vogelsand in the Elbe River
Outlet. Die) Kusitel 2> Nos 25 pp. 157-159.

Aig Sean (1952) Observations of Sand Transport in Lower Ems, "Die Kuste"
io Ds OVA.

OTTO, W. (1952) Sediment Petrographische Observations on the Coast of
Lubeck Bay, "Die Kuste" 1, No. 2, pp. 45-54.

PETERSEN, M. (1954a) The Flood of 4 January 1954 on the Baltic Sea Coast
of Schleswig-Holstein, "Wasser und Boden" No. 2,

qoeenere (1954a) Basis of the Survey of Protective Dykes in Schleswig-
Holstein, "Die Kuste" 3, No. 1/2, pp. 153-180.

53

b- Index of Documentation of Coastal Morphology (Cont. )

PETERSEN, M. (1959) The Topographical Map of Watts and its Significance
for Coastal Protection, '"Wasserwirtschaft"', 49, No. 3.

REINEKE, H. and E, BLAU (1956) Does the Present Organization of the Coastal

Commission Promote the Economic and Technological Progress,
"Wasserwirtschaft-Wassertechnik" No. 8, pp. 261-262.

REINHARD, H. (1953) Development of a Sandbank into a Baltic Sea Island,
"Petermann's Geographische Mitteilungen".

SCHMITZ, H. P. (1956) Critical Observations of Model Presentation of
Streams and Sediment Transport, "Wasserwirtschaft-Wassertechnik"
No. 6,

VALENTIN, H. (1952) The Coasts of the Earth, "Gotha".

VOLPEL, F, (1959) The Behavior of Far Migrating Flatsea Sand, Deutsche,
"Hydrographische Zeitschrift" No. 12. pp.64-76.

VOLLBRECHT, K. (1953) Coastal Dynamics of Tideless Seas,'Wasserwirtschaft-
Wassertechnik" 3, No. 1.

WALTHER, F, (1949) Background of Sea Current Development, "Wasserwirtschaft"
40, No. 1 pp. 1-9, 44-51.

WIRTZ, D. (1949) Relationship between Underwater Abrasion and Sand Migra-
tion..... "Transactions of Geological Institute, Hamburg" No. 18.

WYRTKI, C. (1953) Balance of the Longitudinal Transportation in the Surge
Zone, "Deutsche Hydrographische Zeitschrift" No. 2, pp. 65-76.

54

MODEL STUDY OF OFFSHORE WAVE TRIPPER
by

Frederick F. Monroe
Research Division, Beach Erosion Board

The Galveston District of the U. S. Army Corps of Engineers recently
requested that the Beach Erosion Board's staff perform a series of small-
scale model tests on a proposed offshore structure. This structure would
act as a wave tripper, causing offshore breaking of larger waves, thus
preventing waves of height greater than a particular value from reaching
the shoreline structures. The system of a shoreline structure combined
with an offshore structure was to be considered for providing protection
during hurricanes to the shoreline of Texas City, Texas.

The study was carried out at the Beach Erosion Board laboratory in
a wave tank approximately 74 feet long, 1.5 feet wide, and 2 feet deep.
Waves were generated by a vertical-bladed, pusher-type wave generator,
operated by an arm attached eccentrically to a drive wheel. A bottom
profile, generalized from a hydrographic survey sheet provided by the
Galveston District, was modeled at a 1:50 scale in the wave tank. A
comparison between the bottom profile, as taken from the hydrographic
survey sheet, and the generalized profile used in the model, is shown in
Figure 1. A prototype storm surge level of 15 feet above mean sea level
was used for all tests, as was a prototype wave period of 6 seconds. These
conditions remained constant throughout the duration of the test series.

Two types of offshore structures were included in the test program.
One type simulated a breakwater of rubble-mound construction, and the
other a vertical-face structure. Two structure elevations were tested;
one of 6 feet and the other 2 feet above mean sea level. In conjunction
with the offshore structure variations, two types of shoreline conditions
were also tested. One consisted of a smooth concrete slope to an eleva-
tion of 15 feet above mean sea level, with a rubble absorber landward of
that point, permitting wave reflection to only a negligible extent. The
other shore condition tested consisted of a rubble shore structure that
extended from mean sea level to an elevation of 23 feet above mean sea
level, and which permitted considerable reflection of wave energy.

Wave heights were measured at a number of locations in the wave tank
without an offshore structure present, and both with and without a struc-
ture present on shore, in order to determine the characteristics of the
incident waves in undisturbed form. Then, wave height measurements were
made with each type of offshore structure in place, each with two eleva-
tions, and with different shoreline conditions. The locations of wave
gages relative to the bottom profile may be seen in Figure 1. Figure 2
Shows the wave gage locations with respect to the various test conditions.

Wave heights were measured by means of parallel wire resistance
probes suspended in the tank at various locations. These were calibrated

55

regularly in order to maintain linearity in their recording. The wave
heights thus measured were recorded on paper tape by means of a Brush
recorder, The heights of ten waves for each eccentric setting were read
directly from the recording paper, averaged, and converted to prototype
heights. (For convenience, prototype dimensions are used throughout this
report.) Whenever it was noted that reflection would distort the dimen-'
sions of the recorded waves, less than ten waves (but no less than five)
were taken as being more truly representative.

In order to determine the effect of the offshore structure on the
waves transmitted over it, the wave gage was moved from its initial loca-
tion on the centerline of the offshore structure, without the structure in
place, to a point slightly more than one wave length shoreward from the
structure in place. The depth of the bottom profile at this point was the
same as that at the offshore breakwater location so that any noted changes
in wave characteristics could be directly attributed to the presence of
the structure. This location was approximately 195 feet (prototype) shore-
ward of the breakwater. As both the rubble-mound and vertical-face types
of breakwater fitted quite snugly against the sides of the wave tank, the
leakage of water at effective velocities around the barrier was very small;
hence this factor is considered negligible as a source of error in the test
series,

Figure 3 shows the results of the wave height measurements made 195
feet shoreward of the offshore breakwater, without a shore structure in
the model. The full heavy line at 45-degree slope on the graph in Figure
3, of course, represents the line of f effect; i.e., in the zone above or
to the left of this line, the offshore breakwater had no effect relative
to the dissipation of wave energy. The data points, connected by the
dashed curved line in Figure 4 represent actual measurements of wave
heights at the intersection of the bottom profile of the model with mean
sea level, the measurements taken relative to the undisturbed incident
wave height, with neither the shore structure nor the offshore breakwater
in place. Other curves in Figure 4 show the measured wave heights, rela-
tive to the undisturbed incident wave height taken for each of four con-
ditions for the offshore breakwater in place. Although reflection at this
point was considered negligible due to the presence of an effective ab-
sopber beach landward from the intersection of the bottom profile with the
test water level (15 feet above mean sea level), it is quite possible that
some slight amount of reflection from the bottom slope was responsible for
the crossing of the curves in Figure 4.

The main results of the study are shown in Figures 3 and 4. Figure 3
shows the wave height in the protected area immediately shoreward of the
proposed offshore tripper which wotild be observed for various incident
wave heights and structure conditions. For example, for a water level of
+15 feet MSL, an incident 10-foot wave would be reduced to approximately
a 9-foot wave just shoreward of the tripper if the crest of the wave
tripper is at +2 feet MSL; and to a 7.6-foot wave if the crest of the off-
shore tripper is at +6 feet above MSL. It may be noted that essentially

56

the same reduction in wave height is observed whether the offshore tripper
is of rubble-mound construction or of vertical-face, sheet-pile construction.

Figure 4 shows the wave height which would be incident at the shore
(measured at the loeation of the MSL contour) for various incident wave
conditions. For example, for a 10-foot wave incident to the general area,
the offshore wave tripper would reduce the wave incident on the shore
structure from about 11 feet to between 7.3 and 7.9 feet, depending on
the characteristics of the tripper itseif. Again it may be noted that
very little difference was observed between the rubble and sheet-pile
structures,

Some additional data were obtained from the testing program relative
to reflection conditions existing seaward of the proposed offshore struc-
ture with that structure in place. These data, summarized in Figure 5,
showed no measurable effect on wave heights seaward of the proposed
structure,

+205

Design surge level

+6 Breakwater height tested
LEGEND

+ 2’ Breakwater height tested

------ Actual Bottom Profile
Model Bottom Profile

| Wave Gage Location

800 1000 1200. 1400 1600 1800 2000
Feet

FIGURE |. GENERAL TESTING ARRANGEMENT

57

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60

Wave Height with Breakwater in Place Measured at Point 650°

is)

12'

Seaward of Breakwater Centerline
o

LEGEND

Wave heights with rubble-mound breakwater, +6 above msl.

Wave heights with rubble-mound breakwater, +2 above ms.l.
Wave heights with vertical-face breakwater ,+ 6 above ms.l.

t

NOTE: Smooth concrete shore face; Rubble shore
structure not in place.

2' St 4' 5' 6! 1 8' 9' 10' ti‘ l2' Ise 14! 15'
Wave Height at Location of Proposed Offshore Breakwater (breakwater not in place )

FIGURE 5. EFFEST OF WAVE TRIPPER ON WAVE HEIGHTS
SEAWARD OF THAT STRUCTURE

6

NOMOGRAPH FOR DETERMINING PRODUCT OF
SHOALING AND REFRACTION COEFFICIENTS
FOR USE IN WAVE ANALYSIS

by

R. Q. Palmer
Chief, Planning and Reports Branch
U. S. Army Engineer District, Honolulu

Description of the Nomograph

The nomograph shown on the adjacent page may be used
to readily calculate the combined effects of shoaling and
refraction for a given wave period and depth. The shoaling
coefficient alone may be obtained by using the left third
of the chart. Likewise, the square root of the bo/b value
may be obtained alone by using the right portion of the
chart. However, the chart is most helpful when used, as
shown by the example, to obtain the product of the shoaling
and refraction coefficients. This value is useful in deter-
mining wave height values at a specific location in shallow
water when the deep water height (Ho) iS available from
other means, as by statistical -hindcasting.

62

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Ty

PROGRESS REPORTS ON RESEARCH SPONSORED BY
THE BEACH EROSION BOARD

Compiled by Thorndike Saville, Jr., Research Division
Beach Erosion Board

Summaries of progress made during fiscal year 1963 (i.e. to June
30, 1963) on the several research contracts in force between universities
or other institutions, and the Beach Erosion Board, together with brief
statements as to the status of some research projects being prosecuted in
the laboratory of the Beach Erosion Board, are presented below. These
summaries supplement and continue those contained in prior issues of the
Bulletin.

I. University of California, Contract DA-49-055-eng-8. Sources of
Beach Sand,

This contract was terminated in September 1962 with distribution of
the report, "Beaches in Northwestern California", which was given limited
distribution by the University of California as Institute of Engineering
Research Technical Report, Series 14, Issue 25. This report describes
conditions at the various beaches sampled north of the Russian River, and
indicates differences between them. The report indicates that although
groups of stations having sands that are not significantly different usu-
ally fall within boundaries of geographic units, the sands at any given
locality can seldom be correlated with existing wave exposure; consequently
it is concluded that beach character must reflect other causes as well,
such as material source, location, and quantity.

II. Massachusétts Institute of Technology, Contract DA-49-055-civ-eng-
62-9, Study of Beach Processes in the Inshore and Foreshore Zones.
(Old Contract DA-49-055-eng-16, Sorting of Beach Sand by Waves).

Work previously carried out under Contract DA-49-055-eng-16 was con-
tinued under a new contract, Contract DA-49-055-civ-eng-62-9, with the
new title "Study of Beach Processes in the Inshore and Foreshore Zones".
Development of an adequate orbital velocity probe, utilizing a thermistor,
for use in the study was continued and the probe and its electronic cir-
cuity is described in MIT Hydrodynamics Laboratory Report No. 61, "A
Thermistor Probe for Measuring Particle Orbital Speed in Water Waves",
which has been given limited distribution by MIT. Publication of this
report by the Beach Erosion Board is planned. The thermistor used has a
bead diameter of 0.014 inches, and is mounted at the tip of a probe of
QO.15-inch tubing. Both static and dynamic calibrations have been per-
formed, and compare favorable with each other. If carefully constructed,
the instrument also shows relative direction insensitivity.

Theoretical studies aimed at the description of the geometry and
kinematics of the shoaling wave were continued,

64

III. University of California Contract DA-49-055-civ-eng-63-4, Transport
Of Coastal Sediments. (Old Contract DA-49-055-eng-17, "Fundamental
Mechanics of Sand Movement by Waves" )

Work previously carried out under Contract DA-49-055-eng-17 was con-
tinued under a new contract, Contract DA-49-055-civ-eng-63-4, "Transport
of Coastal Sediments".

A report "Sand Movement by Wind" was given limited distribution by the
University of California as Institute of Engineering Research Technical
Report Series 72, Issue 7, and is now being published as a Beach Erosion
Board Technical Memorandum, This report discusses earlier experimental
results in wind tunnels of sand movement by wind, and describes and com-
pares results obtained from new wind tunnel tests. Findings of previous
investigators with respect to rate of sand transport were generally re-
affirmed, but average flying distance of sand particles was found to be
much greater, possibly due to the method of calculation. Of particular
interest are tests on the influence of moisture content on sand movement.
The experimental data clearly demonstrate that, as the sand moisture con-
tent increases, the value of the threshold shear velocity of sand movement
may also materially increase. A quantitative expression of this effect is
obtained. A further report, "Sand Transport by Wind - Studies with 0.145
Millimeter Sand", given limited distribution by the University of Cali-
fornia as Institute of Engineering Research Technical Report HEL 2-5, is
also included as an appendix. This appendix extends the investigation of
sand movement by wind to smaller sand particle size ranges, and indicates
that threshold velocity is best determined by experiment rather than by
formula when the sand grain size is less than about 0.2 millimeters.

Another report, "Beach Profile as Affected by Vertical Walls", was
published as Beach Erosion Board Technical Memorandum No. 134. This report
presents the results of a laboratory model study to investigate the equi-
librium beach profile resulting when vertital walls of various top eleva-
tions above or below the water surface elevation were located in the beach
zone and subjected to wave action. As might be expected, walls of highest
relative crest elevation, by allowing less energy to pass over the wall,
resulted in greater scour in front of the wall; lower walls resulted in
increased scour areas behind the wall. Effects of wave steepness and grain
size of beach material were also investigated. As appreciable scale effect
may be involved in such a study, care must be exercised in interpretation
of the data for prototype use; nevertheless the data is considered of value
in considering practical problems involving vertical face walls.

A further report "Investigation on a Two-Phase Problem in Closed
Pipes" was given limited distribution by the University of California as
Institute of Engineering Research Technical Report HEL 2-2, This report
concerns transportation of sediment in pipelines, and particularly dis-
cusses two systems for measurement of concentration of the water-sediment
mixture, and hence the transportation characteristics. Two measuring
devices were tested, a loop-system consisting of two identical vertical

65

pipe sections with opposite flow direction, from which head-loss readings
could be obtained and correlated with flow rate and sediment concentration;
and a Venturi meter, in which the pressure drop was again measured and
correlated with sediment concentration,

A further report "Sand Movement on Coastal Dunes" was given limited
distribution by the University as Institute of Engineering Research Tech-
nical Report HEL-2-3, and is also being published in the Proceedings of
the Federal Interagency Sedimentation Conference in Jackson, Mississippi,
28 January - 1 February 1963. This report summarizes the results of
laboratory studies of sand movement by wind, discussed more fully in the
report, “Sand Movement by Wind", and its appendix discussed above.

A further report, "Transportation of Bed Material Due to Wave Action"
was given limited distribution by the University as Institute of Engineer-
ing Research Technical Report HEL-2-4, and is now being published as a
Beach Erosion Board Technical Memorandum, This report discusses the
mechanism of sediment transport in a layer immediately adjacent to the
ocean floor for long waves of small amplitude in relatively deep water.
The fundamental principle of the supporting theory is that at equilibrium
the submerged weight of the solid particle is balanced by the vertical
component of the resultant hydrodynamic force exerted on the particle by
the flow above. Effects of both the unsteady mean flow velocity and the
turbulent fluctuations are taken into account. The distribution of the
lift forces associated with the former was determined experimentally,
while a statistical approach based on experience with the same phase of
the problem in a steady mean flow was used to determine the latter.

IV, University of California, Contract DA-49-055-civ-eng-63-5. Wave
Diffraction and Refraction Studies, (Old Contract DA-49-055-eng-44,
"Laboratory Study of Wave Refraction")

’ Work previously carried out under Contract DA-49-055-eng-44 was con-
tinued under a new contract, Contract DA-49-055-civ-eng-63-5, "Wave Dif-
fractiofxand Refraction Studies". A report, "Higher Approximation to
Non-Linear Water Waves and the Limiting Heights of Cnoidal, Solitary, and
Stokes* Waves", was supported partially under this contract and published
as Technical Memorandum 133 of the Board. This report presents a mathe-
matical description of some of the higher approximations to non-linear
water waves and is particularly important in indicating limiting heights.
First and second approximations to solitary and cnoidal waves are obtained
by carrying the shallow water expansion method of Friedrichs and Keller

to the fourth order, The rigorous first approximation to these finite
amplitude waves of permanent form is identical to earlier solutions. The
second approximation, however, results in new expressions for predicting
behavior of long waves in shallow water. The limiting height for solitary
waves is found to be 8/llths of the free water depth. The third approxi-
mation to Stokes’ waves in water of finite depth is verified by use of
classical small-perturbation expansion methods, For finite amplitude waves
the series expansion is found to be in terms of a parameter that is most

66

suitable for wave lengths shorter than eight times the depth. Rather
severe restrictions inherent in the analogy between non-linear shallow
water flow and two-dimensional perfect gas flow are also pointed out.

A report, "Effect of Bottom Slope on Wave Diffraction" was given
limited distribution by the University as Institute of Engineering
Research Technical Report Series 89, Issue 8. The report discusses a
laboratory study of the combined problem of wave diffraction and refrac-
tion in a harbor. Several different bottom configurations were used in
the protected area behind the breakwater, including both continuous slopes
and abrupt changes. The resulting data are compared graphically with data
for a horizontal slope in the sheltered area, such that refraction and
shoaling would have no effect.

Work was continued on study of the Mach-stem phenomenon, and a report
"Diffraction of Periodic Waves Along a Vertical Breakwater for Small Angles
of Incidence"' was given limited distribution by the University as Institute
of Engineering Research Technical Report HEL-1-2. This report discusses
the laboratory investigation of the reflection of periodic gravity waves
as they advance along a straight vertical breakwater for the case of
initial angle between the breakwater and the direction of incident wave
advance of less than 20 degrees. The results were similar to phenomena
observed for solitary waves, in that the waves were not regularly reflected
from the breakwater, but a wave energy concentration was found next to the
breakwater. Apparently this was a non-deep water phenomenon,

Theoretical work was carried out on the problem of two-dimensional
spectra of wind-generated waves, and preliminary tests were made in the
newly modified 12-foot wide wind wave tank.

V. Dr. W. C. Krumbein (Consultant). Study of Beach Phenomena.

A report, “Geological Process -Response Model for Analysis of Beach
Phenomena" has been prepared, and is published elsewhere in this Bulletin.
This report describes beach processes and deposits in terms of a conceptual
process-response model that considers the processes and deposits as sepa-
rate though closely related aspects of shoreline phenomena. The model
provides a formal framework for analysis of natural beaches as they may
be modified or controlled by the coastal engineer. Further study is being
made of the application of computing machine methods to the study of factors
influencing beach characteristics and stability.

A pilot study of sand sample data collected near the mouth of the Cape
Fear River, North Carolina, has been subjected to analysis by computer

methods and results are being analyzed.

VI. Virginia Institute of Marine Science. Contract DA-49-055-civ-eng-63-6
Study of Beach Response Relationships.

A new contract was negotiated with the Virginia Institute of Marine
Science to study beach and bottom processes and response elements in an

67

attempt to better determine their interrelationships. The investigation
involves the simultaneous observation of the various elements, with subse-
quent data analysis using statistical and high-speed computer techniques.
Progress so far has involved establishment of horizontal and vertical con-
trol along three profile lines in the Virginia Beach area. Simultaneous
observations of wave, tide, and current data have been made on several
occasions, together with obtention of bottom sediment samples and profile
data. Computer analysis for the development of trend surface data is
underway.

VII. University of California Contract DA-49-055-civ-eng-63-8. Wave Forces
On Coastal Structures

A new contract was negotiated with the University of California in
Berkeley for the laboratory study of wave forces on coastal structures.
In particular, information will be obtained on the vertical forces
exerted by water waves on structural members of various types of coastal
structures; and the details of eddy formation by waves moving past verti-
cal cylinders will be investigated. Laboratory work on study of vertical
forces induced by waves on a dock has been initiated, as has theoretical
work on the distribution functions of wave forces on a circular pile.

VIII. Texas A & M Contract DA-49-055-civ-eng-63-9. Modification of Two-

A new contract was negotiated with the Agricultural and Mechanical
College of Texas to investigate the modification of free gravity waves in
variable depth, including reflection and transmission aspects, especially
considering those long wave phenomena where simple refraction theory is
inadequate. The study will have particular application to propagation of
tsunami wave packets and solitary surges over the continental shelf.
Initial phase of the work has been to establish a modified long wave
equation which can properly take into account the dispersive character
of quasi-long waves.

IX. Scripps Institution of Oceanography Contract DA-49-055-civ-eng-63-10
Mechanics of Sediment Transport by Waves and Currents.

A new contract was negotiated with the Scripps Institution of Oceano-
graphy to study the mechanics of sediment transport by waves and currents
in shallow water. Major objectives of the study are to obtain quantitative
measurements of the sediment movement associated with the motion of waves
and currents and to compare and relate this transport to measurements of
the basic properties of the fluid inducing the transport. Particular
attention is to be given the critical boundary of the sediment-water inter -
face, Initial work under this contract will be to design a data acquisi-
tion system to give analog records permitting later computer processing
for power spectra and cross spectral analysis.

68

X. Professor Frank D. Masch (Consultant). Wave Characteristics in
Shoaling Water

A consultant contract has been negotiated with Professor Masch at
the University of Texas for study of wave characteristics in shoaling
water, with particular attention to cnoidal wave theory. The basic pur-
pose is to present a workable and convenient method for computing water
wave characteristics in shoaling water utilizing the non-linear cnoidal
wave theory. Basically the method involves calculating power transmission
for a wave train in shallow water from cnoidal theory and equating this to
the wave power in deep water. Computation has been made of the average
cnoidal wave power by integrating the product of the pressure in the hori-
zontal component of water particle velocity over the distance from the
bottom of the fluctuating water surface and over one wave period, This
integration has involved determination of the various integrals of the
powers of the cnoidal functions in terms of the wave characteristics and
the complete integrals.

XI. University of Miami (Marine Laboratory). Contract DA-49-055-civ-eng-
63-12. The Role of Shell Material in the Natural Sand Replenishment
Cycle of the Beach and Nearshore Area.

A new contract has been negotiated with the University of Miami to
investigate the role of natural shell replenishment as a contributing
element in the nourishment of beach material along the beach and nearshore
area. Particular attention will be paid to the area lying between Lake
Worth Inlet and the Miami Ship Channel on the Atlantic Coast of Florida,
Study will be made of the kind and amount of shell being contributed to
this area, its source, its disposition, and its duration as a component
of the beach materials.

XII. The University of Southern California. Contract DA-49-055-civ-eng-

63-13, Shelf Sediment Transport.

A new contract has been negotiated with the University of Southern
California (Department of Geology) to study the pattern of sediment move-
ment in the nearshore shelf area, and in particular of sediment transport
in submarine canyons. The investigation will utilize fluorescent tracers,
and is pointed toward determination of quantitative estimates of material
movement down submarine canyons from the littoral zone near the shore.

XIII. University of Southern California. Contract DA-49-055-civ-eng-
63-14. Surf Zone Transport

A new contract was negotiated with the University of Southern Cali-
fornia (Department of Geology) to study the movement of sediment within
the surf zone, and its relation to the distribution of water particle
velocity in the surf area. A telemetering dynamometer will be used to
obtain velocity measurements, and fluorescent dyed sand grains will be
used as tracers.

69

XIV. Beach Erosion Board Laboratory.
(a) Wave Forces on Structures

Analysis was continued on the wave force data obtained in the large
wave tank on a vertical 12-inch diameter pile. A report presenting some
of this data was prepared. in draft form.

In connection with another study concerning transmission of wave
energy over low-crested breakwaters, a small, though useful, amount of
information was obtained on stability of rubble breakwaters under heavy
overtopping conditions.

(b) Wave Run-up.

The joint distribution of wave height and wave period for a fully
developed sea, as developed by Bretschneider's method, has been used to
obtain the distribution of relative wave run-ups in a sea condition, and
also the distribution of actual run-up. This latter distribution turns
out to be essentially identical with that for wave height as developed by
Puttz, Longuet-Higgins, and others (at least for conditions examined). As
such, it appears that about 13% of the run-ups exceed the run-up of the
significant wave, about 1% of run-ups will be 1.5 times (R/Hy,), and about
1 in 1,000 will be about 2 times (R/Hy,). This analysis has Been made
only for the case of relatively deep water fronting a structure (d/Ho > 3)
and for a fully developed sea, though it may be extended to include normal
generating areas. A report, " An Approximation of the Wave Run-up Fre-
quency Distribution", by Thorndike Saville, Jr. was published in the
Proceedings of the 8th Conference on Coastal Engineering, Council on
Wave Research, Engineering Foundation (1963).

A graphical method was developed for checking the design height of
protective dunes for beach fills which are to be constructed along an
existing shoreline. This design height is dependent on the maximum run-up
which could be expected on the structure. The method involves computing
a "critical profile'’ which, when plotted on transparent paper, can be
overlayed on field profile plots to determine if run-up from expected
waves will exceed the structure height. A report, "A Graphical Method for
Checking the Design Height of Structures Subjected to Wave Run-up", by
R. P. Savage was published in the Bulletin of the Beach Erosion Board,
Volume 16, July 1962.

Wave run-up testing was carried out at small scale on some stepped
seawall designs, The tests reaffirmed previous conclusions that arti-
ficial roughening of sloped seawalls by steps materially decreased wave
run-up below that which would be expected on a smooth slope. Tests were
made for both 1 on 2 and 1 on 3 slopes. Tests were made for vertical
steps and also for a re-entrant type step. Essentially the same run-up
was obtained for both types of step, although there is an indication that
slightly lesser run-ups may occur with the re-entrant type step. This

70

indication is masked within the general scatter of data for both types.
Results have been given limited distribution by the Board in an interim
report, "Interim Report on Interlocking Precast Concrete Block Seawall
Study", by R. A. Jachowski and J. R. Byerly, May 1963. Later formal
publication is planned,

(c) Study of Sand Bypassing Operations,

Efforts were continued to collect all available data on sand by-
Passing operations (past, present, or planned) for correlation and study.
Analysis continued of the hydrographic survey data obtained in the Port
Hueneme area in June 1959, and comparison of this data with previous sur-
vey data. Coordination with Palm Beach County officials was continued
for compiling data information on the operation of the sand transfer plant
at Lake Worth Inlet, Florida. A field observation program was continued
in the vicinity of Ventura County Harbor, California, in which an offshore
breakwater (parallel to the shore) forms a protected area serving as a
sand trap. Use of 3 wave gages at this location, each with different de-
grees of sheltering, permits some degree of evaluation of wave direction.
A summary report was initiated which will summarize pertinent details of
all operations of sand bypassing at coastal inlets in the United States.

Award of contract was made to install in the Beach Erosion Board
Laboratory a mass flow density meter using a radioactive source to measure
flow of sand through a 3-inch pipe. Delivery of the component parts is
being made separately, and some of these are considerably delayed. Com-
plete installation of the gage is expected sometime in August 1963, at
which time it will be tested for acceptance.

(d) Laboratory Study on Relation of Littoral Drift Rate to
Incident Waves.

Yearly summaries of the littoral transport tests for 1961 and 1962
were prepared. These summaries are in draft form, but are planned for
limited distribution about the end of the calendar year.

Considerable effort was expended in attempts to secure a more ade-
quate measurement of littoral current velocities, and the variations
thereof. A sonic current meter developed by Westinghouse has shown con-
siderable promise, but still appears to have certain drawbacks. In the
meantime estimates of current velocities by dye tracers are being
continued,

Testing was continued on determination of the relationship between
incident wave characteristics and the amount of littoral transport.
Measurement and analysis of waves has continued in an attempt to determine
the cause of apparent resonance phenomena in the model basin, and the
meaning of these phenomena. Of particular concern is the fact that this
phenomenon results in a change in wave characteristics, not only with time-
duration in a particular test run, but also for the same time-durations of
otherwise identical test runs. Some of the effect is caused by inconsistency

7\

in the machine operation, and may be eliminated by, for example, always
starting the machine with the generating blade in the same position, In
addition, baffles have been attached to the wavé-generating bulkheads and
are being studied for effectiveness in reducing parasitic crossS-—waves.
Consideration is now being given to the possibility that some of the ef-
fect may result from slightly changed reflection patterns caused by slight
changes in the beach face due tothe incident wave action. In the meantime,
accurate determination of the incident wave conditions for the littoral
tests, or rather, interpretation of the wave records obtained during these
tests, remains a problem. In general, incident wave values are obtained
from a 1 to 2 scale model of the generating system in a narrow wave flume,
in which reflection-caused resonance phenomena are not a problem.

Two of the tests conducted this past fiscal year were used as the
vehicle for radioactive and luminescent tracer studies. The primary pur-
pose of these tests was to develop procedural techniques, although limited
research objectives were also explored. In both tests, glass grains con-
taining an irradiated element, having the same specific gravity and size
distribution as the beach sand, were injected onto the beach. Following
injection, waves were generated at an angle to the beach, moving material
alongshore, The first test involved a wave of constant height and period,
and the second a wave of varying characteristics. The beach and bottom
were periodically sampled to allow counts of luminescent and radioactive
grains, and a radiological survey was made with a scintillation counter.
The tracer used in the first test was sodium 24 (with a half-life of 15
hours), and the tracer in the second test was lanthanum 40 (with a half-
life of 40 hours). The techniques used and the data collected inthe first
test are presented in a report, "Laboratory Applications of Radioisotopic
Tracers to Follow Beach Sediments", by N. E. Taney in the Proceedings of
the 8th Conference on Coastal Engineering, Council on Wave Research,
Engineering Foundation (1963). Particle velocity in the second test was
as great as 15 feet per minute. Maximum depth of burial of tracer part-
icles, determined from a relatively small number of cores, was 0.1 foot.
Analysis of the data gathered from the fluorescent samples is still under-
way with particular attention now being applied to determination of size
of sample and number of samples required in such tests to give statistical
validity to the resulting grain count contours.

(e) Measurement of Suspended Material in Laboratory Wave Tanks.

Additional suspended samples were obtained under wave action using a
pump-type sampler in a wave flume testing crushed coal rather than sand.
It is hoped that these measurements may aid in defining scale relations by
comparison with prototype measurements. An eductor type sampler was tested
in conjunction with other tests in the large tank, and found satisfactory.
It provides certain advantages and convenience of use over the previously
used centrifugal pump-type sampler.

(f) Equilibrium Profile, Beach Deformation, and Model Scale Effect
Studies.

Testing was continued in a small tank using low specific gravity
crushed coal to study the effect of scale on movable bed models under

72

wave action. Some of the tests were repeated with a shorter length of
tank, to correspond to the prototype tank length for tests involving a
0.4-millimeter sand. Use of this length will, by comparison with results
using a previous tank length, permit an evaluation of the comparability

of tests in the prototype tank with 0.2 and 0.4-millimetér sand where
different tank lengths were used for each sand. Comparison of the results
of the tests in the big tank with the two sands of different size was made
to enable rapid estimates of the greater width of beach fill required for
smaller grain sands to provide protection equivalent to that for coarser
sands. Application was necessary for emergency protection following the
March 1962 Atlantic coast storm. More complete analysis of the data is

now underway.

(g) Wave Measurements and Analysis.

The cooperative visual surf observation program was continued by the
Research Division of the Board, This program consisted originally of 27
observation stations distributed along the coasts of the continental
United States which were operated in cooperation with the U. S. Coast
Guard. Visual observations of surf characteristics are made at 4-hour
intervals by the Coast Guard and sent to the Beach Erosion Board weekly.
The program was initiated in 1954 and has operated continuously since,
although the number of stations has varied from time to time.

The instrumented wave gaging program was also continued and wave
gage records were taken as continuously as possible at all field gage
locations by the Board, The wave gage at Atlantic City, destroyed in the
March 1962 storm, was reinstalled. The primary installation was the normal
BEB relay-type step resistance gage, but several other gages were in-
stalled to afford comparison. Comparison is being made of pen-and-ink
records, and also by spectral analysis of records obtained on magnetic
tape. Of particular interest will be comparison of spectrum analyses for
a pressure type gage installed near the sea bottom with those of the sur-
face type step resistance gage.

A programming device has been developed and installed with certain
reservoir gages. It permits continuous sampling of the waves, and when
specific pre-set height is increased, the recorder is turned on for a
pre-set duration. Sampling continues after this recording, but the re-
corder will not be turned on unless a second pre-set height is measured.
If after a pre-set duration the sampled height has not reached this value,
the recorder will be turned on if the height exceeds the first pre-set
height. Any number of such height settings can be incorporated in the
Programmer to enable recording of all desired waves, but eliminate re-
cording during periods of no interest.

A 45-foot gage has been installed on the Coast Guard tower at

Buzzards Bay. This gage is of particular interest in that it may record
either over the bottom 15 feet of the gage with recording plugs spaced

73

at 0.2-foot intervals, or over the entire 45-foot length of gage with
recording plugs spaced at 1-foot intervals. It thus gives finer detail
for the normal smaller waves, but also affords measurement of the very
large waves associated with higher water levels during severe storms.

(h) Regional Studies,

Additional compilations are underway on geomorphological and littoral
material data for the coastal sector from Cape Henlopen, Delaware, to Cape
Charles, Virginia. The report on the geomorphology of this area is under
preparation.

A comprehensive program was initiated late in FY 1962 to develop

data on offshore deposits of material along the Atlantic coast that could
be utilized in beach fill and nourishment projects. The study of the off-
shore deposits was intended to encompass all factors pertinent to the use
of such deposits in the beach zone. A pilot study for the offshore pro-
gram was completed in the Miami Beach - Palm Beach, Florida area during
August 1962. Comparative profiles and geophysical exploration of the
shallow sub-bottom strata were studied to locate potential offshore borrow
. sites. Surface samples of the bottom sediments were obtained by the

dredge ESSAYONS in the vicinity of Hillsboro Inlet and Bakers Haulover.
A further pilot study involving sediment core sampling as well as geo-
physical exploration of the bottom is planned early in FY 1964, probably
for an area off the middle Atlantic coast.

(i) Re-examination of Beach Protection Projects.

A continuing program is being carried out on the re-examination of
beach fill and periodic nourishment projects to determine the effective-
ness of the fill material within the beach zones, and to better establish
the factors upon which the desired characteristics of fill material are
based, Continuing studies of other projects constructed following Beach
Erosion Control studies are also underway to determine effectiveness of
various structure components. In particular data have been obtained on
behavior of fill placed at Seaside Park and Sherwood Island State Park,
Connecticut, and at Key West, Florida. These data are being compiled and
a report is under preparation.

Over the past 25 years many ground level photographs have been taken
of beaches on the New Jersey coasts. This photographic data has been
brought up to date as of 1962, and a pictorial history type report is
essentially completed.

Data collection program has also been carried out at the Port Mans-
field, Texas, entrance channel. The navigation project at Port Mansfield
involves a jettied entrance with a channel cut through the offshore barrier
(Padre Island) into Laguna Madre and on to Port Mansfield. The data col-
lection program involves both shoaling and tidal data. Tidal elevations

74

are recorded at several points in the channel and also in the lagoon.
Some small amount of tidal current data has also been obtained.

(J) Experimental Studies, Effectiveness of Sand Fences.

In cooperation with the State of North Carolina and the Wilmington
District of the Corps of Engineers, a study has been underway on Core
Bank, a part of the Outer Banks of North Carolina, on the effectiveness
of various types of sand fence in building and stabilizing dunes. The
portable wind station in the fence area has been operating more or less
continuously, and has recorded wind data through two hurricanes. The
drive system for the recorder has been converted from a spring-would
system to an electric motor powered by a gas thermo-couple generator; a
battery system has also been installed as standby in case the gas gene-
rator stops operating. Installation of tide gages on both the sound and
sea side of the Banks has been considered, but not yet carried out. With
the filling of the first fences installed, an additional 2,000 feet of
fence was installed to give further information on the rate of dune growth,
and the effectiveness of various types of fencing. This fencing was in-
stalled on top of the dune generated by the earlier fences. Roughly half
of this new fencing was destroyed during a heavy storm in the spring of
1963, but this has since been replaced. Periodic profiles were again
taken of the accumulation area of the fences to indicate effectiveness of
the various types. A report "Experimental Study of Dune Building with
Sand Fences" by R. P. Savage was published in the Proceedings of the 8th
Conference on Coastal Engineering, Council on Wave Research, Engineering
Foundation (1963).

(K) Study of Proposed Los Angeles-Santa Monica Causeway.

Several proposals have been made to the State of California for con-
struction of an offshore causeway across a portion of Santa Monica Bay.
One of these proposals involves an offshore sand barrier which would
serve not only as a causeway, but also provide a large recreational beach
frontage on the ocean side, and a large area of marina facilities on the
shore side, One of the proposals for such a sand barrier also involves a
submerged rock barrier seaward of the sand barrier itself -.to hold the sea-
ward end of the barrier, The rock barrier would be submerged to perhaps
15 feet to prevent damage to swimmers and small craft. This rock barrier
thus would eliminate the large quantity of sand otherwise necessary to
form the toe of the sand barrier. This perched beach type of construction
is virtually unknown, and an abbreviated set of model tests was carried
out to give an indication of the effect of the submerged rock barrier in
inducing scour adjacent to and landward of it, and also some indication
of the proportion of the scoured material which might be expected to move
seaward across the barrier and thus be lost to the shore regime. The
model was to a 1 to 2 scale, and it involved waves of 3 to 6-foot model
height. The test series was quite abbreviated, and a much fuller set of
data would be desirable should such a proposal ever reach design stage.

ve

However, the tests indicated that the amount of scour depends quite crit-
ically on wave height, and that the direction of movement of the scour
material depends primarily on sand size (being greater offshore with finer
sands) and wave period (being greater offshore with shorter periods).

(1) Wave Transmission Over Low-Crested Breakwaters,

A study was made for the Navy Bureau of Yards and Docks of wave trans-
mission over certain proposed low-crested breakwaters which would permit
considerable overtopping of storm waves. Tests involved only rubble-mound
breakwaters, but both permeable and impermeable breakwaters were tested,
thus affording a comparison of the amount of energy transmitted through
the breakwater as opposed to that transmitted over the crest of the break-
water, A report discussing the tests for the Navy is under preparation,
and it is hoped that it can be published in 1964. It is planned to follow
these tests with additional small scale tests on submerged breakwaters of
both rubble and vertical pile types.

A small test of similar type was also carried out for the Galveston
District of the Corps of Engineers and is reported in an article, "Model
Study of Offshore Wave Tripper" by F. F. Monroe.

(m) Beach Vulnerability as Related to Storm Wave and Water Level
Conditions,

Following Congressional discussion of the March 1962 Atlantic storm
investigations have been initiated by various Government agencies on the
improvement of storm warning data. Responsibility for issuance of storm
Warnings is that of the Weather Bureau, but the Weather Bureau and the
Corps of Engineers have initiated a study to provide data on the vulner-
ability of shore areas for particular storm waves and tides which might
occur from a particular storm. It is recognized that the Weather Bureau
may be able to forecast relatively accurately the water levels and waves
which may occur from a particular storm, but the damage which may result
from these water levels and waves will then depend primarily on the con-
dition of the elevation and width of the beach area on which it impinges.
The beach condition, and hence the shore vulnerability, is different for
different locations and also varies from time to time at any given
location. Study has now been initiated on several beaches in the New
Jersey, New York, and New England area in an attempt to relate observed
beach changes and/or damage to observed water level and wave conditions,
with the aim of accumulating data which may be used to prepare vulner-
ability charts for different types of beaches in other areas.

?

(n) Interlocking Precast Concrete Block Seawall Study.

A study is being made of various types of interlocking precast con-
crete blocks for use as seawall protection: It is felt that such type
walls might afford relatively inexpensive backshore protection for severe
storms, although they may not be expected to substitute for normal pro-
tection in the immediate normal wave action zone. Field installations

76

of various types are being examined, with an eye to their effect on the
fronting and adjacent shores, and their stability. A particular type of
block resulting in a stepped seawall has been designed and is being in-
vestigated at the Board Laboratory. Run-up tests have been made, and are
discussed earlier in this report (see paragraph b), and stability tests
are now underway. Stability tests are being carried out for two beach
conditions, one a normal condition with a beach fronting the seawall and
the wave breaking somewhat offshore, and the other an extreme storm con-
dition at which considerable scour is hypothesized to have taken place in
front of the seawall, and the wave breaks directly on the wall. A pre-
liminary report discussing the data to date "Interim Report on Interlocking
Precast Concrete Block Seawall Study" by R. A. Jachowski and J. R. Byerly
has been given rather limited distribution. Testing is continuing, and a
more comprehensive report will be prepared when more conclusive data are
available.

(0) Propagation of Mechanically Generated Waves.

A short series of tests have been made on the propagation down a wave
tank of the first waves generated by a wave generator. Normally used
methods predict each wave to move down the tank at a constant speed de-
pendent on the period of the generator and the water depth. In each wave
length of travel, each wave leaves behind it a particular portion of its
energy (again dependent only on the wave period and depth), transmitting
the rest forward with the wave form. Such has not been found the case.

The waves are more dispersive in character, the first wave having a longer
period than that of the generator, and travelling at a greater velocity.
The velocity of each successive wave decreases until finally the velocity
appropriate to the period of the wave generator is reached, after which
both wave period and speed remain constant. The wave height at a point
increases with each successive wave until its full height is reached,

after which time it also remains constant. The rate increase is faster
than would be predicted in the way discussed above, and the energy front
arrives earlier. When the wave generator is stopped abruptly (so that no
extraneous longer period waves are generated by "coasting" of the generator
blade), the waves do not die down gradually, but cease relatively abruptly.

XV Publications

Technical Memoranda published by the Board during fiscal year 1963
are listed below. Copies can be furnished on request to persons within
the United States to the extent of a limited printing.

ee MiemNoO Title and Date
131* Littoral Studies Near San Francisco Using Tracer Techniques ,

November 1962,

632) Waves in Inland Reservoirs (Summary Report on Civil Works
Investigation Projects CW-164 and CW-165) November 1962.

*This number is already out of print.

te

133 Higher Approximation to Nonlinear Water Waves and the Limiting
Heights of Cnoidal, Solitary, and Stokes‘ Waves, February 1963.

134 Beach Profile as Affected by Vertical Walls, June 1963.

S}5 The Relationship Between Watershed Geology and Beach Radio-
activity, August 1963.

Material covered by Technical Memoranda listed above, excepting num-
bers 132 and 135, is briefly described in foregoing paragraphs II and IV
of Research Progress, or in the section of Research Progress in Volume 16,
July 1962, of the Annual Bulletin of the Beach Erosion Board, The work
covered in Technical Memorandum No. 132 was carried out by several U. S.
Army Corps of Engineers' installations, including the Beach Erosion Board,
under the CWI program related to design, construction, and operation of
flood control, navigation, and multiple purpose projects involving major
reservoirs, levees and channel improvements. An abstract of its contents
follows:

The report summarizes wave observations in Fort Peck Reservoir and
Lake Texoma, the latter formed by Denison Dam. It briefly reviews
certain investigational programs and publications pertinent to wave
study in inland reservoirs, and summarizes analytical studies made
to adapt, modify or supplement procedures currently used in estimat-
ing wave characteristics corresponding to wind and related factors
to conform with observations in the two reservoirs. It presents
procedures for quantitatively determining wave characteristics,

and briefly outlines additional investigations needed to further
improve methods and criteria. Certain general guidance and ap-
proximate formulas are presented for interim use in estimating

wind tide effects in deep reservoirs.

The work described in Technical Memorandum No. 135 was done at the
University of California, supported by an Atomic Energy Commission grant,
but because of a close relationship to the Beach Erosion Board's research
program it was published in the Technical Memoranda series. An abstract
of the contents follows:

Correlation between watershed geology of the Ben Lomond Mountain
area, north of Santa Cruz, California, and radioactivity of beaches
receiving sediment from the watershed is attempted. Radioactivity
of stream and littoral sediments are presented in terms of thorium
concentration determined by gamma-ray spectroscopy. Results are
inconclusive regarding watershed geology - beach radioactivity
relationship. Radiometric determination for littoral samples are
remarkably constant with low activity indicated, but considerable
variation in thorium content of stream sediment is found which is
not consistent with any known geological variation. It is concluded
that studies of geological maps and petrographic descriptions are
not sufficient to determine applicability of the radioactive tracer
technique.

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BEACH EROSION STUDIES

Beach erosion control studies of specific localities in the United
States and its territories are usually made by the Corps of Engineers under
provisions of Section 2 of the River and Harbor Act approved 3 July 1930
and amended by Public Law 87-874 approved 23 October 1962. Prior to the
1962 amendments to the law, beach erosion control studies could be author-
ized for specific problem areas by the Chief of Engineers under authority
of the Secretary of the Army and were made in cooperation with appropriate
agencies of the various States. By executive ruling the costs of these co-
operative studies were divided equally between the United States and. the
cooperating agencies. The law as presently amended provides that beach
erosion control studies now be made as Federal surveys wholly at Federal
expense and such surveys be authorized by Resolution of the Public Works
Committee of either the U. S. Senate or House of Representatives. Those
studies still in progress at the time of adoption of the amendments will
be completed on the cooperative basis, but new studies are authorized by
Resolution as Federal surveys. Information concerning the initiation of
such studies may be obtained from any District or Division Engineer of the
Corps of Engineers. After a report on a beach erosion control study has
been transmitted to Congress, a summary thereof is included in the next
issue of this Bulletin. Summaries of reports transmitted to Congress
since the last issue of the Bulletin and lists of completed and author-
ized studies follow.

SUMMARIES OF REPORTS TRANSMITTED TO CONGRESS

ROCKPORT , MASSACHUSETTS

The purpose of the investigation was to determine the best method
of restoring the beach and protecting the beach and cottage development.
The study area, located on the Atlantic Ocean shore in Essex County, Massa-
chusetts, about 30 miles northeast of Boston, comprises about 1.5 miles of
the southeast shore of Cape Ann between Brier Neck and Lands End, about
500 feet of which is in the city of Gloucester and the remainder in the
town of Rockport. In 1960 the permanent population of Essex County was
about 569,000. The population of Rockport and Gloucester is about 30,000,
but is greatly increased by summer residents. The study area included
three barrier pocket beaches known as Long Beach, Cape Hedge Beach and
Pebbly Beach. Most of the shore is in public ownership, but the backshore
lots at Long Beach are leased for private use which limits the access to
the public beach. Long Beach is developed with resort commercial enter-
prises along the private frontage in Gloucester and summer cottages along
the remaining frontage. The developed areas in Rockport are protected by
a continuous concrete seawall, portions of which were rebuilt in 1959 after
severe damage in an April 1958 storm. A narrow tidal creek separates Long
Beach from Cape Hedge Beach to the east. There is no development at Cape
Hedge Beach, but there is some development consisting of inns and resi-
dences at the privately owned rocky promontory between this beach and

79

Pebbly Beach to the east. A natural barrier consisting of a high-peaked
shingle ridge backs the western half of Cape Hedge Beach and gradually
flattens to the east. An unpaved road paralleling Pebbly Beach is’ sep-
arated from the beach by a low shingle or cobble ridge and there is resi-
dential development at Lands End at the eastern end of this pocket beach.

The shores of the study area are directly exposed to waves from the
Atlantic Ocean from the Southeast quadrant but are sheltered in varying
degrees from other directions. Tides are semi-diurnal, the mean and spring
ranges being respectively about 8.6 and 10 feet. Maximum tides are esti-
mated at about 13 feet above mean low water. There is little evidence of
a predominant direction of littoral drift, but rather that principal
material movement is offshore and onshore. However, such evidence as is
available indicates the predominant direction of alongshore movement would
be toward the northeast. Sources of beach material have been the eroding
rocky headlands and glacial overburden. Depletion of this material has
reduced the supply, but the pocket beaches are reasonably stable. Widening
of the beaches may be accomplished by artificial placement of sand. The
rate of loss of beach material is presently low, but would probably be
greater from a widened beach,

The problem causing concern to the cooperating agency consisted of
erosion of the beaches, particularly during storms, and damages to existing
protective structures and development due to wave attack. Undermining or
overtopping of beaches by wave run-up with accompanying deposition of beach
material and debris on adjacent roads and developed areas also occurs along
the unprotected frontage. At Long Beach a tidal drainage creek meanders
across the east end of the beach. Reconstruction of the failed portions
of the seawall at Long Beach and placement of a stone apron in front of
its seaward face affords adequate protection to the Long Beach developed
areas, but the cooperating agency desired a plan for improving the beach
for possible future use.

The Division Engineer developed a plan for improvement of Long Beach
consisting of widening the beach to a 150-foot width between the seawall
and mean high water and construction of a training jetty at the mouth of
the tidal creek, and found that overtopping of the beach and transport of
beach material onto backshore improvements at Cape Hedge Beach and Pebbly
Beach can be prevented or reduced by construction of barriers to landward
movement. The Division Engineer and Beach Erosion Board concluded that the
improvement and protective plans considered cannot be justified by evalu-
ated benefits and recommended that no project be adopted at this time by
the United States for the protection or improvement of Long, Cape Hedge or
Pebbly Beaches at Rockport, Massachusetts. They further recommended that
protective measures which may be undertaken by local interests, based upon
their own determination of economic justification, be accomplished in
accordance with plans and methods considered in this report. The Chief of
Engineers concurred in the views and recommendations of the Beach Erosion
Board,

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SALISBURY BEACH, MASSACHUSETTS

The purpose of the investigation was to determine the best method of
restoring and protecting the beach, and protecting the beach development.
Salisbury Beach is located in Essex County about 35 miles north of Boston.
It is about 3.5 miles long, extending from the New Hampshire State line to
the jettied mouth of Merrimack River. The shore area consists of a barrier
beach ranging from 600 to1,500 feet in width. Salisbury Beach is a popular
summer resort with a permanent population of about 3,100. The estimated
peak population on summer weekends is 12,000. The shore of the study area
is publicly owned. The southerly 0.6 mile has been developed as a State
beach reservation, but the remainder of the shore is backed by private
development. The beaches are used for recreational purposes. The tides
in the study area are semi-diurnal. The mean and spring ranges are re-
spectively 8.3 and 9.5 feet. The estimated highest tides are 12.5 feet
above mean low water. The shores of the study area are exposed to waves
from the east with unlimited fetch. The fetch to the northeast and south-
east are limited by the peninsulas of Nova Scotia and Cape Ann respectively.
However, the greater energy of waves from the northeast quadrant cause a
predominant southward littoral transport. The source of littoral materials
is adjacent beaches to the north.

The Division Engineer studied the sources and movement of the beach
material and the changes in the shore line and the offshore bottom, and
found that accretion occurred to the shore line from 1953 to 1960, that
existing beaches are generally adequate for protection of the beach de-
velopment, but that, if recession of the shore occurs, restoration can be
accomplished by direct placement of sand along the shores or in stockpiles
to be distributed by wave action. He concluded that minor infrequent dam-
ages which have occurred do not warrant construction of protective works
at this time, but that surveys should be made to determine trends of shore
line and offshore depth changes and the need for beach restoration or pro-
tection. He recommended that no project be adopted by the United States
for protection of Salisbury Beach and recommended further that future con-
struction of buildings be limited to the area behind the general line of
development and that protective measures which may be undertaken by local
interests based on their determination of need be accomplished in accord-
ance with methods discussed in his report. The Beach Erosion Board con-
curred in the conclusions and recommendations of the Division Engineer,
and noted that minor damages to development features have resulted from
their construction within the zone of seasonal or storm shore line changes,
but in view of shore line accretion in recent years and the small amount
of damages, no protective measures are warranted at this time. The Board
noted further that the erosion which has deepened the nearshore and off-
shore zones since 1940 increases the vulnerability of the area to storm
damages, and emphasized the importance of continued observation of profile
changes to determine need of protective measures before that need becomes
urgent. The Board also noted that periodic nourishment of Hampton Beach
to the north will probably increase the supply of material to Salisbury

8

Beach, but provision for continuation of a supply to Seabrook and Salisbury
Beaches must be included in case navigation improvements are constructed
at Hampton Harbor entrance in the future.

The Chief of Engineers concurred in the views and recommendations of
the Beach Erosion Board.

FORT MACON - ATLANTIC BEACH AND VICINITY, NORTH CAROLINA

The purpose of the investigation was to determine the best method of
protecting the shores of the Fort Macon and Atlantic Ocean shore from fur-
ther erosion. The study area comprises the Atlantic Ocean shore of Fort
Macon and Atlantic Beach and vicinity for a distance of about 5 miles west
from Beaufort Inlet. In 1960 the permanent population of the coastal area
within 50 miles of the study area was about 202,000. About 9,250 feet of
the shore frontage at Fort Macon is publicly owned, including the Beaufort
Inlet shore; the remaining frontage of the study area, about 20,300 feet,
is privately owned. The study area is located on a sandy barrier beach
extending westward from Beaufort Inlet. Extensive dunes on the island have
a maximum height of about 40 feet. Tides in the area are semi-diurnal with
mean and spring ranges of 3.8 and 4.6 feet respectively. The highest water
of record was 12.6 feet above mean low water, during Hurricane Donna in
September 1960. Waves approach the shore from the southeast and southwest
quadrants. The predominance of littoral drift appears to be westward, but
reversals occur especially along the ocean shore of Fort Macon State Park
due to tidal currents in Beaufort Inlet.

The District and Division Engineers and the Beach Erosion Board de-
veloped plans for restoring and protecting the shores of the area, and made
economic analyses of proposed protective measures. They concluded that
practicable plans for the restoration and stabilization of shores within
the study area are as follows:

a. Fort Macon State Park. Restoring approximately 7,750 feet
of beach by direct placement of sand fill, and constructing a groin, re-
vetment and seawall;

b. Atlantic Beach and Vicinity. Restoring approximately 20,300
feet of beach by direct placement of sand fill.

Both plans include periodic nourishment to stabilize the restored beaches.
The reporting officers and The Beach Erosion Board found that restoration
and protection of the shores of Fort Macon State Park and Atlantic Beach
and vicinity are justified by evaluated benefits. They further found that
the nature and amount of benefits warrant Federal participation in protec-
tion of the shore of Fort Macon State Park and recommended adoption of a
project by the United States authorizing, subject to certain conditions,

82

Federal participation by the contribution of Federal funds in amount of
one-third of the first costs and periodic nourishment costs for a period
of 10 years. As no local agency indicated ability to comply with require-
ments of local cooperation for protection of Atlantic Beach, they did

not recommend a Federal project for that shore. The Chief of Engineers
concurred in the views and recommendations of the Beach Erosion Board.

VIRGINIA AND BISCAYNE KEYS, FLORIDA

The purpose of the investigation was to determine the best method
of preventing further erosion and of maintaining and restoring the ocean
beaches. The study area comprises the Atlantic Ocean shore between Govern-
ment Cut, the jettied entrance to Miami Harbor, and Florida Point, the
south end of Key Biscayne. The total length of shore frontage studied
is about 8 miles. The problem area comprises the shores of Virginia and
Biscayne Keys with a total length of about 6 miles. In 1960 the permanent
population of Dade County was about 935,000. The entire shore frontage
of Virginia Key and the northern half of the frontage of Key Biscayne are
publicly owned. The study area is characterized by low sandy barrier beach
islands. Tides in the area are semi-diurnal with mean and spring ranges
of 2.5 and 3.0 feet respectively. A reported high water mark of 9.1 feet
above mean low water occurred during a hurricane in 1926. Waves approach
the shore from directions from northeast through east to southeast. The
directions of waves are such as to produce a southward predominance of
littoral drift during the winter and a northward predominance during the
summer, The fetches in the wave generating area are limited by the islands
of the Bahama group.

The District and Division Engineers developed plans for restoring and
protecting the shores of the area, and made economic analyses of proposed
protective measures. They concluded that practicable plans for the restora-
tion and stabilization of shores within the study area are as follows:

a. Virginia Key - Restoring and widening approximately 1.8 miles
of shore by direct placement of sand fill, three groins for deferred con-
struction, if needed.

b. Key Biscayne - Restoring and widening approximately 4.3 miles
of shore by direct placement of sand fill, two groins for deferred con-
struction if needed.

The plan for Crandon Park, the county-owned shore of Key Biscayne, comprises
beach restoration and widening along 1.9 miles of shore and one groin at
its north end. This plan could be constructed separately or as part of the
plan for the entire key. Both plans include periodic nourishment to stabi-
lize the restored beaches. The District and Division Engineers found that
restoration and protection of the shores of Virginia and Biscayne Keys are

83

justified by evaluated benefits, and further found the nature and amount
of benefits warrant Federal participation. They recommended adoption of
projects by the United States authorizing, subject to certain conditions,
Federal participation by the contribution of Federal funds in an amount
equal to one-third of the first costs and periodic nourishment costs for
a period of 10 years of protecting the public shores of the two keys.

The Beach Erosion Board noted that the existing beaches at Virginia
Key and Key Biscayne appear adequate in width to provide protection to
backshore improvements under moderate storm conditions. Considering
presently unused frontage and area landward of the beach, there appears
to be sufficient area for recreational needs for many years. In view of
these conditions the Board felt there is no justification for Federal
participation in the cost of widening the beach in the near future.
However, the Board believed that stabilization of the shores is desirable
to prevent future beach losses, and that such stabilization can be accom-
plished by periodic nourishment with suitable sand as required. The Board
recommended adoption of projects by the United States authorizing Federal
participation by the contribution of Federal funds in amount of one-third
of the costs of periodic nourishment of the shores at Virginia and Biscayne
Keys, Florida. The plans comprise periodic nourishment of 1.8 miles of
beach on Virginia Key and 1.9 miles of beach on Key Biscayne. The plans
also include three groins on Virginia Key and one groin on Key Biscayne
for deferred construction when experience indicates their justification.
The Board recommended Federal participation in the costs of such periodic
nourishment of the beach for an initial period of 10 years. The Board
further recommended that protective measures which may be undertaken by
local interests for the privately owned portion of the Key Biscayne shore,
based on their own determination of economic justification, be accomplished
generally in accordance with the method developed by the District Engineer.

The Chief of Engineers concurred generally in the findings of the
Board and accordingly, recommended adoption of projects providing for
Federal participation in the cost of periodic nourishment of 1.8 miles of
beach on Virginia Key and 1.9 miles of beach on Key Biscayne for an initial
period of 10 years, and in the cost of deferred construction of groins when
experience indicates their justification, in accordance with the plans pro-
posed by the Beach Erosion Board,

SAN_JUAN, PUERTO RICO
The purpose of the investigation was to determine methods of prevent-
ing further erosion and stabilizing or restoring the beach, with special
emphasis on protecting existing upland properties and future recreational,
industrial or residential areas, and on reclaiming some eroded land at
various locations, The study area comprises the Atlantic Ocean shore of
Puerto Rico between Punta Salinas and Punta Vacia Talega. The total length

84

of shore frontage studied was about 24 miles. In 1960 the permanent
population of the coastal area was about 600,000. About 56 percent of

the shore frontage of the area is publicly owned. The western part of

the study area is characterized by rocky headlands between which are the
deeply indented bays, Ensenada de Boca Vieja and Bahia de San Juan. The
eastern part consists generally of low sandy beaches. Tides in the area
are semi-diurnal with mean and spring ranges of 1.1 and 1.3 feet respect-
ively. The recorded high water was 2.8 feet above mean low water, but a
hurricane stage of 4 to 6 feet in September 1960 was reported. Waves
approach the shore principally from directions from east through north-
northeast, resulting in a general, but minor westward predominance of
littoral drift east of the entrance to Bahia de San Juan. West thereof

in Ensenada de Boca Vieja the direction of drift appears to alternate with
little, if any, predominance in either direction. Deeply eroded embay-
ments prevent normal westward drift, so that there appears to be a general
deficiency in supply, except in the most easterly section.

The District and Division Engineers developed plans for restoring and
protecting the shores of the area, and made economic analyses of proposed
protective measures, They concluded that practicable plans for the restora-
tion and stabilization of shores within the study area are as follows:

a. Ensenada de Boca Vieja - Restoring approximately 1 mile of
beach by direct placement of sand fill;

b. Catano - Restoring approximately 1.4 miles of beach by
direct placement of sand fill and protecting E1 Canuelo by rubble;

c. Condado and Ocean Park - Restoring approximately 0.9 mile
of beach by direct placement of sand fill and construction of a breakwater
129 feet long at the west end of the reach;

d. Isla Verde and International Airport - Restoring approxi-
mately 1.3 miles of beach by direct placement of sand fill;

All plans include periodic nourishment to stabilize the restored beaches.
The District and Division Engineers and the Beach Erosion Board found that
restoration and protection of the Condado-Ocean Park shore are justified
by evaluated benefits. They further found the nature and amount of bene-
fits warrant Federal participation, and recommended adoption of a project
by the United States authorizing, subject to certain conditions, Federal
participation by the contribution of Federal funds in an amount equal to
8.2 percent of the first costs and periodic nourishment costs for a period
of 10 years. The Beach Erosion Board emphasized the importance of sand
supply to the stability of the shore of Playa de las Tres Palmitas and
pointed out that continued removal of sand for commercial purposes from
that shore and from the mouth of Loiza River will result in future shore
recession in that reach. The Chief of Engineers concurred in the views and
recommendations of the Beach Erosion Board,

85

CLARK POINT, NEW BEDFORD, MASSACHUSETTS

The purpose of the investigation was to determine the best method
of restoration and stabilization of the city beaches along Rodney French
Boulevard on the east and west sides of the Clark Point Peninsula. New
Bedford is located in Bristol County about 50 miles south of Boston. The
shores studied are located on the east and west sides of Clark Point, a
peninsula projecting into Buzzards Bay. The peninsula consists of glacial
deposits. Beaches fronting the low banks are narrow. The total length of
the study area is about 3 miles, including about 1 mile of frontage on
the outer tip of the point occupied by Fort Rodman, a Federal military
reservation. New Bedford is a residential and industrial community with
a permanent population of about 102,000. The shore of the study area is
publicly owned except for about 0.1 mile on the east side of the point.
The beaches are used for recreational purposes. The tides in the study
area are semi-diurnal. The mean and spring ranges are respectively 3.7
and 4.6 feet. The maximum tide of record, 14.2 feet above mean low water,
occurred during the hurricane of September 1938. Tides in excess of 3 feet
above mean high water occur about once in 2 years. The shores of the study
area are exposed to waves up to about 6 feet high from the south generated
in the limited fetch of Buzzards Bay. This portion of Buzzards Bay is cut
off from the full fetch of the Atlantic Ocean by the Elizabeth Islands and
Martha's Vineyard. Beach material has been supplied to the shore of the
study area by northward littoral transport from erosion of Clark Point
headland. Protection of the headland shore has reduced this supply with
resultant erosion of the beaches.

The Division Engineer developed plans for restoration and stabiliza-
tion of the beaches. He concluded that practicable plans for protection
and improvement of the shores where recreational beaches are required
comprise sand fills and groin construction, and that for shores where no
fronting beach exists, stone revetment or rubble-mound wall construction
is practicable. He developed two alternative plans for protecting and
improving Rodney French Boulevard West Beach; alternative No. 1 comprises
raising the inshore end of an existing groin, lengthening two existing
groins, and widening the beach by direct placement of sand fill; alter-
native No. 2 comprises raising the inshore end of the same existing groin,
constructing three new intermediate groins, and widening the beach by
direct placement of sand fill. He also developed a plan comprising beach
fill and two new groins for improving Rodney French Boulevard East Beach,
and typical plans comprising stone revetment or rubble-mound wall for
critical sections along Rodney French Boulevard West where no beaches
exist. The Division Engineer concluded that work at the west beach is
justified by evaluated benefits but that the public interest in projects
for the east beach or other city-owned areas is insufficient to warrant
Federal aid. He recommended a project providing for Federal participation
in amount equal to one-third of the first costs of either alternative for
the west beach, subject to certain conditions.

86

The Beach Erosion Board concurred generally in the conclusions of the
Division Engineer that either the groin extension plan or the new groin
plan would be a practicable plan of improvement for Rodney French Boulevard
West Beach, and that either planis amply justified by prospective benefits.
However, the Board noted that the State expressed a preference for the
groin extension plan. As that plan would provide greater beach area and
additional benefits, making the greater cost of the plan incrementally
justified, the Board concurred in the State's preference for that plan, and
recommended adoption of a project by the United States authorizing Federal
participation by the contribution of Federal funds in amount of one-third
of the first costs of measures for the restoration and protection of the
publicly owned shore at Rodney French Boulevard West Beach, New Bedford,
Massachusetts, substantially in accordance with the groin extension plan
of the Division Engineer, with such modifications thereof as may be con-
sidered advisable by the Chief of Engineers. The recommended plan comprises
widening approximately 1,600 feet of beach to a minimum width of 100 feet
by direct placement of suitable sand fill, raising the inshore end of the
existing groin at Dudley Street, and extending two existing groins. The
Chief of Engineers concurred in the views and recommendations of the Beach
Erosion Board.

HILLS BEACH, BIDDEFORD, MAINE

The purpose of the investigation was to determine the best method of
restoration of protective and recreational beaches and protection of shore
property. Biddeford is located on Saco River in the northeast part of
York County, Maine. It has a permanent population of nearly 20,000 and
a somewhat greater summer population. Saco River empties into the south
end of Saco Bay, which is about 7 miles in length and has a maximum width
of 3 miles. Hills Beach is privately owned. It is developed with about
200 cottages, some of which are used as year-round residences. Hills Beach
lies immediately south of the jettied mouth of Saco River. The study area
extends about 14 miles in a general southeasterly direction from the mouth
of Saco River to the entrance to The Pool. The area is a low sandy barrier
beach from 200 to 1,000 feet wide between Saco Bay and The Pool. The tides
at Hills Beach are semi-diurnal. At Wood Island Harbor, just east of the
beach, the mean and spring ranges are respectively 8.7 and 9.9 feet. Waves
affecting the Hills Beach shore approach from between east and northeast
and cause littoral drift principally toward the northwest across the Saco
River south jetty. The problem is erosion and loss of the protective beach
thus exposing the development to storm wave attack. This erosion has re-
sulted in extensive damages to seawalls and bulkheads previously constructed
by local interests to protect upland property.

The Division Engineer developed plans for protecting the shore of the

problem area. He concluded that widening approximately 5,400 feet of beach
by direct placement of sand fill and raising 700 feet of the inshore end of

87

the Saco River south jetty is a practicable method of restoring and
protecting Hills Beach, and that an alternative method of protecting
individual properties consists of constructing stone revetments in front
of existing seawalls or bluffs. The Division Engineer and Beach Erosion
Board found that due to the private ownership of the shore and lack of
public benefits, Hills Beach is not eligible for Federal assistance in con-
struction of protective works. However, the Division Engineer indicated
that placement of suitable sandy spoil on the beach may be possible in
connection with future maintenance of Federal navigation projects for

Saco River and The Pool at Biddeford. They recommended that no project be
adopted at this time by the United States for the protection of the shore
of Hills Beach, They further recommended that protective measures which
may be undertaken by local interests, based upon their own determination
of economic justification, by accomplished in accordance with plans and
methods considered in this report. Local interests stated an opinion that
the United States is responsible for a substantial portion of the erosion
which has occurred at Hills Beach, especially since 1954, as a result of
failure to maintain the existing south jetty at the entrance to Saco River,
and also that the United States should undertake restoration of the jetty
to its as-built condition and replacement of that amount of shore material
determined to have been eroded as a result of the failure to maintain the
south jetty, at no cost to local interests. The Beach Erosion Board be-
lieved that the study did not establish that the recent erosion of Hills
Beach can be attributed to deterioration or lack of maintenance of the
south jetty. It also believed that the United States has neither obli-
gation nor authority to maintain the existing Saco River south jetty,
except in the interest of navigation. The Board stated that in any event
restoration of the jetty to its as-built elevation (5.5 feet above mean
low water as far as can be determined from available records) would result
in only minor accretion to the adjacent shore to the south and would thus
not solve the Hills Beach erosion problem, The Board does not favor piece-
meal protection of separate frontages by individual owners, but concurred
in the plan for beach fill and jetty raising as the most suitable plan of
restoring and protecting the entire beach. The Chief of Engineers con-
curred in the views and recommendations of the Beach Erosion Board,

SAN GABRIEL RIVER _TO NEWPORT BAY, ORANGE COUNTY, CALIFORNIA

The purposes of the investigation were to determine the causes and
most effective and economical methods of controlling erosion of the shore,
and the extent of Federal aid which should be granted to the Anaheim Bay
area in equity without regard to limitations of Federal law applicable to
beach erosion control. Orange County is in Southern California immediately
south of Los Angeles County. Its Pacific Ocean shore line, extending in a
general northwest-southeast direction, is about 42 miles long, the portion
of which covered by this report being about 17 miles long from the mouth
of San Gabriel River to the entrance to Newport Bay. The coastal area

88

consists generally of sandy beaches backed by tidal lagoons and marshes,
except at Seal Beach and Huntington Beach where plateaus 10 to 30 feet
above sea level lie behind the beaches, The principal shore communities
in the study area are Seal Beach, Huntington Beach and Newport Beach, but
the population of Orange County and adjacent counties to which Orange
County beaches are readily accessible is over 6,000,000. Of the shore
frontage, 13.64 miles or 81.8 percent is publicly owned. The principal
publicly owned sections are Bolsa Chica Beach and Huntington Beach State
Parks and the municipal beaches in Huntington Beach and Newport Beach. The
tides in the study area have a diurnal inequality, the mean and diurnal
ranges being respectively about 3.7 and 5.3 feet. The maximum tide each
year is about 7 feet above mean lower low water. Characteristic waves are
swells generated in distant ocean areas. They have heights up to 10 feet
and periods up to 20 seconds with the greater heights and shorter periods
occurring in the winter. Winter waves generally approach the shore from
upcoast of normal, summer waves frequently approach from downcoast of
normal. As a result the predominant direction of littoral transport is
generally toward the southeast. However, Seal Beach is protected from
westerly waves by offshore breakwaters and the predominant direction of
drift is now northwestward. Sand has been supplied to the shore by tribu-
tary streams, especially during storm runoff, but the supply has been
greatly reduced by construction of dams on those streams.

The District and Division Engineers concluded that the most suitable
plan of shore protection for the problem area from Surfside to Newport
Beach comprises a protective beach in the vicinity of Surfside-Sunset Beach
generally 500 feet wide and 9,200 feet long to be provided by artificial
placement of approximately 3,000,000 cubic yards of suitable sand on the
beach, construction of an offshore breakwater at Newport Beach and pro-
viding periodic artificial nourishment of the Surfside-Sunset Beach shore
by transferring sand from the impoundment area of that breakwater. They
made an economic analysis of the plan of protection for the shore from
Surfside to Newport Beach and concluded that the plan is justified by
prospective benefits, and that in equity Federal assistance to the extent
of 61 percent of the costs of protection of these shores is warranted. The
District and Division Engineers recommended modification of the existing
project to authorize Federal participation, subject to certain conditions,
by contribution of funds in amount of 61 percent of the first costs and
periodic nourishment and maintenance costs of the project.

Residents of Newport Beach objected generally to construction of a
breakwater off Newport Beach on the basis that there is presently no
erosion problem at Newport Beach and that protective construction should
preferably be located at Surfside, the site of the present erosion problem.
Some also indicated that surf action at Newport Beach would be reduced and
that use of the sheltered area behind the breakwater for navigational pur-
poses would be objectionable.

89

The Beach Erosion Board considered the apportionment of costs in
equity as derived by the District Engineer and considered that the Anaheim
Bay jetties were of equal importance with the flood control and naviga-
tion improvements in contributing to erosion of the Orange County beaches.
Accordingly the Board recomputed the extent of Federal aid in equity as 67
percent instead of 61 percent of the costs. The Board therefore recommended
that in lieu of the existing project for Surfside, California (Anaheim
Bay Harbor) a project be adopted by the United States authorizing Federal
participation by the contribution of Federal funds in amount of 67 percent
of the first costs and costs of periodic nourishment and maintenance of
a plan comprising restoration of the beach in the Surfside-Sunset Beach
area, a feeder beach for nourishing the shore from Surfside to Newport
Beach, andanoffshore breakwater at Newport Beachto provide an impounding
area from which sand would be transferred periodically to the feeder beach
at Surfside, substantially in accordance with the plan of the District
Engineer, with such modification thereof as may be considered advisable
by the Chief of Engineers. The Chief of Engineers concurred in the views
and recommendations of the Beach Erosion Board.

RECOMPUTATION OF FEDERAL SHARE OF CONSTRUCTION
COSTS UNDER PROVISIONS OF PL 87-874

The 1962 amendments to beach erosion law increased the permissible
Federal share of construction cost. for regular beach erosion control
projects from one-third to one-half and provided further that Federal
participation in the cost of projects for restoration and protection of
State, county, and other publicly owned parks and conservation areas may
be as high as 70 percent of the total cost. These revised cost-sharing
provisions were made applicable to existing authorized projects not sub-
stantially completed as of the date of approval of the amendments (23
October 1962) and the Chief of Engineers through the Beach Erosion Board
was directed to recompute the extent of Federal participation in the
costs of those projects accordingly. On this basis the level of Federal
participation was recomputed and approved by the Chief of Engineers for
projects authorized from two of the foregoing eight summarized reports as
follows:

Fort Macon-Atlantic Beach and Vicinity, N. C. - From 1/3 to 70 percent.
Virginia and Biscayne Keys, Florida - From 1/3 to 70 percent.
In addition a pending recomputation of the level of Federal participation

for the authorized project resulting from the report on San Juan, Puerto
Rico should result in some increase in the Federal share.

90

COMPLETE D COOPERATIVE BEACH EROSION STUDIES

Federal Projects

BEB Report Published in Recommen=- Authorized
Location Completed H, Doc, Cong. dation * by Congress
ALABAMA
Perdido Pass (Alabama Pt.) 18 Jun 54 274 #84 Unfav,.
CALIFORNIA
Santa Barbara = Initial 15 jan 38 552 75 Unfav.*
Suppl, 18 Feb 42
Final 22 May 47 761 80 Unfav.
Ballona Creek & San
Gabriel R, (Partial) 11 May 38 Unfav,*
Orange County 10 Jan 40 C7 1G Unfav.*
Coronado Beach 4 Apr 41 CSO — 4/7/ Unfav.*
Long Beach 3 Apr 42 Unfav.*
Mission Beach 4 Nov 42 Unfav,*
Pt, Mugu to San Pedro BW 2 uinho ZU 83 Fav, 3 Sep 54
Carpinteria to Pt, Mugu 4 Oct Si 29 83 Fav, 3 Sep 54

Oceanside, Ocean Beach,
Imperial Beach & Coronado,

San Diego ‘County Px) Jpeul SS 399 84 Fav. S) Jfoul SS
Santa Cruz County 13 ySepya6 179 85 Fav. 3 Jul 58
Humboldt Bay (Buhne Pt.) 29 Mar 57 AB os Fav. Swiss
Newport Bay to San Mateo

Creek, Orange County 3 Dec 59 398 86 Pav. 14 Jul 60
San Diego County 30 Jun 60 456 86 Fav. 29 Mar 61
Ventura 28 Dec 61 458 87 Fav. 235 OGE Oe
San Gabriel River to

Newport Bay, Orange Co, 20 Apr 62 602 87 Pav, 23 Oct 62

CONNECTICUT
Compo Beach, Westport 18 Apr 35 239 74 Unfav.*
Hawk's Nest Beach, Old Lyme 21 Jun 39 Unfav.*
Ash Crk. to Saugatuck R, 29 Apr 49 454 81 Fav. 17 May 50
Hammonasset R, to East R, 29 Apr 49 474 81 Fav, 3 Sep 54
New Haven Hbr, to
Housatonic R, 29 Jun 51 203 83 Fav. 3 Sep 54

* No established policy for Federal participation in construction of shore
protection works existed prior to 1946,

S)I

Federal Projects
BEB Report Published in Recommen- Authorized

Location Completed H, Doc. Cong, dation * by Congress

CONNECTICUT (Cont.)

Conn, R, to Hammonasset R, 28 Dec 51 514 82 Unfav.
Pawcatuck R, to Thames R, 31 Mar 52 31 83 Unfav.
Niantic Bay to Conn, R. 11 Jul 52 84 83 Unfav,
Housatonic R, to Ash Creek 12 Mar 53 248 83 Fav. 3 Sep 54
East R, to New Haven Hbr, 15 Nov 55 395 84 Fav. 3 Jul 58
Saugatuck R, to Byram R, 14 Nov 56 174 85 Fav, 3 Jul 58
Thames R, to Niantic Bay 17 Jun 57 334 85 Unfav.
DELAWARE
Kitts Hummock to Fenwick Is, 11 Feb 57 216 85 Fav, 3 Jul 58
FLORIDA

Blind Pass (Boca Ciega) 1 Feb 37 187 5 Unfav.*
Miami Beach 1 Feb 37 169 75 Unfav.*
Hollywood Beach 28 Apr 37 253 75 Unfav,*
Daytona Beach 15 Mar 38 571 75 Unfav.*
Bakers Haulover Inlet 21 May 45 527 79 Unfav,*
Anna Maria & Longboat Keys 12 Feb 47 760 80 Unfav.
Jupiter Island 13 Feb 47 765 80 Unfav,
Paim Beach (1) 13 Feb 47 772 80 Fav. 17 May 50
Pinellas County 22 Apr 53 380 83 Fav. 3 Sep 54
Palm Beach County (Lk, Worth

Inlet to S, Lake Worth I.) 12 Jul 57 342 85 Fav, 3 Jul 58
Key West 10 Mar 58 413 85 Fav. 14 Jul 60
Amelia Island 16 Aug 60 200 87 Unfav.
Palm Beach County 23 Aug 60 164 87 Fav, 23 Oct 62
Virginia & Biscayne Keys 6 Apr 62 561 87 Fav. 23 Oct 62
Broward Co, & Hillsboro Inl, 23 Apr 63 Fav.

GEORGIA

St. Simon Island 18 Mar 40 820 76 Unfav.*
(1)

A cooperative study of experimental steel sheet pile groins was also made,
under which methods of improvement were recommended in an interim report
dated 19 Sep 1940, Final report on experimental groins was published in
1948 as Technical Memorandum No, 10 of the Beach Erosion Board.

92

Federal Projects
BEB Report Published in Recommen- Authorized

Location Completed H,Doc, Cong. dation * by Congress
HAWAII
Waikiki Beach 5S Aug 52 227 83 Pav. 3 Sep 54
Waimea & Hanapepe Bay, Kauai 17 Jan 56 432 84 Fav, 3 Jul 58
Haleiwa Beach, Oahu 28 Feb 63 Fav.
ILLINOIS
State of Illinois 8 Jun 50 28 83 Fav. 3 Sep 54
LOUISIANA
Grand Isle 28 Jul 36 92 75 Unfav.*
Grand Isle 28 Jun 54 132 84 Unfav,
Belle Pass to Raccoon Point 13 Jun 61 3338 87 Unfav,
MAINE
Old Orchard Beach 20 Sep 35 Unfav,*
Saco 2 Mar 56 32 85 Unfav.
Hills Beach, Biddeford 27 Nov 61 590 87 Unfav.
MASSACHUSETTS

South Shore of Cape Cod

(Pt. Gammon to Chatham) 26 Aug 41 Unfav.*
Salisbury Beach 26 Aug 41 Unfav.*
Winthrop Beach 12 Sep 47 764 80 Fav. 17 May 50
Lynn=-Nahant Beach 20 Jan 50 134 82 Fav. 3 Sep 54
Revere Beach 12 Jan 50 146 82 Fav, 3 Sep 54
Nantasket Beach 12 Jan 50 ; Unfav.
Quincy Shore 2 May 50 145 82 Fav, 3 Sep 54
Pium Island 18 Nov 52 243 = 883 Unfav.
Chatham 22 Oct 56 167 #85 Unfav.
Pemberton Pt, to Cape Cod

Canal 13 Jan 59 272 86 Fav, 14 Jul 60
Wessagussett Beach, Weymouth 6 Jul 59 334 86 Fav. 14 Jul 60
Cape Cod Canal to

Province town 5 Feb 60 404 86 Fav, 14 Jul 60
Clark Point, New Bedford 14 Aug 61 Se) BY Fav. 23 Oct 62
Rockport 21 Nov 61 515 87 Unfav,
Salisbury Beach 5 Dec 61 Sal7/ 87 Unfav,
Falmouth 28 Feb 63 Unfav.

93

Location

Berrien County (St. Joseph)

Hancock County
Harrison County - Initial
Harrison County - Suppl.

Hampton Beach
Hampton Beach

Atlantic Ocean shore (entire)

Manasquan Inlet &
Adjacent Beaches

Atlantic City

Ocean City

Sandy Hook to Barnegat Inlet

Review Report - Sandy Hook
to Barnegat Inlet

Barnegat Inlet to Delaware
Bay Entrance to Cape May
Canal

Delaware Bay Shore = Cape
May Canal to Maurice River

Raritan & Sandy Hook Bays

Atlantic City

Jacob Riis Park, Long Island
Orchard Beach, Pelham

Bay, Bronx
Niagara County
South Shore of Long Island
Selkirk Shores State Park
Fair Haven Beach State Park
Hamlin Beach State Park

BEB Report
Completed

MICHIGAN

V7 uno,

MISSISSIPPI

3 Apr 42
15 Mar 44
16 Feb 48

NEW HAMPSHIRE

Sy jr 32
14 Sep 53
30 Jun 61

NEW RS EY

94

336

682

325
416

71
538
184
361

332

208

196
464

397

450
271

343
134
138

Published in
H, Doc, Cong,

85

80

83
87

87
87

74

75
78

83
84
84

Federal Projects

Recommen- Authorized

dation * by Congress
Fav. 3 Jun 58
Unfav.*

Fav. 30 Jun 48
Unfav.*

Pav. 3 Sep 54
Fav. 23 Oct 62
Unfav.*

Fav. 3 Sep 54
Fav. 3 Sep 54
Fav,

Fav. 3 Jul 58
Fav. 14 Jul 60
Unfav.

Fav. 23 Oct 62
Fav

Unfav.*

Unfav.*

Unfav.*

Unfav.

Fav. 3 Sep 54
Fav, 3 Jul 58
Fav. 3 Jul 58

Federal Projects
BEB Report Published in Recommen- Authorized

Location Completed H, Doc, Cong, dation® by Congress

NEW YORK (Cont, )

Braddock Bay State Park 15 Apr 55 Unfav.
Fire Island Inlet to
Jones Inlet 10 Feb 56 411 84 Fav. 3 Jul 58

Fire Island Inlet to Montauk
Pt. (combined coop. BEC
and HUR) 30 Jun 59 425 86 Fav, 14 Jul 60

NORTH ‘CAROLINA

Fort Fisher 10 Nov 31 204 72 Unfav.* .
Wrightsville Beach 2 Jan 34 218 73 Unfav.*
Kitty Hawk, Nags Head &
Oregon Inlet 1 Mar 35 155 74 Unfav.*
State of North Carolina 22 May 47 763 80 Unfav.
Carolina Beach & Vicinity 10 Mar 61 418 87 Fav. 23 Oct 62
Fort Macon-Atlantic Beach 30 Apr 62 555 87 Fav. 23 Oct 62
OHIO
Erie County - Vic, of Huron 26 Aug 41 220 79 Unfav.*
Michigan Line to Marblehead 30 Oct 44 177 79 Unfav.*
Cities of Cleveland &
Lakewood 22 Mar 48 502 81 Fav. 3 Sep 54
Chagrin River to Fairport 22 Nov 49 596 81 Unfav.
Vermilion to Sheffield
Lake Village 24 Jul 50 229 83 Fav. 3 Sep 54
Fairport to Ashtabula 1 Aug 51 351 82 Unfav.
Ashtabula to Penna, St, Line 1 Aug 51 350 82 Unfav.
Sandusky to Vermilion 7 Jul 52 32 83 Unfav.
Sandusky Bay 31 Oct 52 126 83 Unfav.
Sheffield Lake Village to .
Rocky R,. 31 Oct 52 127 83 Unfav.
Euclid to Chagrin River 25 Jun 53 324 83 Unfav,.
Michigan Line to Marblehead
(Review) 14 Jun 60 63 87 Fav. 23 Oct 62
Sheffield Lake Community
Park 13 Jun 61 414 87 Fav, 23 Oct 62

95

Federal Projects
BEB Report Published in Recommen=- Authorized

Location Completed H, Doc. Cong, dation* by Congress
PENNSYLVANIA

Presque Isle Peninsula, Erie

(Interim) 3 Apr 42
(Final 23 Apr 52 231 83 Fav, 3 Sep 54
(Review) 21 Jan 60 397 86 Fav. 14 Jul 60
PUERTO RICO
Punta Las Marias, San Juan 5 Aug 47 769 80 Unfav.
San Juan 3 May 62 575 87 Fav. 23 Oct 62

RHODE ISLAND

South Shore (Towns of

Narragansett, South

Kingstown, Charlestown

& Westerly) 4 Dec 48 490 81 Fav, 3 Sep 54
South Kingstown & Westerly 27 Jan 58 30 86 Fav. 14 Jul 60

SOUTH CAROLINA

Folly Beach 31 Jan 35 156 74 Unfav.*
Pawleys Island, Edisto

Beach & Hunting Island 24 Jul 51 Unfav.
Hunting Island Beach 9 May 63 Fav.

TEXAS

Galveston (Gulf Shore) 10 May 34 400 73 Unfav.*
Galveston Bay, Harris County 31 Jul 34 74 74 Unfav.*
Galveston (Gulf Shore) 5 Feb 53 218 83 Unfav.
Galveston (Bay Shore) 19 Jun 53 346 83 Unfav.
Bolivar Peninsula (Gulf Shore

and Rollover Fish Pass) 8 Jun 59 286 86 Unfav.

96

Location

Willoughby Spit, Norfolk
Colonial Beach, Potomac R,
Virginia Beach

Virginia Beach (Review)

Milwaukee County
Racine County
Kenosha
Manitowoc County

BEB Report
Completed

VIRGINIA

20 Nov 37
24 Jan 49
25 Jun 52
13 Jun 61

WISCONS IN

21 May 45
5 Mar 52
16 Sep 54
15 Apr 55

Si,

H, Doc, Cong,

482
333
186
382

75
81
83
87

79
83
84
84

Federal Projects
Recommen- Authorized

dation *

Unfav.*
Fav,
Fav,
Fav,

Unfav.*
Unfav, -
Unfav.

Pav,

by Congress

17 May 50
3 Sep 54
23 Oct. 62

3 Jul 58

CURRENTLY AUTHORIZED BEACH EROSION STUDIES
(Cooperative and Federal Surveys)

Those studies authorized and in progress prior to 23 October 1962,
the date of enactment of Public Law 87-874, were authorized, and are being
continued, on the cooperative basis, Those studies authorized since that
date are full Federal surveys, authorized by Resolution of the Public
Works Committee of either the U. S. Senate or House of Representatives,
under provisions of the amended law. A listing by States of all currently
authorized studies follows:

Locality Date Auth, Study Type
CALIFORNIA
Point Conception to Mexican Boundary 6/12/58 Coop.
(General study)
City of San Diego (Special Study) 5/17/62 Coop.
Alamitos Bay (Special Study) 5/17/62 Coop.
Emma Wood State Park & vicinity 5/17/62 Coop.
(Special Study)
Point Delgada to Point Ano Nuevo 3/18/59 Coop.
Daly City (San Mateo County) 5/2/63 Fed, Survey
Pacifica (San Mateo County) 6/19/63 Fed. Survey
El Grenada Beach 6/19/63 Fed, Survey
DELAWARE
Kitts Hummock to Fenwick Island 1/7/63 Fed, Survey
(Review)
FLORIDA
Bakers Haulover — Miami 5/24/60 Coop.
Fort Pierce 12/30/60 Coop.
Duval County 1/7/63 Fed, Survey
St. John's County 1/7/63 Fed, Survey
Jupiter Island 6/19/63 Fed, Survey
Mullet Key 6/19/63 Fed, Survey
Pinellas County (Review) 6/19/63 Fed. Survey
GEORGIA
Sea Island & St. Simons Island 4/29/63 Fed, Survey
Tybee Island 4/29/63 Fed, Survey
ELAN
State of Hawaii (General Study) 7/17/62 Coop.
Waikiki Beach (Review) 8/25/59 Coop.
Kihei, Maui 4/10/63 Fed, Survey
Kapaa, Kauai 4/10/63 Fed, Survey

98

Locality

ILLINOIS

Evanston (Review)

MARYLAND

Worcester County

MASSACHUSETTS
Marthas Vineyard
Nantasket & Revere Beaches
NEW JERSEY
Perth Amboy
Coastal Inlets of New Jersey
NEW YORK
Staten Island
Fire Island Inlet to Jones Inlet (Review)
East Rockaway Inlet to Norton Point
Jones Inlet to East Rockaway Inlet
Suffolk County (North Shore)
NORTH CAROLINA
Ocracoke Island
Ocracoke Inlet to Cape Lookout

OHIO

Lake Erie Shore: (Ashtabula to Lake
County line)

RHODE ISLAND
Newport

WASHINGTON

Tokeland
Titlow Beach

99

Date Auth,

8/11/59

6/19/63

2/14/61
9/19/61

2/2/61
12/18/61

3/23/59
9/15/60
3/29/61
3/20/63
3/20/63

10/29/57
12/16/59

6/10/63

2/14/61

5/15/62
6/19/63

Study Type

Coop.

Fed. Survey

Coop.
Coop.

Coop.
Coop.

Coop.

Coop.

Coop.
Fed, Survey
Fed, Survey

Coop.
Coop.

Fed. Survey

Coop.

Coop.
Fed, Survey

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