In Glosing

In Closing...

We intend this document to be a beginning, not an end.
Our hope is that this Action Agenda will serve as an
inspiration and a call to action for the millions who live
and work in the Gulf of Mexico region. Together our
coordinated actions can make a difference and reduce the
impacts of erosion on the coastal and estuarine shorelines
of the Gulf of Mexico.

The Gulf of Mexico Program
Goastal & Shoreline Erosion Committee

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) ~ . ag



Participants in the Action Agenda Development Process

Appendix D

Ray Addington
Dennis Barnett
Ken Blan

Floyd Buch

John Burt

Mary Lou Campbell
Tom Campbell
James Cato
Ralph Clark
Tom Czapla
Sally Davenport
Mel Davis
Donna Devlin
John Dingler
Scott Douglass
Russel Eitel

Joe Faggard

Ed Garner

Gil Gilder
Joseph Gill
Linda Glenboski
Bill Holland
Cathy Hollomon
Terry Howey
Herbert Hudson
James Jones
Robert Jones
B.D. King III
Fred Kopfler
Donald Lirette
Jennifer Livingston
Kumar Mahadevan
Brandt Mannchen
Michael Materne
Kim McKenna
Jack Moody

Bob Morton
Joann Mossa
Bob Nailon
Douglas Nester
Rudy Nyc

Steve Oivanki
Shea Penland
Drew Puffer

Highland Supply Company

U.S. Army Corps of Engineers

Soil Conservation Service--Gulf of Mexico Program

Port of Corpus Christi

Soil Conservation Service

Sierra Club

U.S. Army Corps of Engineers

Florida Sea Grant College

Florida Department of Natural Resources

US. Fish & Wildlife Service

Texas General Land Office

Texas Soil & Water Conservation Board

Center for Marine Conservation

U.S. Geological Survey

University of South Alabama

Galveston Beach Preservation Committee

Galveston Beach Preservation Committee

University of Texas at Austin

Alabama Department of Economic & Community Affairs
Mississippi Department of Wildlife, Fisheries & Parks
U.S. Army Corps of Engineers

U.S. Environmental Protection Agency--Gulf of Mexico Program
Mississippi Department of Wildlife, Fisheries & Parks
Louisiana Department of Natural Resources

Galveston Bay National Estuary Program
Mississippi-Alabama Sea Grant Consortium

Terrebonne Parish Government--Louisiana

US. Fish & Wildlife Service

U.S. Environmental Protection Agency--Gulf of Mexico Program
Citizens Advisory Committee--Gulf of Mexico Program
Alabama Department of Economic & Community Affairs
Mote Marine Laboratory

Sierra Club

Soil Conservation Service

Texas General Land Office

Mississippi Department of Environmental Quality
University of Texas at Austin

University of Florida

Texas A&M Marine Advisory Service

U.S. Army Corps of Engineers

U.S. Army Corps of Engineers

Mississippi Office of Geology

Louisiana Geological Survey

U.S. Environmental Protection Agency--Gulf of Mexico Program

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)

113



Céastal & Shoreline Erosion in the Gulf ef Mexico : Chapter 2

State-by-State Overview

All of the Gulf States have serious erosion problems. Rates of erosion vary greatly
depending upon local shoreline characteristics and storm conditions. Parts of
Louisiana retreat 19.8 m (65 ft) or more per year, while erosion rates of 4.5 m (15 ft)
per year can be found in many other areas of the Gulf (Gulf of Mexico Program,
1991). Several rapidly eroding barrier islands are expected to completely disappear
within the next 30 years (USEPA, 1991). Such islands are often the primary defense
for wetlands, estuaries, and bays against storms and other open-Gulf effects.
Quantifying coastal and shoreline erosion is difficult since long-term averages or
trends can mask dramatic short-term reversals and cycles. Although some reaches
of shoreline may appear stable or show slow accretion for certain periods of time,
these conditions are rare in the long-term.

General historical shoreline trends are depicted by a map "Historical Shoreline
Change in the Northern Gulf of Mexico” (available from the Gulf of Mexico
Program Office). This map, which is a product of the Coastal & Shoreline Erosion
Committee, summarizes average rates of change for Gulf shorelines over the
periods for which reliable historical data are available.

The following brief description of erosion in each Gulf State is provided to give a
simplified assessment of the magnitude of shoreline erosion throughout the Gulf of
Mexico.

Alabama

Overview of the Problem. The Alabama coast stretches from eastern Dauphin
Island to the western portion of Perdido Key and includes the shorelines of Mobile
Bay and several other bays and sounds. There are about 75 km (47 mi) of shoreline
which directly front the Gulf of Mexico. All of these Gulf of Mexico beaches are
sandy. One interesting characteristic of the Alabama coast is that the beach sand
color varies considerably. East of Mobile Bay Pass, in Baldwin County, the beach
sands are a bright white, similar to the adjacent Florida panhandle. West of Mobile
Bay Pass, on Dauphin Island, the beach sand is darker, more similar to the
neighboring barrier islands of Mississippi. The geologic origin of the coast,
particularly east of Dauphin Island, is complex and considered largely unknown.
Likewise, the available data documenting historic shoreline change is limited when
compared to that for the other Gulf States.

Alabama also has over 725 km (450 mi) of shoreline on bays, sounds, and coastal
bayous. Mobile Bay, the eastern end of Mississippi Sound, and the western half of
Perdido Bay are the largest estuaries in Alabama. About half of Alabama's total
shoreline was eroding between 1917 and 1973, according to one study (Sapp, et al.
1975). The Alabama Gulf Coast encompasses three and a half tidal inlets, including
one of the world's smallest inlets and one of the world's largest inlets. Human

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



Coastal Shoreline Erosion
Action Agenda

for the

Gulf of Mexico



Glossary Appendix €

undertow A seaward current near the bottom ona sloping inshore zone. It is caused by the
return, under the action of gravity, of the water carried up on the shore by
wave; often a misnomer for RIP CURRENT.

updrift The direction opposite that of the predominant movement of littoral materials.

uplift The upward water pressure on the base of a structure or pavement.

uprush The rush of water up onto the beach following the breaking of a wave; also
SWASH, RUNUP.

waterline A juncture of land and séa. This line migrates, changing with the tide or other
fluctuation in the water level. Where waves are present on the beach, this line
is also known as the limit of backrush. (Approximately, the intersection of the
land with the still-water level.)

wave crest See CREST OF WAVE. -

wave decay See DECAY OF WAVES.

wave direction

wave forecasting

wave generation

wave height
wave pindcasting
wave period
wave propagation
wave, reflected

wave refraction

wave spectrum

wave steepness

wave train

The direction from which a wave approaches.

The theoretical determination of future wave characteristics, usually from
observed or predicted meteorological phenomena.

See GENERATION OF WAVES.

The vertical distance between a crest and the preceding trough. See
SIGNIFICANT WAVE HEIGHT.

See HINDCASTING, WAVE. .

The time for a wave crest to traverse a distance equal to one wavelength. The
time for two successive wave crests to pass a fixed point. See SIGNIFICANT:
WAVE PERIOD.

The transmission of waves through water.

That part of an incident wave that is returned seaward when a wave impinges
on a steep beach, barrier, or other reflecting surface.

See REFRACTION (of water waves).

In ocean wave studies, a graph, table, or mathematical equation showing the
distribution of wave energy as a function of wave frequency. The spectrum may
be based on observations or theoretical considerations. Several forms of
graphical display are widely used.

The ratio of the wave height to the wavelength.

A series of waves from the same direction.

Gulf of Mexico Coastal & Shorellne Erosion Action Agenda (4.1) 109



Federal & State Framework Appendlx A

FEDERAL LEVEL

U.S. Department of Defense (USDOD)
U.S. Army Corps of Engineers (USACE)

Federal interest in shore protection began officially in 1930, with the enactment of
PL 71-520 which authorized and directed the USACE to engage in shore protection
studies in cooperation with state agencies and to establish a special board, the Beach
Erosion Board (BEB), to furnish technical assistance. The present day shore
protection program under USACE is applicable to the shores of the Atlantic and
Pacific Oceans, the Gulf of Mexico, the Great Lakes, the estuaries and bays directly
connected with of each of the states; the Commonwealths of Puerto Rico and
Northern Marianas Islands; the Territories of the U.S. Virgin Islands, Guam, and
American Samoa; and the Federated States of Micronesia and the Marshall Islands.
Authority for shore erosion control activities extends only the distance up tributary
streams where it can be demonstrated that the dominant causes of erosion and.
damage are ocean tidal action (or Gulf of Mexico and Great Lakes water motion) and
wind-generated waves. Erosion control authority does not address erosion at
upstream locations caused by stream flows or vessels. Lake flood protection
activities are generally limited to the Great Lakes, or as otherwise specifically
authorized under public law.

* Project Purposes. Federal shore protection projects have been authorized for a
variety of purposes: beach erosion control, shore or shoreline protection,
hurricane or hurricane wave protection, and storm protection. For project cost-
sharing, the benefits and outputs associated with these purposes conform to the
appropriate purposes specified in Section 103 (c) of PL 99-662 (normally,
hurricane and storm damage reduction, and/or recreation), and costs are shared
in the same percentage as the purpose to which costs are assigned.

+ Preauthorization Studies. USACE undertakes specific studies relating to shore
protection at the request and authorization of Congress, either in response to
resolutions adopted by the Committee on Environment & Public Works of the
U.S. Senate or the Committee on Public Works & Transportation of the House of
Representatives, or by an Act of Congress. Without specific Congressional
authorization, USACE may initiate studies for projects, under the authorities of
Section 103 of PL 87-874, and Section 14 of PL 79-526, as amended, which
comprise part of the USACE Continuing Authorities Program. Reconnaissance
studies are 100 percent federally funded; feasibility studies are conducted under a
contract (Feasibility Study Cost Sharing Agreement) providing 50/50
federal/non-federal cost sharing.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 58



Federal & State Framework Appendix A

The Growth Management Amendment, enacted in 1985, subject to Florida Statutes
subsection 161.053 (6), requires that long-term shoreline change trends be employed
to regulate coastal development activities (Balsillie, 1988). This Act extends
construction jurisdiction upland of Coastal Construction Control Lines (CCCL) and
defines zones where CCCLs are not established. Specifically, local communities are
required to adopt acceptable standards for development activities. This has evolved
into the Thirty-Year Erosion Projection Program.

Regulatory Agencies & Programs

* The Florida Coastal Management Program. Although coastal planning efforts
had been ongoing in Florida prior to 1978, development of the current Florida
Coastal Management Program (FCMP) was authorized by legislation in that year.
Often referred to as the "No New Nothing Act," the Florida Coastal Management
Act of 1978, assigned the Florida Department of Environmental Regulation
(DER) as lead agency and authorized DER to "compile a program based on
existing statutes and existing rules." The resulting plan received federal
approval in September 1981. FCMP networks 26 acts and their implementing
rules and involves 16 state agencies, with DER, DNR, and the Department of
Community Affairs (DCA) responsible for the majority of the day-to-day
program administration.

While coordination of agency activities affecting the coastal zone is a major

function of the coastal management program, the program has also supported
- and coordinated activities intended to carry out the purposes of CZMA and

developed new initiatives to preserve and protect the state's coastal resources.

Section 161.161, F.S., also dictates that DNR, Division of Beaches & Shores, must
develop and maintain a comprehensive, long-term management plan for
Florida's beaches on a district-by-district basis. Responsibilities include
identification of areas of critical beach erosion, determination of the most viable
means to address identified erosion problems, compilation of a list of beach
erosion control projects, and development of solutions for enhancing and
protecting beach resources for review and action by the Governor and Cabinet
and State Legislature (Balsillie, 1988).

* Bureau of Coastal Engineering & Regulation. Regulatory responsibilities for the
Florida coast are conducted by the Bureau of Coastal Engineering & Regulation.

* Bureau of Coastal Data Acquisition. The Bureau of Coastal Data Acquisition of
DNR administers the CCCL program according to Section 161.053, F.S., which in
part reads:

The legislature finds and declares that the beaches of the state, by their nature, are
subject to frequent and severe fluctuations and represent one of Florida's most

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 69



Overview of the Gulf of Mexico . Chapter 1

The Gulf of Mexico Program has established the following eight Issue Committees,
each co-chaired by one federal and one state representative, to address priority
environmental problems:

Q Habitat Degradation of such areas as coastal wetlands, seagrass beds,
and sand dunes;

Q Freshwater Inflew changes resulting from reservoir construction,
diversions for municipal, industrial, and agricultural purposes, and
modifications to watersheds with concomitant alteration of runoff
patterns; :

Qa Nutrient Enrichment resulting from such sources as municipal waste
water treatment plants, storm water, industries, and agriculture;

Q Toxic Substances & Pesticides contamination originating from
industrial and agriculturally based sources;

Q Coastal & Shoreline Eresion caused by natural and human-related
activities;
Q Public Health threats from swimming in and eating seafood products

coming from contaminated water;

Q Marine Debris from land-based and marine recreational and
commercial sources; and

Q Living Aquatic Resources.

Two cross-cutting technical operating committees support the public education and
information and resource management functions of the eight environmental Issue
Committees. These are:

Q Public Education & Outreach Operations

Q Data & Information Transfer Operations

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 7





Federal & State Framework Appondix A

Department of the Interlor (USDOl)
Fish & Wildlife Service (USFWS)

USFWS manages extensive coastal lands as wildlife preserves and conducts research
on coastal wetlands, fish and wildlife populations, and changes in habitat. In order
to reduce impacts on habitats, USFWS coordinates with federal and state action
agencies to ensure that fish and wildlife considerations are incorporated into water
resources projects.

* Fish & Wildlife Coordination Act, as amended in 1958. The Fish & Wildlife
Coordination Act requires that wildlife conservation be given consideration
equal to the concern for other aspects of the water resource development projects
of USACE, Bureau of Reclamation, and other federal agencies. This Act has
empowered USFWS and NMFS to evaluate the impact on fish and wildlife of all
new federal projects and federally permitted projects, including projects
permitted under Section 404.

Endangered Species Act of 1972 (as amended). As habitats for a great variety
of plants and animals, some wetlands are offered protection under this Act. The
principal purposes of the Act are the conservation of threatened and endangered
species and the ecosystems on which they depend. Among its provisions,
Section 7 of the Act requires federal agencies to ensure that any actions they
authorize, fund, or carry out will not jeopardize the continued existence of any
listed species, or result in the destruction or adverse modification of its
designated critical habitat.

National Park Service (NPS)

NPS administers an extensive system of public lands, including lakeshores and
seashores, set aside for the protection of natural environments, the preservation of
historic properties, and the education and enjoyment of citizens. ,

* Statewide Comprehensive Outdoor Recreation Plan (SCORP). SCORP identifies
state wildlife protection and recreation area needs and establishes priorities for
proposed acquisition and development projects.

U.S. Geological Survey (USGS)

USGS conducts research on the geologic framework of coasts and on sediment-
transport processes; collects and analyzes hydrologic data; makes topographic,
geologic, and hydrologic maps of coastal areas; and investigates ancient and modern
coastal environments.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



Coastal & Shoreline Erosion in the Gulf of Mexico Chapter 2

shores (Tanner, 1960), although northern and southern areas grade to low wave
energy. However, a significant characteristic of the entire reach is that calm seas
prevail for up to 30 percent of the average year.

Northern Barrlers (Anclote Key to Tampa Bay). Until recently, the lower Gulf Coast of
Florida was one of the least studied coasts in the nation. While much of this region
as yet requires study, the barrier islands north of the entrance to Tampa Bay have
undergone extensive geophysical studies. From Anclote Key to Tampa Bay, there
are 14 barrier islands and 11 tidal inlets. With no new sediment being supplied to
the beaches, these coastal barriers are comprised of a relatively thin sand lens lying
on top of limestone; the sand lens thins and pinches out within 488 m (1,600 ft) of
the beach (Davis et al., 1982; Evans et al., 1985). Of the barriers, Three Rooker Bar
and North and South Bunces Keys are the youngest, having evolved within the past
20 years. Since 1980, at least five inlets have opened naturally while three others
have closed. Most of the islands are erosional with at least 45 km (28 mi) of the 68.7
km (42.7 mi) of beach (about 65 percent) considered to be erosion problems (USACE,
1984a, 1984b; Clark, 1991b). Net longshore transport volumes are slight and
generally to the south, although local reversals do occur (Balsillie and Clark, 1992b).
Sand Key, the longest barrier island north of Tampa Bay with 22.9 km (14.2 mi) of
beach, is the site of several beach restoration projects; also restored are beaches of
Treasure Island and Long Key lying to the south of Sand Key.

Miggle Islands (Tampa Bay to Charlotte Harbor). From Tampa Bay entrance south to
Charlotte Harbor, a distance of about 98 km (61 mi), are low-lying barrier islands

which for the most part are long and narrow. Wave energy is moderate (Tanner,
1960), and longshore transport, except for localized influences of some inlets, is to
the south. Near the middle of the reach, just to the south of Venice Inlet, lies a 5.6
km (3.5 mi) long mainland beach. Lido Key, near the north central part of the area, .
is a human-made island which has also received beach renourishment, while Don
Pedro Island was within recent times 4 separate keys. Siesta Key, to the south of
Lido Key contains Point O'Rocks with a 550 m (1,800 ft) ledge of rock extending into
the surf. Seismic profiling north of Tampa Bay Entrance (Davis and Kuhn, 1985)
and in the Charlotte Harbor area (Evans and Hine, 1986) indicates that the location
of barrier islands and hence tidal inlets is at least partly controlled by irregular
bedrock topography (Gibeaut and Davis, 1988) and that the coastal barriers and
beaches are comprised of a relatively thin layer of fine quartz sand with only limited
seaward extent. However, such extrapolation can be made only in the most
generalized sense, since the reach requires more extensive geological investigation.
Longshore transport volumes are slight and generally to the south. Clark (1991a)
has determined that 52 km (32 mi) of beach (52 percent of the total beach length)
along this reach is currently experiencing problematic erosion (USACE, 1980, 1984c,
1984d, 1991a, 1991b). Beach restoration is being conducted along the central part of
Anna Maria Island (the northernmost key) and other projects are planned for
Longboat Key and Venice.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 22



Glossary

Appendix C

current, tidal

cuspate spit

datum, chart

datum, plane

debris line

decay of waves

deep water

deflation
delta

depth

depth of breaking

The alternating horizontal movement of water associated with the rise and
fall of the tide caused by the astronomical tide-producing forces; also
CURRENT, PERIODIC. See CURRENT, FLOOD and CURRENT, EBB.

One of a series of low mounds of beach material separated by crescent-shaped
troughs spaced at more or less regular intervals along the beach face; also
BEACH CUSP.

A crescent-shaped bar uniting with the shore at each end. It may be formed by
a single spit growing from shore and then turning back to again meet the shore
or by two spits growing from the shore and uniting to form a bar of sharply
cuspate form.

The spit that forms in the lee of a shoal or offshore feature (breakwater,
island, rock outcrop) by waves that are refracted and/or diffracted around the
offshore feature. It may be eventually grown into a TOMBOLO linking the
feature to the,mainland. See TOMBOLO.

See CHART DATUM.

The horizontal plane to which soundings, ground elevations, or water surface
elevations are referred; also REFERENCE PLANE. The plane is called a
TIDAL DATUM when defined by a certain phase of the tide. The following
datums are ordinarily used on hydrographic charts:

Mean Low Water--Atlantic coast (U.S.)
Mean Lower Low Water--Pacific and Gulf coasts (U.S.)
Low Water Datum--Great Lakes (U.S. and Canada)

A common datum used on topographic maps is based on MEAN SEA LEVEL. See
BENCH MARK.

A line near the limit of storm wave uprush marking the landward limit of
debris deposits.

The change waves undergo after they leave a generating area (FETCH) and
pass through a calm or region of lighter winds. In the process of decay, the
significant wave height decreases and the significant wavelength increases.
Water so deep that surface waves are little affected by the ocean bottom.
Generally, water deeper than one-half the surface wavelength is considered
deep water. See SHALLOW WATER.

The removal of loose material from a beach or other land surface by wind
action.

An alluvial deposit, roughly triangular or digitate in shape, formed at a river
mouth. .

The vertical distance from a specified tidal datum to the sea floor.

The still-water depth at the point where the waves breaks.

Gulf of Mexico Ceastal & Shoreline Erosion Actlon Agenda (4.1) 93



Coastal & Shoreline Erosion in the Gulf of Mexico Chapter 2

Different mixes of these approaches are appropriate for different locations, and
separate but integrated plans can be prepared for the nine hydrologic basins that
make up coastal Louisiana. Individual potential basin strategies are summarized
below.

Pontchartrain Basin. In the Pontchartrain Basin, construction of the Mississippi River
levees has greatly altered the natural hydrology, depriving the basin of periodic
inputs of fresh water, sediments, and nutrients. Further changes arose with the
construction of the Mississippi River-Gulf Outlet, a deep-draft navigation channel,
which elevated salinities in portions of the basin A strategy for this basin can center
around restoration of the hydrologic balance through introduction of Mississippi
River water or through reduction of tidal inflow via the Mississippi River-Gulf
Outlet and through maintenance of the Lake Borgne/Lake Pontchartrain and Lake
Pontchartrain/Lake Maurepas natural land bridges.

Breton Sound Basin. This basin suffers from a lack of freshwater input and extensive
saltwater intrusion. A strategy for the Breton Sound Basin can involve construction
of new, and outflow management of existing, freshwater diversion projects (such as
the USACE project at Caernarvon, completed in 1991). Additionally, the feasibility
of developing new barrier islands near the existing shoreline to protect adjacent ©
wetlands can be investigated.

Mississippi River Delta Basin. Wetlands loss in the Mississippi River Delta Basin results
primarily from subsidence and compaction. The current sediment inputs from the
river are not sufficient to balance this loss. Large-sale, controlled diversion of the
river could be employed to most effectively utilize its valuable sediment load.
However, implementation would require detailed analysis of its effect on existing
economic activity, especially navigation on the river and on federal and state-owned
wildlife lands.

Barataria Basin. This basin suffers from being cut off from the river's freshwater and
sediment inputs by flood protection levees. Additionally, the increasing tidal prism
may be the most significant mechanism by which wetlands are lost in the Barataria
Basin. A strategy for the basin could focus on use of existing and proposed
freshwater diversion projects to deliver sediments and nutrients, reduction of tidal
exchange between the upper and lower basins, maintenance of the existing chain of

barrier islands, and maintenance and enhancement of the fringing marshes in th
basin. :

Terrebonne Basin. Parts of this basin suffer from subsidence and isolation from inputs
of freshwater and sediments. Saltwater intrusion is a significant cause of wetland
loss in these areas, as are historic oil and gas activity and natural deterioration of the
barrier islands. Other areas have experienced substantial freshwater inputs from the
Atchafalaya River and are undergoing stress from high water levels. The wide
range of problems in the basin requires a strategy of similar scope. Potential features
of a plan for this basin include the following: managing high water levels in the

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 29



Bibliography

Morton, R.A. 1991. “Historical Shoreline Change in the Northern Gulf of Mexico."
USEPA/GMP map of coastal erosion--Texas segment. In press.

National Research Council. 1990. Managing Coastal Erosion. National Academy
Press, Washington D.C.

Oivanki, S. M. 1992. An Overview of the Mississippi Gulf Coast. Office of Geology.
State of Mississippi.

Paine, J.G. and R.A. Morton. 1989. Shoreline and Vegetation-Line Movement,
Texas Gulf Coast, 1974 to 1982. The University of Texas at Austin. Bureau of
Economic Geology. Geological Circular 89-1.

Parkinson, R.W. 1989. "Decelerating Holocene Sea-Level Rise and Its Influence on
Southwest Florida Coastal Evolution: A Transgressive/Regressive
Stratigraphy." Journal of Sedimentary Petrology. v. 59, no. 6.

Penland, S. A Review of Coastal Erosion and Wetland Loss in Louisiana. Louisiana
Geological Survey.

Rabalais, N.N., R.E. Turner, W.J. Wiseman, Jr. and D.F. Boesch. 1991. "A Brief
Summary of Hypoxia on the Northern Gulf of Mexico Continental Shelf:
1985-1988." Pages 35-47 in R.V. Tyson and T.H. Pearson (eds.), Modern and
Ancient Continental Shelf Anoxia. Geological Society Special Publication No.
58. The Geological Society. London.

Roberts, H.H., T. Whelan, and W.G. Smith. 1977. "Holocene Sedimentation at Cape
Sable, South Florida." Sedimentary Geology. v. 18.

Sapp, C.D., J.G. Emplaincourt, and J.D. Hardin. 1975. Remote Sensing of Shoreline
Dynamics, Mobile Bay Area. Transactions-Gulf Coast Association of
Geological Societies., Vol. 25.

Scholl, D.W. 1964, "Recent Sedimentary Record in Mangrove Swamps and Rise in
Sea Level Over the Southwestern Coast of Florida." Marine Geology.

Shier, D.E., 1969. "Vermetid Reefs and Coastal Development in the Ten Thousand
Islands, Southwest Florida." Geological Society of America Bulletin. v. 80.

Smith W.G. 1968. “Sedimentary Environments and Environmental Change in the
Peat-Forming Area of South Florida" (thesis). Pennsylvania State University.
University Park, PA.

Stapor, F.W., 1971. "Sediment Budgets on a Compartmented Low-to-Moderate
Energy Coast in Northwest Florida." Marine Geology. v. 10, no. 2.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 54



Coastal & Shoreline Erosion in the Gulf of Mexico Chapter 2

however, that beaches along this reach have not been inventoried). The mangrove
forest, attaining heights of 15 m (48 ft), is distinctly zoned with red mangroves along
the shoreline and black and white mangroves in the upland forest interior.
Although it is known to be subject to erosion, this coast has never been monitored,
and no quantitative rate of erosion is available.

Cape Sable, Along the southern 15 km (9.3 mi) of the reach lies Cape Sable, the best
developed regressional feature on the south Florida coast. The Cape prograded up
to 8 km (5 mi) (Enos and Perkins, 1979), achieving its present status about 1,200 to
1,500 years ago (Roberts et al., 1977). Cape Sable is comprised of three capes (Smith,
1968), which are composed of shell beaches with southeastward longshore transport
and which are linked by narrow shell beaches. Older beach ridges lie behind the
present beaches, are composed of carbonate-mud material (Gleason et al., 1974), and
vegetated with succulents, grasses, and palms with the most landward ridges having
a dense hammock vegetation (Roberts et al., 1977). Cape Sable beaches have not
been monitored to determine quantitative rates of shoreline behavior and even
information to guess at the stability of the reach is not available. .

Florida Keys. The Florida Keys, which stretch for over 354 km (220 mi), are an
elongated, arc-shaped archipelago separated from the mainland by Florida Bay, a
broad but shallow water body compartmentalized by numerous carbonate mud
banks. The Keys were formed as the result of the last major drop in sea level which
exposed the ancient coral reefs. Those keys considered to front directly on the Gulf
of Mexico include the northern shores of the "Lower Keys" and the three distal
sandy island groups to the west. The "Upper and Middle Keys" front not on the
Gulf, but on Florida Bay and the Straits of Florida, and are comprised of coralline
limestone.

Lower Keys, Although the most significant carbonate beaches and dunes of the
“Lower Keys" front on the Straits of Florida, several locally significant beaches are
found along the "back country" islands of the "Lower Keys" fronting the Gulf.
Sedimentation here is due to the entrapping capability of marine grasses and algae.
Beach sediments consist primarily of calcareous green algae, limestone fragments,
and a variety of mollusks and foraminifera (Jindrich, 1969). Such beaches found
along Mud Key, Snipe Point (Snipe Key), Marvin Key (Barracuda Keys), Sawyer Key,
and the Content Keys, total about 1.9 km (1.2 mi) in length and average 8 m (25.6 ft)
in width. Coastal processes have not been documented for these beaches, but it is
thought that the direction of net annual longshore sediment transport is to the
southwest.

Distal Kevs. Beaches of the three island groups west of Key West have not been
studied except in terms of general physiography (Davis, 1942; Stoddart and Fosberg,
1981) and petrography (Ginsburg, 1979). The outer island group (unnamed) nearest
Key West and the Marquesas Keys is located 29 km (18 mi) west of Key West and has
calcareous sand beaches averaging 7.5 m (25 ft) in width (Clark, 1990a). Beach
sediments are comprised of calcareous skeletal fragments of green algae and oolitic

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 25



Bibliography

US. Environmental Protection Agency. 1991. Gulf Facts. Gulf of Mexico Program
Office. John C. Stennis Space Center, MS.

White, W.A. 1970. "The Geomorphology of the Florida Peninsula." Florida
Department of Natural Resources. Bureau of Geology, Geological Bulletin
No. 51.

Williams, 5S. J., K. Dodd, and K. K. Gohn. 1990. Federal Agencies With Regulatory
or Research Responsibilities for Our Coasts. USGS Circular 1075.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



Glossary

Appendix ¢

depth contour
depth controlling

diffraction

dike (dyke)
diurnal
diurnal tide
dolphin
downdrift

drift

drift current
dunes

ebb current

ebb tide

echo sounder

eddy

eddy current
embayed
embayment
entrance

eolian sands

See CONTOUR.

See CONTROLLING DEPTH.

(of water waves) The phenomenon by which energy is transmitted laterally
along a wave crest. When a part of a train of waves is interrupted by a barrier,
such as a breakwater, the effect of diffraction is manifested by propagation of
waves into the sheltered region within the barrier's geometric shadow.

A wall or mound built around a low-lying area to prevent flooding.

Having a period of cycle of approximately one TIDAL DAY.

A tide with one high water and one low water in a tidal day.

A cluster of piles.

The direction of predominant movement of littoral materials.

(noun). (1) Sometimes used as a short form for LITTORAL DRIFT. (2) The
speed at which a current runs. (3) Floating material deposited on a beach
(driftwood).

A broad, shallow, slow-moving ocean or lake current.

Ridges or mounds of loose, wind-blown material, usually sand.

The tidal current away from shore or down a tidal stream; usually associated
with the decrease in height of the tide.

The period of tide between high water and the succeeding low water; a falling
tide.

An electronic instrument used to determine the depth of water by measuring the
time interval between the emission of a sonic or ultrasonic signal and the return
of its echo from the bottom.

A circular movement of water formed on the side of a main current. Eddies may
be created at points where the main stream passes projecting obstructions or
where two adjacent currents flow counter to each other; also EDDY CURRENT.
See EDDY.

Formed into a bay or bays, as an embayed shore.

An indentation in the shoreline forming an open bay.

The avenue of access or opening to a navigable channel.

Sediments of sand size or smaller which have been transported by winds. They

may be recognized in marine deposits off desert coasts by the greater angularity
of the grains compared with waterborne particles.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)





Coastal & Shoreline Erosion in the Gulf of Mexico Chapter 2

channels, and each is isolated from adjacent compartments. As a result of this
isolation and recent interference with littoral drift, little sand is shared among any
of the seven compartments.

Bay Systems. Of the major Texas bays, land losses are greatest in Copano,
Galveston, and Matagorda Bays, the largest bays with the longest open water fetches.
Local rates of land loss are largely controlled by composition of shoreline material,
orientation of the shoreline with respect to the prevailing wind and wave
directions, and the relative rise in sea level. Because the shoreline lengths and

processes are similar in these three bay systems, the rates of land loss are also
similar.

The Galveston, Matagorda, San Antonio, Copano, and Corpus Christi Bay systems
each lost fringing land at gross rates of about 116 hectares/year (287 acres/year)
between 1930 and-1982. Surrounded by over 1,600 km (992 mi) of bluffs, marshes,
and sand and shell beaches, each bay system has a different proportion of these
shoreline types that contributes to differences in land loss rates between the bays.

Responses to Erosion. Only small sections of the Texas Gulf shoreline have been
stabilized by hard coastal structures. Long seawalls [>1200 m (>4000 ft)] have been
constructed on Galveston, North Padre, and South Padre Islands. At each location,
the beaches downdrift of the structures are eroding. Most of the other shoreline
developments use bulkheads constructed on the backbeach. These structures
currently have little effect on beach stability where sand supply is plentiful, but on ©
other beaches they may reduce beach width and prevent the accumulation of
windblown sand.

Local attempts to minimize coastal land loss in Texas have been partly successful.
Only large and expensive projects, such as the Galveston seawall, have prevented
further upland land loss, often at the expense of downdrift shores. Most of the low-
cost shoreline stabilization projects provide temporary protection, but eventually
they fail and land loss resumes. Efforts to create new land or to maintain existing
land are currently underway along the shores of Galveston Bay, but the long-term
durability and effectiveness i in mitigating land loss is still. uncertain.

Another response to erosion on Texas Gulf beaches is the use of a setback boundary.
For post-storm coastal reconstruction activities, this boundary is based on the
location of the vegetation line. In addition, 1991 legislation directed the Texas
General Land Office to work with The University of Texas, Bureau of Economic
Geology, to develop a 50-year erosion-rate setback for new coastal construction.

Erosion is a subject of primary concern.on the Texas coast, where it has many
serious adverse effects in addition to habitat degradation and loss. Prime tourist
beaches are vanishing; the Gulf Intracoastal Waterway is threatened by the
possibility of a major breach at Sargent Beach; and agricultural and industrial lands,
infrastructure, and private homes are being lost. :

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



Federal & State Framework Appendix A

PROJECTS CURRENTLY UNDERWAY TO RESPOND TO
COASTAL & SHORELINE EROSION IN THE GULF OF
MEXICO

This listing can and will be used to make summary statements concerning the "state
of the response" to coastal and shoreline erosion along the Gulf of Mexico.

Alabama

*- Isle Dauphine Club bulkhead--Successive structures on Isle Dauphine have failed
and been re-built to protect a tee on the golf course from erosion. This
shoreline is partially sheltered by ephemeral islands (Sand Island/Pelican
Island) several kilometers offshore. The islands are on the outer edge of the
ebb-tidal delta of Mobile Bay Pass.

. Dauphin Island Park and Beach Board beachfil--To replicate a recently eroded sand
dune, 11,468 m3 (15,000 yd3) of material was placed on the beach in June 1991.
Most of the material washed away within a year. This beach has been
experiencing erosion that threatens the integrity of several structures,
including a fishing pier, a bathroom, and some picnic pavilions. The fill
material was from the other side of the barrier island and, although it was
predominately sand, it had enough silt and oyster shell content to make the fill
unpleasant for bathers.

* East end of Dauphin island seawall and groins--These structures were built in 1909-
1910 by USACE to protect Ft. Gains from erosion. The western groin field has
been flanked several times and is presently several hundred feet from shore.
This shoreline is partially sheltered by ephemeral islands (Sand Island/Pelican
Island), several kilometers offshore.

* West Beach, Gulf Shores beach nourishment--In June 1991, 114,679 m3 (150,000 yd3) of
sand from a nearby lagoon were placed on the beach. More sand from the
lagoon was placed on the beach in the spring of 1992. The nourishment project
was court-ordered. This erosion was downdrift of jetties to Little Lagoon.

* Orange Beach/Perdido Pass inlet sand wansfer--Sand dredged from Perdido Pass has
been occasionally placed on the adjacent beaches and in constructed dunes.

Florida

* — Vista Del Mar Condo, Perdido Key, sand-filled bags--These bags were placed after
Hurricane Elena. There are three elongated bags stacked on each other, two on
the bottom and one on top like a triangle. The bags do not experience wave
action daily because they are located above the day to day shoreline. They
function as a sill during storm overwash events.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 7





Executive Summary

EXECUTIVE SUMMARY

The Gulf of Mexico contains ecological and commercial riches matched by few other
bodies. of water. Yet its blue-green waters disguise the increasing environmental
threats that endanger those resources. In recognition of these threats, Regions 4 and
6 of the U.S. Environmental Protection Agency (USEPA), which share jurisdiction
over the five.Gulf Coast States (Alabama, Florida, Louisiana, Mississippi, and Texas),
initiated the Gulf of Mexico Program in August 1988. The goal of the Gulf of Mexico
Program is to protect, restore, and enhance the coastal and marine waters of the Gulf
of Mexico and its coastal natural habitats, to sustain living resources, to protect
human health and the food supply, and to ensure the recreational use of Gulf
shores, beaches, and waters--in ways consistent with the economic well being of the
region.

The Gulf of Mexico Program is a cooperative partnership among federal, state, and
local government agencies as well as with people and groups who use the Gulf of
Mexico. During the early stages of Program development, eight priority
environmental problems were identified and the following Issue Committees have
been established to address each of these problems: Marine Debris, Public Health,
Habitat Degradation, Coastal & Shoreline Erosion, Nutrient Enrichment, Toxic
Substances & Pesticides, Freshwater Inflow, and Living Aquatic Resources: There
are important linkages among these various Issue Committees and the Gulf of
Mexico Program works to coordinate and integrate activities among them.

The Coastal & Shoreline Erosion Committee was charged with characterizing
erosion problems and identifying ways to reduce the impacts of erosion. The Issue
Committee has been meeting for more than four years--to review information and
data collected by citizens and scientists, identify problem areas, discuss actions that
can resolve the problems, and evaluate methods for achieving and monitoring
results. The culmination of Issue Committee efforts is this Coastal & Shoreline
Erosion Action Agenda which specifies an initial set of activities needed to reduce
the impacts of erosion in the Gulf of Mexico. This Action Agenda is the first
generation of an evolving series of Action Agendas that will be developed to meet
the future needs of the Gulf of Mexico.

Chapter 1 of the Coastal & Shoreline Erosion Action Agenda provides an overview
of Gulf of Mexico resources and the threats now facing those resources. In addition,
Chapter 1 describes the structure of the Gulf of Mexico Program, including the
Action Agenda development process.

Chapter 2 is a summary of the scientific characterization information compiled by
the Coastal & Shoreline Erosion Committee. To illustrate the impacts of erosion,
the Issue Committee has produced a map depicting the historical change of the Gulf
of Mexico coastline. This map is available from the Gulf of Mexico Program Office.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) _ i



Coastal & Shoreline Erosion in the Gulf of Mexico Chapter 2

changes in shape and shoreline movement on the coast. Remnants of a barrier
chain, they exhibit erosion and movement from east to west in the direction of
longshore drift. Ship Island, Horn Island, and Petit Bois Island are elongated east to
west and form part of the Gulf Islands National Seashore. Development on these
islands has been limited to park activities. Cat Island is privately owned. A
prominent north-south spit attached to the east-west trending main island body
reflects sediment redistribution by waves from the eroded eastern island. At one
time, the rest of the island was protected by-a since-extinct Mississippi delta lobe to
the south.

Predominantly westward-oriented current and wave transport of sand along the
high-energy Gulf (south) island shores in historical times has steadily extended the
barrier islands westward between severe erosional episodes | of tropical storm
activity. .

Responses to Erosion. The mainland: coastline is being. artificially maintained in its
central portion by either hard structures, beach nourishment, or both. The extreme -
east and west ends of the mainland shoreline consist of natural tidal marshes and
currently suffer moderate to heavy erosion, The barrier islands protect the -
mainland shoreline from the wave energy of the open Gulf. These islands are
eroding and migrating to the west as a result of longshore drift (Oivanki, 1992).

A 41.6 km-long (26 mi), wide beach had been established in 1951, in place of a
previously destroyed narrow natural beach. The sand was pumped from offshore
sediment sources. Despite heavy erosion by Hurricane Camille in 1969, and the
regular effects of fair weather longshore drift and wind erosion; a somewhat
narrower beach has been artificially maintained ever since. Beach nourishment was
repeated on a smaller scale in 1972-73, and again in 1987-88. Pilot projects are now
underway to stabilize this beach with natural salt tolerant grasses and dune -
formation. The major human factor impacting the beach is the tourist population,
since this is the main tourist attraction on the Mississippi Coast. Continual.
mechanical maintenance is needed to keep the beach free of trash and debris
(Oivanki, 1992). :

Hancock County, west of St. Louis Bay, supports the bare remnants of a 9.6 km (6 mi)
beach emplaced in the mid-1960s to protect the seawall there. Erosion has taken all
but a few pockets of this beach and undermined the seawall and the adjacent Beach
Boulevard in numerous: places. A planned renourishment of this beach is
scheduled for late 1992. The southwest shoreline of Hancock County, past the
seawall, is a salt-tidal marsh and is experiencing moderate erosion due to natural .
wave and storm energy (Oivanki, 1992).

The complex and diverse nature of the Mississippi Coast requires a multi-faceted
approach to the study and solution of problems relating to erosion and land use. In
conjunction with USGS, the Mississippi Office of Geology is currently engaged in a
multi-year program to document past erosion and monitor current erosion rates.

Gulf of Mexico Goastal & Shoreline Erosion Action Agenda (4.1) 32



Federal & State Framework Appendix A

The Act provides for the following mandates and authorizations: establishes an
Office of Environmental Education within USEPA, establishes and operates an
Environmental Education and Training Program, authorizes USEPA to enter
into grants and contracts, requires USEPA to facilitate internships for college
students with agencies of the federal government, requires USEPA to provide
national awards recognizing outstanding contributions in environmental
education, establishes an Environmental Education Advisory Council & Task
Force, establishes a National Environmental Education Foundation, and
authorizes funds to carry out the Act.

U.S. Department of Agriculture (USDA)
Soll Conservation Service (SCS)

SCS is USDA's primary technical agency in the areas of soil and water conservation
and water quality. SCS focuses its assistance on non-federal land. SCS works
primarily with private landowners in planning and applying measures to reduce
soil erosion, conserve water, protect and improve water quality, and protect other
renewable natural resources, such as plants and wildlife. The guiding principle is
the use and conservation treatment of the land and water in harmony with
capabilities and needs.

SCS has an office in almost every county in the U.S. where it works closely with
local subdivisions of state government called Soil & Water Conservation Districts.
The conservation districts are governed by local people and typically have legislative
mandates to plan and implement comprehensive soil and water conservation
programs within their boundaries. These boundaries usually coincide with county
lines.

SCS's basic authorities were created by P.L. (74) - 46, P.L. (83) - 566, and P.L. (78) - 534.
Program authorities were added under various Farm Bills including those enacted
in 1961 (Resource Conservation & Development), 1988 (Swampbuster, Sodbuster,
Conservation Compliance, & Conservation Reserve Program) and 1990 (Wetlands
Reserve Program and others). Under the Swampbuster provisions, SCS assists
landowners to identify and protect wetlands. Loss of USDA benefits and severe
economic consequences can result for agricultural producers who convert wetlands
to make possible the production of agricultural commodities.

SCS also conducts soil surveys and operates a system of 27 Plant Materials Centers
for selecting, developing, testing, and releasing plants for use in conservation
programs.

SCS works with private landowners and others to preserve, protect, and restore
wetlands and to develop wildlife and fisheries habitat.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 63



Federal & State Framework Appendix A

The Enforcement & Monitoring Program ensures that any unauthorized projects
in the coastal zone are investigated and action is taken. The program also
monitors activities permitted by the CUP Program for compliance with permit
conditions. The program also gives the secretary of DNR the authority to enforce
either legal or administrative procedures including fines, cease and desist orders,
and restorative or mitigation work. The field investigative staff regularly
monitors the entire coastal area for unauthorized activities and for non-
compliance with permit conditions.

The Coastal Restoration Division has the responsibility for implementing the
Coastal Wetlands Conservation & Restoration Plan which is designed to restore,
preserve, and enhance Louisiana's coastal wetlands, The plan is the result of
over 25 years of research and involves many innovative techniques designed to
work with nature. The plan is an evolving one and includes a large number of
individual projects which are designed to meet specific needs. Current
restoration techniques include freshwater diversion, sediment diversion, marsh
management, sediment capturing, shallow bay terracing, and structural
shoreline erosion abatement devices.

On the local level, parish programs have been approved in Jefferson, Orleans, St.

Bernard, Cameron, St. James, Lafourche, and Calcasieu. ‘Elements included in

local coastal program include: .

Q Assessment of an area's environment, natural resources, and
socioeconomic and demographic profiles;

Q Plan for the proper management of these resources and their:
interaction with other state and federal programs;

Q Zoning plan for the area;

Q Description of the proposed permit program; and

Q Breakdown of the parish's environmental management units

(EMUs), including a description and analysis of each.

MississipplI
The Mississippi Coastal Program was approved by the Commission on Wildlife
Conservation on August 22, 1980, and has been updated throughout its
implementation. This program is built around ten goals for guiding decisions

affecting the development of Mississippi's coastal resources. These goals include,
but are not limited to, the following:

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 72



United States Office Of Water EPA 800-B-94-003
Environmental Protection Gulf Of Mexico Program July 1994

- Agency Stennis Space Genter, MS 39529

Goastal And Shoreline Erosion
Action Agenda

For The Gulf Of Mexico

First Generation—Management
Committee Report —



Glossary

Appendix C

knot

lagging
lagoon

land breeze

Jand-sea breeze

landlocked

Jandmark

lead line

lee

leeward

length of wave

levee

limit of backrush
(limit of backwash)

littoral
littoral current
littoral deposits

littoral drift

littoral transport

littoral transport
rate

The unit of speed used in navigation equal to 1 nautical mile (6,076.115 feet or
1,852 meters) per hour.

See TIDES, DAILY RETARDATION OF.
A shallow body of water, like a pond or lake, usually connected to the sea.

A light wind blowing from the land to the sea, caused by unequal cooling of land
and water masses.

The combination of a land breeze and a sea breeze as a diurnal phenomenon.

Enclosed, or nearly enclosed, by land--thus protected from the sea, as a bay or a
harbor.

A conspicuous object, natural or artificial, located near or on land, which aids in
fixing the position of an observer.

A line, wire, or cord used in sounding. It is weighted at one end with a plummet
(sounding lead); also SOUNDING LINE.

((1)) Shelter, or the part or side sheltered or turned away from the wind waves.
(2) (Chiefly nautical) The quarter or region toward which the wind blows.

The direction toward which the wind is blowing; the direction toward which
waves are traveling.

The horizontal distance between similar points on two successive waves
measured perpendicularly to the crest.

A dike or embankment to protect land from inundation.

See BACKRUSH, BACKWASH.

Of or pertaining to a shore, especially of the sea.
See CURRENT, LITTORAL.
Deposits of littoral drift.

The sedimentary material moved in the littoral zone under the influence of
waves and currents.

The movement of littoral drift in the littoral zone by waves and currents;
includes movement parallel (longshore transport) and perpendicular (on-
offshore transport) to the shore.

Rate of transport of sedimentary material parallel or

perpendicular to the shore in the littoral zone; usually expressed in cubic meters
(cubic yards) per year; commonly synonymous with LONGSHORE
TRANSPORT RATE.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 98





Glossary

Appendix C

littoral zone

load

longshore
longshore bar
longshore current
longshore
transport rate
low tide

(low water)

low water datum

low water line
lower high water
lower low water
mangrove
marigram

marsh ©

marsh, salt

mean high water

In beach terminology, an indefinite zone extending seaward from the shoreline
to just beyond the breaker zone.

The quantity of sediment transported by a current. It includes the suspended
load of small particles and the bedload of large particles that move along the
bottom.

Parallel to and near the shoreline. See ALONGSHORE.

A bar running roughly parallel to the shoreline.

See CURRENT, LONGSHORE.

Rate of transport of sedimentary material parallel to the shore; usually
expressed in cubic meters (cubic yards) per year; commonly synonymous with
LITTORAL TRANSPORT RATE.

(LW) The minimum elevation reached by each falling tide. See TIDE.

An approximation to the plane of mean low water that has been adopted as a
standard reference plane. See DATUM, PLANE, and CHART

The intersection of any standard low tide datum plane with the shore.
(LHW) The lower of the two high waters of any tidal day.

(LLW)The lower of the two low waters of any tidal day. The single low water
occurring daily during periods when the tide is diurnal is considered to be a
lower low water.

A tropical tree with interlacing prop roots, confined to low-lying brackish -
areas. .

A tropical tree with interlacing prop roots, confined to low-lying brackish
areas.

An area of soft, wet, or periodically inundated land, generally treeless and
usually characterized by grasses and other low growth.

A marsh periodically flooded by salt water.

(MHW) The average height of the high waters over a 19-year period. For
shorter periods of observations; corrections are applied to eliminate known
variations and reduce the results to the equivalent of a mean 19-year value.

All high water heights are included in the average where the type of tide is
either semidiurnal or mixed. Only the higher high water heights are included
in the average where the type of tide is diurnal. So determined, mean high
water in the latter case is the same as mean higher high water.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) . 939



Coastal & Shoreline Erosion in the Gulf of Mexico Chapter 2

of periodically depositing channel maintenance dredging material offshore have
resulted in critical erosion for 11 km (7 mi) west of the inlet. Historical erosion
reaches a maximum of 2.4 m/year (8 ft/year) about 1.8 km (1.1 mi) west of the inlet
(alsillie et al., 1986a, 1986b). Stapor (1973a) identified a drift divide just east of St.
Andrews Inlet with net easterly transport occurring along most of Shell Island.
Measured erosion rates (Balsillie et al., 1986a, 1986b) along the island range between
0.5 m/year (1.7 ft/year) to 2 m/year (6.4 ft/year).

San Blas Realignment. Immediately east of Shell Island is an area of confluence of two
longshore transport cells. To the southeast, along Crooked Island, net longhore
transport is to the northwest. Southeast of Crooked Island is another mainland
reach along which net transport is to the southeast (Stapor, 1973a). St. Joseph
Peninsula to the south, 27 km (17 mi) in length, is a barrier spit of recent geological
age. The spit extends west from the mainland for about 5 km (3 mi) where it forms
Cape San Blas, then trends in a north-south direction. St. Joseph Peninsula ranges
in width from less than 182 to 1,402 m (600 to 4,600 ft) and is subject to overwash and
breaching along several narrow reaches. Primary dunes range in height from 1.5 to
11 m (5 to 37 ft) with beach widths ranging from 21 to 152 m (70 to 500 ft). Except for
the northern 3.5 km (2.2 mi) which is accreting, the peninsula is eroding (Stapor,
1971; Tanner, 1975; Balsillie, 1985a; Clark, 1991a), with the most extreme erosion rate
fronting the Florida Gulf Coast occurring at Stump Hole, along the southern part of
the peninsula just north of Cape San Blas, at 9 m/year (31 ft/year) (Balsillie, 1985a).
Cape San Blas lighthouse has been relocated six times to eastern sites since its
original construction (Tanner, 1975). Sensitivity of shoreline change to storm tides
and wave conditions has been witnessed during two hurricanes in 1985, when 762
m (2,500 ft) of the southward projecting cape disappeared (Clark, 1986). An
alongshore drift divide has been identified somewhere along the southern one-
third of St. Joseph Peninsula (Stapor, 1971) with St. Joseph Point (north end of the
feature) accreting northward due to erosion north of the divide and southerly
transport south of the divide contributing sand to the extensive shoals off of Cape
San Blas.

Apalachicola-Ochiockonee Barriers. To the east of Cape San Blas, historical rates of
accretion are as high as 19 m/year (61 ft/year), suggesting a significant net eastward
transport of Cape San Blas sediment. The mainland segment spans 4.7 km (2.9 mi)
of coast east to Indian Peninsula, a 4.8 km (3 mi) eastward extending spit. East of
Indian Peninsula lies St. Vincent Island, a triangularly shaped barrier comprised of a
unique complex of multiple beach ridges trending generally southeast to east-
southeast. To the east, St. Vincent Island is the barrier island complex of Little St.
George and St. George Islands which is about 47 km (29 mi) long and ranges from
335 to 1,609 m (1,100 ft to 1 mi) in width. Little St. George was once a separate island
that is now part of St. George Island. Along an approximate 10.5 km (6.5 mi) reach
of western St. George Island, erosion appears to exceed 2 m/ year (6.5 ft/year).

Westerly directed net longshore transport occurs along this erosional reach which is
bisected by a small human-made jettied inlet (Bob Sikes Cut). East of St. George

Gulf of Mexico Coastal & Shoreline Erosion Actlon Agenda (4.1) 20



Federal & State Framework Appendix A

. Mexico Beach inlet sand transfer--A small, stabilized inlet channel was developed
from a creek in the 1950s. From 1971-1975, the city removed sand from the
canal by dragline and placed this sand on downdrift beaches. This was the site
of a USACE jet-pump sand bypassing experiment in 1973-1974. From 1974-1975,
the city installed their own fixed jet-pump sand bypassing system that was
destroyed by Hurricane Eloise. It has been estimated that 20,652 m3/year (27; 000

yd3/year) were moved by the jet-pump.

* Mexico Beach bulkheads--Many of the bulkheads were destroyed by Hurricane
Kate.

* St. Joseph Peninsula inlet sand transfer--In 1985, 229,470 m3 (300,000 yd3) of sand
dredged from St. Joseph Point Channel were placed on the updrift beaches.

* Sikes Cut. St. George Island, inlet sang transfer--A pass was cut in 1954 to
Apalachicola Bay. Dredged sand was placed on downdrift, western beaches at a
rate of about 30,596 m3 /year (40,000 yd3/year). During the 1960s and 1970s, this
disposal site was in the bay waters.

° = Si George Island St. Park dune construction and vegetation--Fencing with some sea oat
. Plantings was built to establish a dune field to protect a roadway along the state
park. The project was begun after Hurricane Kate, extending from the late
1970s to early 1980s.

. Alligator Point grain field--Rubble groins were built from 1971-1972. Several ‘sand
bag groins were built also, but they did not survive Hurricane Agnes in 1972.

* — Southwest Cape of Alligator Point retreat and revetment-~Several houses were moved
to the back of lots, and several revetments were constructed. A state study
recommended rebuilding as a cost effective alternative. Other alternatives
were also considered (e.g., redesigning the roadway as a pile-supported elevated
causeway and buying property).

* — Lighthouse Point, Franklin County, roadway not reconstructed~-In 1985, hurricanes
destroyed a roadway and the recommendation was to not rebuilt a section of
the roadway. A 1.4 km (0.9 mi) section of the road has been recommended for
landward relocation, but this recommendation has not yet been implemented.
Approximately 305m (1000 ft) of seawall was destroyed by the same storms.

. Mashes Sands land acouisition--An eroding barrier island was purchased through
the State of Florida's environmentally endangered lands bill. :

* Honeymoon Island State Park beach restoration--Beachfill and some groins were
constructed with sand from a nearby land source and transported to site by
trucks.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 73



Federal & State Framework Appendix A

type of erosion control option, and asserting specific design recommendations for
bulkheads, revetments, and vegetation.

The program calls for support for erosion control projects from USACE and from
local governments. These projects include beach replenishment and dredged
material disposal techniques.

Development is directly regulated to minimize adverse impacts. This is done by
addressing special management areas (SMA). SMAs detail all regulations
affecting an area and specifically state what will and will not happen in an area,
ensuring that development will occur in a predictable manner.

Texas

The Open Beaches Act (Sections 61.001-61.025 of the Texas Natural Resources Code),
passed by the Texas Legislature in 1959, guarantees the public's right of free and
unrestricted access to the "public beach," which extends from the line of mean low
tide to the line of permanent vegetation of the shoreline bordering the Gulf of
Mexico. The Act makes it unlawful to prevent or impede access to or use of the
public beach by érecting barriers or by posting signs declaring a beach closed to the
public.

The Dune Protection Act (Sections 63.001-63.122 of the Texas Natural Resources
Code), prohibits damage to or destruction of dunes or dune vegetation seaward of a
dune protection line. Activities in critical dune areas must be permitted by the
coastal county or municipality which ensures that damage to dunes and dune
vegetation is avoided to the greatest extent practicable.

Regulatory Agencies & Programs

The Texas Legislature has distributed authority for coastal resource management
among a number of state agencies. This system has evolved historically with no
formal coordination mechanism to ensure a consistent management approach.

* Texas General Land Office (GLO). GLO, in conjunction with the School Land
Board, manages the state's coastal public lands. GLO has developed a coastal
management plan for Texas beaches and the state-owned submerged land
underlying the Gulf of Mexico. On June 7, 1991, the Texas State Legislature
passed two bills creating a State-Owned Wetlands Conservation Plan and a
Coastal Management Plan addressing coastal erosion, beach. access, dune
protection, and planning and coordination of these activities. The Governor of
Texas has given notice to the USDOC that Texas will submit a coastal
management plan for approval under the federal Coastal Zone re Management Act.

Gulf of Moxico Coastal & Shoreline Erosion Action Agenda (4.1)



Overviow of the Gulf of Mexico Chapter 1

Q Diversions and consumptive use for human activities have resulted in
significant changes in the quantity and timing of freshwater inflows to
the Gulf of Mexico.

Q More than half of the shellfish-producing areas along the Gulf Coast
are permanently or conditionally closed. These closure areas are
growing as a result-of increasing human and domestic animal
populations along the Gulf Coast (USDOC, 1991).

Q Louisiana is losing valuable coastal wetlands at the rate of
approximately 14-66 km?/year (5-25 mi? /year) (Dunbar, et al., 1992).

Q Almost 1,800 kg/mi (2 tons/mi) of marine trash covered Texas beaches
in 1988. :

Q Up to 9,500 km? (4,000 mi?) of oxygen deficient (hypoxia) bottom. waters,
known as the "dead zone," have been documented off the Louisiana
and Texas coasts (Rabalais, et al., 1991).

Q Gulf shorelines are eroding up to 30 m/year (100 ft/ year). Few coastal
reaches in the Gulf-can be characterized as "stable" or "accreting."

The Gulf of Mexico Program - Goals & Structure

Problems plaguing the Gulf cannot be addressed in a piecemeal fashion. These
problems and the resources needed to address them are too great. The Gulf of
Mexico Program (GMP) was. formed to pioneer a broad, geographic focus in order td
address major environmental issues in the Gulf before the damage is irreversible or
too costly to correct.

The program is part of a cooperative effort with other agencies and organizations in
the five Gulf States, as well as with people and groups who use the Gulf. In addition
to the U.S. Environmental Protection Agency (USEPA), other participating federal
government agencies include: National Aeronautics and Space Administration
(NASA), U.S. Army Corps of Engineers (USACE), U.S. Department of Agriculture
(USDA), U.S. Department of Commerce (USDOC), U.S. Department of Defense
(USDOD), U.S. Department of Energy (USDOE), U.S. Department of the Interior
(USDOD, U.S. Department of Transportation (USDOT), U.S. Food & Drug
Administration (USFDA), and Agency for Toxic Substances & Disease Registry
(ATSDR). :

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 4



The Unfinished Agenda Chapter 4

Erosion Response

The most effective way to reduce the impacts of coastal and shoreline erosion is, first,
to understand the mechanisms and causes and how they affect the coastline and,
second, to incorporate this knowledge into planning. It will cost far more to restore
eroded areas later than to plan for erosion now. This should be a shared
responsibility among all in the Gulf region--federal, state, and local governments, the
private sector, and citizens.

Specific objectives and action items follow:

OBJECTIVE: Evaluate existing and potential response alternatives
for coastal erosion in the Gulf of Mexico region.

Action Item 8 - Existing Erosion Control Projects Gulfwide

Publish a summary listing of existing coastal erosion control
projects Gulfwide. This summary will include pertinent data such
as responsible agencies, type of erosion control, source of
information, monitoring programs, and project status.

Lead: Gulf of Mexico Program Coastal & Shoreline Erosion
Committee.

InItlation Date: 1993

Action Item 10 - Evaluation of Selected Gulf of Mexico Demonstration Projects

Using the summary from Action Item 9, select a representative
group of projects within the Gulf of Mexico region, and task
responsible agencies to submit an evaluative report to the Coastal
& Shoreline Erosion Committee (see Appendix E).

Lead: Gulf of Mexico Program Coastal & Shoreline Erosion
Committee.

InItlation Date: 1994

Gulf of Mexlco Coastal & Shoreline Erosion Action Agenda (4.1) 44



Acronym Guide Appendix B

ACAMP Alabama Coastal Area Management Program

ADECA Alabama Department of Economic and Community Affairs
ADEM Alabama Department of Environmental Management
AL Alabama

ATSDR Agency for Toxic Substances and Disease Registry

BEB Beach Erosion Board

BMR Bureau of Marine Resources

CAC Citizens Advisory Committee, Gulf of Mexico Program
CBRA Coastal Barriers Resources Act

CBRS Coastal Barrier Resources System

CCCL Coastal Construction Control Line

CMD Coastal Management Division

COP Coastal Ocean Program

CUP Coastal Use Permit

CWA Clean Water Act

CWPPRA Coastal Wetlands Planning, Protection, and Restoration Act
CZMA Coastal Zone Management Act

CZMP Coastal Zone Management Plan (or Program)

DCA Department of Community Affairs

DER Department of Environmental Regulation

DOT Texas Department of Transportation

DNR Department of Natural Resources

ECL Erosion Control Line

EEZ Exclusive Economic Zone

EIS Environmental Impact Statement

EMU Environmental Management Unit--Louisiana Parishes
FCMP Florida Coastal Management Program

FEMA Federal Emergency Management Agency

FL Florida

FELDER Florida Department of Natural Resources

GLO Texas General Land Office

GMP Gulf of Mexico Program

GMPO Gulf of Mexico Program Office

LA Louisiana

LCA Local Cooperation Agreement

LCRP Louisiana Coastal Resources Program

LGS Louisiana Geological Survey

MC Management Committee--Gulf of Mexico Program
MMS U.S. Minerals Management Service

MS Mississippi

MSL Mean Sea Level

NASA National Aeronautics and Space Administration
NEEA National Environmental Education Act

NEP National Estuary Program

NEPA National Environmental Policy Act

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 86



Federal & State Framework Appendix A

Scientific studies of sedimentary processes and seismicity traditionally have been
part of the USGS mandate, and recently, Congress directed USGS to take the lead in
geologic studies of the coastal zone and wetlands by creating a National Coastal
Geology Program. Areas of study include erosion, polluted sediments, and wetlands
deterioration.

Minerals Management Service (MMS)

MMS studies the potential impact of offshore activities, including the placement
and construction of petroleum pipelines, on coastal wetlands and resources. MMS
also funds research through state geoscience agencies for identifying mineral
resources in the coastal zone.

U.S. Department of Commerce (USDOC)
National Oceanic & Atmospheric Administration (NOAA) -

NOAA conducts studies of wetlands and coastal habitats that support marine
resources; prepares nautical charts and geodetic surveys of coastal areas; monitors
storm activities; operates an environmental satellite system; and administers a
grants program for marine research. NOAA administers the federal Coastal Zone
Management Program as directed by the Coastal Zone Management Act.

+ Habitat Strategic Plan. NOAA has recently developed the Habitat Strategic Plan, the
agency's long-range strategy for coordinated and concerted action to address the
deterioration of the nation’s coastal, estuarine, and riverine habitats and populations of
living marine resources dependent upon such habitats. NOAA's legislative
responsibilities and capabilities in habitat protection, wetlands ecology, resource
conservation, toxicology, ocean system dynamics, fishery management, biological
processes, and coastal habitat management provide a solid foundation for addressing
these issues through an inter-disciplinary approach. NOAA has invested over $100
million. per year in programs and activities that focus.on habitat-related problems and
issues along the nation’s coasts and throughout the Exclusive Economic Zone (EEZ),
including protectorates and trust territories in the Pacific Ocean and Caribbean Sea.

The NOAA Habitat Strategic Plan provides detailed, agency-wide guidance for
addressing the priority issues affecting habitat important to living marine
resources throughout the nation's coastal waters. This document complements
“NOAA's Investment in Coastal Environmental Quality," which is being
published separately, but focuses specifically on living marine resources' habitats.
NOAA's role in this effort is: 1) to develop the scientific understanding of how
human activities affect natural ecosystem functioning and 2) to assess and predict
the effects of specific land and water development proposals on coastal
environments and their living marine resources. NOAA's goal for habitat

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 65



Coastal & Shoreline Erosion in the Gulf of Mexico Chapter 2

sand. Net longshore sediment transport directions vary according to the beach
alignment and exposure to wave activity. While shoreline stability is apparent in
most areas during the 50 years since Davis conducted his study, significant beach
losses have occurred due to the "quiet invasion" of mangroves (Clark, 1990a).
Although the length of the outer island beaches nearest Key West is over 4.2 km (2.6
mi), these front on the straits of Florida. The northern shores of these islands
appear to be stable mangrove shorelines. The cumulative length of the beaches of
the Marquesas Keys is nearly 7.2 km (4.5 mi). Long Beach Key, with over 4 km (2.5
mi) of continuous Gulf beach front is the longest and largest of all the islands west
of Key West. Beach sediments are predominantly green algae fragments, a material
which is readily produced in the adjacent waters. The dune ridge is stabilized by one
of the densest communities of sea oats found along Florida's beaches. The most
remote beaches of Florida are those of the Dry Tortugas or Tortugas Keys, which are
located about 105 km (65 mi) west of Key West. All six islands of this group have
beaches which cumulatively measure 7.2 km (4.5 mi) and are comprised largely of
coral fragments as well as green algae. The nearly 3.2 km (2 mi) of beach on
Loggerhead Key (the farthest west of all the Tortugas Keys) characterize perhaps the
highest wave energy conditions south of Cape Romano. The steeply sloping beaches
of Loggerhead Key and Sand Key are fronted by a developing beachrock of calcareous
sand which Ginsburg (1979) describes as the only occurrence of marine beachrock in
the continental U.S. Beach processes of the Dry Tortugas are generally unresearched
and in need of further study to determine erosion/accretion patterns and longshore
transport processes.

Historical Shoreline Change Data. Determination of long-term coastal behavior to
be pursued and applied in regulating coastal excavation and construction activities
in Florida became a mandate of the Florida State Legislature pursuant to the Growth
Management Act of 1985. Adopted provisions are set forth in an amendment to the
Beach and Shore Preservation Act, Section 161.053, Subsection (6) of the Florida
Statutes. Pursuant to requirements of this law, the methodology for procuring and
analyzing data, interpreting and accepting results, and application of results are
formalized by rule published in Chapter 16 16B-33 of the Florida Administrative
Code (Balsillie and Moore 1985; Balsillie, 1985b).

Louisiana

Overview of the Problem. The Mississippi River built the coastal wetlands of
Louisiana by taking enormous amounts of sediment eroded from the interior of
North America and depositing the material in delta lobes where the river enters the
Gulf of Mexico. As the river built its delta in this manner, it lengthened its own
route to the Gulf, making it increasingly less efficient hydraulically. Approximately
once every thousand years, the river would not return fully to its channel after the
annual flood, but instead would establish a new, more efficient route to the Gulf.
As the river developed this new route over several flood seasons, it would send less
water and sediment down the old route. The old delta, abandoned by the river,

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



The Unfinished Agenda Chapter 4

4 THE UNFINISHED AGENDA --
Both Current Commitments & Uncommitted Activities

Goal

Q Reduce the impacts of coastal and shoreline erosion in the Gulf of
Mexico.

The scope of this Action Agenda includes the following major areas: mainland
shorelines, barrier islands, major bays and estuaries, major waterways, and
peninsulas.

Objectives & Action Items

Three types of activity have been designed to meet the goal: 1) Erosion
Identification, Characterization, and Assessment; 2) Erosion Response; and 3) Public
Education and Outreach. Specific objectives and action items are grouped according
to these areas (see Index of Coastal & Shoreline Erosion Objectives & Action
Items).

Objectives are the specific, short-term targets for attaining the goal. Each
objective is followed by action items that describe specific tasks to meet the goals
and objectives for the Coastal & Shoreline Erosion Action Agenda. Each action
item is presented under an appropriate objective.

No specific implementation projects are proposed in this iteration of the Action
Agenda. Rather the Coastal & Shoreline Erosion Committee has focused on
development of a consensus on the most effective responses to critical erosion
problems and the monitoring of projects that are already underway at the federal
and state levels. It is anticipated that future iterations of the Action Agenda will
include specific implementation projects.

Lead. The Coastal & Shoreline Erosion Committee has identified a lead agency for
each action item. A proposed action item may involve the execution of legislative
or regulatory authorities or programmatic initiatives which derive from these
authorities. In other cases, a proposed action item may involve the facilitation or
coordination of activities among several agencies or organizations. In these cases,
and where there is no clear legislative authority involved, the "lead" could be the
agency or organization which expresses an interest in taking on the task during Gulf
of Mexico Program Issue Committee deliberations, the action planning workshop or
public comment period, or, in the Issue Committee's judgment, is best able to guide
multiple parties in carrying out the activity. This does not necessarily mean that the

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



Glossary

Appendix ¢

surging breaker
swale

swash

swash mark

swell

terrace

thalweg
tidal current
tidal datum

tidal day

tidal flats

tidal inlet

tidal period
tidal pool

tidal prism

tidal range

tidal wave

See BREAKER.
The depression between two beach ridges.

The rush of water up onto the beach face following the breaking of a wave; also
UPRUSH, RUNUP.

The thin wavy line of fine sand, mica scales, bits of seaweed, etc., left by the
uprush when it recedes from its upward limit of movement on the beach face.

Wind-generated waves that have traveled out of their generating area. Swell
characteristically exhibits a more regular and longer period and has flatter
crests than waves within their fetch (SEAS).

A horizontal or nearly horizontal natural or artificial topographic feature
interrupting a steeper slope, sometimes occurring in a series.

In hydraulics, the line joining the deepest points of an inlet or stream channel.

See CURRENT, TIDAL.

See CHART DATUM and DATUM PLANE.

The time of the rotation of the Earth with respect to the Moon or the interval
between two successive upper transits of the Moon over the meridian of a plane,
approximately 24.84 solar hours (24 hours and 50 minutes) or 1.035 times the
mean solar day; also called lunar day.

Marshy or muddy land areas which are covered and uncovered by the rise and
fall of the tide.

(1) A natural inlet maintained by tidal flow. (2) Loosely, any inlet in which
the tide ebbs and flows; also TIDAL OUTLET.

The interval of time between two consecutive, like phases of the tide,.
A pool of water remaining on a beach or reef after recession of the tide.

The total amount of water that flows into a harbor or estuary or out again with
movement of the tide, excluding any freshwater flow.

The difference is height between consecutive high and low (or higher high and
lower low) waters.

(1) The wave motion of the tides. (2) In popular usage, any unusually high and
destructive water level along a shore. It usually refers to STORM SURGE or
TSUNAMI.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



The Unfinished Agenda Chapter 4

Action Item 8 - Erosion Area Prioritization for Gulf of Mexico States

Develop working definitions of critical erosion and model
frameworks for prioritizing erosion areas within each Gulf State
including major “hot spots."

Lead: Gulf of Mexico Program Coastal & Shoreline Erosion :
Committee, in cooperation with appropriate agencies and Gulf Le
States.

InItlation Date: 1995

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 43



The Unfinished Agenda Chapter 4

agency or organization has agreed to carry out the activity, that it has the necessary
funding, or that it should attempt to accomplish the action solely with its own
resources. These agencies or organizations should provide the leadership needed to
see that action items are executed in an efficient manner. Part of this execution role
should include determining the most appropriate products from each action item
and information needs that, if fulfilled, would enhance the action item's overall
purpose. The Issue Committee understands these action items will require
commitments by agencies and organizations that are dependent on budget, and
perhaps policy or even authority, decisions. However, the Issue Committee
members hope this document provides the rationale and support for such
commitments. It is anticipated that future iterations of this document will
incorporate additional specific commitments including actions to address any
limitations in authority that may become apparent. This is intended to be a
continuous process--as action items are completed they will stimulate the
development of new action items.

Initiation Date. The date indicated represents a determination by the Issue
Committee of the most realistic initiation date for the action item. As lead
agencies begin implementation planning for specific action items, these
initiation dates may change due to resource availability and prioritization within
the individual agencies.

The Gulf of Mexico Program recognizes the need to identify indicators of
environmental progress relative to this Action Agenda for coastal and shoreline
erosion. Many of the action iterns specified in Chapter 4 of this document will aid
the Program in developing a baseline for measuring success in the future. For the
time being, however, acceptance and completion of action items specified in this
Action Agenda will be considered a-:measure of success. As future Action Agendas
are written and current action items are completed, new action items will be
developed to better measure environmental progress. The Gulf of Mexico Program
will coordinate among the eight Gulf of Mexico Program Issue Committees to
eliminate overlap and duplication of efforts, as well as to integrate goals and
activities across environmental issue areas.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 39



Federal & State Framework Appendix A

STATE LEVEL

Alabama

The Alabama Coastal Area Management Program (ACAMP) is currently being
revised. ACAMP divides coastal area program responsibilities between two state
agencies. The Alabama Department of Economic & Community Affairs (ADECA) is
responsible for administration and planning, while permitting and enforcement
activities are conducted by the Alabama Department of Environmental
Management (ADEM).

The Alabama Coastal Construction Control Line (CCCL) is designed to provide long-
term protection of the beach and dune system by prohibiting construction seaward
of the established setback line (ADEM, Administrative Code, 8-1-.16).

The Shoreline Erosion Mitigation Program states that, in mitigating a shoreline
erosion problem, non-structural erosion control methods shall be used to the
maximum extent practicable. Placement of groins, jetties, and breakwaters as
erosion control devices shall be permissible only when no other technically feasible
alternative is available (ADEM, Administrative Code, 8-1-.08).

Statutes
Qa Act 73-971 Prohibition of picking of wild sea oats.

Qa Act 81-563 Prohibition of vehicles on beaches: and dunes.

Florida

The State of Florida has instituted several regulatory initiatives in an attempt to
slow the rate of coastal erosion along its Gulf of Mexico coastline. The thrust of
these initiatives began in 1970, in the Florida State Legislature, with a series of
statements recognizing the harmful effects of beach and shore erosion on "the
economy and general welfare of the people" of Florida (Balsillie, 1988).

Soon after issuing these statements, the legislature passed the Beach & Shore
Preservation Act (Chapter 161, Florida Statutes), charging the Florida Department of
Natural Resources (DNR) with the responsibility for its administration. Through
the years, however, the program of beach and coast preservation has reached a level
of significant specialization with regard to technical issues quantifying natural
processes as well as a broadened program format. Presently, major program
elements include: the establishment of regulatory jurisdictions; construction
regulation, enforcement activities, and associated technical aspects; and a funding
mechanism for public civil works projects (Balsillie, 1988).

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 68



Federal & State Framework Appendix A

* Perdido Key inlet sand transfer--About 5,351,682 m3 (seven million yd3) of sand
from the Pensacola Pass entrance channel deepening were placed on the
Johnson Beach portion of Gulf Islands National Seashore in 1990. Almost
2,293,578 m3 (three million yd3) were placed in the nearshore.

¢ Dunes Motel, Pensacola Beach seawall--Hurricane Elena destroyed the seawall and
undermined a building which was later destroyed by Hurricane Juan. This
structure was located over 30m (100 ft) seaward of all nearby structures. Debris
has now been removed.

* Pensacola Beach overwashed sand replacement--At the request of Florida DNR,
town and homeowners scraped overwashed sand from roads and driveways

and placed it on the beach after Hurricane Frederic.

. East Pass inlet sand transfer--Sand dredged from the Pass has previously been
placed in a storage pile on Eglin Air Force Base property.

* Panama City beach nourishment--During the spring of 1976, sand was pumped from
the nearshore profile onto the beaches to construct a storm berm/dune. This

was paid for with FEMA disaster relief monies after Hurricane Eloise.

. Panama City bulkheads--At least 50 percent of the coast is armored with wooden or
concrete bulkheads. Many of these were destroyed in 1975 by Hurricane Eloise.
Others were destroyed in 1983 storms.

° Treasure Island Motel, Panama City Beach seawall--The seawall was destroyed by
Hurricane Juan. The motel was also damaged, but has since been rebuilt.

Adjacent property was not permitted for repair. This wall was seaward of all
other adjacent property. Its presence probably caused extra erosion/recession
on unprotected adjacent property during Hurricane Juan.

* Pinnacle Port Condo, Bay County, dune/geotextile-- The dune, built in 1985, is
constructed around a staked down geotextile. Periodically, replantings are

placed over geotextile. The dune was designed as a protection from minor high
tides and storms. A requested permit for a seawall was denied by Florida DNR.
The original developer had been strongly warned not to build so close to the
water's edge. .

° — St_Angrews State park inlet sand transfer--A total of over 764,900 m3 (one million
yd) of sand from adjacent St. Andrews Pass placed on beaches during 1985,
1982, and 1973.

* — Shell island land acouisition--The land was purchased with state money under the
Save Our Coast Program.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 78



Coastal & Shoreline Erosion in the Gulf of Mexico Chapter2

This should provide accurate data to the public officials charged with managing the
impact of coastline changes c on the human population and the environment
(Oivanki, 1992).

Texas

Regional Framework. Modern beaches and barrier islands of the Texas coast are
artanged in an orderly pattern with respect to the principal geomorphic elements of
the region. The deltaic systems and a fluvial-deltaic headland referred to as the
Trinity delta are depositional features controlling the spatial arrangement of
shoreline types and, consequently, barrier island types. During the most recent
period of sea level stability, the three headlands formed large promontories in the
Gulf of Mexico that focused wave energy and created three cells of littoral drift
convergence. These headlands are also the sites of transgressive beaches that have
been retreating rapidly for several thousand years.

Field observations and photo interpretations confirm that land losses along the
Texas Gulf of Mexico coast are concentrated in three areas of reduced or low
sediment supply: (1) between Sabine Pass and Bolivar Peninsula, (2) between the
Brazos and Colorado Rivers, and (3) north of the Rio Grande River. Whereas the
first two areas are low-lying headlands characterized by muddy substrates and
narrow, steep beaches, the third area(near South Padre Island) is a former deltaic
headland that was transformed into a transgressive barrier/lagoon complex as the
Rio Grande delta foundered.

Coastal Processes. The Texas coast is a storm-dominated region with a small tide
range that is constantly changing as a result of active coastal processes linked directly
to meteorological vents. Wind and its resulting nearshore processes are clearly the
most important geological agents controlling the sediment transport and evolution
of the Texas shoreline.

Wind directions and intensities are distributed seasonally, with southeast winds of
16 to 24 km/h (10 to 15 mph) prevailing most of the year. Highest sustained wind
velocities accompany major hurricanes, which can drive nearshore currents and
large volumes of beach and shoreface sand to the west and southwest along the
Texas coast.

Overview of the Problem. Of the 591 km (367 mi) of Texas Gulf shoreline,
approximately 60 percent is eroding at rates of between 0.3 and 15 m/year (1 and 50
ft/year), 33 percent is stable, and 7 percent is accreting. Erosion is not confined to the
Texas Gulf beaches. Erosion also affects the bay systems, where it causes the loss of
agricultural, industrial, and residential lands and threatens the productive wetlands
that serve as nursery grounds for sport and commercial fisheries. In total, about
two-thirds of Texas bay shores are eroding. Every year along the Gulf shoreline in

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 33



Glossary

Appendix €

quicksand

radius of
maximum winds

recession
(of a beach)

reef

reef, sand
reference plane
reflected wave
refraction (of
water waves)
retardation
retrogression
(of a beach)

revetment:

ria

ridge, beach

Loose, yielding, wet sand which offers no support to heavy objects. The upward
flow of the water has a velocity that eliminates contact pressures between the
sand grains and causes the sand-water mass to behave like a fluid.

Distance from the eye of a hurricane, where surface and wind velocities are
zero, to the place where surface windspeeds are maximum.

(1) A continuing landward movement of the shore-line. (2) A net landward
movement of the shoreline over a specified time; also RETROGRESSION.

An offshore consolidated rock hazard to navigation, with a least depth of
about 20 meters (10 fathoms) or less.

See BAR.
See DATUM PLANE.

That part of an incident wave that is returned seaward when a wave impinges
on a steep beach, barrier, or other reflecting surface.

(1) The process by which the direction of a wave moving in shallow water at an
angle to the contours is changed; the part of the wave advancing in shallower
water moves more slowly than that part still advancing in deeper water,
causing the wave crest to bend toward alinement with the underwater contours.
(2) The bending of wave crests by currents.

The amount of time by which corresponding tidal phases grow later day by day
{about 50 minutes)

(1) A continuing landward movement of the shore-line. (2) A net landward
movement of the shoreline over a specified time; also RECESSION.

A facing of stone, concrete, etc., built to protect a scarp, embankment, or shore
structure against erosion by wave action or currents.

A long, narrow inlet, with depth gradually diminishing inward.

A nearly continuous mound of beach material that has been shaped by wave or
other action. Ridges may occur singly or as a series of approximately parallel
deposits; British usage, FULL.

A body of water made rough by waves meeting an opposing current, particularly
a tidal current; often found where tidal currents.are converging and sinking.

A strong surface current flowing seaward from the shore. It usually appears as a
visible band of agitated water and is the return movement of water piled up on
the shore by incoming waves and wind. -With the seaward movement
concentrated in a limited band its velocity is somewhat accentuated. A rip
consists of three parts: the FEEDER CURRENTS flowing parallel to the shore
inside the breakers; The NECK, where the feeder currents converge and flow
through the breakers in a narrow band or "rip"; and the HEAD, where the
current widens and slackens outside the breaker line. A‘rip current is often
miscalled a rip tide; also RIP SURF. See NEARSHORE CURRENT SYSTEM.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 103



Participants in the Action Agenda Development Process

Appendix D

Edward Seidensticker
David W. Smith
David Smith

Everett Smith
Thomas Smith

Cliff Truitt

Michael Voisin
Jeffress Williams

Steering Committee:

Thomas Campbell
Sally Davenport
Scott Douglass

Shea Penland
Douglas Ratcliff
Thomas Richardson
Cliff Truitt

Previous Co-Chairs:

Thomas Campbell
Bill Good

Previous Members:

Mark Curran

Larry Goldman
Rob Gorman

Mary Margaret Hamilton
B.D. King, I
Donald Lirette
Kimberly McKenna
Jack Moody
Douglas Ratcliff
James Rucker
Samuel Sanders
Greg Stone

Soil Conservation Service
Houston, Audubon Society
US. Fish & Wildlife Service
Geological Survey of Alabama
U.S. Army Corps of Engineers
Mote Marine Laboratory
Motivatit Seafoods, Inc.

U.S. Geological Survey

U.S. Army Corps of Engineers

“Texas General Land Office

University of South Alabama
Louisiana Geological Survey
Texas Bureau of Economic Geology
U.S. Army Corps of Engineers
Mote Marine Laboratory

U.S. Army Corps of Engineers
Louisiana Department of Natural Resources

U.S. Environmental Protection Agency

US. Fish & Wildlife Service

Citizens Advisory Committee Representative
United Gas Pipe Line Company

US. Fish & Wildlife Service

Citizens Advisory Committee Representative
Texas General Land Office

Mississippi Office of Geology

Texas Bureau of Economic Geology
University of New Orleans

US. Soil Conservation Service

Louisiana State University

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)





Preface

PREFACE

One of the initial goals for the first five years of the Gulf of Mexico
Program was to establish a “framework-for-action” for implementing
management options for pollution controls, determining research
direction and environmental monitoring protocols, and implementing
remedial and restoration measures for environmental losses. As a means
of developing this framework-for-action, the Gulf Program established
eight committees, composed of experts, to deal with the following
environmental issue areas:

Habitat Degradation

Marine Debris

Freshwater Inflow

Nutrient Enrichment

Toxic Substances & Pesticides _
Public Health

Coastal & Shoreline Erosion
Living Aquatic Resources

oooo0ooaoo0

Each committee was charged with: 1) characterizing the status of the issue,
2) developing goals and cbjectives for remedial and restoration activities,
and 3) developing descriptions of the projects and tasks to be implemented
in order to achieve the stated objectives. This information was
incorporated into an “Action Agenda” for each environmental issue area.

This document is the first generation of one of these Action Agendas.
Representing the consensus of a large number of subject specialists, this
document is considered to be a draft working paper for the Gulf of Mexico
Program Management Committee. Since this first generation Action
Agenda has not been reviewed and approved by all agencies, it is being
made available for informational purposes only.

Gulf of Mexico Program Action Agenda



Glossary Appendix C

freeboard The additional height of a structure above design high water level to prevent
overflow. Also, at a given time, the vertical distance between the water level
and the top of the structure. Ona ship, the distance from the waterline to main
deck or gunwale.

full See RIDGE, BEACH.

generation of The creation and growth of waves caused by a wind blowing over a water

waves surface for a certain period of time. The area involved is called the
GENERATING AREA or FETCH.

geomorphology That branch of both physiography and geology which deals with the form of
the Earth, the general configuration of its surface, and the changes that take
place in the evolution of landform.

groin A shore protection structure build (usually perpendicular to the shoreline) to
trap littoral drift or retard erosion of the shore.

groin system. A scries of groins together to protect.a section of beach; commonly called a groin
field.

ground swell A long high ocean swell; also, this swell as it rises to prominent height in
shallow water.

ground water Subsurface water occupying the zone of saturation. Ina strict sense, the term is
applied only to water below the WATER TABLE.

guif A large embayment in a coast; the entrance is generally wider than the length.

gut (1) a narrow passage such as a strait or inlet. (2) a channel in otherwise

half-tide level
harbor

head of rip

height-of wave
hide tide
high water

high water line

higher high water

shallower water, generally formed by water in motion.
See MEAN TIDE LEVEL.
Any protected water area affording a place of safety for vessels. See PORT.

The part of a rip current that has widened out seaward of the breakers. See
CURRENT, RIP; CURRENT, FEEDER; and NECK (RIP).

See WAVE HEIGHT.
(HW) The maximum elevation reached by each rising tide.
See HIGH TIDE.

The intersection of the plane of mean high water with the shore. The
shoreline delineated on the nautical charts of the National Ocean Service is an
approximation of the high water line. For specific occurrences, the highest
elevation on the shore reached during a storm or rising tide, including
meteorological effects.

(HHW). The higher of the two high waters of any tidal day. The single high
water occurring daily during a period when the tide is diurnal is considered to
be a higher high water.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 96



Bibliography

U.S. Army Corps of Engineers. 1969. "Beach Erosion Control Study on Lee County,
Florida." Jacksonville, FL.

U.S. Army Corps of Engineers. 1971. “National Shoreline Study, Regional
Inventory Report, South Atlantic-Gulf Region, Puerto Rico and the Virgin
Islands." Atlanta, GA.

U.S. Army Corps of Engineers. 1972. "Draft of Beach Erosion Control Study, Collier
County, Florida." Jacksonville, FL.

U.S. Army Corps of Engineers. 1980. "Feasibility Report for Beach Erosion Control,
Charlotte County, Florida." Jacksonville, FL.

U.S. Army Corps of Engineers. 1984a. "Beach Erosion Control Project Review Study
and Environmental Impact Statement for Pinellas County, Florida."
Jacksonville, FL.

U.S. Army Corps of Engineers. 1984b. “Pinellas County, Florida, Beach Erosion
Control Project, Sand Key Segment." General Design Memorandum,
Addendum IV and Environmental Impact Statement. Jacksonville, FL.

U.S. Army Corps of Engineers. 1984c. “Beach Erosion Control Study for Sarasota
County, Florida, with Environmental Impact Statement." Jacksonville, FL.

U.S. Army Corps-of Engineers. 1984d. "Sarasota County, Florida, Shore Protection.
General Design Memorandum. Jacksonville, FL.

U.S. Army Corps of Engineers. 1991a. "Lee County, Florida, Charlotte Harbor
Section 933 Study with Environmental Assessment." Jacksonville, FL.

U.S. Army Corps of Engineers. 1991b. "Manatee County, Florida, Shore Protection
Project, General Design Memorandum with Supplemental Environmental
Impact Statement." Jacksonville FL.

U.S. Department of Commerce. 1990. A Special Earthweek Report: 50 Years of
Population Change Along the Nation's Coasts 1960-2010. National Oceanic
and Atmospheric Administration, National Ocean Service. April 1990.

U.S. Department of Commerce. 1991.. The 1990 National Shellfish Register of.
Classified Estuarine Waters. National Oceanic & Atmospheric
Administration. National Ocean Service. Rockville, MD.

U.S. Department of Commerce. 1992. Current Fishery Statistics No. 9100: Fisheries
of the United States, 1991. Fishery Statistics Division, National Marine
Fisheries Service, NOAA, Silver Springs, MD.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 56



The Unfinished Agenda Chapter 4

Aotlon Item 4 - Local Littoral Sediment Budgets for the Gulf of Mexico

Produce local littoral sediment budgets for the Gulf of Mexico,
including contributions to coasts from major sources such as rivers
and streams.

Lead: U.S. Geological Survey and U.S. Army Corps of Engineers.
InItlation Date: 1995

Action Item & - Erosion Predictive Models

Identify, refine, or develop, as necessary, predictive models on
shoreline erosion, sediment transport, and coastal hydrodynamics.
Lead: U.S. Army Corps of Engineers, U.S. Geological Survey, and
Environmental Protection Agency.

Initlation Date: 1996

OBJECTIVE: Assess ‘the severity of coastal erosion Gulfwide, and
evaluate causes and impacts.

Action Item 6 - Causes of Erosion and Shoreline Loss Gulfwide

Identify major causes of erosion and shoreline loss Gulfwide, and
determine their relative magnitude for contributing to erosion
problems.

Lead: U.S. Geological Survey & U.S. Army Corps of Engineers.
InItlation Date: 1994 |

Action Item 7 - Impacts of Erosion Gulfwide

Identify the major impacts of erosion and shoreline loss Gulfwide.
Lead: U.S. Geological Survey & U.S. Army Corps of Engineers.
InItlation Date: 1995

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 42



Glossary

Appendix ¢

cape

causeway

cay

Central Pressure
Index (CPI)

channel

chart datum

chop

coast

coastal area

coastal plain

coastline

continental shelf

contour

A relatively extensive land area jutting seaward from a continent or large
island which prominently marks a change in, or interrupts notably, the coastal
trend; a prominent feature.

A raised road across wet or marshy ground or across water.

See KEY.

The estimated minimum barometric pressure in the eye

(approximate center) of a particular hurricane. The CPI is considered the most
stable index to intensity of hurricane wind velocities in the periphery of the
storm; the highest wind speeds are associated with storms having the lowest
CPI.

(1) A natural or artificial waterway of perceptible extent which either
periodically or continuously contains moving water, or which forms a connection
link between two bodies of water. (2) The part of a body of water deep enough
to be used for navigation through an area otherwise too shallow for navigation.
(3) A large strait, as the English Channel. (4) The deepest part of a stream,
bay, or strait through which the main volume or current of water flows.

The plane or level to which soundings (or elevations) or tide heights are
referenced (usually LOW WATER DATUM). The surface is called a tidal
datum when referred to a certain phase of tide. To provide a safety factor for
navigation, some level lower than MEAN SEA LEVEL is generally selected for
hydrographic charts, such as MEAN LOW WATER or MEAN LOWER LOW
WATER. See DATUM PLANE.

The short-crested waves that may spring up quickly in a moderate breeze and
which break easily at the crest.

A strip of land of indefinite width (may be several kilometers) that extends
from the shoreline inland to the first major change in terrain features.

The land and sea area bordering the shoreline.

The plain composed of horizontal or gently sloping strata of clastic materials
fronting, the coast and generally representing a strip of sea bottom that has
emerged from the sea in recent geologic time.

(1) Technically, the line that forms the boundary between the COAST and the
SHORE. (2) Commonly, the line that forms the boundary between the land and
the water.

The zone bordering a continent and extending from the low water line to the
depth (usually about 180 meters) where there is a marked or rather steep
descent toward a greater depth.

A line on a map or chart representing points of equal elevation with relation to
a DATUM. It is called an ISOBATH when connecting points of equal depth -
below a datum; also called DEPTH CONTOUR.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) of



Coastal & Shoreline Erosion in the Gulf of Mexico Chapter 2

responses to erosion have included a wide variety of attempts at shoreline
stabilization within the bays and rivers, but only a few attempts on Gulf beaches.

Gulf of Mexico Beaches. Alabama's Gulf beaches include the two coastal counties,
Mobile and Baldwin. Mobile Bay Pass is the dividing line between the two counties.
Dauphin Island is a 25 km (15 mi) long barrier island on the Gulf of Mexico west of
Mobile Bay Pass. The eastern 6 km (3.7 mi) is several kilometers wide with a sand
dune field with elevations of over 14 m (46 ft) above sea level and an extensive
maritime forest. The western 19 km (11.8 mi) portion of the island is only several
hundred meters wide and has maximum elevations of less than 3 m (10 ft) above
sea level and no maritime forest. This low, narrow, western portion frequently
overwashes in major hurricanes. Although the island has been continuously
inhabited by descendants of Europeans since the 1700s, modern land development
only began when the first bridge was built to the island in 1958. The western half of
the island is still undeveloped. The western end of Dauphin Island has grown
rapidly westward toward Mississippi. Westward accretion has averaged about 50
m/year (164 ft/year) since the turn of the century. Shoreline protection works built
around the turn of the century to protect Fort Gaines, a Civil War era coastal fort,
have prevented the eastern end of the island from eroding westward.

The easternmost 6 km (3.7 mi) of the island has two reaches of shoreline which are
presently receding and a reach of shoreline in between them which is accreting.
Recession was measured during 1991-1992 at rates up to 15 m/year (49 ft/year)
(Douglass and Haubner, 1992). These changes are consistent with the changes that
have occurred during the past decade. Averaged over the past decade, maximum
recession rates are 6 m/year (19.7 ft/year). The recession-accretion-recession pattern
at the eastern end of the island appears to be a response to changes in the position of
the Mobile Bay Pass ebb-tidal shoals and ephemeral islands immediately offshore.
Mobile Bay Pass is one of the world's largest tidal inlets. The shoals and islands
(commonly called Sand or Pelican Island) provide both sand for the Dauphin Island
beaches and wave sheltering to those beaches. The shoreline along the remainder of
the beaches to the west appears to have been generally stable during the past decade.

The beaches of Baldwin County, while connected to the mainland geographically,
have many characteristics of barrier islands with numerous ponds and tidal lagoons
fronted by dune fields. These beaches have patterns of accretion, stability, and
recession that vary in location and with time. Most of these beaches show relative
stability or accretion from the mid-1800s to the mid-1900s (Stone, 1991), as well as
during the past two decades. Exceptions to this are south of Little Point Clear on the:
Fort Morgan Peninsula and downdrift of Little Lagoon Pass where erosion is
occurring. Historic rates of shoreline change are highly variable with time
apparently because of repetitious foredune breaching and overwash during
hurricanes. In Gulf Shores, Little Lagoon Pass connects the Gulf with Little Lagoon,”
a 12 km (7.4 mi) long by 1 km (0.6 mi) wide tidal lagoon. Prior to stabilization in
1981, the pass was ephemeral and had opened in several different locations. Since
stabilization, at a width of 12 m (40 ft), the pass has remained open for tidal exchange

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 16



Coastal & Shoreline Erosion in the Gulf of Mexico Chapter 2

Vegetation should be considered as a critical feature of any Gulf stabilization project
that includes dune construction or restoration. In addition to stabilizing recently
constructed dunes, appropriate vegetative plantings can help build them by trapping
wind-blown sand. Bay and estuary shorelines can be directly stabilized and even
accreted through well-managed vegetation programs. Such plantings are often
aided at the outset by low-cost structural measures designed to protect the young
plants from direct wave attack until they become established. Following
establishment, vegetative plantings need a program of regular maintenance.

Poorly conceived attempts at shoreline stabilization can create more problems than
they solve. However, even proper design does not guarantee that stabilization will
be an acceptable or even feasible alternative for a particular site. Structural
stabilization methods tend to have high initial costs and may be viewed as
aesthetically or environmentally undesirable. Beach fill requires periodic
maintenance to deliver full recreational and protective benefits, and the large
sources of beach quality sand needed for construction and renourishment are not
always readily available. Beach fill projects can also raise environmental concerns
about nearshore water turbidity, sedimentation on coral reefs and other biological
resources, and impacts on sea turtle nesting.

Management. Management can reduce the impacts of coastal and shoreline erosion
by helping to minimize the degreé to which various resources are placed at risk. For
example, setback lines are a common feature of many coastal zone management
plans. These lines establish seaward limits for permitting various types of buildings
and also may specify zones where no construction of any kind is allowed. Periodic
review and re-establishment of setback lines help ensure that acceptable levels of
erosion risk and resulting impact are maintained.

Construction standards are an important aspect of an overall risk management
program, especially for single-family dwellings. Although building such structures
to proper specifications will not ensure their habitability or survival once long-term
erosion has progressed to a certain point, it can significantly reduce damages due to
the short-term erosion and other effects generated by coastal storms.

Setback lines and construction standards work well to limit risk for new coastal
development but do little to reduce impacts to existing buildings and infrastructure.
Providing financial assistance for relocating or demolishing buildings endangered
by coastal erosion can be an effective way to help implement a risk management
program by giving existing property owners options other than total loss of their
investment. For example, the 1988 Upton-Jones Amendment to the National Flood
Insurance Act provided flood insurance payments for structures that are in
imminent danger of collapse due to shoreline erosion. Homeowners can receive
from the federal government up to 40 percent of the value of a house to relocate it
further inland in an erosion-setback zone and up to 110 percent to demolish the
house (National Research Council, 1990).

Gulf of Mexico Coastal & Shoreline Erosion Actlon Agenda (4.1) 14



Glossary

Appendix C

erosion

escarpment

estuary

eye

fairway

fathom
fathometer

feeder beach

feeder current

feeling bottom

fetch

flood current

flood tide

foam line

following wind

foredune

foreshore

forward speed

The wearing away of land by the action of natural forces. On a beach, the
carrying away of beach material by wave action, tidal currents, littoral
currents, or by deflation.

A more or less continuous line of cliffs or steep slopes facing in one general
direction which are caused by erosion of faulting; also SCARP.

(1) The part of a river that is affected by tides. (2) The region near a river

mouth in which the fresh water of the river mixes with the salt water of the
sea.

In meteorology, usually the “eye of the storm" (hurricane); the roughly circular
area of comparatively light winds and fair weather found at the center of a
severe tropical cyclone.

The parts of a waterway that are open and unobstructed for navigation. The
main traveled part of waterway; a marine thoroughfare.

A unit of measurement used for soundings equal to 1.83 meters (6 feet).
The copyrighted trademark for a type of echo sounder.

An artificially widened beach serving to nourish downdrift beaches by natural
littoral currents or forces.

See CURRENT, FEEDER.

‘The initial action of a deepwater wave, in response to the bottom, upon running
into shoal water.

The area in which SEAS are generated by a wind having a fairly constant
direction and speed.

The tidal current toward shore or up a tidal stream, usually associated with
the increase in the height of the tide.

The period of tide between low water and the succeeding high water; a rising
tide.

The front of a wave as it advances shoreward, after it has broken.

Generally, the same as a tailwing; in wave forecasting, wind blowing in the
direction of ocean-wave advance.

The front dune immediately behind the backshore.

The part of the shore, lying between the crest of the seaward berm (or upper
limit of wave wash at high tide) and the ordinary low-water mark, that is
ordinarily traversed by the uprush and backrush of the waves as the tides rise
and fall. See BEACH FACE.

Rate of movement (propagation) of the hurricane eye in (hurricane) meters per
second, knots, or miles per hour.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) . . 95



Coastal & Shoreline Erosion in the Gulf of Mexico Chapter 2

the south except for local reversals. With the exception of Marco Island's restored
beaches, the beaches of this segment are narrow with about 65 percent [20 km (12.5
mi)].of the total beach length currently experiencing problematic erosion (USACE,
1972; Clark, 1991a). These coastal barrier islands constitute the southernmost extent
of significant amounts of accumulated sand sediments.

Ten Thousand Islands. Appropriately named, this remote group of essentially
uncharted islands is concentrated along 39 km (24 mi "as the crow flies") of Florida
Gulf Coast reaching from the lee of Cape Romano south to Pavilion Key and
occupying a coastal band about 6.4 km (4 mi) in width. White (1970) notes that the
reach differs from sections both north and south and seems to be a gradation
between them. Those islands of the group fronting directly on the Gulf, built over
the past 3,000 to 5,000 years, are the result of vermetid reefs (Shier, 1969). These
colonizing reefs formed the core of the outer islands, which have trapped quartz
sand transported across Gullivan Bay from shoals south of Cape Romano (Davis,
1940; Scholl, 1964; Shier, 1969). More interior islands are long, narrow, and twisted
oyster bars and indian middens (Parkinson, 1989) which to some extent entrap
sediments. Both low-lying island types are vegetated by mangroves and lie atop
bedrock limestone (Lane, 1981). Changes in shoreline configuration of the Gulf-
fronting islands have never been monitored. However, based on geological
evidence, Shier (1969) has noted that storms and hurricanes have caused erosion
and that during the past three centuries vermetid reefs have eroded faster than
vermetid growth could build new reef. While the outer islands maintain
themselves by mangrove and sand migration on their lee sides, they have moved
“bodily" toward the mainland. In the absence of any monitoring and quantitative
information, geological evidence suggests that erosive forces are slowly at work.

Lower Everglades Gulf Coast. This remote and unique coastal segment extends
some 80 km (50 mi) from the vicinity of Pavilion Key at the south end of the Ten
Thousand Islands, southeast to East Cape. It is the southwest drainage terminus of
the Everglades and Big Cypress Swamp. The entire reach is characterized by low
wave energy which increases to the south. Coastal surface sediments are exclusively
mud and shell which extend to depths of 3 to 4.5 m (9.6 to 14.4.ft) below MSL and
give way to peats and freshwater carbonates in the landward direction (Roberts et al.,

The Sloughs Debouchure. At one time, the entire lower Everglades reach was more
homogenous in physiography and mangrove vegetation, similar to that found
along Florida Bay. However, over about the past 3,000 years, erosion along the
northern portion of the reach and southerly directed longshore transport has
resulted in a retreating shoreline (Gleason et al., 1974) along the northern 65 km (40
mi) and deposition along the southern 15 km (9.3 mi). The northern area, which
White (1970) termed the "debouchure of the Everglades Sloughs" with its
numerous mangrove islands and tidal creeks, is largely characterized by low-lying
steep mud banks vegetated by a fringing mangrove forest up to 195 m (640 ft) in
width and by a few discontinuous narrow beaches of shell sediments. (Note,

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 24



Glossary Appendix ¢

sea state Description of the sea surface with regard to wave action; also called state of
sea.

seawall A structure separating land and water areas, primarily designed to prevent
erosion and other damage due to. wave action. See BULKHEAD.

semidiurnal tide A tide with two high and two low waters in a tidal day, each approximately
the same.

set of current The direction toward which a current flows.

setup, wind See WIND SETUP.

shallow water

sheet pile
shelf, continental
shelf, insular

shoal (noun)
shoal (verb)

shore
shoreface

shoreline

silt

slack tide
(slack water)

slip

Water of such depth that surface waves are noticeably affected by bottom
topography. It is customary to consider water of depths less than one-half the

‘surface wavelength as shallow water. See TRANSITIONAL ZONE and DEEP

WATER.

See PILE, SHEET.

See CONTINENTAL SHELF.
See INSULAR SHELF.

A detached elevation of the sea bottom, comprised of any material except rock
or coral, which may endanger surface navigation.

(1) To become shallow gradually. (2) To cause to become shallow. (3) To
proceed from a greater to a lesser depth of water.

The narrow strip of land in immediate cqntact with the sea, including the zone
between high and low water lines. A:shore of unconsolidated material is
usually called a BEACH.

The narrow zone seaward from the low tide SHORELINE, covered by water,
over which the beach sands and gravels actively oscillate with changing wave

“ conditions. See INSHORE (ZONE).

The intersection of a specified plane of water with the shore or beach (e.g., the
high water shoreline would be the intersection of the plane of mean high water
with the shore or beach). The line delineating the shoreline on National
Ocean Service nautical charts and surveys approximates the mean high water
line.

See SOIL CLASSIFICATION.

The state of a tidal current when its velocity is near zero, especially the
moment when a reversing current changes direction and its velocity is zero.
Sometimes considered the intermediate period between ebb and flood currents
during which the velocity of the currents is less than 0.05 meter per second (0.1
knot). See STAND OF TIDE.

» A berthing space between two piers.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) . . 105



The Unfinished Agenda Chapter 4

Action Item 17 - Public Video on Gulfwide Erosion Issues

Develop a basic, general public video of coastal and shoreline
erosion issues throughout the Gulf of Mexico region.

Lead: Gulf of Mexico Program Coastal & Shoreline Erosion
Committee.

InItlation Date: 1995

Action Item 18 - Gulf of Mexico Program Electronic Bulletin Board Erosion Data

Identify data on coastal erosion issues that should be included in
the Gulf of Mexico Program Office electronic bulletin board.

Lead: Gulf of Mexico Program Coastal & Shoreline Erosion
Committee.

Initlation Date: 1993

Action Item 19 - Sources of Funding for Coastal & Shoreline Erosion Education

Identify all sources of funding for environmental education on
coastal and shoreline erosion issues.

Lead: Gulf of Mexico Program Coastal & Shoreline Erosion
Committee, in coordination with U.S. Army Corps of Engineers. |
Initiation Date: 1993

Action Item 20 - Network for Disseminating Coastal & Shoreline Erosion
Information

Identify, develop, and maintain a network of Gulf. of Mexico
Program Issue Committees, National Estuary Programs, schools,
government agencies, interested groups, and coastal and inland
communities to participate in disseminating information on
coastal and shoreline erosion issues and solutions.

Lead: Gulf of Mexico Program Coastal and Shoreline Erosion
Comittee.

InItlation Date: 1994

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 48



Glossary Appendix C

permanent current A current that runs continuously, independent of the tides and temporary causes.
Permanent currents include the freshwater discharge of a river and the currents
that form the general circulatory systems of the oceans. .

permeable groin A groin with openings large enough to permit passage of appreciable quantities
of LITTORAL DRIFT.

pier A structure, usually of open construction, extending out into the water from the
shore, to serve as a landing place, recreational facility, etc., rather than to
afford coastal projection. In the Great Lakes, a term sometimes improperly
applied to jetties.

pile Along, heavy timber or section of concrete or metal to be driven or jetted into

pile, sheet

piling
Plain, Coastal
planform

plateau

plunging breaker

point

port

prism

Propagation of
waves

prototype

quarrystone
quay

the earth or seabed to serve as a support or protection.

A pile with a generally slender flat cross section to be driven into the ground or
seabed and meshed or interlocked with like members to form a diaphragm,
wall, or bulkhead.

A group of piles. *

See COASTAL PLAIN.

The outline or shape of a body of water as determined by the still-water line.
A land area (usually extensive) having a relatively level surface raised
sharply above adjacent land on at least one side; table land; a similar undersea
feature.

See BREAKER.

The extreme end of a cape; the outer end of any land area protruding into the
water, usually less prominent than a cape.

A place where vessels may discharge or receive cargo; it may be the entire
harbor including its approaches and anchorages, or only the commercial part of
a harbor where the quays, wharves, facilities for transfer of cargo, docks, and
repair shops are situated.

See TIDAL PRISM.

The transmission of waves through water.

In laboratory usage, the full-scale structure, concept, or phenomenon used as a
basis for constructing a scale model or copy.

Any stone processed from a quarry.

(Pronounced KEY). A stretch of paved bank, or a solid artificial landing place
parallel to the navigable waterway, for use in loading and unloading vessels.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 102



Fedoral & State Framework Appendix A

protection is to "protect, conserve, and restore the quantity and quality of habitats
of living marine resources to maintain populations of commercial, recreational,
and ecologically important species at optimal sustainable levels."

* Goastal Barrier Resource Act (CBRA) of 1982. CBRA prohibits any federal
program from supporting construction in areas within the Coastal Barrier
Resources System (CBRS). Exceptions to CBRA include development associated
with conservation, public recreation, research, and national security. CBRA
became effective in 1982, and helps to protect the important wetland resources of
coastal barrier islands. One program restricted by CBRA in many high-risk
coastal areas is the federal Flood Insurance Program.

Coastal Barrier Improvement Act of 1990. CBRA was amended by the 101st Congress
and titled the "Coastal Barrier Improvement Act of 1990." This Act mandates
technical revisions to the CBRS maps, modifies CBRS boundaries, and allows
additions to CBRS. The Act names exceptions to the prohibition of federal
expenditures such as mineral extraction, navigation improvements, road
maintenance, and projects that protect wildlife resources.

* Coastal Zone Management Act (CZMA) of 1972. In 1972, CZMA was passed. "to
preserve, protect, develop, and where possible, to restore or enhance, the
resources of the nation's coastal zone for this and succeeding generations."
CZMA was designed to help coastal states, on a voluntary basis, develop plans to
manage and protect coastal zone resources, including those affected by offshore
energy development projects. CZMA provides financial and technical assistance
during the planning and administration of programs that meet minimum
federal standards. Approval of state plans is the responsibility of the Secretary of
Commerce, acting through NOAA.

The implementation of many of these plans requires active involvement of local
communities. In accordance with the federal Act's "consistency" provisions,
states with approved plans have the authority to veto federal permits for
activities in wetlands or coastal waters that are inconsistent with the state's
coastal zone management plan. These states receive various grants for
construction and land acquisition projects and permitting efforts. Under the
Estuarine Research Reserve System, the Act also provides matching grants to
states for the acquisition of estuarine areas for research and education.

* National Sea Grant College Program. The National Sea Grant College Program
conducts research and supports extension programs in wetlands, coastal habitats,
and coastal engineering. The four Gulf of Mexico programs are at Texas A&M,
Louisiana State University, Mississippi/ Alabama Consortium, and the
University of Florida.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 66



Coastal & Shoreline Erosion in the Gulf of Mexico Chapter 2

Florida*

*NOTE: This account is directly quoted from Balsillie and Clark (1992b) with the
authors' permission. .

Overview of the Problem. The State of Florida has over 1,202 km (747 mi) of
shoreline fronting directly upon the Gulf of Mexico of which about 671 km (417 mi)
are sandy beaches. Of the sandy beaches, 309 km (192 mi) are currently experiencing
problematic erosion, of which 163 km (101 mi) are considered critical, and 146 (91
mi) noncritical (Clark, 1991a). In addition, there are at least 5,028 km (3,125 mi) of
bay and estuarine shoreline. Not counting river entrances of the Big Bend and tidal
channels of the Ten Thousand Islands, Lower Everglades, and the Florida Keys,
sandy beaches of the Gulf are affected by 55 barrier tidal inlets resulting, on the
average, in an inlet for every 11 km (7 mi) of beach. Presently, except for the
Apalachicola River entering the Gulf of Mexico near the east part of the Panhandle
Gulf Coast, the rivers of Florida do not contribute appreciable quantities of sand-
sized sediment to the state's coasts.

Typically, Florida's Gulf Coast beaches have long-term historical erosion rates of less
than 0.5 m/year (1.6 ft/year). Many problem areas have erosion rates on the order of
1.5 m/year (4.8 ft/year), with an extreme erosion rate of 7 m/year (22.4 ft/year)
occurring along the southern part of St. Joseph Peninsula. Most of Florida's beach °
erosion problems, particularly critical erosion, have resulted from stabilization,
construction, and development of barrier tidal inlets. Many of the natural
undeveloped inlets, being dynamic in their behavior, are also responsible for
causing adjacent shoreline shifts viewed to be erosion. Of the 55 barrier beach tidal
inlets along the Gulf, 36 have not been altered by humans (i.e., no jetties and no
maintenance dredging). Of the remaining, 19 have been dredged to maintain
navigation channels, 17 have jetties or terminal groins, and 11 have bridges crossing
them. To mitigate adjacent shoreline erosion, sand transfer projects have been
conducted at 21 Gulf inlets. Coastal armoring, too, can complicate long-term
shoreline behavior. However, except for Panama City Beach along the panhandle
and highly developed barrier islands of the lower Gulf Coast, Florida's Gulf coastal
regions are generally devoid of such structures.

The geology, physiography and erosional history of Gulf Coast Florida is highly
variable. To facilitate more efficient discussion, Florida's Gulf Coast is divided into
six general regions: Panhandle, Big Bend, Lower Gulf Coast, Ten Thousand Islands,
Lower Everglades, and Florida Keys. These are for the most part further divided
into subregions.

Panhandle Gulf Coast. Extending from the Alabama-Florida state line on the west
to the mouth of the Ochlockonee River to the east, the panhandle has 351 km (218
mi) of sandy Gulf-fronting beaches and 13 barrier tidal inlets. There are, in addition,
1,358 km (844 mi) of interior bay and estuarine shorelines. On the basis of general
shoreline shape, the panhandle can be divided into western and eastern segments,

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 418



Fedoral & State Framework Appendix A

Grang Isle beach nourishment--Portions of a dune cross-section that includes a clay
core was built in the 1980s.

Grand Isle seawall--This rock seawall with groins was built during the last several
decades. The structures are seaward of the constructed dune. This shoreline
overlaps with USACE beach nourishment projects.

Mississippi

.

Hancock County seawall--This stepped seawall is several decades old. Some sand
‘was pumped onto beaches before Hurricane Camille. This coastline is partially
protected by a chain of barrier islands about 16 km (10 mi) offshore.

Fort Massachusetts beach nourishment--Sand from the dredging of the Gulfport ship
channel has been placed around the historic fort four times.

lox! i ch hment--This beach has been nourished
from borrow areas several hundred meters offshore several times in the past
few decades. Much of the seawall protects US Highway 90. This coastline is
partially protected by a chain of barrier islands about 16 km (10 mi) offshore.

Horn Island Pass inlet sang transfer--Sand from the dredging of the Pascagoula ship
channel in Horn Island Pass has been placed to the west to form an entirely
constructed island.

Jackson County seawalls and bulkheads--Much of this seawall is a rounded paved.
retaining wall protecting roadways. Some of the wall is fronted by pocket
beaches, and some is fronted by water. This coastline is partially protected by a
chain of barrier islands about 16 km (10 mi) offshore.

Texas

South Pagre island bulkheads--Individual property owners after 1967 built vertical
concrete bulkheads within foredunes.

North Pagre Island seawall--The beach has a stepped seawall .

Brazorla County Christmas trees--This project involves dune construction with
Christmas trees followed by planting. A volunteer effort has evolved into a
formal “Dune Day" program with 4-H Clubs, Scouts, and private industry
support. Up to 300 volunteers and 10,000 trees are employed each year.

Surfside inlet sand transfer--Sand from the Freeport ship channel was placed on the
beach in the summer of 1991.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



Overview of the Gulf of Mexico Chapter 1

1 OVERVIEW OF THE GULF OF MEXICO

The Gulf of Mexico - A Vast & Valuable Resource

Bounded by a shoreline that reaches northwest from Florida along the shores of
Alabama, Mississippi, and Louisiana, and then southwest along Texas and Mexico,
the Gulf of Mexico is the ninth largest body of water in the world. The Gulf's U.S.
coastline measures approximately 2,609 km (1,631 miles)--longer than the Pacific
coastline of California, Oregon, and Washington. The Gulf region covers more than
1.6 million km? (617,600 mi?) and contains one of the nation's most extensive
barrier-island systems, outlets from 33 major river systems, and 207 estuaries (Buff
and Turner, 1987). In addition, the Gulf receives the drainage of the Mississippi
River, the largest river in North America and one of the major rivers of the world.
A cornerstone of the nation's economy, the Gulf's diverse and productive
ecosystem provides a variety of valuable resources and services, including
transportation, recreation, fish and shellfish, and petroleum and minerals.

Encompassing over two million hectares (five million acres) (about half of the
national total), Gulf of Mexico coastal wetlands serve as essential habitat for a large
percentage of the U.S.'s migrating waterfowl (USEPA, 1991). Mudflats, salt marshes,
mangrove swamps, and barrier island beaches of the Gulf also provide year-round
nesting and feeding grounds for abundant numbers of gulls, terns, and other
shorebirds. Five species of endangered whales, including four baleen whales and
one toothed whale, are found in Gulf waters. These waters also harbor the
endangered American crocodile and five species of endangered or threatened sea
turtles (loggerhead, green, leatherback, hawksbill, and Kemp's Ridley). The
endangered West Indian (or Florida) manatee inhabits waterways and bays along the
Florida peninsula.

In addition, a complex network of channels and wetlands within the Gulf shoreline
provides habitat for estuarine-dependent commercial and recreational fisheries.
The rich waters yielded approximately 771 million kg (1.7 billion pounds) of fish and
shellfish in 1991. Worth more than $641 million at dockside, this harvest
represented 19 percent of the total annual domestic harvest of commercial fish
(USDOC; 1992). The Gulf boasts the largest and most valuable shrimp fishery in the
U.S. and also contributed 41 percent of the U.S. total oyster production in 1991
(USDOC, 1992). Other Gulf fisheries include diverse shellfisheries for crabs and
spiny lobsters and finfisheries for menhaden, herring, mackerel, tuna, grouper,
snapper, drum, and flounder. The entire U.S. Gulf of Mexico fishery yields more
finfish, shrimp, and shellfish annually than the South and Mid-Atlantic,
Chesapeake, and Great Lakes regions combined.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) - 4



Fedéral & State Framework Appendix A

Coastal Ocean Program (COP). COP is a cross-cutting NOAA effort to provide the
highest quality science delivered in time for important coastal policy decisions. COP
activities are organized around four goals. These address the major coastal ocean issues
of Environmental Quality, Fisheries Productivity, and Coastal Hazards; and the fourth,
Information Delivery, operates at the science-policy interface.

National Aeronautics & Space Administration (NASA)

NASA's Space Shuttle Earth Observations Office (SSEOO) is responsible for
photographing and cataloging photos of the earth from Space Shuttle missions.
Astronauts are trained in scientific observation of geological, oceanographic,
environmental, and meteorological phenomena. During each mission, project
personnel monitor the Earth for events of special interest such as hurricanes and
floods. Real color, black and white, and color infrared photos are taken by
astronauts with a hand-held camera at altitudes ranging from 204 to 555 km (127 to
214 mi) above the Earth.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



Federal & State Framework Appendix A

Q Providing for reasonable industrial expansion in the coastal area and
ensuring the efficient utilization of waterfront industrial sites so that
suitable, sites are conserved for water dependent industry.

Q Favoring the preservation of the coastal wetlands and ecosystems, except
where a specific alteration of a specific coastal wetland would serve a
higher public interest in compliance with the public purposes of the
public trust in which the coastal wetlands are held.

Q Encouraging the preservation of natural scenic qualities in the coastal
area.

Q Considering the national interest involved in planning for and siting
facilities in the coastal area.

Regulatory Agencies & Programs

The agencies responsible for the Coastal Program are the Bureau of Marine
Resources (BMR), the Bureau of Pollution Control, the Bureau of Land & Water
Resources, and the Department of Archives & History. These four agencies are :
responsible for monitoring state and federal decisions that affect the coastal area and
for ensuring that such decisions are made in accordance with program councils.

* Bureau of Marine Resources. BMR is the lead agency responsible for the overall
administration of the coastal program. This agency regulates projects and
activities under the Wetlands Protection Law and saltwater fisheries statutes.
There are three types of activities regulated under BMR's jurisdiction. These are
activities physically located in coastal wetlands (i.e., piers, bulkheads), those not
located in the coastal wetlands but affecting them by indirect means (i.e.,
construction), and the erection of structures on sites suitable for water dependent
industry. - -

The Mississippi Coastal Program calls for the accurate, long-range assessment of
shore-line erosion based on scientific research. The subjects where research will
be concentrated include: wave refraction diagrams; long-term changes in the
shoreline, wind transport, littoral transport rates, wave spectra, and source
materials for beach nourishment; and erosion by boat wakes.

The program also makes funds available for the preservation or restoration of
wetlands and access areas. These funds will be used to restore and preserve
beaches in areas that have been subject to severe wind erosion. Local
governments will play a lead role in any such project.

BMR has also set marine construction standards for shoreline erosion control.
This includes discussing which protection methods are recommended for each
type of shoreline and defining these methods, explaining the impacts of each

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 73



pes Table of Contents

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‘Gulf of Mexico Coastal & Shoreline Erosion Actlon Agenda (4.1) v



Glossary

Appendix C

nearshore
current system

nodal zone
nourishment

oceanography

offshore

offshore barrier
offshore current
offshore wind
onshore
onshore wind

opposing wind
outfall
overtopping

overwash
parapet

pass
peninsula

perched beach

The current system caused primarily by wave action in and near the breaker
zone and which consists of four parts: the shoreward mass transport of water;
longshore currents; seaward return flow, including rip currents; and the
longshore movement of the expanding heads of rip currents. See NEARSHORE
CIRCULATION.

(1) The narrow band of water flowing seaward through the surf; also RIP. (2)
The narrow strip of land connecting a peninsula with the mainland.

An area in which the predominant direction of the LONGSHORE
TRANSPORT changes. .

The process of replenishing a beach. It may be brought about naturally by
longshore transport or artificially by the deposition of dredged materials.

The study of the sea, embracing and indicating all knowledge pertaining to the
sea's physical boundaries, the chemistry and physics of seawater, and marine
biology.

(1) In beach terminology, the comparatively flat zone of variable width,
extending from the breaker zone to the seaward edge of the Continental Shelf.
(2) A direction seaward from the shore.

See BARRIER BEACH.

(1) Any current in the offshore zone. (2) Any current flowing away from shore.
A wind blowing seaward from the land in the coastal area.

A direction landward from the sea.

A wind blowing landward from the sea in the coastal area.

In wave forecasting, a wind blowing in a direction opposite to the ocean-wave
advance; generally, a headwind.

A structure extending into a body of water for the purpose of discharging
sewage, storm runoff, or cooling water.

Passing of water over the top of a structure as a result of wave runup or surge ~
action.

That portion of the uprush that carries over the crest of a berm or of a structure.

-A low wall built along the edge of a structure such as a seawall or quay.

In hydrographic usage, a navigable channel through a bar, reef, or shoal, or
between closely adjacent islands. .

: An elongated body of land nearly surrounded by water and connected to a larger

body of land.

A beach or fillet of sand retained above the otherwise normal profile level by a
submerged dike.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 101



Federal & State Framework ; Appendix A

(subject to provisions of sections 161.141 through 161.211, F.S.), to guarantee public
use of beach resources seaward of the ECL; and 2) project applicants must provide
permanent public access to project areas at approximately 1/2-mile intervals with
adequate vehicle parking areas (Balsillie, 1988).

Loulsiana

The State & Local Coastal Resources Management Act (SLCRMA) La. R.S. 49:21, was
passed by the Louisiana Legislature in 1978, and received federal approval in October
1980. Presently the program is being administered by the Coastal Management
Division (CMD) within the Department of Natural Resources (DNR), Office of
Coastal Restoration & Management.

During the Second Special Session of 1989, the Louisiana Legislature passed Act 6,
which requires. the State of Louisiana to annually develop a Coastal Wetlands
Conservation & Restoration Plan from both a short and long range perspective. The -
initiative for passing Act 6 was provided when it passed a voter referendum by
approximately 75 percent.

Regulatory Agencies & Programs

+ Department of Natural Resources (DNR). CMD of DNR is charged with :
implementing the Louisiana Coastal Resources Program (LCRP). LCRP attempts
to protect, develop, and restore or enhance the resources of the state's coastal
zone. Its broad intent is to encourage multiple.uses of resources and adequate
economic growth while minimizing adverse effects of one resource upon
another without imposing undue restrictions on any user.

CMD's regulatory responsibilities include administering the Coastal Use Permit
(CUP) Program, the Consistency Program, & the Enforcement Program.

CUP is the basic regulatory tool of CMD and is required for certain projects in the
coastal zone, including, but not limited to, dredge and fill work, bulkhead
construction, shoreline maintenance, and other development projects. CMD has
processed about 15,500 CUP applications since the inception of the program.

The Consistency Program requires activities of all federal and some state
governmental agencies to be consistent with LCRP. Particular attention is given
to environmental, economic, and cultural concerns. Most federal agencies
conduct their own consistency determination, and, if projects are found to be
inconsistent with state regulations, they are not pursued. Examples of projects
requiring a consistency determination are hurricane protection levees; USACE
maintenance, dredging, locks, and drainage structures; navigation projects;
freshwater diversions; and beach restoration projects.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 71



Glossary

Appendix €

higher low water

hindcasting, wave

hook

hurricane

hurricane path
or track

hydrography

impermeable groin

inlet

inlet gorge

inshore (zone)

inshore current

insular shelf

isobath

isthmus

jet

jetty

key

(HLW). The higher of two low waters of any tidal day.

The use of historic wind charts to calculate characteristics of waves that
probably occurred at some past time.

A spit or narrow cape of sand or gravel which turns landward at the outer end.

An intense tropical cyclone in which winds tend to spiral inward toward a core
of low pressure, with maximum surface wind velocities that equal or exceed 33.5
meters per second (75 mph or 65 knots) for several minutes or longer at some
points. TROPICAL STORM is the term applied if maximum winds are less than
33.5 meters per second.

Line of movement (propagation) of the eye through an area.

(1) A configuration of an underwater surface including its relief, bottom
materials, coastal structures, etc. (2) The description and study of seas, lakes,
rivers, and other waters.

A groin through which sand cannot pass.

(1) A short, narrow waterway connecting a bay, lagoon, or similar body of
water with a large parent body of water. (2) An arm of the sea (or other body
of water) that is long compared to its width and may extend a considerable
distance inland. See TIDAL INLET.

Generally, the deepest region of an inlet channel.

In beach terminology, the zone of variable width extending from the low water
line through the breaker zone; also SHOREFACE.

Any current in or landward of the breaker zone.

The zone surrounding an island extending from the low water line to the depth
(usually about 183 meters (100 fathoms)) where there is a marked or rather
steep descent toward the great depths.

A contour line connecting points of equal water depths on a chart.

A narrow strip of land, bordered on both sides by water, that connects two larger
bodies of land. .

To place (a pile, slab, or pipe) in the ground by means of a jet of water acting at
the lower end.

On open seacoasts, a structure extending into a body of water, which is designed
to prevent shoaling of a channel by littoral materials and to direct and confine
the stream or tidal flow. Jetties are built at the mouths of rivers or tidal inlets
to help deepen and stabilize a channel. See TRAINING WALL.

A low, insular bank of sand, coral, etc., as one of the islets off the southern coast
of Florida; also CAY.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 97



Federal & State Framework Appendix A

Slesta Kev bulkheads and revetments--No additional information was available.

Casey Key revetment--A revetment has replaced an older, failed groin field with
bulkheads.

Venice Beach bulkheads and revetment--Venice Beach has mostly vertical concrete
bulkheads with rubble toe protection in front.

Casperson Beach groin field--Casperson Beach has a series of five rubble mound.
groins. There is erosion downdrift of the groin field.

Mansoto Key revetment--No additional information was available.

Englewood Beach groin field with bulkheads--No additional information was
available.

Mansoto Key inlet sand transfer--Sand from Stump Pass was placed on beaches in
1980.

Boca Grande bulkheads--There has been some sand from inlets placed on beaches
at the tip of Gasparilla Island. There is a terminal groin at the south end of the
island.

North Captiva Island land purchases--Several houses at the north end of North
Captiva Island were abandoned when the land was purchased by the state.
Several attempts at short segments of revetment have failed.

Captiva Island beach renourishment--In 1981, 497,185 m3 (650,000 yd) of sand were
placed along 3.2 km (2 mi) of beach; this was extended with 1,223,840 m3 (1.6
million yd3) in 1989.

Et. Myers Beach inlet sand transfer--Theré was an inlet sand transfer from the
north. :

Lover's Key land purchase--An eroding island was purchased by the state.

Bonita Beach seawall--Beach nourishment is being planned for this area.

Deinor-Wiggins beach nourishment/iniet sand transfer--To maintain Wiggins Pass, sand
has been placed on the adjacent beaches three times: 38,245 m3 (50,000 yd) to
the north in 1984; 25,242 m$ (33,000 yd3) to the south in 1990; and 26,007 m3
(34,000 yd3) to the south in 1991.

Naples grain field--No additional information was available.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



Bibi I

Balsillie, JH. 1975. “Analysis and Interpretation of Littoral Environment
Observation (LEO) and Profile Data Along the Western Panhandle Coast of
Florida." Coastal Engineering Research Center Technical Memorandum.
No. 49. '

Balsillie, JH. 1977. “Accuracy of Computer Refraction Simulation for Predicting
Breaking Wave Characteristics and Longshore Transport." Coastal
Sedimentology 1977. Geology Department. Florida State University.
Tallahassee, FL.

Balsillie, J.H. 1985a. "Long-Term Shoreline Change Rates for Gulf County, Florida--
A First Appraisal." Florida Department ‘of Natural Resources. Beaches and
Shores Special Report No. 85-3.

Balsillie, JH. 1985b. "Establishment of Methodology for Florida Growth
Management 30-Year Erosion Projection and Rule Implementation." Florida
Department of Natural Resources. Beaches and Shores Technical and Design
Memorandum No. 85-4. -

Balsillie, J.H. 1985c. “Post-Storm Report: Hurricane Elena of 19 August to 2
September 1985." Florida Department of Natural Resources. Beaches and
Shores Post-Storm Report No. 85-2. :

Balsillie, J. H. 1988. Florida's Beach and Coast Preservation Program: An Overview.
Beaches and Shores Special Report No..88-2. Florida Department of Natural
Resources, Division of Beaches and Shores.

Balsillie, JH. and R.R. Clark. 1979. “Preliminary Report on Coastal and Shoreline
Damage Resulting from the Impact of Hurricane Frederic on the
Northwestern Panhandle of Florida." Florida Department of Natural
Resources. Beaches and Shores Post-Storm Report No. 79-1.

Balsillie, JH. and R.R Clark. 1992a. "Current Beach Conditions and
Recommendations for Alleviating Critical Beach Erosion From the Southern
Town Limits of Belleair Shore to Clearwater Pass including the City of
Belleair Beach." Florida Department of Natural Resources. Division of
Beaches and Shores.

Balsillie, J.H. and R.R. Clark. 1992b. "The Gulf Coast of Florida: Overview of
Physiography, Geology, and Historical Shoreline Change." Florida
Department of Natural Resources. Division of Beaches and Shores.

Gulf of Mexico Coastal & Shoreline Erosion Actlon Agenda (4.1) ° 50



The Unfinished Agenda Chapter 4

Action Item 14 - Gulfwide Erosion Response Strategies

Develop Gulfwide strategies for responding to coastal and
shoreline erosion. Strategies should include recommendations for
improved coordination at the state and federal levels and should
identify any limitations in authority that could impede execution
of strategies.

Lead: Gulf of Mexico Program Coastal & Shoreline Erosion
Committee.

Initiation Date: 1996

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 46



Overview of the Gulf of Mexico Chapter i

Asbury Sallenger Jr. U.S. Geological Survey
Samuel Sanders Soil Conservation Service
Edward Seidensticker Soil Conservation Service
David W. Smith Houston Audubon Society
David Smith U.S. Fish & Wildlife Service
Everett Smith Geological Survey of Alabama
Thomas Smith U.S. Army Corps of Engineers
Cliff Truitt » -.' Mote Marine Laboratory
Michael Voisin Motivatit Seafoods; Inc.
Jeffress Williams U.S. Geological Survey

Thomas Campbell U.S. Army Corps of Engineers
Bill Good Louisiana Department of Natural Resources :

The Coastal & Shoreline Erosion Committee developed the following long-term
goal for addressing coastal and shoreline erosion in the Gulf of Mexico:

Q Reduce the impacts of coastal and shoreline erosion in: the Gulf of Mexico.

In developing this Action Agenda, the Coastal & Shoreline Erosion Committee has sought
input and advice from other. technical Issue Committees, as well as from organizations,
interest groups, and private concerns outside of the Gulf of Mexico Program. An "Action
Agenda Workshop" was sponsored by the Coastal & Shoreline Erosion Committee in
Galveston, TX, on March 4-5, 1992. Approximately 35 persons, comprising a mix of
Program and non-Program participants, gathered there to review an early version of this
Action Agenda. In addition to Gulf of Mexico Program participants, representatives from
the following agencies, organizations, and industries attended the workshop: Highland
Supply Company, Florida Sea Grant College, Center for Marine Conservation, Galveston
Beach Preservation Committee, Louisiana Department of Natural Resources, Galveston
Bay National Estuary Program, Mississippi-Alabama Sea Grant Consortium, Alabama
Department of Economic & Community Affairs, Mississippi Office of Geology, Louisiana
State University, Texas A&M University at Galveston, and Brown & Root, Inc.

This meeting generated a significant number of comments that were addressed in
the present document. (See Appendix D: Participants in the Action Agenda
Development Process.)

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



Federal & State Framework . Chapter 3

3 FEDERAL & STATE FRAMEWORK FOR ADDRESSING
COASTAL & SHORELINE EROSION

This section describes the legal and institutional framework currently in place in the
Gulf of Mexico to address coastal and shoreline erosion issues. It also outlines some
of the positive efforts already underway at the federal, regional, and state levels. (For
a description, see Appendix A.)

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) . 37



The Unfinished Agenda Chapter 4

Erosion Identification, Characterization, & Assessment

The rates, distribution, and causes of coastal and shoreline erosion in the Gulf of
Mexico are currently reported on a limited basis. Current and historical information
should be used to develop and refine a statistically valid baseline from which to
assess changing erosion conditions throughout the five Gulf States. Future
activities and information collection can then be incorporated into the data base and
improvements can be measured.

Specific objectives and action items follow:

OBJECTIVE: Characterize the Gulf of Mexico shoreline, and identify
trends and patterns of shoreline change.

Action Item 1 - Sources of Gulfwide Eresion Data

Identify and compile, into both bibliographic and spatial data bases,
sources of Gulfwide data pertinent to coastal and shoreline erosion
including bibliographic sources, data from aerial and sea-borne
remote sensing, and field data (i.e., process, morphologic, sediment,
and stratigraphic).

Lead: U.S. Army Corps of Engineers.

Initiation Date: 1994

Action Item 2 - Gulf of Mexico shoreline Characteristics

Determine major categories of Gulf shoreline, assemble best
estimates of length for each category, determine historical erosion
trends for each category (cause and extremes), and prepare report
incorporating appropriate graphics to depict distributions, types,
and trends.

Lead: U.S. Geological Survey.

Initiation Date: 1994 :

Action Item 3- Gulfwide Sand Inventory

Develop a Gulfwide offshore sand inventory which describes
sources, volumes, and quality.

Lead: U.S. Geological Survey.

InItlation Date: 1995

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



Fedoral & State Framework Appendix A

valuable natural resources and that it is in the public interest to preserve and
protect them from imprudent construction which can jeopardize the stability of
the beach-dune system, accelerate erosion, provide inadequate protection to
upland structures, and endanger adjacent property and the beach-dune system.
In furtherance of these findings, it is the intent of the Legislature to provide that
the department, acting through the division, shall establish coastal construction
control lines on a county basis along the sand beaches of the state fronting on the
Atlantic Ocean and the Gulf of Mexico. Such lines shall be established so as to
define that portion of the beach-dune system which is subject to severe
fluctuations based on a 100-year storm surge or other predictable weather
conditions, and so as to define the area within which special structural design
consideration is required to insure protection of the beach-dune system, any
proposed structure, and adjacent properties, rather than to define a seaward limit
for upland structures (Balsillie, 1988).

Counties not considered "sandy-beach" countiés do not have CCCLs. As of
February 1988, all counties within program jurisdiction had setback or control
lines established, and a second review phase was underway. Establishment of
CCCL's on a county-by-county basis requires three significant efforts: (1) field
data collection, (2) storm tide and dune erosion modeling, and (3) CCCL restudy
and adoption (Balsillie, 1988). :

Beach Erosion Control Program. Chapter 16B-36, F.A.C., sets forth policies and
procedures for administering the Beach Erosion Control Assistance Program to

provide funding assistance to local governments in support of alleviating
serious sandy beach erosion problems and for the protection and preservation of
sandy beach resources of Florida. Projects may include:

Beach restoration/renourishment

Sand transfer, bypassing, and stockpiling
Jetties, groins, breakwaters, revetments

Sand trap construction and maintenance

Dune construction and revegetation
Beach-dune overwalks

Protective walkways or other measures for dune protection/preservation
Sand fencing

Biological and hydrological monitoring studies,
Sand source studies

Educational signs

Other projects of desirable intent

gooooog0000000

Two guidelines accompany these projects: 1) Erosion Control Lines (ECL) must be
located a sufficient distance landward of the line of mean high water to provide for
an equitable distribution of a restored beach between State and upland ownership

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



Overview of the Gulf of Mexico Chapter 4

The Gulf of Mexico Program also works in coordination and cooperation with the
five National Estuary Programs (NEPs) within the Gulf: Tampa Bay, Sarasota Bay,
Galveston Bay, Corpus Christi Bay, and the Barataria-Terrebonne Estuarine
Complex. The Gulf of Mexico Program supports and builds on certain activities of
these programs, bringing a Gulfwide focus and providing a forum for addressing
issues of Gulfwide concern.

By building on and enhancing programs already underway, as well as by
coordinating new activities, the Gulf of Mexico Program will serve as a catalyst for
change. The program's overall goals are to provide:

Q A mechanism for addressing complex problems that cross federal, state,
and international jurisdictional lines;

Q Better coordination among federal, state, and local programs, thus
increasing the effectiveness and efficiency of the long-term effort to
manage and protect Gulf resources;

Qa A regional perspective to address research needs, which will result in
improved transfer of information and methods for supporting
effective management decisions; and

Q A forum for affected groups using the Gulf, for public and private
educational institutions, and for the general public to participate in the
solution process.

The Gulf of Mexico Program is supported by four committees: Policy Review Board
(PRB), Management Committee (MC), Citizens Advisory Committee (CAC), and
Technical Advisory Committee (TAC) (see Figure 1.2). Composed of 20 senior level
representatives of state and federal agencies and representatives of the technical and
citizens committees, the Policy Review Board guides and reviews overall program
activities. The Management Committee guides and manages Gulf of Mexico
Program operations and directs the Action Agenda activities of the Issue
Committees. The Citizens Advisory Committee is composed of five governor-
appointed citizens who represent environmental, fisheries, agricultural,

business /industrial, and development/tourism interests in each of the five Gulf
Coast States. This committee provides public input and assistance in publicizing the
Gulf of Mexico Program's goals and results. Representatives of state and federal
agencies, the academic community, and the private and public sectors are members
of the Technical Advisory Committee and provide technical support to the
Management Committee.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 5



The Unfinished Agenda Chapter 4

Action Item 11 - Past Experiences Regarding Erosion Along the Gulf of Mexico
Coast

Develop a critical review of past experiences regarding shoreline
and coastal erosion along the Gulf of Mexico Coast. The review
should focus on the "big picture" (with respect to measures a-g in
Action Item 13) including the decision making process, the
philosophies that led to the selection of the alternatives, and the
costs and benefits that have been realized.

Lead: U.S. Army Corps of Engineers, U.S. Geological Survey, and
Soil Conservation Service.

Initiation Date: 1994

Action Item 12 - Selection of Representative Erosion Sites Gulfwide

Identify a set of critically eroding sites that feature causes, physical
and socioeconomic situations, and responses that are
representative Gulfwide. Also, identify the agencies developing or
administering the responses; this information should be
summarized graphically or in chart form for distribution.

Lead: Gulf of Mexico Program Coastal & Shoreline Erosion
Committee.

Initlation Date: 1995

&
Action Item 13 - Gulf of Mexico Erosion Response Evaluation

Evaluate the effectiveness of erosion impact responses at
representative critically eroding sites. These measures may include
but not be limited to:
(a) Beach nourishment;
(b) Coastal structures for property protection and to extend the
life of beach nourishment projects;
(c) Vegetative approaches to shoreline protection;
(d) Beneficial uses of dredged material on shorelines(including
inlets and bypassing);
(e) Abandonment/retreat including public acquisition;
(f) Release/mobilization of riverine sands from dams and
stream beds; and
() Innovative technologies.
Lead: Responsible agencies identified in Action Item 12.
Initlation Date: 1996

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 45



Executive Summary

Chapter 3 describes the legal and institutional framework currently in place in the _
Gulf of Mexico to address erosion issues and support coastline protection efforts.

Chapter 4, The Unfinished Agenda, contains the goal, objectives, and specific
activities established by the Gulf of Mexico Program to address coastal and shoreline
erosion. The primary goal is to: : ;

Qa Reduce the impacts of coastal and shoreline erosion in the Gulf of Mexico.
The scope of this Action Agenda includes the following major areas: mainland
shorelines, barrier islands, major bays and estuaries, major waterways, and
peninsulas. . :

Four objectives and 20 action items have been developed to support the goal and
these are grouped under three types of activities (see Index of Coastal & Shoreline
Erosion Objectives). The action items included (in Chapter 4) have been screened
by the Gulf of Mexico Program and represent those activities that are currently the
most significant and most achievable. This is a fairly comprehensive, but not
exhaustive, list. This document begins an evolving process of Action Agendas in
which action items are designated, implemented, and then reassessed as progress in
the Gulf is made. In the future, new coastal and shoreline erosion action-items will
be developed to meet the changing needs in the Gulf of Mexico.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



Federal & State Framework Appendix A

of Section 404 exemptions. As a jointly administered program, USACE and
USEPA share responsibility for enforcing the Section 404 Program. USEPA can
also enforce against non-compliance with permit conditions; however, USEPA
generally focuses its resources towards discovering and enforcing against
unpermitted (unauthorized) discharges.

National Estuary Program (NEP). In 1987, Congress realized the special need to protect
estuaries and established the NEP to protect and improve water quality and

enhance living resources. NEP jurisdiction applies not only to the mouth of a
river or stream, but to "associated aquatic ecosystems and...tributaries draining
into the estuary," up to the historic height of fish migration or tidal influence,
whichever is higher.

USEPA, in managing NEP, is directed to identify nationally significant estuaries
threatened by pollution, development, or overuse, and to promote the
preparation of comprehensive management plans to ensure their ecological
integrity. Specifically, NEP: 1) establishes working partnerships among federal,
state, and local governments; 2) transfers scientific/management information
and expertise to program participants; 3) increases public awareness of pollution
problems; 4) promotes area-wide planning to control pollution and manage
resources; and 5) oversees development and implementation of pollution
reduction and control programs.

The five NEPs within the Gulf of Mexico region are Tampa Bay, Sarasota Bay,
Galveston Bay, Corpus Christi Bay, and the Barataria-Terrebonne Estuarine
Complex.

* National Environmental Policy Act (NEPA) of 1969. NEPA requires
consideration of the adverse impacts on environmental resources caused by any
federal action, including federally funded or permitted projects. It also requires
examination of alternatives to minimize those impacts. Compliance with NEPA
is an additional requirement to regulatory programs such as Section 404 of CWA
when federal agencies or federal monies are involved in a proposed project.
Environmental investigations carried out in accordance with NEPA are
documented in an Environmental Assessment or an Environmental Impact
Statement (EIS).

+ National Environmental Education Act (NEEA) of 1990. NEEA is designed to
increase public understanding of the natural environment and to advance and
develop environmental education and training. The Act builds upon the efforts
that USEPA has undertaken and establishes formal communication and
advisory links with educational institutions and other federal agencies. NEEA
also requires partnership among federal government agencies, local education
institutions, state agencies, not-for-profit educational and environmental
organizations, and private sector interests.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 62



Coastal & Shoreline Erosion in the Gulf of Mexico . Chapter 2

and is one of the world's smallest tidal inlets. The 180 m (590 ft) long, shore-
perpendicular jetties caused shoreline recession of the adjacent western beaches, i.e.
downdrift beaches, and accretion on the adjacent eastern beaches. By 1991, the
western shoreline had receded into private homes along 1.2 km (0.7 mi) of
beachfront, and a lawsuit was filed by the homeowners against the state agency
responsible for the jetty construction. Because of the lawsuit, the State of Alabama
has constructed beachfills along the affected shoreline, but the matter is still in
litigation. The Alabama coast includes the western 3 km (1.9 mi) of Perdido Key.
Perdido Pass is at the western end of Perdido Key. Prior to its stabilization in the
1960s, the pass had migrated westward over several kilometers during its recorded
history.

Bays and Sounds. Shoreline erosion is apparent along many of the bay and sound
shorelines of Alabama. Approximately 2 m/year (6.6 ft/year) of recession has been
calculated for the northern shoreline of Mississippi Sound, the western shoreline of |
Mobile Bay, and the shoreline of Bon Secour Bay (north shore of Fort Morgan
Peninsula). Peat outcroppings in the nearshore and tree root exposure are clearly
evident along many of these shorelines. Erosion is generally less than 1 m/year (3.3
ft/year) along the eastern shore and the northern end of Mobile Bay (the "Mobile
Delta") and the southern shoreline of Mississippi Sound (north side of Dauphin
Island). These lesser, but significant, rates of erosion are also common along bayou
and estuarine shorelines in the area.

Responses to Erosion. Most of the responses to erosion in Alabama have been
along the bay and bayou shorelines. Many private homeowners have built vertical
bulkheads. Along the more densely populated areas, including portions of the
eastern shore of Mobile Bay, the City of Mobile, the north side of Dauphin Island,
and around Perdido Pass, the shoreline is a series of nearly continuous, individual
bulkheads. On Gulf of Mexico beaches, most construction is far enough landward of
the shoreline to preclude erosion problems. Exceptions include a few private
bulkheads at motels and condominiums in Gulf Shores, the jetty-caused erosion
west of Little Lagoon Pass in Gulf Shores, and the eastern tip of Dauphin Island.
Two successive beachfills have been recently placed in the Lagoon Pass erosion area.
A rubble-mound seawall was built on the eastern tip of Dauphin Island around the
turn of the century to protect Fort Gaines. An adjacent groin field has failed and is
presently flanked. Several minor attempts at shoreline stabilization using other
(not rubble-mound) construction materials have structurally failed and were, thus,
fairly insignificant in affecting coastal processes.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 417



Fedoral & State Framework Appendix A

Periodic Nourishment. Periodic nourishment, by placement of suitable material
on a beach at appropriate intervals of time, is considered "construction" for cost
sharing purposes when, in the opinion of the Chief of Engineers, such periodic
nourishment would be a more economical erosion protection measure than
retaining structures such as groins.

Clean Water Act (CWA) Section 404. The U.S. Congress enacted CWA to
"restore and maintain the chemical, physical, and biological integrity of the
nation's waters." Section 404 regulates the discharge of dredged and fill material
into waters of the U.S., and establishes a permit program to ensure that such
discharges comply with environmental requirements. The Section 404 program
is administered at the federal level by USACE and USEPA. USFWS and the
National Marine Fisheries Service (NMFS) have important advisory roles.

Activities regulated by Section 404 include discharges of dredged and fill material
commonly associated with activities such as port development, channel
construction and maintenance, fills to create development sites, transportation
improvements, and water resource projects (such as dams, jetties, and levees).

River & Harbor Act of 1899. The River & Harbor Act regulates all construction
in or modification of traditionally navigable waters. In many respects, its
provisions are similar to those of Section 404 of CWA. For example, Section 10
of the River & Harbor Act requires permits issued by USACE for any dredging,
filling, or obstruction of navigable waters. Sections 9, 11, and 13 are also relevant
to some activities in wetlands and near coastal waters. When a project requires
applications for permits under both CWA & River & Harbor Act, USACE often
conducts the two permit reviews concurrently.

Despite its similarity to’ Section 404, the River & Harbor Act differs from Section
404 in two important ways. First, the activities it covers are much broader than
those regulated under Section 404. Second, its jurisdiction extends only to the
high water line. As a result, this Act offers the federal government greater
regulatory authority within certain areas, but does not apply to all areas regulated
under Section 404.

Coastal Wetlands Planning, Protection, & Restoration Act (CWPPRA).
CWPPRA establishes a mechanism to plan and fund implementation of wetland
protection and restoration projects in coastal Louisiana.. Planning and
implementation activities are managed by a six-person/federal-state task force.
In addition, CWPPRA calls for development of a Conservation Plan for the State
of Louisiana, and provides funds for matching grants to assist other coastal states
in implementing wetland conservation projects (i.e., projects to acquire, restore,
manage, and enhance real property interest in coastal lands and waters).

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



Bibllography

Gleason, P.J., A.D. Cohen, H.K. Brooks, P. Stone, R. Goodrick, W.G. Smith, and W.
Spackman, Jr. 1974. "The Environmental Significance of Holocene
Sediments From the Everglades and Saline Tidal Plain." Environments of
South Florida: Present and Past. Miami Geological Society, Memoir 2.

Harvey, J. 1979. "Beach Processes and Inlet Dynamics in a Barrier Island Chain,
Southwest Florida." Environmental Studies Program Publication No. 22.
New College of the University of South Florida. Sarasota, FL.

Hatch, H. J. 1990. Statement of New Environmental Approaches. Division
Memorandum. Department of the Army, U.S. Army Corps of Engineers,
Washington, D.C.

Hine, A.C. 1987. "Evaluation of the Lee County Coastline: Dominant Processes,
Shoreline Change, Stabilization Efforts, and Recommendations for Beach
Management." Department of Marine Science. University of South Florida.
St. Petersburg, FL.

Hine, A.C. and D.F. Belknap. 1986. "Recent Geological History and Modern
Sedimentary Processes of the Pasco, Hernando, and Citrus County Coastline:
West Central Florida." Florida Sea Grant College Report No. 79. University
of Florida. Gainesville, FL.

Hine, A.C., D.F. Belknap, J.G. Hutton, E.B. Osking, and M.W. Evans. 1988. "Recent
Geological History and Modern Sedimentary Processes Along an Incipient,
Low-Energy, Epicontinental-Sea Coastline: Northwest Florida." Journal of
Sedimentary Petrology. v. 58.

Hine, A.C., D.L. Mearns, R.A. Davis, Jr., and M. Bland. 1986. “Impact of Florida's
Gulf Coast Inlets on the Coastal Sand Budget." Departments of Marine

Science and Geology. University of South Florida. St. Petersburg and Tampa,
FL.

Jindrich, V. 1969. "Recent Carbonate Sedimentation by Tidal Channels in the
Lower Florida Keys." Journal of Sedimentary Petrology. v. 39.

Lane, E., 1981. “Environmental Geology Series, Miami Sheet." Florida Department
of Natural Resources. Bureau of Geology Map Series 101.

McGowen, J. H., L. E. Garner, and R. G. Wilinson. 1977. The Gulf Shoreline of
Texas: Processes, Characteristics, and Factors in Use. The University of Texas
at Austin, Bureau of Economic Geology Geological Circular 77-3, 26p.

Morton, R.A. 1977. Historical Shoreline Changes and Their Causes, Texas Gulf
Coast. Transactions Gulf Coast Association of Geological Societies, v. 27.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 53



Coastal & Shoreline Erosion in the Gulf of Mexico Chapter 2

the regional coastal sediment supply. Material dredged from coastal navigation
channels and disposed offshore often constitutes a net loss to the coastal sediment

supply.

Natural wave action and water level variations cause significant shoreline erosion.
Although storms generate the most visible shoreline retreat, such erosion is often
substantially "repaired" soon after the storm by the movement of sand back on
shore from the same natural forces. Different shorelines are adjusted to different
wave and storm climates. For example, whereas New England shorelines are
subjected to frequent northeastern storms on an annual basis, Florida's Gulf of
Mexico beaches may be most affected by hurricanes spaced decades apart. Changes in
the average frequency or intensity of storm events can have a significant effect on
shoreline change rates, and some scientists speculate such changes may occur if
theories about global warming prove correct.

Responses to Coastal & Shoreline Erosion

The basic problem with responding to coastal erosion is the same one found in
dealing, with most environmental issues where humans are a significant causative
factor; i.e., there are often conflicting priorities that are difficult, if not impossible, to
meet fully. For example, one priority may be the protection of coastal buildings,
property, and infrastructure. In the U.S., development near the coast is often highly
valued. This valuation can serve as a legitimate economic basis for justifying
significant expenditures on erosion control measures. However, the most effective
erosion control measures for a particular site may conflict with a second priority,
which is preservation of recreational beaches and the natural coastal environment.
Beaches are utilized and valued by the population at large, and they also serve as
important habitats and as nesting areas for species as diverse as least terns and sea
turtles. Shoreline erosion that removes beach material seaward of "permanent"
human-made structures also removes valuable shoreline habitat that cannot be
replaced through natural processes, as it typically would be if the structures were
absent. Other erosion control measures may be less effective at dealing with the
original problem and, therefore, may violate a third priority, which is the
governmental imperative to get the most result for public funds invested in such
projects. State or local policies may restrict the range of options available for dealing
with an erosion problem, thereby creating constraints that amount to a fourth
“priority.”

The two principal approaches to reducing the impacts of coastal and shoreline
erosion are stabilization and management. The two are not mutually exclusive; in
fact, a combination of both often provides the best compromise among competing
priorities. Stabilization consists of stopping or slowing the rate of erosion by
employing structures, additional sediment, or a combination of structures and
sediment. Vegetation can also be used as a stabilization project feature on the open
coast or as a principal form of stabilization in sheltered waters. Management

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



Coastal & Shoreline Erosion in the Gulf of Mexico Chapter 2

would begin to lose land to the Gulf as a result of subsidence (consolidation of
underlying soil strata) and Gulf tides, waves, and'currents. Meanwhile, the delta at
the mouth of the new route would begin to grow. For the last several thousand
years, the natural processes were in approximate equilibrium, creating a coast
composed of wetlands in all stages of building and loss.and an ecosystem of
tremendous diversity and productivity.

The natural processes were at odds with humans' desire to inhabit and develop the
resources of coastal Louisiana. In the eighteenth century, when Europeans began
settling in significant numbers in the Lower Mississippi Valley, they began
constructing levees to contain the Mississippi River. In the nineteenth century,
when the commercial navigation potential of the river became apparent, Congress
initiated actions to clear the Mississippi and maintain it for navigation. In the
twentieth century, oil and gas exploration, land reclamation projects, and
construction of ports and channels along Louisiana's coast further developed the
economic potential of coastal Louisiana. The state and the nation benefited greatly
from these developments, but at a very high cost to Louisiana's coastal wetlands.

Today, flood control projects (such as levees) ensure that most sediment now
bypasses the areas where it would naturally build and nourish wetlands. As a result,
soil deposits no longer compensate for the effects of natural subsidence. These
conditions are compounded in many locales where channels dredged for navigation
or oil and gas exploration allow salt water to penetrate far inland. In other areas,
urbanization, highways, and spoil banks from channel dredging disrupt natural
drainage. Stressed by these changes in hydrology or salinity, hundreds of thousands
of acres of vegetated wetlands have been lost. In addition, the land--no longer held
together by a living root system-—has eroded.

Only a small amount of current annual losses results from new human activity in
the coastal zone. Through actions taken by the state, private landowners, and
industry, the number of coastal wetlands acres destroyed for development under
permit has dropped from 1,214 hectares /year (3,000 acres/ year) in 1980 to less than 81
hectares/year (200 acres/year) during the 1990s. The.vast majority of losses
occurring today are the result of continuing, long-term impacts of actions taken by
humans decades earlier.

The net impact of human activities on Louisiana's coastal wetlands is that, instead
of a natural equilibrium between gain and loss, today the coast has a net loss of some
64.8 km? /year (25 mi?/year). Louisiana, which contains about 40 percent of the
coastal wetlands in the lower 48 states, is suffering 80 percent of all coastal wetlands
losses. While the deteriorating system is highly productive today, the long-term
prospect is for catastrophic decline in the economic and other values of the
ecosystem and a future shoreline far inland of its present location.

These losses will have impacts well beyond the borders of Louisiana. Populations of
migratory birds and other animals, which are directly dependent on the marsh and

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 27



The Unfinished Agenda

Public Education & Outreach

Effective responses to the impacts of erosion require an ongoing commitment from
an informed citizenry. Public outreach nurtures such a commitment. Public
information, education, and involvement are three components of an effective
outreach strategy, which can reap significant benefits for the Gulf of Mexico. More
and more, public outreach is recognized as an effective resource management tool to
address problems resulting from individual actions and to create a sense of
stewardship within the community. A committed citizenry presents both a
supplement and an alternative to enforcement programs.

Public outreach can foster recognition of the Gulf of Mexico as a regional and
national resource, stimulate civic, governmental, and private sector support for
changing lifestyles, and develop the financial commitments necessary to preserve
the resource. A strong outreach program showing the effects human activities have
upon the Gulf will enable all individuals to see themselves as caretakers of a vital,
shared resource:

Specific objectives and action items follow:

OBJECTIVE: increase individual and public awareness of erosion
impacts in the Gulf of Mexico region and the importance of
appropriate control measures and options.

Action Item 15 - Slide Presentation on Coastal & Shoreline Erosion

Develop a generic slide presentation on coastal and shoreline
erosion issues.

Lead: Texas Bureau of Economic Geology.
Initiation Date: 1993

Action Item 16 - Public Information Materials on Coastal & Shoreline Erosion

Develop an inventory of projects, a primer, and other public
information materials (i.e., pop-up display for conferences,
educational package for elementary and secondary schools) on
coastal and shoreline erosion.

Lead: Gulf of Mexico Program Coastal & Shoreline Erosion
Committee.

Initiation Date: 1994

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



Coastal & Shoreline Erosion in the Gulf of Mexico Chapter 2

State-by-State Overview

All of the Gulf States have serious erosion problems. Rates of erosion vary greatly
depending upon local shoreline characteristics and storm conditions. Parts of
Louisiana retreat 19.8 m (65 ft) or more per year, while erosion rates of 4.5 m (15 ft)
per year can be found in many other areas of the Gulf (Gulf of Mexico Program,
1991). Several rapidly eroding barrier islands are expected to completely disappear
within the next 30 years (USEPA, 1991). Such islands are often the primary defense
for wetlands, estuaries, and bays against storms and other open-Gulf effects.
Quantifying coastal and shoreline erosion is difficult since long-term averages or
trends can mask dramatic short-term reversals and cycles. Although some reaches
of shoreline may appear stable or show slow accretion for certain periods of time,
these conditions are rare in the long-term.

General historical shoreline trends are depicted by a map "Historical Shoreline
Change in the Northern Gulf of Mexico" (available from the Gulf of Mexico
Program Office). This map, which is a product of the Coastal & Shoreline Erosion
Committee, summarizes average rates of change for Gulf shorelines over the
periods for which reliable historical data are available.

The following brief description of erosion in each Gulf State is provided to give a
simplified assessment of the magnitude of shoreline erosion throughout the Gulf of
Mexico.

Alabama

Overview of the Problem. The Alabama coast stretches from eastern Dauphin
Island to the western portion of Perdido Key and includes the shorelines of Mobile
Bay and several other bays and sounds. There are about 75 km (47 mi) of shoreline
which directly front the Gulf of Mexico. All of these Gulf of Mexico beaches are
sandy. One interesting characteristic of the Alabama coast is that the beach sand
color varies considerably. East of Mobile Bay Pass, in Baldwin County, the beach
sands are a bright white, similar to the adjacent Florida panhandle. West of Mobile
Bay Pass, on Dauphin Island, the beach sand is darker, more similar to the
neighboring barrier islands of Mississippi. The geologic origin of the coast,
particularly east of Dauphin Island, is complex and considered largely unknown.
Likewise, the available data documenting historic shoreline change is limited, when
compared to that for the other Gulf States.

Alabama also has over 725 km (450 mi) of shoreline on bays, sounds, and coastal
bayous. Mobile Bay, the eastern end of Mississippi Sound, and the western half of
Perdido Bay are the largest estuaries in Alabama. About half of Alabama's total
shoreline was eroding between 1917 and 1973, according to one study (Sapp, et al.
1975). The Alabama Gulf Coast encompasses three and a half tidal inlets, including
one of the world's smallest inlets and one of the world's largest inlets. Human

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 15



Federal & State Framework Appendix A

. Clearwater Beach groin field and bulkhead--No additional information available.

* Clearwater Beach fishing piers which function as groins--"Wave deflection" panels
were built under the piers. These panels extend down into the waves so the
piers function as permeable groins.

* Clearwater beach inlet sand transfer--Sand was transferred from the inlet onto the
beaches in front of vertical bulkheads in 1982. A terminal groin is located
adjacent to the pass.

* — Clearwater/Sand Key Inlet sand transfer/peach nourshment~-In 1981-1984, 458,940 m3
(600,000 yd3) of sand from Clearwater Pass was placed on beaches of the city of
Clearwater along the north portion of Sand Key. In 1990-1991, 14,533 m3 (19,000
yd3) of sand was truck-hauled to the beaches from an inland site. Previously,
sand from Clearwater Pass had been pumped onto these beaches in 1972 [50,483
m3 (66,000 yd3)] and 1977 [142,271 m3 (186,000 yd).

* Belair Beach and Belair Shores bulkheads--There are approximately 3.2 km (2 mi) of
different bulkhead types, predominately privately constructed, vertical concrete
bulkheads. This stretch of coast is probably 100 percent armored. Much of the
bulkheads were destroyed by Hurricane Elena. ~

. Indian Rocks Beach beach nourishment--In 1990, 994,370 m3 (1.3 million yd) of sand
were placed on the beach. Previous smaller, emergency beachfills were placed
on this in 1969 [109,381 m3 (143,000 yd3)] and 1973 [305; 960 m3 (400,000 ya) The
source of the sand was Egmont shoals.

* Indian Shores beach nourishment--In 1991, 841,390 m$ (1.1 million yd3) of sand were
placed on the beach. The source of the sand was Egmont shoals.

* — Redington Shores and North Redingten Beach nourishment--In 1986, an offshore
breakwater was constructed with 290,662 m3 (380,000 yd) of beachfill. The
elevation of the top of the breakwater was lowered in 1988 from +.5 m (1.5 ft)
(mean low water) to +.2 m (0.5 ft). There are many private bulkheads in the
area. This is a case where the results of a formal coastal engineering
monitoring program were used to improve the engineered solution after
several years.

. Madlera Beach groin field--This groin was built in the 1950s.

+ Treasure Island Beach Nourishmenvinlet sand transfer--In 1986, 415,341 m3 (543,000 yd3)
of sand from offshore of Pass-a-Grille were placed on the beach. Previously,
there were nine other beachfills totaling 1,376,820 m3 (1.8 million yd3), from
1964 to 1985, with sand sources including Johns Pass, Blind Pass, and offshore.
Coastal structures are common along the beaches. The beachfills bury an old

Gulf of Mexico Goastal & Shoreline Erosion Action Agenda (4.1) 80



Coastal & Shoreline Erosion in the Gulf of Mexico Chapter 2

Texas, near bay margins, and within alluvial valleys, nearly 607 hectares (1500 acres)
are lost to erosion and land submergence. Wetlands constitute about 75 percent of
this loss.

Total land losses and rates of loss along the shoreline were estimated by combining
historical data of Morton (1977) and Paine and Morton (1989). The results showed
that more than 10,927 hectares (27,000 acres) of beachfront land was lost between the
mid-1800s and 1982, at an average long-term rate of about 91 hectares/year (225
acres/year). Although some segments of the Gulf shoreline are eroding at an
accelerated rate, the rate of total land loss has remained nearly uniform since the
1950s.

The highest rates of historical shoreline movement along the Texas coast are the
direct result of human activities. The long-term sustained rates of erosion are
greatest at Sargent Beach, which is located between the Brazos and Colorado Rivers.
Here, the beach retreats at an average rate of 9. 2 m/ year (30 ft/year). More
important, the rate of erosion has been accelerating since diversion of the Brazos _
River impounded sediment that would have normally been transported to Sargent
Beach by longshore currents.

In the fall of 1989, the Texas Department of Transportation closed Texas State -
Highway 87 in Chambers and Jefferson counties from High Island to Sabine Pass .
because of dangerous conditions resulting from severe erosion. In some areas, the
highway lies at the water's edge, protected only by a makeshift metal bulkhead.
Erosion rates are 1.4 to 2.8 m/year (4.6 to 9.2 ft/year) along this segment of the Texas
coast. The elevation of the beach and adjacent coastal lands is less than 1.4 m (4.6 ft)
above sea level. Beaches are narrow and dunes are limited. The beaches and
surrounding wetlands are frequently inundated by waves of even minor storms.

Gulf of Mexico Shorelines. Accelerated erosion in other areas or recent erosion of
formerly stable beaches is attributed to the relative rise in sea level, a lack of near-
surface sand in the littoral system, the reduction of sand transported by rivers
emptying into the western Gulf, and the impoundment of littoral sand by jetties at
harbor entrances.

Rivers are the primary source of sand for building barriers and beaches in the
western Gulf of Mexico. Reductions in the sediment supply have occurred due to
natural factors such as climatic cycles, but human activities have exacerbated the
problem. Flood-control structures have caused many rivers to lose their sediment-
transporting capacity.

In addition, structures used to protect navigational inlets and deep-draft channels
(jetties) disrupt the longshore current and compartmentalize the coast, preventing
sediment exchange from one coastal segment to another. The maintenance of these
inlets has generated seven coastal compartments on the open Gulf. Each
compartment is bounded by long impermeable jetties and deep navigation

Gulf of Moxleo Coastal & Shoreline Erosion Action Agenda (4.1) 34



Federal & State Framework Appendix A

The Commissioner of the GLO may issue permits for geological, geophysical, and
other investigations within the tidewater limits of the state. The Commissioner
may also grant easements or leases for rights-of-way across state lands for
pipelines and other transmission lines. In addition, the Commissioner is
responsible for technical assistance and compliance under the Dune Protection
Act and implementation of the Texas Coastal Preserve Program with the Texas
Parks & Wildlife Department.

* School Land Board. The School Land Board, in conjunction with the GLO,
manages the state's coastal public lands. The Board may grant leases to certain
governmental bodies for public purposes; leases for mineral exploration and
development; easements to littoral landowners; channel easements to surface or
mineral interest holders; leases to educational, scientific, or conservation
interests; and permits for limited use of previously unauthorized structures.

* Soil & Water Conservation Board. The Texas State Soil & Water Conservation
Board has the responsibility to plan, implement, and manage programs and
practices for abating agricultural and silvicultural nonpoint pollution. The State
Board also administers a voluntary conservation program with and through 212
local soil and water conservation districts which encompass over 99 percent of
the surface acres of Texas. With a voluntary program, conservation practices are
being applied: by over 215,000 cooperating landowners on more than 120 million
acres.

* Texas Parks & Wildlife Department (TPWD) . TPWD operates the state parks
- system and wildlife refuges. A permit must be obtained from TPWD for the

disturbance or dredging of sand, shell, or marl in public waters not authorized by
other state or federal agencies. Public waters are defined as all the salt and fresh
waters underlying the beds of navigable streams under the jurisdiction of the
Parks & Wildlife Commission. TPWD is responsible for reviewing and
commenting on state and federal permits affecting Texas wildlife resources and
for protection of endangered or threatened species.

+ Texas Railroad Commission. The Commission has extensive authority in the
oil and gas industry and in pollution prevention and abatement. The
Commission also regulates intrastate natural gas pipelines and issues drill
permits for oil and gas wells. In addition, the Commission regulates surface
mining for lignite, uranium, and iron ore to make sure that the resources are
properly developed and the environment protected.

* Texas Department of Transportation (DOT). DOT is responsible for road
construction and planning. DOT administers federal funds for mass transit and
may plan, purchase, construct, lease, and contract. for public transportation
systems in the state. DOT constructs and maintains bridges and ferries, serves as
the state sponsor of the Gulf Intracoastal Waterway, and can acquire easements
and rights-of-way from GLO for channel expansion, relocation, or alteration.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1). J 7s



Bibliography

Coastal Planning and Engineering. 1989. "Lee County, Florida, Beach Erosion
Control Project, Captiva Island Segment." General and Detailed Design
Memorandum. Coastal Planning and Engineering, Inc. Boca Raton, FL.

Davis, JH. 1940. "The Ecology and Geologic Role of Mangroves in Florida."
Washington, D.C. Carnegie Institute Publication 517. Papers of the Torgugas
Laboratory. v. 32, no. 16.

Davis, J.H. 1942. “The Ecology of the Vegetation and Topography of the Sand Keys
of Florida." Carnegie Institute of Washington. Papers from Tortugas
Laboratory. Publication 524, v.3.

Davis, R.A., Jr., A.C. Hine, and D.F. Belknap. 1982. "Coastal Zone Atlas: Northern
Pinellas County, Florida.". Florida Sea Grant Project. R/OE-17.

Davis, R.A., Jr. and DJ. Kuhn. 1985. "Origin and Development of Anclote Key,
West Peninsular Florida." Marine Geology. v. 63.

Douglass, S. L. and D. R. Haubner. 1992. Coastal Processes of Dauphin Island,
Alabama. University of South Alabama. College of Engineering Report No.
92-1.

Dunbar, J.B., L.D. Britsch, and E.B. Kemp III. 1992. Land Loss Rate: Report 3,
Louisiana Coastal Plain. USACE Technical Report. GL-90-2.. Department of
the Army-WES-CE. Vicksburg, MS. 28 pp.

Enos, T. and R.D. Perkins. 1979. "Evolution of Florida Bay from Island ~
Stratigraphy." Geological Society of America Bulletin. v. 90.

Evans, M.W., A.C. Hine, D.F. Belknap, and R.A. Davis, Jr. 1985. "Bedrock Controls
on Barrier Island Development: West-Central Florida Coast." Marine
Geology. v. 63.

Evans, M.W. and A.C. Hine. 1986. "Quaternary Infilling of the Charlotte Harbor
Estuarine/Lagoonal System, Southwest Florida: Implication of Structural
Control." SEPM Annual Midyear Meeting Abstracts. Raleigh, NC. v. 3.

Fischer, D.W. et al. 1984. "Beach Management Plan: University of West Florida,
Pensacola, FL." Florida Department of Natural Resources. Division of
Beaches and Shores. Tallahassee, FL.

Gibeaut, J.A. and R.A. Davis, Jr. 1988. "Morphodynamic Classification of Tidal
Inlets." Beach Preservation Technology '88.

Ginsburg, R.N. 1979. “Beach Rock in South Florida." Guide to Sedimentation for
the Dry Tortugas. Southeastern Geological Society Publication No. 21.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) - $2



Federal & State Framework Appendix A

* Texas Natural Resource Conservation Commission (TNRCG). TNRCC has the
responsibility for protecting surface and groundwater quality. In addition to this
responsibility, the Commission oversees surface water rights administration,
dam safety management, the NFIP and flood control improvement project
administration, injection well program administration, waste minimization
initiatives, and water district supervision. (Effective September 1, 1993, the Texas
Water Commission was combined with the Texas Air Control Board to form the
Texas Natural Resource Conservation Commission.)

TNRCC has the authority to develop/enforce regulations affecting streamflow to
the Gulf. These regulations are contained in Chapters 11.147 and 11.152 of the
Texas Water Code. The 69th Texas Legislature assigned the responsibility for
water rights permitting to TNRCC and gave the TPWD authority to be a party in
hearings on applications for permits to store, take, or divert water--actions that
can change the pattern or quantity of freshwater inflow. The Legislature directed
TNRCC to consider effects on bays and estuaries for all water rights permits, with
a specific directive to include protective provisions in certain permits by applying
a performance standard when making decisions concerning water rights on
rivers and streams leading to bays and estuaries.

+ Texas Antiquities Committee. The Texas Antiquities Committee, created by the
Texas Antiquities Code, is responsible for preserving and protecting the state's
historical and archaeological resources. The Committee requires permits for
activities involving salvage or study of state archaeological landmarks, including
historical sites and artifacts of interest such as sunken ships, buried treasure, and
art works. The Committee issues eight types of permits covering virtually every
aspect of historical and archaeological investigation, including reconnaissance,
testing, excavation, and destruction.

* Texas Attorney General's Office. The Texas Attorney General's Office is not a
regulatory agency, but it has a role in resource management as the state's
enforcement agency for the Open Beaches Act and other coastal legislation. The
office protects the public's beach access rights and can bring suit on behalf of
other state agencies to enforce state laws.

* Bureau of Economic Geology. The Bureau of Economic Geology at The
University of Texas is responsible for much of the mapping of coastal resources,
energy, minerals, land, geology, and biology. It also monitors erosion along the
Texas Gulf Coast. .

* Governor's Office of Budget & Planning. The Governor's Office of Budget &
Planning prepares recommendations for the budget and is responsible for
administration of state review and comment procedures for all federal or
federally funded projects.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 76



Participants in the Action Agenda Development Process

Appendix D

Ihe Coastal & Shoreline Erosion Committee

Co-Chairs:

Thomas Richardson
Sally Davenport

Members:

Robert Baker

Frank Blanchard
Floyd Buch

Mary Lou Campbell
Ralph Clark

Mel Davis

John Dingler

Peter Doragh

Scott Douglass
James Edmondson
Edwin Garner
Mark Gates

Linda Glenboski
Andrew Grayson
Deborah Heibel
Cathy Hollomon
Richard Hoogland
Charles Hunsicker
James Johnston
Robert Jones

Jeff Kellman

B.D. King III

Cragin Knox

Herb Kumpf
Bennett Landreneau
John Lawrence
Klaus Meyer-Arendt
Robert Morton
Joann Mossa
Robert Nailon
John O'Connor
Ervin Otvos

Shea Penland

Ric Ruebsamen
Asbury Sallenger Jr.
Samuel Sanders

U.S. Army Corps of Engineers
Texas General Land Office

U.S. Geological Survey

Collier Beach Society

Port of Corpus Christi

Sierra Club

Florida Office of Beach Erosion Control

Texas Soil & Water Conservation Board

U.S. Geological Survey

Citizens Advisory Committee

University of South Alabama

South-Central Planning & Development Commission
The University of Texas at Austin

Texas Natural Resource Conservation Commission
US. Army Engineer District

Florida Department of Natural Resources -

U.S. Army Corps of Engineers

Department of Wildlife, Fisheries & Parks

Gulf of Mexico Fishery Management Council
Assistant City Manager--Clearwater, Florida

US. Fish & Wildlife Service

Terrebonne Parish Government--Louisiana
Agency for Toxic Substances & Disease Registry
USS. Fish & Wildlife Service

Mississippi Department of Environmental Quality
National Marine Fisheries Service

Soil Conservation Service

' Soil Conservation Service

Mississippi State University

University of Texas at Austin

University of Florida

Texas A&M Marine Advisory

Florida Association of Conservation Districts
Gulf Coast Research Laboratory

Louisiana Geological Survey

National Marine Fisheries Service

U.S. Geological Survey

Soil Conservation Service

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) qit



Participants in the Action Agenda Development Process Appendix D

Laura Radde US. Environmental Protection Agency--Region 6
Doug Ratcliff Texas Bureau of Economic Geology

Ray Reesby Unaffiliated

Tom Richardson U.S. Army Corps of Engineers

Hermann Rudenberg Coastal Environmental Evaluation (consultant)
Ric Ruebsamen National Marine Fisheries Service

Abby Sallenger U.S. Geological Survey

Eddie Seidensticker Soil Conservation Service

Tom Smith U.S. Army Corps of Engineers

Greg Stone Louisiana State University

Sid Tanner U.S. Army Corps of Engineers

Cliff Truitt Mote Marine Laboratory

David Vigh Brown & Root, Inc.

Y.H. Wang Texas A&M University at Galveston

Jeff Williams U.S. Geological Survey

Harley Winer Brown & Root, Inc.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 114



Coastal & Shoreline Erosion in the Gulf of Mexico Chapter 2

Island, and separated by 3.2 km (2 mi) wide East Pass, lies Dog Island, the
easternmost coastal barrier island in the northern Gulf of Mexico. Irregularly
shaped Dog Island is 11 km (6.9 mi) long with narrow western and broad eastern
segments. Two low and narrow areas along the western portion of the island are
less than 150 m (500 ft) wide and subject to inundation and breaches from even
moderate storm impacts; the eastern segment attains a width of about 1,311 m (4,300
ft). Net longshore transport is bidirectional along the island with the dominant
transport occurring westward toward the narrows and eastward near the broadest
reach. Long-term trends suggest a maximum erosion rate of over 2 m/year (6.5
ft/year), although more recent data suggest an acceleration in the erosion rate to
perhaps 6 m/year (20 ft/year) (Clark, 1986). The easternmost segment of the
panhandle region is a mainland peninsula, known as St. James Island, which lies
between the Gulf and Ochlockonee Bay. The eastern end of the peninsula extends
for a distance of 5.5 km (3.4 mi) from Bald Point southward to Lighthouse Point.
From Lighthouse Point, a recent barrier spit extends for about:8 km (5 mi) to the
west past Southwest Cape, and terminating in Alligator Point. New longshore
transport is to the west along the barrier spit. The reach between Southwest Cape
and Lighthouse Point constitutes perhaps the most critical erosion reach along the
panhandle. Severe erosion and costly property and structural damages have been
incurred by a number of storms during the past 30 years (Clark, 1986).

Big Bend Gulf Coast. The Big Bend is defined as a low to zero wave energy shore
(Tanner, 1960) stretching for some 386 km (240 mi) from Ochlockonee Bay to
Anclote Key just north of Tampa. It is unique because of its marsh-dominated
open-marine character, very wide and shallow fronting shelf, highly crenulated
shoreline shape with thousands of creek outlets and embayments, and general lack
of beach sands. Concerted geological exploration of the Big Bend is just beginning
(e.g., Hine and Belknap, 1986; Hine et al., 1988) with a cooperative effort organized by
the University of South Florida, Florida Geological Survey, and the U.S. Geological
Survey (USGS). Of the 390 km (241.8 mi) of shoreline (measured "as the crow
flies"), only 11.9 km (7.4 mi) have quartz sand beaches. Mashes Sands just north of
the Ochlockonee Bay entrance (Clark, 1991b), Shell Point along the northern
extremity of the Big Bend, and the Cedar Keys (including Seahorse Key and North
Key) and Pine Island along the eastern flank of the Big Bend, represent the major
localized deposits of quartz sand beaches along the reach. Of the 11.9 km (7.4 mi) of
beach, Clark (1991a) reports that 6.8 km (4.2 mi) are experiencing erosion, of which
4.8 km (3 mi) are critical and 1.9 km (1.2 mi) are noncritical.

Lower Gulf Coast. The barrier islands of the lower Gulf Coast constitute a near
continuous chain extending from Anclote Key to Cape Romano, a distance of 295
km (183 mi). Barriers have not formed to the north of Anclote Key due to the lack
of sand and low wave energy. There is one sound [7.7 km (4.8 mi)], one mainland
reach [5.6 km (3.5 mi)], one relict upland coast [17.9 km (11.1 mi)], and 41 inlets,
which are indicative of the number of barrier islands found in this region. The
majority of the lower Gulf Coast is characterized as having moderate wave energy

Guif of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 21



List of Figures

LIST OF FIGURES

Figure 1.1 Gulf of Mexico Coastal County Population
per Shoreline Mile...

Figure 1.2 Gulf Program Structured Partnership...cccccssessccrssserens ae S

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) vii



Coastal & Shoreline Erosion in the Gulf of Mexico Chapter 2

Conclusion

Coastal and shoreline erosion is one of the major factors threatening the Gulf
coastal environment. Mainland Gulf shorelines and shorelines of major estuarine
water bodies and waterways are highly visible and represent the edge of the coastal
environment. In spite of the fact that these eroding and disappearing shorelines are
obvious, the loss of this valuable resource continues.

One or more of the following factors may be a primary cause of coastal erosion at'a -
given location: sea level rise, land subsidence, coastal storms and wave action,
reduced or diverted river sediment loads, navigation channels and canals, and some
coastal protection projects. The relative importance of these factors and the nature
of their physical effects differ from site to site. :

Throughout the Gulf, erosion rates vary, and only a few areas remain stable or
actually accrete. The impacts of this erosion include loss of habitat, reduced fishery
resources, saltwater intrusion, and loss or degradation of recreational use. The
combined causes of erosion accelerate the loss of the natural environment, while
the impacts of erosion reduce the area's financial resource base.

All of the federal, state, local; and private interests concerned about the coastal
environment are struggling to determine solutions. As these efforts continue, the”
coastal resources dwindle, as.do the natural ingredients needed for restoration. At
the same time, competition for these natural ingredients is growing rapidly. ‘The
key to limiting further coastal erosion is to develop-solutions that are agreeable to. ’
all and affordable within limited resources. The more permanent and long-term
comprehensive solutions are elusive and will require greater knowledge,
assessment of the supporting nearshore and estuarine areas, and continuous"
maintenance.

Through the Coastal & Shoreline Erosion Committee, the Gulf of Mexico Program
presents an opportunity. to address .the shoreline problems facing the coastal areas of
the Gulf in an interagency manner. Expertise and information can be intensified
and focused on the many issues in the coastal area by sharing the institutional
knowledge and experience accumulated within each agency and the private sector.
A team approach by all involved, utilizing all available resources, is the key to -
developing a successful response to the problem of coastal and shoreline erosion.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) : 36



Table of Contents

APPENDIX A Federal & State Framework sressssscssseerseessenenecsnesennsens 5B
APPENDIX B Acromym Guidesecssessssesscrencesssccececenccescensecsncceesersscssecesenese 86
APPENDIX C GIOSSALYsvvsesnsesnseensnensst atten tte READ 88
APPENDIX D Participants in the Action Agenda ProcesSrsssessessssesccssstanenne TUF

APPENDIX E Potential Demonstration Projects srssssscsssssnssssnnneeeessssneneees WE

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) vi



Coastal & Shoreline Erosion in the Gulf of Mexico Chapter 2

upper basin; developing sources of freshwater and sediment for exploring the
potential of the Gulf Intracoastal waterway as a freshwater and sediment conduit;
and restoring of the barrier islands to provide increased protection from the natural
forces of the Gulf of Mexico.

Atchafalaya Basin. The Atchafalaya basin is unique in that it contains a growing delta
which has only recently (1973) emerged above the waters of the bay. A basin
restoration strategy would probably emphasize delta growth in a manner consonant
with the needs of navigation and flood control.

Ieche/Vermilion Basin, This is a relatively stable basin which has reached the endpoint
of typical deltaic evolution. A strategy here would likely concentrate on protecting
against shoreline erosion.

Mermentay Basin. The upper part of the basin suffers from high water levels that
stress marshes and contribute to erosion of lake shorelines. Additionally, bank
erosion is a problem along waterways in the basin. The lower basin is affected by
shoreline erosion, reduced freshwater input, and hydrologic alterations (largely as a
result of agricultural and oil and gas activities). A basin strategy could emphasize
management of the freshwater resources to reduce stages in the upper basin and
increase input to the lower basin. Critical areas of bank erosion would also be
addressed.

Caleasiew/Sabine Basin. The hydrology and saltwater regime of ‘this basin were

radically altered by construction of the Calcasieu Ship Channel, the Sabine-Neches
Waterway, and the Gulf Intracoastal Waterway. A strategy could center around a
perimeter defense for the interior marshes, a plan that provides protection against .
salt water and high water levels through a series of hydrologic restoration, projects.
The strategy could also include shoreline protection along the Gulf of Mexico and
bank protection on the Gulf Intracoastal Waterway.

Mississippi

Overview of the Problem. In Mississippi, the shorelines of all the barrier islands
have experienced significant erosion. The beaches of the mainland Gulf shoreline
of Mississippi have been lost and rebuilt several times in the last fifty years and
significant erosion is occurring along the remaining shorelines (Campbell, 1990).

Comprised of barrier islands, tidal inlets, beaches, and estuaries, the Mississippi Gulf
Coast is constantly undergoing environmental and physical changes. Its
classification as a micro-tidal, storm-dominated coastline suggests that the
occasional short-lived storm events play a significant role in shaping the coastal
configuration.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



Glossary Appendix C

wave trough The lowest part of a wave form between successive crests; also that part of a
wave below still-water level.

wave, wind See WIND WAVES.

wavelength The horizontal distance between similar points on two successive waves
measured perpendicular to the crest. :

weir jetty An updrift jetty with a low section or weir over which littoral drift moves into
a predredged deposition basin which is dredged periodically.

wharf A structure built on the shore of a harbor, river, or canal, so that vessels may lie
alongside to receive and discharge cargo and passengers.

whitecap On the crest of a wave, the white froth caused by wind.

wind chop See CHOP.

wind, following See FOLLOWING WIND.

wind, offshore A wind blowing seaward from the land in a coastal area.

wind, onshore A wind blowing landward from the sea ina coastal area.

wind, opposing See OPPOSING WIND.

wind setup On reservoirs and smaller bodies of water (1) the vertical rise in the still-water
level on the leeward side of a body of water caused by wind stresses.on the
surface of the water; (2) the difference in still-water levels on the windward
and the Ieeward sides of a body of water caused by wind stresses on the surface
of the water. See STORM SURGE (usually reserved for use on the ocean and
large bodies of water).

wind tide See WIND SETUP, STORM SURGE.

wind waves (1) Waves being formed and built up by the wind. (2) loosely, any wave
generated by wind.

windward The direction from which the wind is blowing.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 4110



Coastal & Shoreline Erosion in the Gulf of Mexico Chapter 2

2 COASTAL & SHORELINE EROSION IN THE GULF OF -
MEXICO

What is Coastal & Shoreline Erosion?

Erosion is the wearing away of land by the action of natural forces. Ona beach, _
erosion is the carrying away of beach material by wave action, tidal currents, littoral
currents, or by deflation.

Erosion is a natural process that has affected the coastal environment for thousands
of years. Coastal erosion is a major problem for developed shorelines everywhere
in the world. In the U.S., coastal erosion is becoming more critical as it threatens
buildings, transportation infrastructure, and environmental habitats, and as it
gradually removes natural barriers that buffer the devastating effects of coastal
storms. .

Causes of Coastal & Shoreline Erosion

Beaches are dynamic systems. Major factors driving coastal change include sea
level, sediment supply, and wave and tidal energy. A change in one of these factors
can result in visible adjustments to the beach as it seeks a new balance with its
physical environment. In a simplified sense, the rate and amount of beach
adjustment are functions of the degree of change in its equilibrium factors.

Sea level is rising at a relative rate of about 0.3 m (1 ft) per century along U.S. coastal
plains and at varying rates along other coasts. Due to the flat slope of much of the
Gulf's coastline, even a relatively low rate of sea level rise can produce substantial
shoreline erosion. The highest relative sea level rise rate in the U.S., approximately
1.2 m (3.9 ft) per century, may be found in parts of the Mississippi River delta, where
land is also sinking (Titus, 1988).

Sea level rise tends to cause relatively gradual erosion at comparable rates over an
entire region. On the other hand, sediment starvation can generate rapid erosion
with intense localized effects. Much of this change is due to natural or human-
induced gradients in longshore sand transport, which is driven largely by waves.
Construction of dams and other river alterations can accelerate erosion by reducing
the supply of sediment to the coastal zone. Because individual shoreline reaches
often depend on a unique combination of sediment sources, including rivers,
eroding bluffs and cliffs, and the continental shelf, any decrease in the supply from
these sources may lead to erosion. Seawalls can cut off the sediment supply from
eroding bluffs. Poorly designed projects involving groins, breakwaters, or jetties
may divert, slow down, or trap moving sediment in their vicinity at the expense of

Gult of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) . 41



Overview of the Gulf of Mexico . Chapter 1

Figure 1.2

Gulf Program Structured Partnership

Program Operations Support
Policy Review Board

Gulf of Mexico
Program Office

Public Education &

Cltlzens Advisory
| Committee
Management Committee )
Technical Advisory
Committee

issue Committees

Outreach Operations

Data & Information
Transter Operations

Habitat Degradation

Public Health
Freshwater Intiow

Marine Debris
Coastal & Shoreline Erosion
Nuteient Enrichment

Toxic Substances &
Pesticides

Living Aquatic Resources

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 6



Executive Summary

No specific implementation projects are proposed in this iteration of the Action
Agenda. Rather the Coastal & Shoreline Erosion Committee-has focused on the
development of a consensus on the most effective responses to critical erosion
problems and the monitoring of projects that are already underway at the federal
and state levels. It is anticipated that future iterations of the Action Agenda will
include specific implementation projects.

Action items contained in Chapter 4 are not listed in priority order. Some of the
actions are already underway but not yet completed. Others are included because
they will guide federal, state, and local government agencies and private sector
‘organizations in allocating resources where they are most needed and in justifying
future management strategies. This Action Agenda should prompt specific agencies
and groups to become involved.

-The Gulf of Mexico Program recently developed ten short-term environmental,
‘challenges to restore and maintain the environmental and economic health of the
Gulf. Within the next five years (1993-1997), through an integrated effort that
complements existing local, state, and ‘federal programs, the Program has pledged
efforts to obtain the knowledge and resources to:

Q_ Significantly reduce the rate of loss of coastal wetlands.

Achieve an increase in Gulf Coast seagrass beds.

Enhance the sustainability of Gulf commercial and recreational fisheries.

Protect the human health and food supply by reducing input of nutrients, toxic substances, and
pathogens to the Gulf.

Increase Gulf shellfish beds available for safe harvesting by ten percent.
Ensure that all Gulf beaches are safe for swimming and recreational uses.
Reduce by at least ten percent the amount of trash on beaches.

Improve and expand coastal habitats that support migratory birds, fish, and other living
resources.

Expand public education/outreach tailored for each Gulf Coast county or parish.
Q_ Reduce critical coastal and shoreline erosion.

This Coastal & Shoreline Erosion Action Agenda supports these five year
environmental challenges.

For the public, this Gulf of Mexico Action Agenda should serve three purposes.
First, it should reflect the public will with regard to addressing coastal and shoreline
erosion. Second, it should communicate what actions are needed for reducing
erosion and provide the momentum for initiating these actions. Third, it should
provide baseline information from which success can be measured.

Gulf of Mexico Goastal & Shoreline Erosion Action Agenda (4.1)



Glossary

Appendix C

mean low water

mean sea level

mean tide level

median diameter

middle-ground shoal

mixed tide

monochromatic
waves
monolithic

nautical mile

neap tide

nearshore (zone)

nearshore circulation

(MLW) The average height of the low waters over a 19-year period. For
shorter periods of observations, corrections are applied to eliminate known
variations and reduce the results to the equivalent of a mean 19-year value.
All low water heights are included in the. average where the type of tide is
either semidiurnal or mixed. Only lower low water heights are included in the
average where the type of tide is diurnal. So determined, mean low water in
the latter case is the same as mean low water.

The average height of the surface of the sea for all stages of the tide over a 19-
year period, usually determined from hourly height readings; not necessarily
equal to MEAN TIDE LEVEL.

A plane midway between MEAN HIGH WATER and MEAN LOW WATER;
not necessarily equal:to MEAN SEA LEVEL; also HALF-TIDE LEVEL.

The diameter which marks the division of a given sand sample into two equal
parts by weight, one part containing all grains larger than that diameter and
the other part containing all grains smaller.

A shoal formed by ebb and flood tides in the middle of the channel of the
lagoon or estuary end of an inlet.

A type of tide with a large inequality in either the high or low water heights,
with two high waters and two low waters usually occurring each tidal day. In
strictness, all tides are mixed, but the name is usually applied without definite
limits to the tide intermediate to those predominantly semidiurnal and those
predominantly diurnal.

A series of waves generated in a laboratory; each wave has the same length
and period.

Like a single stone or block. In coastal structures, the type of construction in
which the structure's component parts are bound together to act as one.

The length of a minute of arc, 1/21,600 of an average great circle of the Earth.
Generally one minute of latitude is considered equal to one nautical mile. The
accepted U.S. value as of 1 July 1959 is 1,852 meters (6,076.115 feet),
approximately 1.15 times as long as the U.S. statute mile of 5,280 feet; also
geographical mile.

A tide occurring near the time of quadrature of the moon with the sun. The neap
tidal range is usually 10 to 30 percent less than the mean tidal range.

In beach terminology an indefinite zone extending seaward from the shoreline
well beyond the breaker zone. It defines the area of NEARSHORE
CURRENTS.

The ocean circulation pattern composed of the CURRENTS, NEARSHORE and
CURRENTS, COASTAL. See CURRENT.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



Federal & State Framework Appendix A

Projects undertaken by USACE must meet certain requirements or conditions,
and be formulated in accordance with specific criteria. Some of the more
important requirements, conditions and/or criteria are:

Q Beach Creation, Existing shore erosion control authority provides for
"restoration" and "protection." It does not provide for federal cost
sharing in extending a beach beyond its historic shoreline unless the
extension is needed for engineering reasons to provide protection from
erosion or as otherwise specifically authorized under public law.

Q Coastal Zone Management Plans. Project proposals must be consistent to the
maximum practicable extent with approved state coastal zone
management plans cleveloped under the authority of the Coastal Zone >
Management Act.

Q Coastal Barrier Resources System. Project proposals must comply with the
Coastal Barrier Resources Act of 1982 PL 97-348. .

+ Postauthorization Studies. Planning and engineering studies for shore
protection projects authorized under Section 105 (a) and (b) of PL 99-662 are
conducted under a contract providing for 50/50 federal/non-federal cost sharing.
Evaluation studies for disposal of materials dredged from navigation inlets and
channels, during either original federal improvement or maintenance, onto
adjacent beaches under Section 145 of PL 94-587, as amended, are initially
financed by USACE; the cost of the evaluation report is added to the separable
construction costs for placement of dredged material on beaches and cost shared
accordingly. Studies for extension of beach nourishment periods under Section
934 of PL 99-662 are initially financed by the federal government. If extension of
periodic nourishment is approved, the cost of preparing the reevaluation reports
is shared in the same proportion as the allocation of construction costs to the
type of benefits accruing from the project.

* Lecal Cooperation Agreements. The commitment of a sponsor of a shore
protection project to the non-federal obligations and requirements discussed
above is effected through a written Local Cooperation Agreement (LCA), as
required by Section 221 of PL 91-611, as amended, to provide local cooperation
satisfactory to the Secretary of the Army.

* Construction. Construction of authorized projects is a responsibility of USACE.
However, local interests may construct portions of projects after they are
authorized by Congress and be reimbursed by the federal government within the
limitations of Section 215 of PL 90-483, as amended, if prior approval is obtained
from the Chief of Engineers.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 59



Coastal & Shoreline Erosion in the Gulf of Mexico Chapter 2

responses to erosion have included a wide variety of attempts at shoreline
stabilization within the bays and rivers, but only a few attempts on Gulf beaches.

Gulf of Mexico Beaches. Alabama's Gulf beaches include the two coastal counties,
Mobile and Baldwin. Mobile Bay Pass is the dividing line between the two counties.
Dauphin Island is a 25 km (15 mi) long barrier island on the Gulf of Mexico west of
Mobile Bay Pass. The eastern 6 km (3.7 mi) is several kilometers wide with a sand
dune field with elevations of over 14 m (46 ft) above sea level and an extensive
maritime forest. The western 19 km (11.8 mi) portion of the island is only several
hundred meters wide and has maximum elevations of less than 3 m (10 ft) above
sea level and no maritime forest. This low, narrow, western portion frequently
overwashes in major hurricanes. Although the island has been continuously
inhabited by descendants of Europeans since the 1700s, modern land development
only began when the first bridge was built to the island in 1958. The western half of
the island is still undeveloped. The western end of Dauphin Island has grown
rapidly westward toward Mississippi. Westward accretion has averaged about 50
m/year (164 ft/year) since the turn of the century. Shoreline protection works built
around the turn of the century to protect Fort Gaines, a Civil War era coastal fort,
have prevented the eastern end of the island from eroding westward.

The easternmost 6 km (3.7 mi) of the island has two reaches of shoreline which are
presently receding and a reach of shoreline in between them which is accreting.
Recession was measured during 1991-1992 at rates up to 15 m/year (49 ft/year)
(Douglass and Haubner, 1992). These changes are consistent with the changes that
have occurred during the past decade. Averaged over the past decade, maximum
recession rates are 6 m/year (19.7 ft/year). The recession-accretion-recession pattern
at the eastern end of the island appears to be a response to changes in the position of
the Mobile Bay Pass ebb-tidal shoals and ephemeral islands immediately offshore.
Mobile Bay Pass is one of the world's largest tidal inlets. The shoals and islands
(commonly called Sand or Pelican Island) provide both sand for the Dauphin Island
beaches and wave sheltering to those beaches. The shoreline along the remainder of
the beaches to the west appears to have been generally stable during the past decade.

The beaches of Baldwin County, while connected to the mainland geographically,
have many characteristics of barrier islands with numerous, ponds and tidal lagoons
fronted by dune fields. These beaches have patterns of accretion, stability, and
recession that vary in location and with time. Most of these beaches show relative
stability or accretion from the mid-1800s to the mid-1900s (Stone, 1991), as well as
during the past two decades. Exceptions to this are south of Little Point Clear on the
Fort Morgan Peninsula and downdrift of Little Lagoon Pass where erosion is
occurring. Historic rates of shoreline change are highly variable with time
apparently because of repetitious foredune breaching and overwash during
hurricanes. In Gulf Shores, Little Lagoon Pass connects the Gulf with Little Lagoon,
a 12 km (7.4 mi) long by 1 km (0.6 mi) wide tidal lagoon. Prior to stabilization in
1981, the pass was ephemeral and had opened in several different locations. Since
stabilization, at a width of 12 m (40 ft), the pass has remained open for tidal exchange

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



Overview of the Gulf of Mexico . Chapter 1

The Gulf's bountiful waters draw millions of sport fishermen and beach users each
year. It is estimated that the Gulf supports more than one-third of the nation's
marine recreational fishing, hosting four million fishermen in 1985 who caught an
estimated 42 million fish (USDOC, 1992). Popular nearshore catches include sea
trout (weak fish), cobia, redfish, flounder, grouper, red snapper, mackerel, and
tarpon; offshore catches include blue marlin, white marlin, sailfish, swordfish,
dolphin, and wahoo. Tourism-related dollars in the Gulf Coast States contribute an
estimated $20 billion to the economy each year (USEPA, 1991).

Gulf oil and gas production are equally valuable to the region's economy and are a
critical part of the nation's total energy supply. In 1990, more than 1,600 Outer
Continental Shelf (OCS) leases were in production, yielding approximately 90
percent of U.S. offshore production. These OCS royalties annually contribute about
$3 billion to the Federal Treasury. Thirty-eight percent of all petroleum and 48
percent of all natural gas reserves in the U.S. are estimated to be in the Gulf of
Mexico. The industry employs some 30,000 people in the Gulf of Mexico.

Approximately 45 percent of U.S. shipping tonnage passes through Gulf ports,
including four of the nation's busiest: Corpus Christi, Houston/Galveston, Tampa,
and New Orleans. The second largest marine transport industry in the world is
located in the Gulf of Mexico. According to USEPA, vessel trips in and out of
American Gulf ports and harbors exceeded an estimated 600,000 trips in 1986. The ,
U.S. Navy is also implementing its Gulf Coast Homeporting Plan, designed to dock
at least 25 vessels in Ingelside, TX, Pascagoula, MS, and Mobile, AL.

Millions of people depend on the Gulf of Mexico to earn a living and flock ‘to its
shores and waters for entertainmerit and relaxation. The temperate climate and
abundant resources are attracting more and more people. The region currently
ranks fourth in total population among the five U.S. coastal regions, accounting for
13 percent of the nation’s total coastal population. Although the Gulf region is not
as densely settled as others, it is experiencing the second fastest rate of growth;
between 1970 and 1980, the population grew by more than 30 percent (USDOC, 1990).
According to the U.S. Department of Commerce, the Gulf's total coastal population
is projected to increase by 144 percent between 1960 and 2010, to almost 18 million
people. Figure 1.1 shows the Gulf of Mexico coastal population density or
population per shoreline mile projected to the year 2010. Florida's population alone
is expected to have skyrocketed by more than 300 percent by the year 2010. The
increasing coastal population is of concern because as the population increases, so
does the potential for environmental degradation.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



Coastal & Shoreline Erosion in the Gulf of Mexico Chapter 2

divided roughly in the vicinity of St. Andrews Bay East Entrance. To the west, the
shoreline trend is arcuate but smooth; to the east shoreline azimuths change
abruptly with peninsulas and barrier islands of varying physiographic form. On the
basis on general physiographic factors, each segment can be further divided into two
subsegments. :

Western Barriers. The western 98 km (61 mi) of the panhandle is characterized by two
barrier islands and interspersed beach ridge plateaus. Perdido Key, the westernmost
island, is about 24 km (15 mi) in length, of which 20.3 km (12.6 mi) lie in Florida. To
the east, Santa Rosa Island, 76.8 km (48 mi) in length, is the longest unbroken barrier
island along the Gulf Coast of Florida. These barriers range from 150 to 1000 m (500
to 3,250 ft) in width with dune heights averaging +5 m (17 ft) mean sea level (MSL).
Maximum dune crest elevations of up to +12 m (40 ft) MSL can be found. Net
sediment transport along these barriers is westward, although a west-east reversal is
evident along the eastern tip of Perdido Key (Stone, 1991; Stone, et al., 1992). Erosion
occurs along the eastern end of Perdido Key and western end of Santa Rosa Island
(Balsillie et al., 1986a, 1986b) ranging from about 1 to 1.5 m/year (@ to 5 ft/year) and
has been attributed to historical, repetitious overwashing during hurricanes (Stone
and Salmon, 1988) and an increasing wave energy gradient particularly along
western Santa Rosa Island (Stone, 1991; Stone et al., 1992).

Middle Mainland. To the east of Santa Rosa Island and East Pass lies a 81.4 km (50.6 mi)
reach of mainland coast, an unusual feature in Florida coastal physiography. Back
beach primary dunes along this mainland reach attain elevations of from 3.6 to 13.7
m (12 to 45 ft) and beach widths average 60 m (200 ft) (Fischer et al., 1984). Upland
coastal terrain is drained by a number of streams flowing to the Gulf from a series of
small to medium-sized freshwater lakes. These seasonal outlets are periodically
closed due to predominantly westward longshore sediment transport (Stone, 1991).
With the exception of relatively short reaches of slight, noncritical erosion near
Navarre Beach and just east of East Pass, the reach, extending 57 km (35.5-mi) west of
East Pass to 52 km (32.3 mi) east of East Pass, is the longest [109 km or (67.6 mi) total]
.Stable segment of beach long the Gulf Coast of Florida. However, extreme event
impacts have resulted in significant dune erosion and associated coastal recession
(e.g., Chiu, 1977; Balsillie and Clark, 1979; Balsillie, 1985c; Balsillie et. al. 1986a,
1986b).

East from Lake Powell, the shore is characterized by mainland beaches to the vicinity
of Panama City Beach where a barrier spit has formed, trending to the southeast
across the entrance to St. Andrews Bay. This barrier spit has been bisected by the
dredging of an artificial channel (St. Andrews Inlet) for navigation into St. Andrews
Bay, creating Shell Island which extends to the east for about 10 km (6.2 mi). New
longshore transport of the panhandle west of the inlet is to the west with reversals
occurring on a sub-seasonal time framework (Balsillie, 1975, 1977). West of St.
Andrews Inlet the barrier spit ranges in width from about 396 to 457 m (1,300 to 1,500
ft), while Shell Island to the east ranges in width from 182 to 1,220 m (600 to 4,000 ft).
New westward longshore transport from St. Andrews Inlet and the historic practice

Gulf of Mexico Goastal & Shoreline Erosion Action Agenda (4.1)



Glossary

Appendix C

accretion

advance

aggradation

alluvium.

alongshore

amplitude, wave

artificial

awash

backbeach

backrush

backshore

backwash

bar

barrier beach

May be either NATURAL or ARTIFICIAL. Natural accretion is the buildup of
land, solely by the action of the forces of nature or a BEACH by deposition of
water- or airborne material. Artificial accretion is a similar buildup of land by
reason of a human act, such as the accretion formed by a groin, breakwater, or
beach fill deposited by mechanical means. See AGGRADATION.

(of a beach). (1) A continuing seaward movement of the shoreline. (2) A net
seaward movement of the shoreline over a specified time. See PROGRESSION.

See ACCRETION.

Soil (sand, mud, or similar detrital material) deposited by streams, or the
deposits formed. .

Parallel to and near ‘the shoreline. See LONGSHORE.

The magnitude of the displacement of a wave from a mean value. An ocean
wave has an amplitude equal to the vertical distance from still water level to
wave crest. For a sinusoidal wave, the amplitude is one-half the wave height.

A relatively large quarrystone or concrete shape that is selected to fit specified
geometric characteristics and density. It is usually of nearly uniform.size and
usually large enough to require individual placement. In normal cases it is used
as primary wave protection and is placed in thicknesses of at least two units.

The process of replenishing a beach with material (usually Nourishment sand)
obtained from another location.

Situated so that the top is intermittently washed by waves or tidal action.
Condition of being exposed or just bare at any stage of the tide between high
water and chart datum.

See BACKSHORE.

The seaward return of the water following the uprush of the waves. For any
given tide stage the point of farthest return seaward of the backrush is known
as the LIMIT of BACKRUSH or LIMIT BACKWASH.

That zone of the shore or beach lying between the foreshore and the coastline
comprising the BERM and BERMS and acted upon by waves only during severe
storms, especially when combined with exceptionally high water. See
BACKBEACH.

(1) See BACKRUSH. (2) Water or waves thrown back by an obstruction such as
a ship, breakwater, or cliff.

A submerged or emerged embankment of sand, gravel, or other unconsolidated
material built on the sea floor in shallow water by waves and currents. See
BAYMOUTH BAR, CUSPATE BAR.

A bar essentially parallel to the shore, the crest of which is above normal high
water level; also called OFFSHORE BARRIER and BARRIER ISLAND.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



Federal & State Framework Appendix A

groin field, and there is a terminal groin at Blind Pass at the south end of
Treasure Island. There is a dune restoration project on the current beachfill.

St. Petersburg Beach/Long Kev beach nourishment~-In 1991, 152,980 m3 (200,000 yd3) of
sand from Blind Pass were placed on the north end of the beach. In 1986, 84,139
m3 (110,000 yd3) were placed on the southern portion of the island. In 1980,
185,871 m3 (243,000 yd°) were placed on the north end. About half of the 1980
fill was placed in shallow water, not directly on the beach. Smaller fills, in 1968
and 1975, totaled 80,315 m3 (105,000 yd). There is a terminal groin, detached
breakwater, and about 304.8 m (1,000 ft) of presently buried bulkheads at the
north end of the island. There are intermittent and buried bulkheads along the
remainder of the island. There is a terminal groin at the south end of the
island which has been rehabilitated twice since construction in 1941.

-a-Grille Dun tion/revegetation--Constructed dunes within a public park
have been stabilized with vegetation.

Mullet Key Beach nourishment/iniet sand transfer-~Three channel dredging projects
have used Mullet Key beaches for sand disposal. In 1977, 573,675 m (750,000
yd3) of sand from Tampa Harbor were placed on the Gulf beaches. About half
as much sand was also placed on the Mullet Key beaches that face Tampa Bay.
In 1973 and 1964, 382,450 m3 (500,000 yd3) and 106,321 m3 (139,000 yd3) of sand
from Egmont Channel were placed on the island beaches.

Et. Desoto Park interlocking waffle-block revetment--The history of this revetment is

unknown, but probably it was built by federal interests.

i igld--This history of this groin field is unknown,
but it is possibly 1800s vintage. It has failed and is visible in the water.

--All of Bradenton Beach and most of Holmes
Beach are armored with seawalls, bulkheads, revetments, rubble groins, pier
groins, and a terminal groin at Longboat Pass. Many of these structures were .
damaged and failed during Hurricanes Elena and Juan. A federal beach
nourishment project was scheduled to be constructed in 1992-1993.

Anna Marla Island beach nourishment--Construction of a large beach nourishment
project was scheduled to begin at this beach in the fall of 1992.

Longboat Key groins and seawails--This coast has had a serious erosion problem

since initial construction in the 1950s. There have been many generations of
failed erosion control projects (e.g., seawalls, revetments, groins). A locally-
funded beach nourishment project is scheduled for the fall of 1992.

Ido Key beach nourishmentinlet sana transfer--Lido Key beach was restored in the

1970s, with sand transferred from New Pass.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



Overview of the Gulf of Mexico Chapter 1

Figure 1.4 Gulf of Mexico Coastal Population per Shoreline Mile
2000
1800
~ 1600 bo
S 120 . CS
% 1000 :
5 800
3 a —~
E 600 <a e
400 E : <s
. | Le
a ft
Shs

(Source: USDOC, 1990)

The Gulf of Mexico - A Resource At Risk

Increasing population pressures mean increased use and demands on Gulf of
Mexico resources. Until recently, the Gulf was considered too vast to be affected by
pollution and overuse. Recent trends indicate, however, serious long-term
environmental damage unless action is initiated today. Signs of increasing
degradation throughout the Gulf system include the following (USEPA, 1991):

Q Fish kills and toxic "red tides," and “brown tides" were an increasing
phenomenon in Gulf waters during the 1980s.

Q Alabama, Mississippi, Louisiana, and Texas are among those states that
discharge the greatest amount of toxic chemicals into coastal waters.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 3



Acronym Guide Appendix B

NFIA National Flood Insurance Act

NFIP National Flood Insurance Program

NMFS National Marine Fisheries Service

NOAA National Oceanic and Atmospheric Administration
NPDES ~ National Pollutant Discharge Elimination System
NPS National Park Service

Oocs Outer Continental Shelf

PRB Policy Review Board, Gulf of Mexico Program
SCORP Statewide Comprehensive Outdoor Recreation Plan
scs Soil Conservation Service -

SLCRMA State and Local Coastal Resources Management Act’
SMA Special Management Area .

SSEOO Space Shuttle Earth Observations Office

TAC Technical. Advisory Committee

TSC Technical Steering Committee, Gulf of Mexico Program
TPWD Texas Parks & Wildlife Department

TNRCC Texas Natural Resource Conservation Commission
TX Texas

USACE U.S. Army Corps of Engineers

USDA U.S. Department of Agriculture

USDOC U.S. Department of Commerce

USDOD U.S. Department of Defense

USDOE U.S. Department of Energy

USDOI U.S. Department of the Interior

USDOT U.S. Department of Transportation

USEPA U. S. Environmental Protection Agency

USFDA U.S. Food & Drug Administration

USFWS USS. Fish & Wildlife Service

USGS U.S. Geological Survey

WES USACE Waterways Experiment Station

Gulf of MexIco Coastal & Shoreline Erosion Action Agenda (4.1) . 87



Glossary Appendix C

controlling depth The least depth in the navigable parts of a waterway, governing the maximum
draft of vessels that can enter. :

core A vertical, cylindrical sample of the bottom sediments from which the nature
and stratification of the bottom may be determined.

cove A small, sheltered recess in a coast, often inside a larger embayment.

crest of berm The seaward limit of a berm; also called BERM EDGE.

crest of wave (1) The highest part of a wave. (2) That part of the wave above still-water

crest width, wave
cuzrent

current, drift

current, ebb

current, eddy

current, feeder

current, flood

current, inshore

current, littoral

current, longshore

current, nearshore
current, offshore
current, periodic
current, permanent
current, rip
current, stream

current system,
nearshore

level.
See CREST LENGTH, WAVE.
A flow of water.

A broad, shallow, slow-moving ocean or lake current; opposite of CURRENT,
STREAM.

The tidal current away from shore or down a tidal stream; usually associated
with the decrease in the height of the tide.

See EDDY.

Any of the parts of the NEARSHORE CURRENT SYSTEM that flow parallel
to shore before converging and forming the neck of the RIP CURRENT.

The tidal current toward shore or up a tidal stream; usually associated with
the increase in the height of the tide.

See INSHORE CURRENT.

Any current in the littoral zone caused primarily by wave action; e.g.,
LONGSHORE CURRENT, RIP CURRENT. See CURRENT, NEARSHORE.

The littoral current in the breaker zone moving essentially parallel to the
shore, usually generated by waves breaking at an angle to the shoreline.

A current in the NEARSHORE ZONE.
See OFFSHORE CURRENT.

See CURRENT, TIDAL.

See PERMANENT CURRENT.

See RIP CURRENT.

A narrow, deep, and swift ocean current, as the Gulf Stream. See CURRENT,
DRIFT.

See NEARSHORE CURRENT SYSTEM.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 92



Glossary

Appendix C

tide

tide, daily
retardation of

tide diurnal

tide, ebb

tide, flood

tide, mixed

tide, neap

tide, semidiurnal
tide, slack

tide, spring

tide station

tide, storm

tombolo

topography

training wall
tropical cyclone

tropical storm

trough of wave

tsunami

typhoon

The periodic rising and falling of the water that results from gravitational
attraction of the Moon and Sun and other astronomical bodies acting upon the
rotating Earth. Although the accompanying horizontal movement of the water
resulting from the same cause is also sometimes called the tide, it is preferable
to designate the latter as TIDAL CURRENT, reserving the name TIDE for the
vertical movement.

The amount of time by which corresponding tides grow later day by day (about
50 minutes); also LAGGING. ‘

A tide with one high water and one low water in a day.

See EBB TIDE.

See FLOOD TIDE. +

See MIXED TIDE.

See NEAP TIDE.

See SEMIDIURNAL TIDE.

See SLACK TIDE.

See SPRING TIDE.

A place at which tide observations are being taken. It is called a primary tide
station when continuous observations are to be taken over a number of years to
obtain basic tidal data for the locality. A secondary tide station is one
operated over a short period of time to obtain data for a specific purpose.

See STORM SURGE.

A bar or spit that connects or "ties" an island to the mainland or to another
island. See CUSPATE SPIT. .

The configuration of a surface, including its relief and the positions of its
streams, roads, building, etc.

A wall or jetty to direct current flow.
See HURRICANE.

A tropical cyclone with maximum winds less than 34 meters per second (75 miles
per hour). See HURRICANE.

The lowest part of a waveform between successive crests; also, that part of a
wave below still-water level.

A long-period wave caused by an underwater disturbance such as a volcanic
eruption or earthquake; also SEISMIC SEA WAVE; commonly miscalled "tidal
wave."

See HURRICANE.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 108



Bibliograph

Stapor, F.W. 1973a. “History and Sand Budgets of the Barrier Island System in the
Panama City, Florida, Region." Marine Geology. v. 14.

Stapor, F.W. 1973b. "Coastal Sand Budgets and Holocene Beach Ridge Plain
Development, Northwest Florida" (Ph.D. dissertation). Florida State —
University. Tallahassee, FL.

Stapor, F.W., T.D. Mathews and F.E. Lindfors-Kearns. 1987. "Episodic Barrier Island
Growth in Southwest Florida: A Response to Fluctuating Holocene Sea
Level?" Miami Geological Society Memoir 3.

Stone, G.W. 1991. “Differential Sediment Supply and the Cellular Nature of
Longshore Transport Along Coastal Northwest Florida and Southwest
Alabama Since the Late Holocene." Ph.D. dissertation. University of
Maryland. College Park, MD.

Stone, G.W. and J.D. Salmon. 1988. "Hurricane-Related Morphodynamics and
Implications for Hazard Mitigation, Perdido Key, Florida, USA." Coastal
Management. v. 16.

Stone, G.W., F.W. Stapor, J.P. May and J.P. Morgan. 1992. “Multiple Sediment
Sources and a Cellular, Non-Integrated, Longshore Drift System: Northwest
Florida and Southeast Alabama Coast, USA." Marine Geology. v. 105.

Stoddart, D.R. and E.R. Fosberg. “1981. "Topographic and Floristic Change, Dry
* Tortugas, Florida, 1904-1977. : The Smithsonian Institution. Atoll Research
Bulletin No. 253.

Tanner, W.F. 1960. “Florida Coastal Classification." Transactions of the Gulf Coast
Association of Geological Societies. v. 10.

Tanner, W.F. 1975. "Historical Beach Changes, Florida Big Bend Coast."
Transactions of the Gulf Coast Association of Geological Societies. v.25.

Texas General Land Office. 1990. “Coastal Erosion and Shoreline Preservation."
Issue Brief. Austin, TX. February 28, 1990.

Texas General Land Office, 1991. "Coastal Responsibilities of Texas State Agencies"
in Appendix III, Texas Coastal Management Plan.

Texas Natural Resources Code. 1991. Section 33.601. Subchapter M, Coastal Erosion.

Titus, J.G. (ed.) 1988. Greenhouse Effect, Sea Level Rise and Coastal Wetlands. U.S.
Environmental Protection Agency.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 55



Federal & State Framework Appendix A

Federal Emergency Management Agency (FEMA)

FEMA administers the National Flood Insurance Program (NFIP), which provides
federally subsidized insurance protection in many coastal and flood-prone areas of
the U.S. FEMA maps flood-prone areas, establishes criteria for land management
and use, and gives planning recommendations for flood- and erosion-prone areas.
FEMA and the designated state agency liaison assist local communities with the
development of quality floodplain management programs.

* National Flood Insurance Act (NFIA) of 1968. NFIA was enacted by title XIII of
the Housing & Urban Development Act of 1968 (PL 90-448) to provide previously
unavailable flood insurance protection to property owners in flood-prone areas.
It established the NFIP, which is administered by FEMA. NFIP offers flood
insurance coverage to participating coastal communities who adopt and enforce
floodplain management regulations in flood hazard areas mapped by NFIP.
Some of the regulations are designed to protect dunes and mangroves from
human alteration.

In 1988, Congress passed the Upton-Jones Amendment to NFIA to provide an
incentive for retreat from the shoreline and to reduce future flood losses. The
amendment allows payments of up to 40 percent of the value of the structure for
relocation or up to 110 percent to demolish a structure imminently threatened by
erosion.

The National Flood Insurance, Mitigation & Erosion Management Act of 1991
(passed in the House in 1991 and awaiting endorsement by the Senate) adds
significant erosion management and mapping authorities to NFIP. The goals of
the proposed Act are to: identify the risks associated with flood and erosion
hazards; further stabilize NFIP by reducing potential liability after erosion
hazards have been fully disclosed; promote relocation of structures prior to
damage; and encourage communities to develop long-term coastal erosion
management programs.

U.S. Environmental Protection Agency (USEPA)

* The Clean Water Act (CWA) of 1977, as amended by the Water Quality Act of
1987. Waters of the U.S. protected by the Clean Water Act include rivers,

streams, estuaries, the territorial seas, and most ponds, lakes, and wetlands.

- Section 404, USEPA has primary roles in several aspects of the CWA Section 404
program.(see CWA under USACE) including development of the
environmental guidelines by which permit applications must be evaluated;
review of proposed permits; prohibition of discharges with unacceptable adverse
impacts; approval and oversight of state assumption of the program;
establishment of the jurisdictional scope of waters of the U.S.; and interpretation

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 61



Overview of the Gulf of Mexico Chapter 1

The action planning process used by each Gulf of Mexico Program Issue Committee
includes the following key activities:

Q
Q

im)

6000 0

Definition of environmental issues;

Characterization of identified problems,. including sources, resources,
and impacts;

Establishment ¢ of goals and objectives;

Evaluation/ assessment of corrective actions and control measures,

including cost/benefit analysis;
Selection of priority action items;
Establishment of measures of success;
Implementation of actions; and

Evaluation of success and revision of the Action Agenda.

As the Issue Committees progress through each of these activities, ample
opportunities are provided for public review and Policy Review Board endorsement
is requested at appropriate points. The Gulf of Mexico Program will continuously
work to integrate related activities of the eight Issue Committees. Through the
consensus of Program participants, a coordinated response will be directed to the
successful maintenance and enhancement of resources of the Gulf of Mexico.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) . 8



Glossary _ Appendix C

barrier lagoon A bay roughly parallel to the coast and separated from the open ocean by
barrier islands.

basin, boat A naturally or artificially enclosed or nearly enclosed harbor area for small
craft.

bathymetry The measurement of depths of water in oceans, seas, and lakes; also information
derived from such measurements.

bay A recess in the shore or an inlet of a sea between two capes or headlands, not so
large as a gulf but larger than a cove. See BIGHT and EMBAYMENT.

baymouth bar A bar extending partly or entirely across the mouth of a bay.

bayou A minor sluggish waterway or estuarial creek, tributary to, or connecting, other
streams or bodies of water, whose course is usually through lowlands or
swamps; sometimes called SLOUGH.

beach The zone of unconsolidated material that extends landward from the low water

beach accretion

beach berm

beach cusp

beach erosion
beach face

beach fill
beach ridge
beach scarp
beach width

bench mark

berm, beach

line-to the place where there is marked changed in material or physiographic
form or to the line of permanent vegetation (usually the effective limit of storm
waves). The seaward limit of a beach--unless otherwise specified--is the mean
low water line. A beach includes FORESHORE and BACKSHORE. See
SHORE.

See ACCRETION.

A nearly horizontal part of the beach or backshore formed by the deposit of
material by wave action. Some beaches have no berms, others have one or
several.

See CUSP.

The carrying away of beach materials by wave action, tidal currents, littoral
currents, or wind.

The section of the beach normally exposed to the action of the wave uprush; the
FORESHORE of a BEACH. (Not synonymous with SHOREFACE.)

Material placed ona beach to renourish eroding shores.

See RIDGE, BEACH.

See SCARP, BEACH.

The horizontal dimension of the beach measured normal to the shoreline.

A permanently fixed point of.known elevation. A primary bench mark is one
close to a tide station to which the tide staff and tidal datum originally are

referenced.

See BEACH BERM.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 39



Coastal & Shoreline Erosion in the Gulf of Mexico Chapter 2

involves regulating land use, establishing and enforcing coastal construction
standards, and providing for or requiring specific response options such as structure
relocation.

Stabilization. Breakwaters, groins, revetments, and seawalls are the structural types
most commonly used for shoreline stabilization on the open coast. Breakwaters
function by reducing the wave energy impacting the shoreline, therefore lowering
the ability of the waves to move sediment. Groins work by blocking the longshore
movement of sediment, causing it to accrete or remain in place. Revetments are
used to "armor" a shoreface, thereby protecting it from direct wave impact and
resulting erosion. Seawalls serve an armoring function as well, although their
main purpose is usually to reduce damage caused by storm surge and storm wave
impacts on buildings and other property.

Within each structure type, a number of variations are possible. By altering design
parameters such as length, spacing, height, porosity, and location, both breakwaters
and groins can be configured to have more or less impact on coastal sediment
movement. Although the most common form of construction is the: engineered
pile of rock called “rubble mound," breakwaters, groins, and revetments can be built
using a number of material types and design approaches.

Providing additional sediment to an eroding stretch of shoreline is often a preferred
way to arrest its recession. The most common method used in this approach is the
beach fill project. Large quantities of sand are removed from offshore or inland
sources and placed on the eroding beach by dredges or land-based earth-moving
equipment. The result, usually in a few months, is a dramatically “restored” beach
zone that often includes wide berms and high dunes to protect inland development
against storm effects. Stabilization of eroding barrier islands by adding sediment
may also be an effective way of preserving their function of sheltering interior
shorelines and habitat from open-water wave impact, storm surge, and salt water
intrusion. A less common method of providing additional sediment, at least on the
Gulf Coast, is sand bypassing at tidal inlets. This technique involves the transfer of
sand from one side of an inlet to another by a dredge or special plant in an attempt
to emulate the natural transfer that would take place without jetties or artificially
deepened channels. Unlike beach fill, this technique does not restore an eroded
shoreline, but it may aid in stabilizing it.

Structures and beach fill often are used in combination, since their characteristics are
complementary. Used alone, structures such as breakwaters or groins can "trap"
moving coastal sediments at the expense of adjacent areas downdrift. Adding
additional sediment to the structure field can help reduce or eliminate such effects.
Conversely, a major beach fill project that incorporates breakwaters or groins will
require less frequent renourishment and may provide a higher level of sustained
protection to inland development. Fill in front of a revetment or seawall helps to
ensure that such a structure remains intact for protection against more extreme
events.

Guif of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



The Unfinished Agenda Chapter 4

Index of Erosion Objectives & Action Items

Erosion Identification, Characterization, & Assessment.

Objective: Characterize the Gulf of Mexico shoreline, and identify trends and patterns of shoreline
change. .

Action Item 1 Sources of Gulfwide Erosion Data

Action Item 2 Gulf of Mexico Shoreline Characteristics

Action Item 3 Gulfwide Sand Inventory

Action Item 4 Local Littoral Sediment Budgets for the Gulf of Mexico
Action Item 5 Erosion Predictive Models

Objective: Assess the severity of coastal erosion Gulfwide, and evaluate causes and impacts.

Action Item 6 Causes of Erosion and Shoreline Loss Gulfwide
Action Item 7 Impacts of Erosion Gulfwide ~ _ —

Action Item 8 _Efosion Area Prioritization for Gulf of México States

Erosion Response

Objective: Evaluate existing and potential response alternatives for coastal erosion in the Gulf of
Mexico region.

Action Item 9 Existing Erosion Control Projects Gulfwide

Action Item 10 Evaluation of Selected Gulf. of Mexico Demonstration Projects
Action Item 11 Past Expericnces Regarding Erosion Along the Gulf of Mexico Coast
Action Item 12 Selection of Representative Erosion Sites Gulfwide

Action Item 13 Gulf of Mexico Erosion Response Evaluation

Action Item 14 Gulfwide Erosion Response Strategies

Public Education & Outreach

Objective: Increase individual and public awareness of erosion impacts in the Gulf of Mexico
region and the importance of appropriate control measures and options.

Action Item 15 Slide Presentation on Coastal & Shoreline Erosion

Action Item 16 Public Information Materials on Coastal & Shoreline Erosion
Action Item 17 Public Video on Gulfwide Erosion Issues

Action Item 18 Gulf of Mexico Program Electronic Bulletin Board Erosion Data

Action Item 19 Sources of Funding for Coastal & Shoreline Erosion Education

Action Item 20 Network for Disseminating Coastal & Shoreline Erosion Information

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 40



Federal & State Framework Appendix A

. Galveston seawall and grain fieig--A large, curved, gravity seawall was built in
segments beginning in 1902 and ending in 1961. An extensive groin field was
built to protect the beach sands at the toe of the seawall in 1939. Toe protection
rubble has been added to the toe:of the seawall as recently as 1989. The wall is
one of the largest seawalls in the U.S. It was built after America's deadliest
natural disaster, the hurricane of 1900, which killed 6,000 people, to prevent
future flooding disasters. A beach nourishment project is planned for the
beaches in front of the wall in 1993.

* Highway 87 (Jefferson County) relocation-This project is a highway re-alignment
away from the Gulf. The highway is often overwashed during storms and has
been occasionally rebuilt farther from the sea to prevent undermining, The
highway was closed by the Texas Department of Transportation in 1989,
following damage caused by Hurricane Jerry. There is a proposed roadway
reconstruction approximately 91.4 m (300 ft) inland of its present position.
Excess construction fill material will be used to reconstruct dunes between the
existing beach and the new road right-of-way.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) . Bs



Coastal & Shoreline Erosion in the Gulf of Mexico Chapter 2

Charlotte Harbor Complex (Charlotte Harbor 19 San Carlos Bay Entrance). From the northern
extent of Charlotte Harbor at Gasparilla pass south, a distance of 59.5 km (37 mi), lies
a sequence of five coastal barrier islands separated from the mainland by the wide
bodies of water of Charlotte Harbor, Pine Island Sound, and San Carlos Bay. Within
Pine Island Sound lies Pine Island, a large feature about which curves Sanibel
Island, the southernmost of this Gulf-fronting coastal barrier island group. These
islands range in length from 6.6 to 21 km (4.1 to 12.9 mi), in width from 60 to 4,000
m (200 to 13,000 ft), and have peak coastal elevations of from 1 to 3 m (3 to 10 ft)
(Fischer et al., 1984). Wave energy is moderate (Tanner, 1960). Longshore transport
processes operate within a series of partially integrated cells (Harvey, 1979).

While the sedimentary environment is currently dominated by sand, the
proportion of shell fragments is significant and relatively rare in the southeastern
U.S. These sediments have formed the beach ridges by both longshore and onshore
sediment transport process (Stapor et al., 1987). High resolution geophysical studies
are needed to determine the depth and extent of sand volumes comprising these
barriers as well as their offshore extent. Clark (1991a) has determined that 27.4 km
(17 mi) of Gulf-fronting beaches of these barriers are experiencing problematic
erosion (USACE, 1969; Coastal Planning and Engineering, 1989). The erosion areas
are largely confined to the north end of Sanibel Island and islands to the north, with
the southern 17.7 km (11 mi) of Sanibel Island being stable to accreting. Note,
however, that the entire length of Captiva Island's beach has been restored.

San Carlos-Estero Reentrant (San Carlos Bay Entrance to Gordon Pass), The coast from just
south of San Carlos Bay to Wiggins Pass, a distance of 46.7 km (29 mi), is unique by
virtue of its change in physiography from north to south. The northern 20 km (12
mi) is characterized by a group of low-lying, narrow islands, of which all but two are
small, tightly-packed, and mobile. This reach contrasts with barrier islands farther
to the north because: (1) it is sheltered from northwest approaching waves by
“Sanibel Island, and (2) bays behind the coastal barriers are much smaller and, hence,
so are the associated 5 inlets (Hine, 1987). The bay backing the coastal barriers
becomes gradually, but distinctly, constricted toward the south where it loses
continuity just to the south of Wiggins Pass. Continuing south to Doctor's Pass,
some 10 km (6.4 mi), the coast embodies a line of small, discontinuous back-beach
water bodies (except where dredged for marinas). Wave energy is moderate to low
(Tanner, 1960) with longshore transport small and to the south except for reversals
along the northern part of the reach. Beaches along the reach are continuous but
narrow, and Clark (1991a) reports that 26 km (16.2 mi) of beach are experiencing
problematic erosion due not to a high rate of shoreline change but to the degree of
threat to adjacent development (USACE, 1972).

Southern Barriers (Gordon pass to Cape Romano), To the south of Gordon Pass, the coast is
again characterized by a chain of six recognized barrier islands with at least eight
tidal inlets (inlets frequently open and close along this segment). This
southernmost reach of the lower Gulf Coast extends south a distance of about 32 km
(20 mi). Wave energy is low (Tanner, 1960), with slight net longshore transport to

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



Overview of the Gulf of Mexico

Chapter 4

The Coastal & Shoreline Erosion Committee

The Co-chairs and membership of the Coastal & Shoreline Erosion Committee are

as follows:

Co-Chairs:

Thomas Richardson
Sally Davenport

Members:

Robert Baker
Frank Blanchard
Floyd Buch

Mary Lou Campbell
Ralph Clark

Mel Davis

John Dingler
Peter Doragh

Scott Douglass
James Edmondson
Edwin Garner
Mark Gates

Linda Glenboski
Andrew Grayson
Deborah Heibel
Cathy Hollomon
Richard Hoogland
Charles Hunsicker
James Johnston
Robert Jones

Jeff Kellman

B.D. King IT
Cragin Knox

Herb Kumpf
Bennett Landreneau
John Lawrence
Klaus Meyer-Arendt
Robert Morton
Joann Mossa
Robert Nailon
John O'Connor
Ervin Otvos

Shea Penland

Ric Ruebsamen

U.S. Army Corps of Engineers
Texas General Land Office

U.S. Geological Survey

Collier Beach Society

Port of Corpus Christi

Sierra Club

Florida Office of Beach Erosion Control

Texas Soil & Water Conservation Board

U.S. Geological Survey

Citizens Advisory Committee

University of South Alabama

South-Central Planning & Development Commission
The University of Texas at Austin

Texas Natural Resource Conservation Commission
U.S. Army Corps of Engineers

Florida Department of Natural Resources

U.S. Army Corps of Engineers

Mississippi Department of Wildlife, Fisheries & Parks
Gulf of Mexico Fishery. Management Council
Assistant City Manager--Clearwater, Florida

U.S. Fish & Wildlife Service

Terrebonne Parish Government--Louisiana
Agency for Toxic Substances & Disease Registry
U.S. Fish & Wildlife Service

Mississippi Department of Environmental Quality
National Marine Fisheries Service

Soil Conservation Service

Soil Conservation Service

Mississippi State University

University of Texas at Austin

University of Florida

Texas A&M Marine Advisory

Florida Association of Conservation Districts

Gulf Coast Research Laboratory

Louisiana Geological Survey

National Marine Fisheries Service

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



Bibliography

Balsillie, J.H. and B.D. Moore. 1985. "A Primer on the Application of Beach and
Coast Erosion to Florida Coastal Engineering and Regulation." Florida
Department of Natural Resources. Beaches and Shores Technical and Design
Memorandum No. 85-3.

Balsillie, J.H., T.Y. Chiu, and S. Demirapolat. 1986a. "Long-Term Shoreline Change
Rates for Escambia County, Florida." Florida Department of Natural
Resources. Beaches and Shores Special Report No. 86-1.

Balsillie, J.H., T.T. O'Neal, and WJ. Kelly. 1986b. "Long-Term Shoreline Change
Rates for Bay County, Florida." Florida Department of Natural Resources.
Beaches and Shores Special Report No. 86-1.

Boesch, D. F. (ed). 1982. Proceedings of the Conference on Coastal Erosion and
Wetland Modification in Louisiana: Causes, Consequences and Options. U.S.
Fish and Wildlife Service, Biological Program, FWS/OBS-82/59.

Buff, V. and S. Turner. 1987. "The Gulf Initiative." Coastal Zone.

: Campbell, T. R. 1990. The Magnitude of the Problem. America's Sea - A National
Resource at Risk, New Orleans LA.

Chiu, T.Y. 1977. "Beach and Dune Response to Hurricane Eloise of September
1975." Coastal Sediments ‘77.

Clark R.R. 1986. "Hurricane Kate, November 15-23, 1985." Florida Department of
Natural Resources. Beaches and Shores Post-Storm Report No. 86-1.

Clark, R.R. 1990a. "The Carbonate Beaches of Florida: An Inventory of Monroe
- County Beaches." Florida Department of Natural Resources. Beaches and
Shores Technical and Design Memorandum No. 90-1.

Clark, R.R. 1990b. "Beach Management - The Planning Process." America's Sea - A
National Resource at Risk, New Orleans LA, December 2-5,'1990.

Clark, R.R. 1991a. "Beach Conditions in Florida: A Statewide Inventory and
Identification of the Beach Erosion Problem Areas in Florida." Florida
Department of Natural Resources. Beaches and Shores Technical and Design
Memorandum No. 89-1. :

Clark, R.R. 1991b. "Discussion and Recommendations to Solve Beach Erosion
Conditions at Mashes Sands, Wakulla County, Florida." Florida Department ,
of Natural Resources, Division of Beaches and Shores.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 54



Glossary

Appendix C

rip surf
riparian

riparian rights

riprap

rubble

rubble-mound
structure

runnel

salt marsh
sand

sandbar

sand bypassing,
sand reef
scarp

scarp, beach

sea breeze

sea level

seas

See RIP CURRENT.
Pertaining to the banks of a body of water.

The rights of a person owning land containing or bordering on a watercourse or
other body of water or its banks, bed, or waters.

‘A protective layer or facing of quarrystone, usually well graded within wide

size limit, randomly placed to prevent erosion, scour, or sloughing of an
embankment of bluff; also the stone so used. The quarrystone is placed ina
layer at least twice the thickness of the 50 percent size or 1.25 times the
thickness of the largest size stone in the gradation.

(1) Loose angular waterworn stones along a beach. (2) Rough, irregular
fragments of broken rock.

A mound of random-shaped and random-placed stones protected with a cover
layer of selected stones or specially shaped concrete armor units. (Armor units
in a primary cover layer may be placed in an orderly manner or dumped at
random.)

A corrugation or trough formed in the foreshore or in the bottom just offshore by
waves or tidal currents.

The rush of water up a structure or beach on the breaking of a wave; also
UPRUSH, SWASH. The amount of runup is the vertical height above still-
water level to which the rush of water reaches.

A marsh periodically flooded by salt water.

See Soil CLASSIFICATION.

(1) See BAR. (2) Ina river, a ridge of sand built up to or near the surface by
river currents.

See BYPASSING, SAND.

See BAR.

See ESCARPMENT.

An almost vertical slope along the beach caused by erosion by wave action. It
may vary in height from a few centimeters to a meter or so, depending on wave

action and the nature and composition of the beach.

Removal of underwater material by waves and currents, especially at the base
or toe of a shore structure.

A light wind blowing from the sea toward the land caused by unequal heating
of land and water masses.

See MEAN SEA LEVEL.

Waves caused by wind at the place and time of observation.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 104



Glossary

Appendix C

slough
sound (noun)

sound (verb)
sounding,

sounding datum

sounding line

spilling breaker

spit

spit, cuspate

spring tide

stand of tide

still-water level

stockpile

storm surge

See BAYOU.

(1) A wide waterway between the mainland and an island or a wide waterway
connecting two sea areas. See STRAIT. (2) A relatively long arm of the sea or
ocean forming a channel between an island and a mainland or connecting two
larger bodies, as a sea and the ocean, or two parts of the same body; usually
wider and more extensive than a strait.

To measure the depth of the water.

A measured depth of water; on hydrographic charts the soundings are adjusted
to a specific plane of reference (SOUNDING DATUM).

The plane to which soundings are referred. See CHART DATUM.

A line, wire, or cord used in sounding, which is weighted at one end witha
plummet (sounding lead); also LEAD LINE.

See BREAKER.

A small point of land or a narrow shoal projecting into a body of water from the
shore. .

See CUSPATE SPIT.

A tide that occurs at or near the time of a new or full moon and which rises
highest and falls lowest from the mean sea level.

An interval at high or low water when there is no apparent change in the
height of the tide. The water level is stationary at high and low water for
only an instant, but the change in level near these times is so slow that it is not
usually perceptible. See SLACK TIDE.

The elevation that the surface of the water would assume if all wave action
were absent.

Sand piled on a beach foreshore to nourish downdrift beaches by natural
littoral currents or forces. See FEEDER BEACH.

Arise above normal water level on the open coast due to the action of wind
stress.on the water surface. Storm surge resulting from a hurricane also includes
that rise in level due to atmospheric pressure reduction as well as that due to
wind stress. See WIND SETUP.

See STORM SURGE.

A relatively narrow waterway between two larger bodies of water. See
SOUND.

The wave activity in the area between the shoreline and the outermost limit of
breakers.

The area between the outermost breaker and the limit of wave uprush.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



Executive Summary

This Action Agenda is a living document; therefore, the Gulf of Mexico Coastal &
Shoreline Erosion Committee intends to periodically revise and update the
document. :

Index of Coastal & Shoreline Erosion Objectives

Erosion Identification, Characterization, & Assessment

Objective: Characterize the Gulf of Mexico shoreline, and identify trends and patterns of shoreline change.

Objective: Assess the severity of coastal erosion Gulfwide, and evaluate causes and impacts.

Erosion Response

Objective: Evaluate existing and potential response alternatives for coastal erosion in the Gulf of Mexico
region.

Public Education & Outreach

Objective: Increase individual'and public awareness of erosion impacts in the Gulf of Mexico region and the
importance of appropriate control measures and options.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) iv



Federal & State Framework : Appendix A

Keewaydin Island inlet sand tansfer--Sand was removed from Gorden's Pass and
placed on Keewaydin Island.

Keewaydin Island artificial seaveed--A seaweed experiment failed.

Marco Island beach nourlshment--Three segments of fill were placed on the beach
in 1991. Prior to the fill there was a revetment armoring the coast.

Louisiana

Holly Beach offshore breakwaters--Rubble-mound breakwater sections were
constructed in 1990-1992 with lengths of 91.4 m (300 ft) and gap widths between
the breakwater of roughly 76.2 m (250 ft). The breakwaters are roughly

122-183 m (400-600 ft) offshore. There is no beachfill behind the breakwaters.

Highway 82 seawall--The seawall is gobi block articulated revetment. It was built
in the 1950s or 1960s and failed structurally due, apparently, to underlying
sediments being pulled out from the units, contributing to unit-by-unit
unraveling. The remains of the seawall are still visible and still providing
some limited protection. The 1990 Holly Beach breakwater project is built
seaward along this same stretch of coastline.

isle Deneirs barrier island restoration--This restoration project was constructed in
1985-1986, to raise the profile of the uninhabited barrier island to prevent
overwashing and eventual reduction to a submerged shoal. A 3.2 km (2 mi)
long section of barrier island restoration, adjacent to the 1986 project, is planned
for 1993.

Wine Island Shoal restoration--In 1990, a rock containment dike/pond was filled
with dredged material from the Houma ship channel and overfilled with sand.

‘Timbalier Island canal filling--In 1988, Texaco filled in a section of an existing canal
which ran parallel to the barrier island. The barrier island had historically
breached at this location, and the canal was filled to prevent future breaching.

West Timbalier Island seawail--This is a rubble revetment seawall that was built in
the 1970s as a public works project to protect a barrier island breach to a canal
which is perpendicular to the barrier island.

West Timbalier Island beach nourishment--This sand dune construction/barrier
island restoration project was built, in 1986, to seal a threatened breach in the
barrier island. The project was damaged, in 1992, by Hurricane Andrew.

East Timbalier Island seawall--Petroleum interests surrounded a barrier island with
rubble to protect the integrity of the island. The island was providing wave
sheltering for their production facilities.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 83



Coastal & Shoreline Erosion in the Gulf of Mexico Chapter 2

swamp lands, will decrease dramatically. .The impact on commercial fisheries alone
will be enormous: projections indicate that by the year 2040, the harvest will have
declined by 70 percent. Foreign sources will likely replace this lost production, as is
presently the case for some shellfisheries, further aggravating the nation's trade
deficit and placing at risk the nearly 50,000 jobs directly related to fishing, processing,
and wholesaling activities.

A number of other food staples and basic minerals, such as sugar, rice, salt, sulfur,
and lime, are also produced in coastal Louisiana. Lost or reduced production of
these basic items will impact national markets.

Flood control works comprising a national investment of nearly $12 billion protect
much of the infrastructure in the coastal area. Because the surrounding marshes are
integral to the.design of these works, continued, substantial loss of wetlands. will
require that levees and other structures be enlarged or relocated. Outside existing
lines of protection, highways, ports, waterways, railroads, pipelines, and other
utilities will need to be relocated, or experience major escalations in maintenance
and replacement costs. As the coast deteriorates, billions of dollars of infrastructure
could be surrendered to the Gulf of Mexico and billions of dollars more spent
protecting the remainder.

Responses to Erosion. Several basic approaches using natural processes can be
employed to promote optimum benefits from the ecosystem.

. Creation. New wetlands can be built on a large scale by making maximum
use of the sediment resources of the Mississippi and Atchafalaya Rivers and,
on a smaller scale, through use of dredged material and trapping of longshore
sediment.

. Restoration. Freshwater can be added, salt water blocked, and dredged
material banks breached in order to restore the hydrologic conditions which
existed before construction of channels and other structures.

. Protection. Vulnerable marshes can be protected by repairing and
strengthening the landforms which compose the natural skeleton of the
region--barrier islands, shorelines, and distributary ridges. Protection also can
be accomplished by control and management of particular stresses, such as
herbivory.

. Enhancement. Overland flow and sinuous channel flow--the natural
hydrologic processes of the wetlands--can be promoted where possible, while
active management of water levels can be undertaken where necessary.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 28



Potential Demonstration Projects Appendix E

As determined by the members of the Coastal & Shoreline Erosion Committee, the
following is the updated list of potential demonstration projects to address shoreline
and coastal erosion.

g y nee te Explanation as

93-013 TX Plant smooth cordgrass to reduce hhoreline erosion.

93-056 TX Stabilize eroding shoreline along the Gulf Intracoastal
waterway with rock riprap.

93-060 FL Construct a dune with vegetation to protect against a barrier
breach.

93-088 LA Establish a fringe marsh along Bayou Lafourche.

93-212 TX Stabilize eroding shorcline along the Gulf Intracoastal.
Waterway using concrete mat, rock groin, and cordgrass.

93-213 TM Restore an existing levee and protect with vegetation.

93-218 FL Restore primary dune system on a heavily used island.

93-233 FL Recreate red mangrove habitat and protect it with a
temporary tire breakwater.

93-291 MS Place sand on a beach to test a coastal dynamics model.

93-305 LA Install 130 timber pylons to dissipate wave energy. 4

93-001 LA Install temporary ring wall enclosures for protecting seed
germination sites.

93-017 LA Construct a stone levee to protect marshes.

93-020 AL Restore marsh using vegetation and hay bales.

93-032 AL Use fertilizer to enhance disturbed dune vegetation.

93-041 TX Restore a Gulf beach using material dredged from the
submerged portion of an accreting spit. .

93-055 + TX Document physical coastline and map vegetation.

93-061 FL Construct elevated dune walkovers to enhance protection of
the dune system.

93-140 FL Provide a source of plant materials for restoring dunes.

93-181 LA Monitor marsh management structures,

93-182 LA Document effectiveness of X-mas tree sediment fences.

93-194 TTM Use X-mas trees for dune restoration.

93-208 TM Use space shuttle imagery to monitor shoreline changes.

93-245 AL Relocate structures and create dunes.

93-268 FL Develop a shoreline erosion computer model.

93-295 TTM Evaluate impacts of sediment mining on erosion and habitat.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1) 145



Glossary

Appendix C

berm crest
bight
blown sands
bluff
bottom

bottom (nature of)

boulder
breaker

breaker depth

breakwater

bulkhead

buoy

buoyancy

bypassing, sand

The seaward limit of a berm; also called BERM EDGE.

A bend ina coastline forming an open bay; a bay formed by such a bend.
See EOLIAN SANDS. —

A high, steep bank or cliff.

The ground or bed under any body of water; the bottom of the sea.

The composition or character of the bed of an ocean or other body of water (e.g.,
clay, coral, gravel, mud, ooze, pebbles, rock, shell, shingle, hard, or soft).

A rounded rock more than 10 inches in diameter; larger than a cobblestone.

A wave breaking on a shore, over a reef, etc. Breakers may be classified into
four types.

Spilling--bubbles and turbulent water spill down the front face of a wave. The
upper 25 percent of the front face may become vertical before breaking; breaking
generally occurs over quite a distance.

Plunging--crest curls over an air pocket; breaking is usually with a crash;
smooth splash-up usually follows.

Collapsing--breaking occurs over the lower half of a wave, with minimal air
pocket and usually no splash-up; bubbles and foam are present.

Surging--wave peaks up, but bottom rushes forward from under a wave, and the
wave slides up the beach face with little or no bubble production. Water
surface remains almost plane except where ripples may be produced on the
beachface during runback.

The still-water depth at the point where a wave breaks; also called
BREAKING DEPTH.

A structure protecting a shore area, harbor, anchorage, or basin from waves.

A structure or partition to retain or prevent sliding of the land. A secondary
purpose is to protect the upland against damage from wave action.

A float; especially a floating object moored to-the bottom to mark a channel,
anchor, shoal, rock, ctc.

The result of upward forces, exerted by the water on a submerged or floating
body, equal to the weight of the water displaced by this body.

Hydraulic or mechanical movement of sand from the accreting updrift side to
the eroding downdrift side of an inlet or harbor entrance. The hydraulic
movement may include natural movement as well as movement caused by
humans.

An artificial watercourse cut through a land area for such uses as navigation
and irrigation.

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)



Coastal & Shoreline Erosion in the Gult of Mexico Chapter 2

The sea level rise of the past 18,000 years has continually changed the shape and
location of the Mississippi coastline. If the present world-wide rise in sea level
continues or accelerates, the low-lying delta area of the Pearl and Pascagoula Rivers
will be the most severely impacted. The result would be a loss of vast areas of .
wetlands. Sediment deficiency is another important factor in the Mississippi coastal
erosion scenario. Sediment removal from the active nearshore environment by
natural processes, such as storm surges and longshore transport, and human © .
activities such as dredging, river damming, and coastal armoring contributes to the
general eroding of the shoreline. :

Hancock County. Hancock County has two shoreline types along its 32 km (20 mi)
coastline. From the Pearl River boundary with Louisiana east to Bayou Caddy the
shore consists of natural salt tidal marsh. Portions of this 19.2 km (12 mi) section of
coastline have retreated at an average rate as high as 3.9 m/year (13 ft/year) over the
last 70 years. From Bayou Caddy east to St. Louis Bay, the shoreline is armored with
a seawall constructed from 1915 - 1928. A 9.6 km (6 mi) beach pumped in place to
protect the seawall in 1966 has been eroded to only a few remnant pocket beaches
despite a renourishment in 1972. Seawall failure and collapse of adjacent Beach

Boulevard in several places has prompted a rebuilding of this beach scheduled to
begin in the fall of 1992.

Harrison County. The mainland Harrison County shoreline consists of a seawall
fronted by 41.6 km (26 mi) of artificially maintained sand beach. The beach was
constructed in 1952 to protect the seawall and has been maintained since that time
by renourishment from offshore sources. Approximately 650,165 m3 (85,000
yd3/year) of sand is lost from this beach due to wave erosion, longshore drift, and
aeolian losses. Pilot projects are now underway to stabilize the beach with salt
tolerant grasses and dune formation. This beach is a major tourist attraction, and
human impacts require continual mechanical maintenance to keep the beach free of
trash and debris. The major port of Gulfport is located in the central portion of this
shoreline.

Jackson County. Jackson County contains three basic shoreline regimes. The
western third is a natural shoreline with single family home sites, where erosion
threatens to undermine numerous homes. The central portion contains the
Pascagoula River Delta and the major port of Pascagoula, which is modified and
maintained by heavy industry. Extensive dredging of channels here may be
contributing to the erosion down-drift to the west. The eastern third of the Jackson
County coast is a natural salt marsh which is rapidly retreating due to erosion. The
Grande Batture Islands offshore have been completely eroded within recent
memory.

Barrier Islands. Four barrier islands, located approximately 6-12 miles offshore, are
separated from the mainland by a relatively shallow Mississippi Sound and act as a~
storm buffer for the mainland. These islands are subjected to the highest wind and
wave energies of the Mississippi coast and therefore exhibit the greatest relative

Gulf of Mexico Coastal & Shoreline Erosion Action Agenda (4.1)