|
Items in cart [4] |
Questions? Call 888-624-8373 |
| Copyright © 2009. National Academy of Sciences. All rights reserved. Terms of Use and Privacy Statement |
Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 27
Management Strategies for Shore Protection
This chapter appraises management strategies for shore protection and, in
particular, examines public issues. Legal constraints, uncertainties, and the eco-
nomics of the three basic strategies for addressing shoreline erosion are dis-
cussed.
THE DECISION PROCESS
Each beach nourishment or other shore protection program begins in a
beachfront community that perceives a problem. The loss of a recreational beach,
damage to private buildings or public facilities, flooding, or loss of tax revenues
can all be symptoms that shoreline changes are affecting the utility, safety, or
social or economic well-being of a community. The community must then decide
how to respond. In some cases, the aftermath of a severe storm results in pres-
sures to act quickly, but often the problems are chronic and discussions continue
for years before an action plan evolves.
Assuming that the shore erosion and recession cannot be eliminated, three
broadly defined strategies are available to a community:
construct a structure, such as a seawall or groin, to limit the continuing
damage or threat of damage;
initiate a program of periodic renourishment of the beach to provide the
desired level of protection, perhaps in conjunction with hard structures; or
· abandon or move buildings or other facilities that are damaged or endan-
gered by continuing erosion.
27
OCR for page 28
28
BEACHNOURISHMENT AND PROTECTION
In practice, protection achieved through installation of hard structures, beach
restoration, and selective removal of buildings and infrastructure have all been
undertaken in varying degrees. Restoration of severely eroded beaches is accom-
plished by removing hard structures that interrupt littoral drift, providing mea-
sures for sand to bypass such structures, replenishing the lost sand, or a combina-
tion of these three measures. Reestablishing a beach that provides recreational
opportunity as well as shore protection from storm damage is becoming the
management option preferred by many communities. Abandonment was the
choice in some locations following the 1962 Ash Wednesday storm that caused
extreme damage to many Atlantic coast communities (New Jersey State Highway
Department, 1962; Shore and Beach, 1962a,b,c). In Nags Head and Kitty Hawk,
North Carolina, the retreat option is being implemented through the gradual
removal of individual buildings buildings are removed by owners or they are
destroyed in relatively small storms. Abandonment or retreat may not be a politi-
cally viable option regardless of technical merit, except following a severe storm.
It is not uncommon for upgraded redevelopment to follow destructive coastal
storms even before shore protection is fully restored.
As described in the following sections, the appropriate option for a particular
location and set of circumstances often depends on engineering and economic
analyses. Both initial costs and continuing costs differ for the three options, and
opportunities to share these costs vary with the federal and state governments.
There are local perceptions of the relative importance of maintaining a recre-
ational beach in addition to actual economic impacts. Each of the options has
different long-term consequences, with potentially widely diverging effects on
the character and economy of the community, the region, and the nation.
If a federal interest is involved in the region impacted by erosion, federal
involvement is often sought early in the decision. "Federal interest" is condi-
tioned by the ownership of land or facilities adjacent to the beach by public
entities or from public access to a recreational resource, the economic return (as
measured by the increase in national economic development benefits), and the
disaster outlays and insurance payouts associated with federal disaster assistance
and flood insurance programs. Thus, only in the case of completely private own-
ership of a continuous strip of property with no public access is the federal
government excluded from participation in shore protection projects. Further, the
federal government could participate in the cost of the abandonment or move-
ment option for privately owned structures under the Housing and Urban Devel-
opment Act of 1987 (commonly known as the Upton-Jones Amendment), al-
though this enabling authority was rarely used and has now been rescinded by
subsequent legislation.
An important but often inadequately addressed component of beach nourish-
ment programs involves the inclusion of diverse interested and affected parties to
ensure that their concerns are accommodated. This inclusion is necessary in order
for these parties to accept "ownership" in project goals and objectives (see NRC,
OCR for page 29
MANAGEMENT STRATEGIES FOR SHORE PROTECTION
29
1992, 1994~. Local public support is fundamental to program initiation and imple-
mentation because the public is directly affected by erosion and storm hazards,
responses to these hazards, and local cost-sharing responsibilities. Public support
is also important with respect to the authorization and funding of federal cost
sharing for shore protection works. Significant debate is often associated with
public discussion of beach nourishment as a shore protection measure. Recogniz-
ing that beach nourishment is complex and controversial and that public support
is essential, an open planning and implementation process is an important way to
ensure that all pertinent interests and concerns are identified and addressed by
decision makers.
Congress may be requested by a local sponsor (city, county, state, or regional
authority) to direct the U.S. Army Corps of Engineers (USAGE) to undertake a
reconnaissance study of the problem area. The advantage of this arrangement
from the perspective of the local sponsors is that the federal government assumes
all the costs of the study. (However, the costs of any follow-on feasibility study
must be shared 50-50 by the federal government and the local sponsor.) One
disadvantage is that the process is slow, and several years may pass before a final
recommendation is made. Alternatively, a local sponsor, sometimes in partner-
ship with the state, may engage a private firm to study the technical and economic
options. In either case, the result is a preliminary evaluation of the problems and
solutions. The technical feasibility of each of the three options is then assessed,
and preliminary estimates are made of the costs and benefits. Several states have
legal impediments to hard structures as solutions, thereby reducing possible op-
tions to relocation or nourishment. Following this preliminary study, the local
sponsor, utilizing the appropriate political process, decides on the preferred ap-
proach. This report focuses on beach nourishment as the preferred alternative.
Included in the analysis is the potential for beach nourishment program enhance-
ment using hard structures.
Erosion and storm hazard problems that are critical to public safety, or that
have resulted in high exposure to risk from storm damage, often result from
decisions made decades ago. One example is the continuing serious erosion
problem associated with a seaward bulge in the shoreline at Wrightsville Beach,
North Carolina. The bulge was created in 1966, when Moore Inlet was closed and
filled as part of a hurricane and shore protection project (USAGE, 1977, 1982,
1989~. The anomalous shape of Wrightsville Beach results in wave energy being
concentrated along the bulge and wave breaker angles on the bulge transition that
vary from normal breaker angles. These conditions alter the normal rates of
sediment transport and cause increases in sediment transport away from the bulge
in both the north and south directions. Without continued nourishment, the natu-
ral tendency would be for Wrightsville Beach to assume a convex (inward) shape
between Masons and Masonboro inlets, with the resulting shoreline near the
center of the island eventually moving several blocks inland (USAGE, 19891.
A natural shoreline rearrangement is Assateague Island, a barrier island in
OCR for page 30
l~i~
~^#~ ~~=c~#
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 B ~ l h l l l l l l l l E ~ ~ l o l l l l l l l F o I l o w I l ~ ~ ~ ~ ~ I l n I l l l l l l l ~ l l l l ~ l A ~ ~ e ~ g ~ e l l l l l ~ l I l s I a n d l l l l l l l ~ l ~ l l l l l
s~s:s:s:s~s:s:s:s:s:ssisisissss:s:s~ssissss:s:ssissssss:s:ssissss:s:sss:s:sss:s:s:s~s:sssssssssss:s~sss:s:s:s~ssiss:s:s:sssssss:s:sss:s:s:sssss~s:s~sss:s~sss~s:s:s:s:s:sss::::~::::s~sss~s:::::ss::~s~::::s~sss~s:::::s~s:~:s~s:::::s~s:::s~s:::s~s::::
sou~em H~yland and Virginia ~at ~as created ~ben an inlet ~ed during a
bu~c~e in 1933. Public respoDse to tbe complex Ocean Chy, H=yland-
Assateague Island sand-sb~ing reladonship and erosion problems set in motion a
series of events tbat culminated in an ongoing m~or beacb nourishment program
and con~oversy over dghts to use sand hom tbe Ocean City Inlet ebb hde sboa1
(Box 2-1~.
On ~e Pacidc coast beacbes tend to be n~ow bands belo~ blu~ of v~-
ing beights. Tbese blu~ provide consider~le natural protection against ~e sea.
In Oce=~de, Cab~mia, some beacbbont residences ~e located belo~ tbe blu~
OCR for page 31
MANAGEMENT STRATEGIES FOR SHORE PROTECTION
31
line on the beach and thus are more vulnerable to wave-induced damage from
severe episodic storms
than are those built well landward of the bluff. Such situations are found through-
out the nation's seacoasts. Rather than fault past decisions, those made today with
respect to shore protection are likely to affect and constrain the hazard mitigation
responses of shorefront communities for decades and thus must be understood in
that context.
Faced with a diminished beach and declining demand for rental units and
commercial establishments, beachfront communities may perceive beach nour-
ishment projects as a means to reverse declining local economic trends associated
with a decline in recreational activity. The potential for such reversals is
exemplied by the economic revitalization of Miami Beach. Following completion
of the beach nourishment project during 1982, investment in new and updated
facilities substantially increased tourism there. Increased building density imme-
diately adjacent to the beach often resulted as older buildings were replaced by
much larger ones that accommodate more beach users (see Wiegel, 19921. Such
development is in itself an incentive to maintain the beach in order to sustain
revenues derived from recreational activities and tourism and to protect the in-
vestment from erosion and storm damage or loss (Stronge, 1994J. Unlike the
National Flood Insurance Program discussed in Chapter 3, no zoning or construc-
tion standards are imposed by the federal government as a condition for imple-
mentation of beach nourishment projects. However, state and local restrictions
may apply.
Because sand moving along a beach does not respect city, county, or state
boundaries, one community's activities can negatively or positively affect neigh-
boring communities. In general, a single large shore protection program is cheaper
overall than several smaller ones done separately. There are irreducible costs
associated with the preparation of study reports, information dissemination meet-
ings and similar activities, equipment mobilization, permitting, and other factors
that may result in economies of scale for regional approaches to shore protection
problems. Not the least in importance, the combined political power of larger
entities has great impact on state and federal agencies and legislative bodies. For
these reasons, some regions find that it is in their best interest to collaborate in
formulating and implementing shore protection strategies.
An example of regional planning developed over the past decade is the
experience of San Diego County in Southern California. The county has a north-
south coastline of about 40 miles that stretches from the Orange County border at
Dana Point to the international border with Mexico. The actual shoreline is con-
siderably longer. The area is topographically complex, with rocky headlands, a
large spit, a major harbor, several rivers (most of which flow only periodically),
long unbroken stretches of beach, easily erodible seacliffs, and several coastal
lagoons. The entire county has three natural major littoral cells that function as
systems but that have little apparent interaction with each other. Only one of
OCR for page 32
32
BEACH NOURISHMENT AND PROTECTION
these cells is contained within a single community; the largest embraces many
jurisdictions. Acting jointly, the communities began by forming a shore erosion
task force, which determined that beach nourishment was the solution of choice.
They subsequently formulated a long-term plan that includes consideration of
costs, funding sources, and the preservation of sand sources for future needs. It
precludes independent action by a community action that would be detrimental
to the overall region and the objectives of the plan (San Diego Association of
Governments, 1995~.
PROJECT FORMULATION AND DESIGN
Once a program of beach nourishment is selected as the primary approach to
shore protection, the process of creating a project- the first element of the pro-
gram begins. The local sponsor (designated in the reconnaissance study phase,
as described above), together with the appropriate federal and state agencies,
defines the project. The definition process includes a determination of the project
boundaries and a preliminary assessment of the desired configuration of the
designed beach, including the type and location of structures if they are being
considered in the design. The configuration would include consideration of beach
width for recreational activities as well as for dissipation of wave energy, and it
would consider berm or dune height, as appropriate, for protection from wave
attack and flooding. The end products of this phase are a designed beach configu-
ration, identification of the sand source for construction of the beach, and the
placement of sufficient sand seaward of the designed beach to account for erosion
and other losses prior to the next renourishment.
The design of the beach follows the methodology described in Chapter 4 and
Appendix D. In general, designers use whatever is known about the performance
of the natural, or existing, beach as a starting point. Because of the need to
determine average or "background" erosion rates, the amount of sand lost over a
long enough observation period is of particular interest. The designers then pre-
dict the response of the beach that will meet the desired characteristics to an
assumed climate of storms that might be anticipated over the planned interval
before the next renourishment. Prediction typically involves both simple analyti-
cal models based on general beach performance and more detailed computer
models specific to the site (see Chapter 4 and Appendix C). Because the predicted
performance of the beach depends on the quality and type of sand available for
nourishment, the design must include identification of sand sources that can be
used economically. Placement of the sand on the beach is an element of the
design and is usually dictated by the minimum-cost construction technique for
this site and the sand source. Placement, as discussed below, affects the near-term
performance of the beach but in the long term is not expected to be significant to
performance. Except for the rare case where the nourished beach is naturally
contained between headlands or large structures forming a pocket beach, the
OCR for page 33
MANAGEMENT STRATEGIES FOR SHORE PROTECTION
33
FIGURE 2-1 Ocean City Inlet, Maryland, ebb-tide shoal. Photograph by Steve Under-
wood.
FIGURE 2-2 Oceanside, California, beach and bluff. Photograph by Wayne Young.
OCR for page 34
34
BEA CH NO URISHMENT AND PR O TECTI ON
action of waves and currents will spread (diffuse) the placed sand along the shore,
resulting in losses of the sand to areas outside the defined project. In a long
project these losses may be a small factor in the overall performance of the beach
fill. In a short-length project they can be important in the design and in the
prediction of performance, except for projects at pocket beaches.
Public Expectations About Design Performance
A public dialogue on alternative responses to the erosion problem always
precedes the emplacement of a replenished beach. Each project involves impor-
tant public issues that must be understood and accepted by project sponsors and
community leaders. Through analysis of the dialogue, beach nourishment can be
evaluated as a shore protection alternative. For example, a community needs to
know the reliability and reasonableness of cost and beach durability estimates,
possible secondary effects on the community's quality of life, and possible eco-
nomic and environmental impacts. Experience with public issues of beach re-
plenishment on the U.S. Atlantic, Gulf, Pacific, and Great Lakes coasts provides
a basis for identifying the issues critical to communities, both with "first-time"
beaches and those with multiple nourishment projects.
Part of the controversy associated with beach nourishment projects is related
to public perceptions about the value of beach nourishment as a shore protection
measure. These perceptions vary and, as will be shown later, may or may not
correlate with scientific data and engineering principles. To gain a better under-
standing of the state of practice, including insights into public perceptions about
beach nourishment projects and programs, the committee addressed inquiries to
federal, state, and local beach managers. The responses generally suggested that
public understanding at the local level was better than the committee expected
with respect to specific projects and economic potential. But there was less appre-
ciation of the importance of renourishment issues that could impact decision
making about the long-term viability of a beach nourishment program. Public
understanding of beach nourishment beyond the areas of public involvement and
more complete news media coverage of local projects and programs are probably
less well developed than indicated by the responses to the committee's inquiry
(see Box 2-23.
All beach nourishment project designs are based on assumptions that contain
some element of uncertainty. The contributions to risk resulting from these un-
certainties are discussed later in this chapter. A survey conducted by the commit-
tee (see Box 2-2; the survey background paper is listed in Appendix B) revealed
that the public is sometimes ill informed about these risks and uncertainties and
even about the behavior of the beach fill itself. The responses to the committee's
survey questions indicate that:
· Public expectations for the performance of beach nourishment projects,
OCR for page 35
MANAGEMENT STRATEGIES FOR SHORE PROTECTION
$'~2:~ ~.~.,,,,:....
, . . ~ . ~ , . . , . . . ~ . . ~ . ~ ~ ~ , ~ ~ ~ ~ ~ '
~_-_~¢ wp ~ !_ a ~!
. _ ~
. ~
. ~. ~
; , ~: ~
........................ ~5 . ~
.......................... - . . ~
. ~; ~,.,.~
. j0 ~
~ ~ 8
, .
. ~
~.~ ~ ~.~.~.~.~.~=,~.~,~ ~'~ a. ..............
. ~. ~
21
i8 15
,.,.,!.,.,I.,.,~.,lf I~! .
1~.~....~ .
1101~! .
35
.,., ..~.......
tI§~: ~ .
~ ~ ~ ~ ~ ~ _ _
how these expectations were formed, and the public's understanding of
technical aspects of project performance have all factored into public
debate over the efficacy of beach nourishment as a shoreline protection
measure. The committee's questionnaire included a series of yes-no ques-
tions (Box 2-2) intended to ascertain the level of understanding of impor-
tant technical and policy issues at the time of project initiation. Although
the sources of information are secondary and largely governmental, it is
believed that public representatives and officials could, based on their
public involvement experiences, provide reasonable, if not complete, in-
dications of public understanding.
Responses to the questions suggest that the interested and affected publics
OCR for page 36
36
BEACHNOURISHMENT AND PROTECTION
were generally well informed about many aspects of beach nourishment
projects with respect to the technical and policy issues. However, lack of
public understanding was reported to have the potential to stimulate con-
troversy over project performance.
Lack of public understanding was indicated for three economic factors that
could potentially affect long-term support for beach nourishment projects, de-
pending on how they ultimately affect property owners and business:
there might be an intensification of shore development,
- there is potential for broadly applied and selective increases in property
taxes to help defray the costs of beach nourishment, and
- there could be an increase in property taxes as a result of increased
property values.
· A second area in which public understanding could be improved is in the
awareness of visible performance of beach nourishment projects. The two
factors that were reported were:
the likelihood of an initial readjustment of the nourished beach during
which there would be some loss of sand from the subaerial (dry) beach and
storm occurred.
sand loss during initial readjustment could be quite large if a major
These responses suggest that the manner in which fill is placed and the
expected initial performance may not be effectively conveyed to or under-
stood by the public in some projects. In particular, the questions and
responses suggest that the practice of placing sand on the visible beach
where its movement can be observed by the public, regardless of technical
soundness, exposes technical performance to cursory assessment based
on visual observations rather than empirical data. The degree to which
public understanding could be improved with respect to technical issues
through various public awareness and involvement measures was not
addressed in the questionnaire. Also not examined were public perspec-
tives with respect to alternative fill placement techniques, such as placing
fill in the nearshore area rather than on the beach.
In many project designs the fill material is placed primarily on the beach
face, resulting in a wide subaerial beach with an unnaturally steep seaward face
for two reasons: (1) the cost of material placement on the beach face is low
compared with that of a carefully contoured placement, and (2) it can reduce the
threat from flooding. The designer anticipates that much of this material will be
moved seaward to form the more gradual slopes found in nature. Having borne
some portion of the cost of this project, a public that is not well informed sees
only that a large fraction of the acquired beach width has disappeared rapidly.
OCR for page 37
MANAGEMENT STRATEGIES FOR SHORE PROTECTION
37
There are slower losses from the ends of the project and losses of sand because
the selected source contains some sand that is too fine to remain on the beach.
The beach will continue to erode, of course, as it did naturally. The public needs
to know that this erosion is an expected part of the project design. In a few
projects all the fill material is placed offshore to reduce construction costs, and
the design beach width is approached only slowly if the waves move the sand
shoreward. Again, if public expectations do not include this delay, the project
may be viewed as a failure.
Beach nourishment projects that require local participation in the costs ben-
efit from public participation in that local, state, and federal officials discuss not
only bond bills, beach-use tax, hotel-room tax, and other taxes to fund the
sponsor's part of the costs but also beach access and other issues as the studies
progress.
Although public understanding may be well developed at the beginning of a
beach nourishment program (see Box 2-2), public perceptions and support for
beach fill initiatives are influenced by the visible response of a beach fill to
storms. Further, storms often have considerable media value; a costly beach fill
can result in additional public interest and news media coverage. The media
generally report the visual results of a storm but often fail to note that designers
expected and planned for significant movement of sand off a beach during a
storm. Nor do the media report on the return of sand during fair weather follow-
ing the storm. How well a beach fill performs with respect to design criteria for
the storm that was experienced and the storm damage prevented as a result are
more realistic indicators of project success than how much sand moved off the
dry beach.
Media coverage of beach fill performance at Ocean City, Maryland, is a case
in point. A dune and berm were constructed as oceanfront storm damage barriers
in 1990 and 1991. Severe storms occurred during the following two winters. The
sequence of storms included an event on January 4, 1992, with a recurrence
interval of about once every 10 years and an event on December 11, 1992, with a
recurrence interval of about 5 years. Although each storm was less intense than
storm criteria with a 100-year recurrence interval that the design had allowed for,
each resulted in appreciable adverse effects on the project. Designed storm dam-
age reduction levels were restored by using additional fill in both 1992 and 1994,
and the beach was rehabilitated by mechanical redistribution of sand in 1993. The
considerable commitment of resources ($ 12 million) that was required to reestab-
lish levels of protection was offset by the fact that damage to oceanfront property
was notably slight despite the severity of the storms. The project prevented dam-
age to buildings and infrastructure of an estimated $93 million (Houston, 1995~.
An extensive data collection program has monitored the physical effects of these
events on the project, providing essential information to enable technical analysis
of how actual performance compares with projections made in the design process
OCR for page 47
MANAGEMENT STRATEGIES FOR SHORE PROTECTION
47
Storm damage reduction benefits are currently measured as the difference in
expected losses in property values owing to storm damage with and without the
beach nourishment project. The problems of measuring these effects are consid-
erable; they depend on both predictions of storms and projections of damage
under different scenarios. Areas already highly developed have much larger gains
from storm damage reduction because the amount of capital (both private and
public) at risk is comparatively large.
Recreational benefits are only slightly more straightforward to measure.
Current USACE guidelines allow travel costs or contingent valuation methodolo-
gies to be used in assessing recreational benefits. Descriptions of the methodolo-
gies for measuring nonmarket benefits are found in Appendix E. These methods
depend on survey techniques to estimate the value (consumer surplus) associated
with current beach use for individual beach users, whether one uses revealed
preferences techniques (e.g., "travel cost models") or hypothetical questioning
techniques (e.g., contingent valuation). But the methodology for measuring rec-
reational benefits has undergone considerable theoretical and empirical develop-
ment over the past several years (see Freeman, 1993; Bockstael et al., 1991), and
current procedures used by the USACE should be updated in light of the new
literature.
Despite these developments, there are always both data limitations and fore-
casting difficulties. In the beach nourishment case, the problem is one of valuing
a change in the quality of the beach, and this requires estimating the effect on
demand and therefore on consumer surplus of that quality change for current
users, as well as of predicting the number of additional users that may be attracted
by the increase in quality. The problem is further complicated if the attraction of
new users further alters the quality of the beach experience by altering the level of
congestion.
There are potentially other, less obvious costs and benefits from beach nour-
ishment projects. At one time, labels such as "indirect" or "secondary" were
given to these other effects, but these distinctions are not at all clear. Perhaps a
better nomenclature would be "unintentional," because these effects are "by-
products" of a project. Whether intentional or not, decision makers concerned
with making the best use of public funds would presumably want to consider
those cost-benefit effects expected to be of significant magnitude for any given
project.
One such unintentional effect might be the change in the amenity values of
living near a beach when the nature of that beach is changed by a project. This
change would be an effect other than storm damage reduction and recreation,
both of which were already "counted" above. These cost-benefit effects include
changes in scenic amenities, wildlife-watching opportunities, privacy, or conges-
tion, any of which could improve or deteriorate as a consequence of a beach
nourishment project.
A change in the market value of an adjacent property in response to a beach
OCR for page 48
48
BEACH NOURISHMENT AND PROTECTION
nourishment project will be a reflection of the present value of all the project's
benefits expected to accrue to the property owner into the future. However, using
changes in property values to determine changes in amenities is not altogether
straightforward (see Appendix EJ. Additionally, care must be taken to avoid
double counting. For example, estimates of recreational benefits based on estab-
lished empirical methodologies are likely to capture the recreational benefits
accruing to adjacent property owners as well as to visitors to the area, but a
recreational component of benefits will also be captured in the change in adjacent
property values. Another drawback to using changes in market values to measure
benefits is that they will reflect individuals' expectations of future states of the
beach, expectations that might be misinformed.
Another external effect of a beach nourishment project might be "out-of-
project" sand deposition or other effects at beaches beyond the official extent of
the project. Under present USACE regulations, such benefits may not be included
in the cost-benefit analysis, even though they can be estimated with the same
precision as the within-project protection benefits.
Unintentional effects might also include beneficial or deleterious environ-
mental effects, described in Chapter 5 of this report. Methodologies for measur-
ing the value of environmental changes to humans are being developed, although
most depend on a clear understanding of the (possibly long-term) biological and
ecological consequences. These methods for measuring the cost-benefit effects of
environmental changes have been developed for use in natural resource damage
assessment under the Comprehensive Environmental Response, Compensation,
and Liability Act of 1980 (also referred to as CERCLA and Superfund' and the
Oil Pollution Act legislation (Kopp and Smith, 19933. In other settings, decision
makers often consider the environmental effects in physical terms and produce
their own trade-offs with other costs and benefits to society.
Frequently, the argument is made that a beach nourishment project stimu-
lates increased economic activity and new economic development in a coastal
area and that these economic effects should somehow be counted in the benefits
of the project. Economic activity, per se, is not a measure of well-being. The
appropriate measures are the increased profits and income generated. But these
are the categories of benefits that need careful counting because for the most part
they tend to cancel out on a regional or national scale. A gain in profits or
incomes from increased tourist demand in one region is likely to be offset to a
large extent by losses from the resulting decreased business someplace else in the
United States. An exception is when such gains are generated by new tourist
demand from a foreign source. For example, foreign tourists spend $2 billion a
year at Miami Beach. The Miami Beach fill has been in place since the late 1970s
at a cost of $52 million. The capitalized cost of the fill is about $3 million per
year. Thus, the fill provides about $700 annually in foreign revenue for each $1
invested in beach nourishment. This amount is a remarkable return considering
that agricultural subsidies do not result in much more than $1 in revenue per $1 in
OCR for page 49
MANAGEMENT STRATEGIES FOR SHORE PROTECTION
49
subsidy. Nationally, foreign revenues from tourism total about $80 billion per
year, and in view of the fact that beaches are the number one U.S. tourist attrac-
tion, benefit calculations should include expected returns from foreign tourists
(Houston, 19951.i Federal guidelines (e.g., WRC, 1983) tend to labelthese "indi-
rect" or "secondary" benefits and prescribe their omission from cost-benefit cal-
culations to avoid adding them up nationally only to find the net effect is approxi-
mately zero. Foreign tourism clearly is not an "indirect," or "secondary," or
regional benefit. Of course, these local gains are critical to the cost-benefit
analyses undertaken by the locality proposing a beach nourishment project in
order to determine whether local support of the project is justified. Yet counting
local benefits while ignoring losses in other regions for U.S. tourism is inappro-
priate for federal cost-benefit analysis.
Increased profits and income may not be the only local consequence of
increased economic activity and new development, and the consequences might
not all be desirable, as many localities are discovering. State and local growth
controls and land-use management strategies are becoming more prevalent, espe-
cially in coastal areas of the United States, where the largest percentage of land is
already developed. The reason for the control measures is that local governments
have come to recognize some of the negative externalities associated with devel-
opment. Development places infrastructure burdens on a community, changes the
nature of the surrounding community, adds to congestion, and reduces open
space and natural environments that people value. Assessing the value to society
of any particular development activity is exceedingly complicated because it
requires identifying the true benefits (in increased profits and incomes) net of
transfers from elsewhere and the true costs in terms of these local externalities.
It is unreasonable to expect beach nourishment project planners to assess this
complex pattern of effects, especially because the problem of land-use manage-
ment and growth control is far broader and more pervasive than beach nourish-
ment. But it is equally unreasonable to ignore the ramifications and attempt to
add economic development measures to the cost-benefit analysis. A more reason-
able approach may be to encourage localities to develop rational land-use man-
agement plans and require that all public actions, including beach nourishment
projects, be consistent with these plans. Some states are further along in develop-
ing such plans than others.
iThe reader should bear in mind that, while it is true that foreign tourism generates local economic
benefits that are not offset by losses elsewhere in the United States, the proper measure of these
benefits is the increase in producer s surplus, not the increase in tourist spending.
OCR for page 50
so
Time Horizon
BEACH NOURISHMENT AND PROTECTION
Special Features of the Beach Nourishment Problem
Beach nourishment projects provide two kinds of public goods: changes in
local amenities and reductions in risk of property loss. Like other public invest-
ment projects (e.g., dams, highways) beach projects both incur costs and generate
benefits over decades, and the stream of costs and benefits is uncertain. The
temporal nature of a project's impacts poses special problems for valuation,
including extrapolating future costs and benefits, accounting for behavioral re-
sponses to the project, and evaluating the effects of uncertainty associated with
random future events.
Valuation first requires the choice of a rate at which to discount future costs
and benefits. A dollar spent (or received) now is not the same as a dollar spent (or
received) 10 years from now. For several reasons, the appropriate choice of a
discount rate for public projects is not a commercial market rate of interest, but
the social rate of discount, which is an elusive concept. The federal government
currently uses 7.75 percent for public investment projects of this sort, although
there continues to be much debate over the level of this discount factor.
A second problem, uncertainty about the future stream of costs and benefits,
is even more troublesome. Much of this report examines the nature of this uncer-
tainty. For the purposes of the economic evaluation of a proposed beach nourish-
ment project, however, some information about likely outcomes is necessary.
Simple expected values or averages are not useful because both the public and the
private sectors tend to be averse to risk. For example, knowing with certainty that
over the next 20 years renourishment of a beach will cost $3 million (present
value) is likely to be preferred to a 50/50 chance of its costing $1 million or $5
million. Information about projected costs and benefits should include as much
about the underlying probability distributions as possible, certainly not just the
means of those distributions, in order to reduce the level of uncertainty in cost-
benefit analyses.
As explained elsewhere in this report, a beach nourishment program incorpo-
rates a series of beach renourishment projects over a long time horizon or life
cycle of a program. This fact poses difficulties in predicting benefits as well as
costs, because of both uncertain project performance (under unpredictable weather
events) and future markets for necessary inputs. Sand is the most important input,
and with demand for sand increasing, it is difficult to predict the cost of sand a
decade or more into the future. Outer continental shelf sand resources, for ex-
ample, are allocated by competitive bidding (except for sand to be used on public
projects, which is allocated by negotiated agreements), which in itself is likely to
be an efficient allocation mechanism, but currently no institutions will contract
forward for these resources. Because of the need to estimate long-term costs of
OCR for page 51
MANAGEMENT STRATEGIES FOR SHORE PROTECTION
51
the complete life cycle of a renourishment project, institutions for efficiently
allocating sand resources are well worth further investigation.
Alternative Scenarios
Cost-benefit analysis makes sense only when defined in terms of compari-
sons. That is, when the costs and benefits of a project are assessed, they are
assessed relative to a best guess of what would happen in the absence of the
project. Defining the alternative scenario to a beach nourishment project can be
problematic because there is no status quo but an ever-changing situation.
Consideration of alternative public actions is an essential element of the
planning and design stages of a project. Presumably, decision makers would want
to take into account all of the above considerations in selecting a preferred design
for a beach protection project, and at that point the costs and benefits of the
preferred design could be compared with the alternative of no public action at all.
This choice provides the process internal consistency, if the same congressionally
mandated criteria used to determine whether a project can be accomplished with
federal funds are used to select the best design. However, this process is costly
and may often be infeasible. In the absence of a federally funded project, locali-
ties may undertake projects on their own, or private individuals may pursue
individual protection strategies. The possibilities are dictated by the regulatory
environment (e.g., hard structures are prohibited in some areas) and by the wealth
of the local community.
Financing and the Distributional Implications of
Beach Nourishment Projects
Two of the most commonly invoked justifications for public-sector interven-
tion in the economy are the existence of public goods and externalities. The latter
arise when the actions of one individual have significant but uncontrollable ef-
fects on the welfare of others. Classic examples of this are air, water, and noise
pollution. Beach protection projects have associated externalities, both poten-
tially positive and negative. What happens along one stretch of beach can have
effects up and down the coast.
Public goods are particular kinds of goods whose consumption is not appro-
priable by a single user. Unlike a slice of bread, a bicycle, or a gallon of gas, a
public good can be used by a number of people simultaneously without its value
to any one individual being reduced (e.g., national defense). Both storm damage
reduction and recreational use are public goods generated by beach nourishment
projects. Some goods are local public goods whose public good nature extends
over only a small geographic range. Storm damage reduction, in particular, tends
to be a local public good in the sense that the benefits accrue to individuals in the
near vicinity. These local public goods should be balanced against the larger
OCR for page 52
52
BEACH NOURISHMENT AND PROTECTION
public costs of disaster relief when localities or states fail to maintain or replenish
beach nourishment projects at appropriate intervals. Clearly, the attendant public
costs associated with monitoring and maintenance efforts by recipients of public
funds for beach nourishment must be considered as well. Except where the beach
is particularly renowned, recreational benefits may also accrue largely to area
residents. Other effects of beach nourishment projects, such as environmental
effects, may have broader appeal or concern. The preservation of endangered and
threatened ecosystems or species is important to individuals even when they
never visit the natural system.
Beach nourishment projects are associated with both positive and negative
externalities, arguing for public-sector coordination and regulation. The projects
are also quasi-public goods, a point that argues for public provision. But for a
variety of reasons, the federal government has become involved in beach nour-
ishment project planning and construction, and federal cost-sharing policies ac-
company this involvement. As a result, those who pay a large portion of the costs
do not necessarily receive the benefits. This mismatch is not rare among public
programs, although society sometimes decides to finance this kind of public
project by beneficiary charges. Yet beach nourishment projects are generally
supported by public funds, not user charges, and cost sharing takes place between
federal and more localized governments.
The financing scheme affects those who benefit and those who lose from the
project, but it will also affect the total net benefits generated by the project. A
project's total net benefits depend on whether financing is tied in any way to use
or incidence of benefits. Recreational benefits differ depending on whether beach
access fees (e.g., for parking, entrance) are charged to help finance the project.
Higher fees may reduce use of the beach. Likewise, financing schemes that
require contributions from local property owners based on increased property
values may affect the amount and type of private investment. Pricing schemes
that require property owners or investors to share liability for storm damage or
renourishment projects may alter long-term liability costs.
The present arbitrary scheme for cost allocation is unrelated to who receives
the benefits, in general, requiring only a cost-benefit ratio greater than unity for
approval. However, the federal procedure for cost-benefit analyses, which con-
sider only storm damage reduction and limited recreation benefits, clearly does
not take into account local indirect or secondary benefits that may greatly exceed
the federally acceptable benefits. Recognizing the fact that public actions can
cause private-sector reactions suggests that projects may well be coupled with
public policies designed either to regulate private activities or to provide the
"right" incentives. One possible policy is the negotiation of cost-sharing ratios
related directly to the benefits accruing to each sponsoring agency.
The above considerations suggest that careful evaluation is necessary of
those cost and benefit elements included in cost-benefit analyses of beach protec-
tion projects and to the possible options available for financing projects.
OCR for page 53
MANAGEMENT STRATEGIES FOR SHORE PROTECTION
PUBLIC SUPPORT FOR BEACH NOURISHMENT
53
Decision makers faced with determining whether to support beach nourish-
ment as a shore prole`;lion measure could mount a public awareness campaign to
improve the basis for informed decision making. Such a program could include
the following topics.
Purpose of Beach Replenishment
The problem of shore protection being addressed by sand replenishment is
created by the presence of shorefront property and infrastructure on an eroding
beach. Replenishment in a developed area, whether for storm damage reduction
or improvement Of a recreational beach, would not be required in the absence of
buildings or if the buildings were moved back from the retreating shoreline. In
the absence of buildings or public infrastructure, beach erosion or shoreline re-
treat generally creates no problems for development or for the quality of recre-
ational beaches. Unless there is a natural obstruction or an obstruction of human
origin, beaches experiencing erosion simply move landward, in response to the
forces of waves and currents, while retaining their general shape and size.
Commitment Required for a Replenished Beach
Replenishing a beach is the first step in a long-term continuous program of
nourishment to mitigate erosion losses. A long-term realistic financial commit-
ment is needed on the part of government at all levels. It is important for the
public to understand that funding is not guaranteed beyond the first emplacement.
In effect, a typical 50-year USACE nourishment program constitutes permission
only to request project-by-project funding from Congress for the next 50 years
when it is technically and economically feasible. A contingency arrangement for
near-term funding of renourishment to restore designed features is prudent be-
cause storms may remove sand at much more rapid rates than estimated in design
documents, and emergency or special funding from federal sources may not be
available when needed. If such a commitment were not in place, there might be a
period of time, perhaps extended, when a beach that eroded more rapidly than
expected could furnish less-than-design storm damage reduction and recreational
benefits.
Gauging the Realism of Cost Projections
The assumed rate of loss of a replenished beach determines the long-term
costs, the long-term sand volume requirements, and even the long-term feasibil-
ity of beach replenishment as an alternative for managing an eroding shore. Cost
estimates for beach replenishment are not precise, because the need for replenish
OCR for page 54
54
BEACHNOURISHMENT AND PROTECTION
ing a beach is controlled by the frequency and magnitude of storms rather than
the statistically derived frequency and severity on which the design is based.
Predictions of costs, including the future cost of money and of sand volumes,
need to account for such uncertainties through the use of error bars and probabil-
ity estimates. Even when the predictions in published design documents do not
reflect the vicissitudes of storms, planners and the public need to recognize that
uncertainties exist in long-term costs, and they should plan accordingly. In gen-
eral, beaches have a longer renourishment cycle on low-energy coasts (e.g., south
Florida) and will have a shorter renourishment cycle on exposed higher-energy
coasts (e.g., the mid-Atlantic states'. Replenished beaches with high preproject
erosion rates will likely also suffer continued high erosion rates.
A useful though not precise measure of predicted beach life span is the
nourishment interval the assumed time between nourishment operations that
are required to replace erosion losses and to bring the beach back to its design
width. In recent Gulf of Mexico and Atlantic coast beach nourishment projects,
replenished interval estimates have ranged from 2 years (Sandbridge, Virginia) to
10 years (Panama City, Florida). An examination of the actual nourishment inter-
vals of neighboring replenished beaches, when such beaches exist, is one way to
determine whether nourishment interval predictions are reasonable. A recent
report (USAGE, 1994) analyzes beach fills for the past 44 years and clearly
shows that, in the aggregate, cost projections for beach fills have been fairly
accurate. On average, actual costs have been 4 percent less than estimated costs.
The volume of sand used was about 5 percent greater than estimated.
Visible Beach Versus the Underwater Beach
Two major purposes of beach replenishment are the creation of a storm
barrier and the creation of a recreational beach. In both cases, the retention of a
subaerial beach is important. Storm damage reduction is afforded by the beach
and, when present, the dune. If one or the other is lost by offshore or lateral sand
removal, storm damage reduction is greatly lessened. Sand on the underwater
profile, in the absence of dry beach and dune, contributes less to protecting the
community from storms than the subaerial portion would. This is especially so in
combating the effects of storm surges. However, the underwater profile is essen-
tial to maintaining the dry beach. Without it the beach would simply move sea-
ward to build an equivalent profile.
An important measure of the quality of the recreational beach is dry beach
width at normal high tide. When dry beach disappears at high tide, the recre-
ational benefits are significantly reduced. Because of the importance of the sub-
aerial beach, storm damage and monitoring reports need to note clearly the evo-
lution of the subaerial replenished beach. Although reports noting only the
percentage of sand remaining in the entire system (including the underwater
shoreface) are useful to engineers and scientists for understanding the fate of
OCR for page 55
MANAGEMENT STRATEGIES FOR SHORE PROTECTION
55
replenishment sand, they are not well understood by the public. Statements such
as "96 percent of the sand remains in the system" need to be augmented by an
explanation of how the behavior of the beach provides protection to the develop-
ment and public infrastructure.
Use of Hard Structures
The use of groins, seawalls, or jetties in replenished beaches combines "hard"
(i.e., concrete, rock, steel, wood) and"soft" (i.e., sand) stabilization solutions
with the advantages and disadvantages of each. The life span of replenished
beaches can in some cases be significantly increased by the use of hard structures
in the replenishment shoreline reach. However, downdrift erosion problems may
arise from the use of groins, which will necessitate the use of sand redistribution
techniques. This is discussed further in Chapter 4.
Cost-Sharing Responsibilities
Solutions to shore protection problems always involve significant costs. In
most cases, the local sponsoring body is responsible for raising a share of these
costs. The public needs to understand that these costs will continue beyond the
initial project, may come due sooner than anticipated if the storm climate is worse
than predicted, will escalate with inflation, and may increase as sand sources
become more distant or are otherwise less desirable.
Gauging the Success of a Replenished Beach
Project or program success is likely to vary across the range of objectives
that a beach fill is intended to serve. Even when shore protection benefits are
achieved, economic benefits may or may not occur as projected. In some cases, a
beach fill may be only partially successful with respect to planned physical
performance but may nevertheless stimulate considerable economic activity. Such
economic results may be seen as either a benefit or disbenefit, depending upon
individual points of view.
In order to provide a common framework for determining a project's perfor-
mance, the criteria by which a project will be judged with respect to goals and
objectives should be established through a public involvement process. Although
considerable effort is probably necessary, establishing a consensus-based frame-
work for project evaluation would provide the common ground necessary to
facilitate decision making.
OCR for page 56
56
BEACH NOURISHMENT AND PROTECTION
REFERENCES
Bockstael, N. E., K. E. McConnell, and I. E. Strand. 1991. Recreation. In: J. B. Braden and C. D.
Kolstad, eds., Measuring the Demand for Environmental Quality. New York: North Holland.
Freeman, A. M. 1993. The Measurement of Environmental and Resource Values. Washington, D.C.:
Resources for the Future.
Grosskopf, W. G., and D. Behnke. 1993. An emergency remedial beach fill design for Ocean City,
Maryland. Shore and Beach 61(1):8-12.
Grosskopf, W. G., and D. K. Stauble. 1993. Atlantic coast of Maryland (Ocean City) shoreline
protection plan. Shore and Beach 61(1):3-7.
Haveman, R. H., and B. A. Weisbrod. 1975. The concept of benefits in cost-benefit analysis: with
emphasis on water pollution control activities. In: ~t-Benefit Analysis and Water Pollution
Policy. Washington, D.C.: The Urban Institute.
Houston, J. R. 1995. Beach nourishment. Shore and Beach 63(1):21-24.
Joint Economics Committee, U.S. Congress. 1969. The Analysis and Evaluation of Public Expendi-
tures: The PPB System. Washington, D.C.: U.S. Government Printing Office.
Just, R. E., D. L. Hueth, and A. Schmitz. 1982 (with new edition forthcoming). Applied Welfare
Economics and Public Policy. Englewood Cliffs' N.J.: Prentice-Hall.
Kopp, R. J., and V. K. Smith. 1993. Valuing Natural Assets: The Economics of Natural Resource
Damage Assessment. Washington, D.C.: Resources for the Future.
Kraus, N. C. 1993. Guest editorial: the January 4, 1992 storm at Ocean City, Maryland. Shore and
Beach 61(1):2.
Leatherman, S. P., R. G. Dean, C. E. Everts, and E. Fulford. 1987. Shoreline and sediment budget
analysis of North Assateague Island. Proceedings of Coastal Sediments 87:1460-1471.
Nelson, W. G. 1985. Physical and Biological Guidelines for Beach Restoration Projects. Part I.
Biological Guidelines. Report No. 76. Florida Sea Grant College, Gainesville.
Nelson, W. G. 1989. An overview of the effects of beach nourishment on the sand beach fauna. Pp.
295-309 in Proceedings of the 1988 National Conference on Beach Preservation Technology.
Tallahassee: Florida Shore and Beach Preservation Association.
New Jersey State Highway Department. 1962. Sea Isle City Disaster Survey Part One. April 4.
Trenton, N.J.: New Jersey State Highway Department.
NRC. 1992. Coastal Meteorology: A Review of the State of the Science. Board on Atmospheric
Sciences and Climate, Commission on Geosciences, Environment, and Resources. Washing-
ton, D.C.: National Academy Press.
NRC. 1994. Restoring and Protecting Marine Habitat. Marine Board, Commission on Engineering
and Technical Systems. Washington, D.C.: National Academy Press.
San Diego Association of Governments. 1995. Shoreline preservation strategy for the San Diego
region. Shore and Beach 63(2):17-30.
Seymour, R. J., R. R. Strange III, D. R. Cayan? and R. A. Nathan. 1984. Influence of El Nino on
Californiats wave climate. Pp. 577-592 in Proceedings of the 19th International Conference on
Coastal Engineering. New York: American Society of Civil Engineers.
Shore and Beach. 1962a. East Coast Atlantic storm: preliminary report, Weather Bureau, Department
of Commerce. Shore and Beach 30(1):4-5.
Shore and Beach. 1962b. The March storm and Ocean City, Maryland: preliminary report, The
District Engineer, U.S. Army District, Baltimore, Maryland. Shore and Beach 30(1):7-8.
Shore and Beach. 1962c. The March storm: New Jersey and Delaware. Shore and Beach 30(1):9.
Stauble, D. K., and W. G. Grosskopf. 1993. Monitoring project response to storms: Ocean City,
Maryland beachfill. Shore and Beach 61(1):23-33.
Stronge, W. B. 1994. Beaches, tourism and economic development. Shore and Beach 62(2):6-8.
USACE. 1977. Masonboro Inlet, North Carolina, South Jetty: General Design Memorandum.
Wilmington, N.C.: Wilmington District, U.S. Army Corps of Engineers.
OCR for page 57
MANAGEMENT STRATEGIES FOR SHORE PROTECTION
57
USACE. 1982. Feasibility Report and Environmental Assessment on Shore and Hurricane Wave
Protection: Wri~g,htsville Beach, North Carolina. Wilmington, N.C.: Wilmington District, U.S.
Army Corps of Engineers.
USACE. 1989. Wrightsville Beach North Carolina Renourishment Report and Supplement to the
Environmental Assessment and Finding of No Significant Impact (EA/FONSI). Wilmington,
N.C.: Wilmington District, U.S. Army Corps of Engineers.
USACE. 1994. Shoreline Protection and Beach Nourishment Projects of the U.S. Army Corps of
Engineers. IWR Report 94-PS-1. Fort Belvoir, Va.: Institute of Water Resources, Water Re-
sources Support Center, U.S. Army Corps of Engineers.
Wiegel, R. L. 1992. Dade County, Florida, beach nourishment and hurricane surge protection. Shore
and Beach 60(4):2-28.
WRC. 1983. Economic and Environmental Principles and Guidelines for Water and Related Land
Resources Implementation Studies. U.S. Water Resources Council. Washington D.C.: U.S.
Government Printing Office.
Representative terms from entire chapter:
shore protection
