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OCR for page 1
Executive Summary
Historically, coastal development in the United States was dom-
inated by major urban regions oriented to commercial ports and
defense installations. Elsewhere, coastal settlements were typically
quiet fishing visages, vacation refuges, and older seaside resorts grad-
ually evolving into year-round communities. Since the advent of
the Interstate Highway System in the 1960s, increasing demand for
coastal resources has expanded and transformed settlement patterns
along accessible tidal and Great Lakes shorelines. Much of the U.S.
population now lives within a two-hour drive of a coast and mil-
lions of inianders travel much farther to spend vacations or transact
business in coastal locations. Large numbers of retirees also have
migrated coastward.
These population and economic pressures have transformed the
lightly developed shorelines of earlier years into higher density resorts
and urban complexes, for example, Ocean City, Maryland; Clearwa-
ter, Florida; Gulf Shores, Alabama; Galveston, Texas; and Newport
Beach, California. In the process, conflicts arise between adjoining
private owners, between units of political jurisdiction, between pri-
vate and public rights on the shore, and between human activities
and natural coastal processes, such as erosion.
The costs of shore erosion are varied and can be burdensome.
Private homes, commercial structures, and government-owned
buildings are undermined and sometimes destroyed if they are not
1
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2
MANAGING COASTAL EROSION
protected or relocated from a retreating shoreline. Public infrastruc-
ture (e.g., roads, sewers, water lines, parking lots, pavilions, toilets,
bath houses) are similarly threatened by erosion. Shoreline engineer-
ing structures built to protect landward development from flooding
and erosion themselves if improperly designed, constructed, n.n<3
maintained—can be undermined, overtopped, outflanked, or oth-
erwise incapacitated by ongoing erosion. Beach erosion also exac-
erbates the vulnerability of coastal development to flood damage
during hurricanes and other major storms.
Coastal erosion is a complex physical process involving many
natural and human-induced factors. The natural factors include
such variables as sand sources and sinks; changes in relative sea level
or Great Lakes water levels; geological characteristics of the shore;
sand size, density, and shape; sand-sharing system of beaches, dunes,
and offshore bars; effects of waves, currents, tides, and wind; and the
bathymetry of the offshore sea bottom. Human intervention alters
these natural processes through such actions as the dredging of tidal
entrances, construction of harbors in nearshore waters, construction
of groins and jetties, hardening of shorelines with seawalis or revet-
ments, construction of sediment-trapping upland dams, and beach
nourishment.
The National Flood Insurance Program (NF1P) was establisher!
by the National Flood Insurance Act of 1968 as the primary federal
program to reduce future flood costs to the nation. The NF1P pro-
vides insurance coverage for "damage and loss which may result from
erosion and undermining of shorelines by waves or currents in lakes
and other bodies of water exceeding anticipated cyclical levels." A
fundamental goal of the NF1P is to be actuarially sound namely, to
cover all claims out of premium income and thereby reduce future de-
pendence on federal tax money to subsidize the program. Since 1981
insurance premium rates have doubled, bringing the NF1P closer
to being actuarially sound and self-supporting. Although NF1P in-
surance covers flood-related erosion losses, the Federal Emergency
Management Agency (FEMA) has not yet exercised its legislative au-
thority to identify flood-related erosion zones in coastal areas. Even
though specific land management criteria for participating commu-
nities in flood-related erosion-prone areas were promulgated, they
are inoperable without Ozone identification. However, several states
and local governments have undertaken management programs to
address erosion.
The Upton-Jones Amendment to the NF1P (P.~. 100-242, Sec-
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EXECUTIVE SUMMARY
3
tion 544; see Appendix A) adopts an approach that encourages re-
treat from eroding shorelines. Instead of insuring coastal structures
until they collapse, Section 544 authorizes advance payment of cer-
ta~n insurance benefits if the owner demolishes or relocates a struc-
ture "subject to imminent collapse or subsidence as a result of erosion
or undermining caused by waves or currents of water exceeding an-
ticipated cyclical levels." Payment for demolition prior to collapse
would be 110 percent of the value of the structure (as defined in the
amendment). Payment for relocation would be the actual cost of
relocation up to 40 percent of the value of the structure.
The Upton-Jones Amendment represents an effort by Congress
to identify those structures most at risk from erosion and storm haz-
ards and to encourage action to reduce Tosses prior to their total
destruction. So far the Upton-Jones Amendment has had only mod-
est influence on the owners of property at risk from erosion. As of
August 1989, only 266 claims had been filed. This is modest in com-
parison with the total number of coastal structures threatened by
erosion. However, the committee believes it is too soon to evaluate
the true effectiveness of this amendment.
In 1988 FEMA's Federal Insurance Administration (FEMA/FlA)
asked the National Research Council (NRC) to provide advice on ap-
propriate erosion management strategies, supporting data needs, and
applicable methodologies to administer these strategies through the
NF1P. Using the resources of both the Water Science and Technology
Board (WSTB) and the Marine Board, the NRC began this assess-
ment of options for coastal erosion zone management. The study
reviews (1) existing end proposed NF1P legislative requirementsrel-
at~ve to coastal erosion; (2) existing coastal erosion management
programs on the Great Lakes and the oceans surrounding the United
States, particularly those programs administered by the states, that
would be potentially applicable under the NF1P; (3) technical stan-
dards, methods, and data to support existing management programs
potentially applicable under the NF1P; and (4) the relationship be-
tween the structural and other alternatives for erosion control and
the land use management and zoning approach used under the NF1P.
Based on this review and the current state of knowledge of coastal
processes, the committee was asked to provide options for FEMA's
consideration to implement a coastal erosion zone management pro-
gram.
Appendix B provides definitions of many terms used throughout
this report. The committee has provided its own definition of an E-
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4
MANAGING COASTAL EROSION
zone. The term "erosion, as used in this report, denotes the process
of wearing away of land by natural forces. It is not intended that
erosion imply loss due to flooding. However, as explained in Chapter
4, this is a gray area under the existing legislative guidelines.
In order to provide rational and defensible options, the com-
mittee believes it is necessary to evaluate and present information
on:
natural shore processes,
sources and sinks,
.
environmental conditions,
human-induced changes to the coast,
examples of erosion and likely causes, and
.
examples of erosion control and reasons for their success.
The study was carried out by the Committee on Coastal Ero-
sion Zone Management over a 17-month period. The committee
included expertise in coastal engineering, geomorphology, geogra-
phy, photogrammetry, sediment transport, law, policy, and land use
planning.
The first meeting was held in May 1988 when the committee was
briefed by FEMA/FlA officials on the nature and scope of the as-
signed task. At its second meeting held in July 1988, the committee
heard presentations on California's coastal erosion management pro-
gram from representatives of the Corps of Engineers, the California
Coastal Commission, and a Ventura County supervisor. Addition-
ally, two committee members briefed the committee on Great Lakes
states coastal erosion zone management programs. An outline for
the committee's report also was developed at this meeting.
At its third meeting, September 29-30, 1988, held in Florida,
the committee was briefed on Florida's coastal erosion management
programs. Viewpoints from the private insurance industry, private
developers, and the FlA were expressed by invited speakers. A brief
field trip was taken to the site of several successful beach nourishment
projects in Florida. The committee next met in March 1989 to draft
conclusions and recommendations for FEMA, and several members
of the committee met on May 8-9, 1989, in Washington, D.C., to
review and reorganize the report. A final committee meeting was
held on August 21-22, 1989, in Washington, D.C.
The Committee on Coastal Erosion Zone Management recog-
nizes that the NF1P, through the requirement for minimum elevation
standards, has been successful in protecting structures located in
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EXECUTIVE SUMMARY
5
coastal areas prone to flooding and wave inundation. In the com-
mittee's view an erosion element of the NFIP should incorporate the
following objectives:
1. Transfer economic costs of erosion Tosses from all federal tax-
payers to the property owners at risk by charging premiums that
approximate the risks of Toss. The program should eventually be-
come actuarial.
2. Discourage inappropriate development from occurring in ero-
sion zones as delineated by FEMA or the states.
3. Promote the improvement of development and redevelopment
· · —
practices In eros~on-prone areas.
Pursuant to these objectives, the committee has reached the
following conclusions and recommendations.
FEMA's Office of General Counsel has determined that certain of
the following recommendations would require legislative action, par-
ticularly those concerned with erosion zone management and denial
of NF1P coverage. This committee has not attempted to determine
independently whether or not new legislation would be required for
FEMA to implement any of these recommendations.
CONCLUSIONS AND RECOMMENDATIONS
Erosion Hazard Reduction
HAZARD DELINEATION
Conclusion
FEMA has not identified erosion hazard zones (E-zones) in im-
plementing the NF1P. An accurate delineation of coastlines subject
to erosion is essential to effective erosion and flood loss reduction and
to an actuarially sound program.
Recommendations
. In addition to flood depth, frequency, and velocity, FEMA's
coastal hazard delineations should incorporate methodologies and
data on erosion hazards.
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6
MANAGING COASTAL EROSION
RECEDING REFERENCE E-10
SHORELINE FEATURE LINE
ZONES
SETBACKS
FLOOD
INSURANCE
NOTICE OF
EROSION
HAZARD
Shoreline
E-60
LINE
_ E Zones
E-10
Imminent
Hazard
No New
Habitable
Structures
Eligible
For
Relocation
Benefits.
No New
NFIP
Policies
E-30
Intermediate
Zone
Moveable
Single Family
Structures
E-60
Longer Term
Hazard
Readily
Movable
Structures
Existing
Coverage Required
To Be Maintained
Reference E-10 E-30
Feature Line Line
E-60
Line
_ ._
, ~~
Zone ~ Zone
~ Zone ~
E- 10 1 E-30 ~ E-60
- 1 - '
Large
Structures
Allowed
Example Profile
With Lines and Zones Illustrated
(Not to scale)
FIGURE E-1 Summary chart of Lines and E-zones.
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EXECUTIVE SUMMARY
7
. FEMA should delineate coastlines subject to erosion (E-
zones)O These should include areas subject to imminent erosion
hazards (within 10 years, ~10 zone), intermediate hazard (within
30 years, ~30 zone), and long-tenn hazard (within 60 years, ~60
zone) (see Figure ~1~.
The physical location of Rezones is dyn~nic. Therefore E-
zone delineations should be based on a reference point (such as an
erosion scarp, bluff, or vegetation line) that is a suitable indicator
for determining E-zones. The location of this reference point m~es
as erosion takes place, and this fact nest be incorporated in Ozone
delineation.
RECOMMENDED METHODOLOGIES
Conclusion
FEMA's present methodology for determining shoreline reces-
sion rates should be improved to properly delineate ~zones. A his-
torical shoreline change method would be least costly to implement.
However, a more precise methodology based upon oceanographic
data is preferable.
Recommendations
Thus, the committee recommends that FEMA:
. Utilize the historical shoreline change method to immediately
begin mapping erosion hazard zones. FEMA should use existing
acceptable shoreline change data and obtain additional erosion rate
data to delineate Rezones for the N]?IP. Care should be exercised in
extrapolating erosion rate data owing to variable geologies and other
factors; for example, the land may change from easily erodible sand
to resistant material such as beach rock or Rice verea.
. Farther, the committee strongly urges that PEMA develop a
preferred methodology based upon oceanographic data and statisti-
cal techniques. This methodology involves using available records of
shoreline recession for analysis of the tane history of oceanographic
forces.
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8
MANAGING COASTAL EROSION
STANDARDS FOR DEVELOPMENT
Conclusion
Comprehensive management programs should be developed for
all areas experiencing significant erosion.
However, a single uniform national "answer" to erosion prob-
lems is neither practical nor desirable. In addition, public planners
and decision makers should avoid basing policies on stereotypes or
preconceptions as to "typical" shorelines and their state of develop-
ment and governance. Setbacks for new development, relocation of
endangered structures, beach nourishment, and engineered shore pro-
tection structures or doing nothing may each be appropriate under
specific localized conditions. In regard to the following recornrnenda-
tions, it is understood that if a program of coastal erosion control is
implemented then E-zones shall be reassessed.
Recommendations
A. MINIMUM STANDARDS FOR STATE OR LOCAL MANAGE-
MENT PROGRAMS
. No new development should be permitted seaward of the
E-10 line, except coastal-dependent uses, such as piers and docks.
. Only readily movable structures should be permitted seaward
of the E-60 line. Within this area, most development should be
landward of the ~30 line, with states and local governments having
the option of allowing variances for single family structures up to
the ~10 tine on preexisting lots that cannot meet an E-30 setback
(see Figure ~1~.
. New large structures In excess of 5,000 square feet (as In
North Carolina) should not be allowed seaward of the E-60 line.
. FEMA should incorporate state setbacks that conform to or
are more stringent than federal standards wherever possible.
~ For new structures seaward of the E-60 line, pilings should
be required (except on high bluffly to be embedded to withstand a
100-year erosion event.
. While flexibility to address local needs should be retained,
FEMA should establish minimum standards for local erosion man-
agement regulations. Coverage by state or local regulations that
meet these minimum standards should be a prerequisite for comum-
nity WHIP participation. Coverage by such a program also should be
OCR for page 9
EXECUTIVE SUMMARY
9
a prerequisite for a property's eligibility for disaster relief and the
co~n~n;ty's eligibility for other federal programs, including recre-
ation and open space funds, coastal management funds, highway
and transportation funds, water and sewer funds, and beach nour-
ishment projects other than those involved with the correction of
hums educed erosion.
B. INSURANCE RATES AND AVATLABILITY
. No new NF1P policies should be issued for structures in
delineated ~10 zones.
. NF1P policies for new structures in other Rezones should be
actuarial.
. The portion of NF]P premiums that reflects erosion risk
should decline with distance from the reference feature. This amount
should be distinguished from that portion of the premium attribut-
able to flood risk in annual NF1P billings to policy holders. (The
purchase of Good insurance including the appropriate premium sur-
charge reflecting the erosion risk coverage should be mandatory for
aB buildings within the ~60 zone.)
. Communities shoed be encouraged through the proposed
Community Rating System (CRS) to adopt stricter erosion zones-
for example, ~50 for small structures and ~100 for large ones. Un-
der the CRS, credits should be awarded toward reduced community-
wide premium rates for adopting such stricter standards. For exist-
ing structures, lower premiums should be available if the buildings
are retrofitted with pilings long enough to provide structural in-
tegrity and reduce the chance of structural failure.
. NFIP coverage should be maintained on eligible structures in
the E-60 zone (excluding the ~10 zone) over the life of any federally
related financing, including secondary mortgage market transfers.
. NF1P should establish insurance rates based on anticipated
relocation benefits of 40 percent of the structure's Prague (as deter-
mined under Section 544~.
C. SECTION 544 (UPTON-JONES) RELOCATION AND DEMO-
LITION BENEFITS
. FEMA should define E-10 zones as being subject to `'imm~-
nent threat of collapse due to erosions and therefore eligible for
benefits under Section 544.
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10
MANAGING COASTAL EROSION
. Owners of structures in danger of imminent collapse (~10
zones) should be notified of levels of risk and availability of Section
544 benefits.
. Two years after such notification, NF]P prem~n~n~ on struc-
tures remaining in an ~10 zone should be increased substantially.
Alternatively, coverage may be frozen at 40 percent of the current
value of the structure (equivalent to maxim,~rn payable for a '~proper
relocations under Section 544~.
. No Section 544 relocation payment should be made if any
part of the structure remains seaward of the ~30 zone (~60 for
large structures) after relocation.
Sites vacated by demolition or relocation funded by Section
544 should be covered by deed restrictions prohibiting *nature rede-
velopment involving an enclosed structure.
. Relocation should be encouraged over demolition for pur-
poses of Section 544. Demolition should be employed only where
a. relocation is tethnicaBy unfeasible;
b. there is no feasible site beyond the E-30 or E-60 tine
where the structure may be econom~caBy relocated;
c. the structure poses an imminent danger to the public
safety in its ~10 location; or
d. demolition would be less e~ensive than relocation.
. An appeal procedure should be established by FEMA where-
by aggrieved prop eats owners may challenge a presumption that
erosion is continuing at the estimated rate.
IMPACTS OF NAVIGATIONAL AND FLOOD CONTROL PROJECTS
ON SHORE STABILITY
Conclusion
Jettied entrances and breakwaters forming harbors along sandy
coasts often cause accretion upUrift and erosion downdrift of the
project. Up-river deforestation can cause erosion of banks and depo-
sition at the river estuary and along the coast. Additionally, when
rivers that deliver sand and sediment to the coast are dammed for
flood control and other purposes, beach erosion can result over the
Tong term.
OCR for page 11
EXECUTIVE SUMMARY
Recommendations
11
. Sand dredged Tom entrances and harbors, if of beach qual-
ity, can be used effectively to enhance beach nourishment. How-
ever, much of this resource has been deposited offshore and lost to
the littoral system. A national policy should be adopted that re-
quires placement of good-quality sand, dredged from harbors and
entrances, as beach nourishment.
. Procedures should be developed, as a part of the environ-
mental impact statement process, to evaluate the erosion potential
and costs of navigation structures such as jetties and breakwaters.
Studies should be made on advisability and means of shifting the
cost of erosion from downdrift property owners (public and private)
to the sponsors of the projects responsible for erosion.
. Studies Should be conducted to develop recommendations
on a proper procedure to mitigate negative effects of existing and
planned structures that cause adverse effects on the adjacent prop-
erty owners. Examples are sand bypassing coastal structures and
beach nourishment using sand sources other than sand bypassing.
. Planners and decision makers should consider the effects of
dame and flow regulation upon the supply of sand to beaches.
EROSION CONTROL THROUGH COASTAL ENGINEERING
Conclusion
There are many examples of properly planned, designed, con-
structed, and maintained seawalis and revetments that have pre-
~ ented further retreat of the shoreline, but beaches sometimes have
been lost as a result. There are also examples of properly planned, de-
signed, constructed, and maintained detached breakwaters and groin
fields that have been effective in the local control of coastal erosion;
however, impacts on downdrift beaches must be considered. Beach
nourishment is now the method of choice for beach preservation in
many coastal communities. While some beach fill projects are per-
form~ng well (e.g., Miami Beach, Florida), there is little monitoring
of these projects, which is necessary for long-term evaluation.
Recommendations
. The use of properly engineered structures should be permit-
ted in regions where they are physically and econom~caBy justified
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12
A~4NAGING COASTAL EROSION
and consistent with state and local programs and where possible
adverse impacts are properly evaluated.
. The main purposes of beach nourishment are to provide
beaches for recreational me and as storm buffers for shore devel-
opment. A secondary benefit is coastal erosion control. Investiga-
tione shown be made of the economics of transporting sand by bulk
carriers from relatively distant sources to densely used coastal areas
where the value of beaches is great and coastal erosion control is
amenable to this approach of beach nourishment.
SAND AND GRAVEL MINING
Conclusion
Sand and gravel mined from beaches and riverbeds near the coast
can result in beach erosion.
Recommendations
. Procedures should be developed, as a part of the env~ron-
mental impact statement process, to evaluate the erosion potential
and costs of sand and gravure] mining.
Policies should be developed to shift the cost of erosion re-
~ting Tom min ng sand and grave] from downdrift property owners
to those responsible for the raining operations.
SUBSIDENCE
Conclusion
Many coastal regions have subsided owing to both natural and
human-induced causes. This has resulted in coastal erosion in some
areas.
Recommendations
. Procedures should be developed, as a part of the environ-
mental impact statement process, to evaluate the subsidence caused
by removal of subsurface fluids and to evaluate the erosion poten-
tial and costs. Studies should be made on determination of cause and
OCR for page 13
EXECUTIVE SUMMARY
13
means of shifting the costs of erosion to those responsible for the
erosion from those affected by the erosion.
. Methods of mitigating erosion-causing subsidence should be
approved, where possible, and anplemented where economically fea-
s~ble.
Education
Conclusion
The current state of public education about coastal erosion, the
causes of coastal erosion, its long-term impacts, anc] the possible
responses to it is inadequate. A more informer] or educatec! public
(inclucling buyers, sellers, clevelopers, planners, engineers, anc] public
officials) would be able to make better long-term coastal development
· ~
c .eclslons.
Recommendations
o A public education program carried out at the national, state,
and local levels should be an integral part of the national policy on
coastal erosion. FEMA should strive to inform the general public of
the risks associated with development in the coastal zone.
. Methods should be established by FEMA to provide effective
and regular notice to aB land owners in Rezones as to the existence
and magnitude of erosion (e.g., through notations on annual flood
insurance pr~minm notices, notations on deeds or otherwise included
In the property's cIann of titIe).
Data Base Development and ResearEh
Conclusion
Available data and methodologies are adequate for FEMA to
develop an interim erosion insurance element for the NF1P. However,
better knowledge and understanding of processes and a better data
base are necessary for a long-term, risk-quantified (based) program
and should be developed and incorporated into the NF1P as soon as
available.
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14
Recommendations
MANAGING COASTAL EROSION
. FEMA should develop a shoreline change data base for use
In implementing a national erosion insurance element of the NF1P.
This data base mast incorporate the local character of spatial and
temporal shoreline changes, properly evaluating the impact of major
coastal storms and shore engineering projects on the erosional trend.
The ferret of detail require shows be commensurate with local land
me change.
. Unevaluated shoreline data exist for the U.S. coasts, but
considerable analytical effort worm be necessary to develop these
data into a readily applied, reliable, and consistent form. FEMA
should develop standards, based on a technical analysm, that can be
applied to developing a national data base in an appropriate form.
Florida and New Jersey have established such a data base and may
serve as models for FEMA's data acquisition program.
. Ultimately, FEMA should use a statistical method for mod-
elmg erosion rates; however, presently the necessary data are not
avaBable.
RESEARCH
Conclusion
The state of the art in predicting erosion rates is poor and is
technically difficult without both general and sit~specific research.
The ability to predict erosion and coastal change is fundamental to
coastal management, environmental decision making, and shoreline
preservation.
Recommendation
. FEMA should actively support efforts to develop research
on defining long-term statistical oceanographic climate, particularly
the wave climate, shore processes near tidal inlets, and coastal re-
sponge to atom and hurricanes. FEMA shoed also encourage the
U.S. Arnold Corps of Engineers, the National Oceanic and Atmo-
spheric Administration (NOAA), and other appropriate agencies to
conduct research on the effect of engineering structures (seawalIs,
revetments, groins, detached structures), beach nourishment, and
dredging operations on coastal erosion.
OCR for page 15
EXECUTIVE SUMMARY
Unified National Program for Floodplain Management
Conclusion
15
The Unified National Program for Floodplain Management
(March 1986) in its current form lacks any component to address
erosion. It contains no explicit discussion of erosion as a contributing
factor in coastal flood Tosses. If suitably revised, it could serve an the
funda~nental expression of a national policy on coastal erosion.
Recommendations
. FEMA shown revise the Unified National Program for Flood-
plain Management to reflect federal policies and programs concern-
ing erosion zone management.
FE:MA Should convene a national Task Force on Coastal
Erosion Zone Management. This body would include experts from
universities and federal agencies having policy or program respon-
sibilities affecting coastal erosion. Experts Tom states with critical
erosion problems and/or significant coastal erosion management pro-
grams also should be inherited to participate. The purposes of the Mask
Force would include:
a. assisting FEMA in developing and promulgating nation-
wide standards for erosion hazard reduction equivalent
to the 100-year Good standard;
b. reviewing internal procedures of participating agencies to
deterniine compatibility with erosion management pro-
visione of the Unified National Program (as revised);
c. reviewing the applicability of Executive Orders 11988
and 11990 to the management of E-Zones and, If appro-
priate, recommend revisions to the President; and
d. serve as an ongoing "ethnical advisory committee con-
cerning coastal erosion with the capability of commis-
sioning special studies and research projects where ap-
propriate to further goals of the Unified National Pro-
gram.
Representative terms from entire chapter:
beach nourishment
