• TABLE OF CONTENTS
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 Front Cover
 Title Page
 Table of Contents
 Executive summary
 Introduction and Natural setti...
 Perdido Key nourishment projec...
 Summary of monitoring study...
 Synthesis of study components
 Future nourishments
 Summary and conclusions
 References






Title: Perdido Key Beach nourishment project: a synthesis of findings and recommendations for future nourishments
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Title: Perdido Key Beach nourishment project: a synthesis of findings and recommendations for future nourishments
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Publisher: Coastal Engineering
Publication Date: 1995
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Table of Contents
    Front Cover
        Front Cover
    Title Page
        Page i
    Table of Contents
        Page ii
        Page iii
        Page iv
        Page v
    Executive summary
        Page 1
        Page 2
    Introduction and Natural setting
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
    Perdido Key nourishment projects
        Page 15 (MULTIPLE)
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
    Summary of monitoring study results
        Page 21 (MULTIPLE)
        Page 22
        Page 23
        Page 24
        Page 25
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
        Page 33
        Page 34
    Synthesis of study components
        Page 35 (MULTIPLE)
        Page 36
        Page 37
        Page 38
    Future nourishments
        Page 39
        Page 40
        Page 41
    Summary and conclusions
        Page 42
        Page 43
    References
        Page 44 (MULTIPLE)
        Page 45
        Page 46
        Page 47
Full Text





UFL/COEL-95/011


PERDIDO KEY BEACH NOURISHMENT PROJECT
A SYNTHESIS OF FINDINGS AND RECOMMENDATIONS FOR
FUTURE NOURISHMENTS




Robert G. Dean
Emre Otay
and
Paul A. Work





May, 1995





Submitted to:

Department of the Navy
Southern Division
Naval Facilities Engineering Command
Charleston, SC 29411-0068









UFL/COEL-95/011


PERDIDO KEY BEACH NOURISHMENT PROJECT
A SYNTHESIS OF FINDINGS
AND RECOMMENDATIONS FOR FUTURE NOURISHMENTS

by

Robert G. Dean
Emre Otay
Paul A. Work


May, 1995















Submitted to:

Department of the Navy
Southern Division
Naval Facilities Engineering Command
Charleston, SC 29411-0068











TABLE OF CONTENTS


PAGE


LIST OF FIGURES .......

LIST OF TABLES .......

EXECUTIVE SUMMARY .

INTRODUCTION .......

THE NATURAL SETTING


.. iii


...................................................v


G general ..................
Geology ..................
Sea Level Change ..........
Tides ....................
W aves ...................
Longshore Sediment Transport


PERDIDO KEY NOURISHMENT PROJECTS .....

G general ..............................
1985 Nourishment ......................
1989-1991 Nourishment ..................
1989-1990 Beach Nourishment .......
1990-1991 Profile Nourishment ......

SUMMARY OF MONITORING STUDY RESULTS.


Physical Monitoring .............
Benthic Studies ................
Vegetation Studies ..............
Perdido Key Beach Mouse ........

SYNTHESIS OF STUDY COMPONENTS

FUTURE NOURISHMENTS ...........

SUMMARY AND CONCLUSIONS ......

ACKNOWLEDGMENTS ..............

REFERENCES ......................


...3
...6
S. .11
..11
..11



..15
. 13

. 15

. 15
. 15
..17
..17

. 21

S. 21


.................. .................... 35

. ...... .. .......... .... .. ..... ........ 39

. . . . . . . . . . 4 2

. . . . . . . . . . 4 4

. . . . . . .. . . 4 4









LIST OF FIGURES

FIGURE PAGE

1 Location map (W ork et al., 1991c) ........................................ 4

2 Components of beach nourishment monitoring project (Work et al., 1991b) .......... 5

3 Geologic column of formations in western panhandle of Florida (Marsh, 1966) ....... 7

4 Geologic cross-section through western Florida's Gulf coast (Marsh, 1966) .......... 8

5 Geologic profiles through Pensacola Bay area (Marsh, 1966) .................... 10

6 Relative sea level elevations, Pensacola, FL gage. Arbitrary datum ................ 12

7 Hypothetical sediment transport quantities illustrating relevance of net and gross
transport rates .................................................... 14

8 Sand transport losses and beach profiles associated with a beach nourishment
project (Dean and Abramian, 1993) ....................................... 16

9 Shoreline changes associated with first (1985) nourishment (Rutgers, Personal
Com m unication) ................................................... 18

10 Average shoreline changes associated with and within first (1985) nourishment
project area (D ean, 1988b) ............................................. 18

11 Profiles collected during this study at Range R-58, showing beach and profile
evolution ................................... ....................... 19

12 Percentage of fines for 5 m samples for all years of study (Otay and Dean, 1994) ..... 20

13 Percentage of fines for 8 m samples for all years of study (Otay and Dean, 1994) ..... 20

14 Longshore averaged cross-shore distribution of D50. Temporal variation for all
years of study (Otay and Dean, 1994) ..................................... 23

15 Average of profiles within nourished area. Averages based on profiles at R-45,
R-46, R-48, R-50, R-52, R-54, R-56 and R-58 (Otay and Dean, 1994) ............. 23

16 Averages of profiles west of nourished area. Averages based on profiles at R-30,
R-32, R-34, R-36 and R-38 (Otay and Dean, 1994) ........................... 24

17 Proportion of sand remaining in project area vs time ........................... 24

iii









18 Map of the study area at Perdido Key. Locations of transects: A at DNR R-32, B
at DNR R-40, C at DNR R-50, and D at DNR R-60. (Adapted from Rakocinski et
al., 1993b) .......................................................... 26

19 Time-course variation in faunal indices at station 7 for transects A-D across ten
completed sampling periods (Rakocinski et al., 1994) .................. ....... 28

20 Time-course variation in faunal indices at station 9 for transects A-D across ten
completed sampling periods (Rakocinski et al., 1994) .......................... 29

21 Schematic profile of Perdido Key showing the distribution of vegetation types
(Gibson and Ely, 1994) .................................. ........... 30

22 Frequency distribution of number of continuous seasons that a plot below old
MHW was colonized with vegetation (Gibson and Ely, 1994) ................... 32

23 One-hundred year simulation of vegetation types above old MHW starting from
Autumn 1989 field values (Gibson and Ely, 1994) ............................ 34

24 Variation with time in mice captured in three segments of the GINS trapping area
(Holler and Moyers, 1994) ............................................ 36

25 Results from trapping data at Florida Point (Holler and Moyers, 1994) ............. 37

26 Recommended location for future beach nourishment .......................... 40

27 Predicted planform evolution for project of 500,000 cubic meters ................ 41

28 Recommended characteristics of nourished profile. Shown for R-58 ............... 43









LIST OF TABLES


TABLE


Estimates of Longshore Sediment Transport by Different Investigators ............ 13

Characteristics of Averaged Profiles ..................................... 222


PAGE









EXECUTIVE SUMMARY


The eastern end of Perdido Key was nourished in 1989-1990 with the placement of
approximately 4.1 million m3 of sand in a manner that extended the beach seaward by approximately
140 m over a distance of 7.3 km. In the following year (1990-1991), an additional 3 million m3 was
placed in water depths ranging from approximately 5.5 to 6.5 m. All of this nourishment took place
within the Gulf Islands National Seashore ginsS), a unit of the National Park Service. With the
exception of the placement of approximately 7.5 km of sand fencing, no efforts were made to stabilize
the nourishment nor to expedite recovery of the vegetation. Prior to the nourishment, the channel at
the eastern end of Perdido Key had been dredged for more than a century which had reduced the
natural flow of sediment from the east. In 1985, an earlier beach nourishment project of
approximately 2.5 million cubic yards had been placed on Perdido Key; however, only limited
monitoring of this first project was conducted. Although the quantities associated with the two 1989-
1991 projects were large, they are substantially less than the amount of material which would have
been supplied to the eastern end of Perdido Key if the more than one century of Pensacola Pass
channel dredging with predominant disposal at sea had not been carried out.

The large amounts of sand placed in the 1989-1991 nourishment represented a substantial
perturbation to the physical and biological systems and gave rise to a number of questions relating
to effects on the natural attributes of the GINS. A wide low unvegetated berm was present whereas
in the natural state the unvegetated berm had been much narrower and somewhat higher. It was
generally agreed that the system would return to nearly natural conditions; however, there was
considerable interest in the time scales of recovery and the use of information gained in providing
guidance for possible future nourishments.

The central questions addressed in this report relate to (1) the beneficial and adverse short and
long term effects of the Perdido Key beach nourishment, (2) the time scales of such effects, and (3)
the development of recommendations in the event of future nourishments. The impacts can be to the
physical, vegetative, benthic systems and to the Perdido Key Beach Mouse and are summarized
below.

From physical considerations, the effects of restoration of the width of Perdido Key in the
areas most affected by more than a century of partial or complete interruption of longshore sediment
transport are primarily a benefit. Prior to the nourishment, the eastern end of Perdido Key was
receding at a rate of approximately 2 m per year (Dean, 1988a). In some places, the island had been
reduced to approximately one-half its original width and severe storms overwashed the island. Any
negative impacts would fall in the category of beach profiles that are initially steeper than natural and
possibly disturbances arising from the dredging activities and the latter are reasonably short lived.

Beach nourishment projects bury those animals that reside in the area and cannot either leave
sufficiently rapidly to avoid burial or move upward in the placed sediment. Also, if the nourishment
material contains substantial fine material (silts and clays), the water turbidity may be affected and
may smother those animals which are not sufficiently motile to leave the area. The impact of direct
burial and smothering is somewhat short lived due to the availability of larvae carried by the waves
and currents that can initiate repopulation of the affected area. The unanticipated placement of









sediment finer than the native was also found to impact the benthic populations in the area so
affected. The percentage of fine sediments decreased over the monitoring period and the impacted
area approached natural conditions; however, conditions had not returned to normal at the end of the
monitoring period.

Possible vegetative concerns included the composition of plants that would colonize the new
beach and the rates at which this would occur. Additionally, the effect of a much wider berm on the
plant communities landward of the Old Mean High Water (OMHW) line, and the development of a
seed bank in the zone seaward of the OMHW line were concerns. Analysis of sampling results
showed that the vegetation community is being established with the types representative of coastal
systems, effects on the vegetation landward of OMHW are minimal, and the development of a seed
bank on the new berm is relatively slow and may be due in part to saltwater inundation by Hurricane
Andrew in 1992.

The Perdido Key beach mouse was observed to decrease in numbers over the monitoring
period. However, previous studies had established that the population fluctuations were erratic and
thus it is not possible to relate the decline to the beach nourishment project. Considering a longer time
scale, the nourishment project will be beneficial in restoring a more viable barrier island and stable
dune field and thus may provide a more robust habitat.

Based on the results developed through the monitoring program, it is recommended that
future nourishment material be examined to ensure compatibility with the native sediments and that
an attempt be made to limit volumes placed to less than approximately 500,000 m3 where practical
and that placement occur over shoreline lengths of about 2 km commencing no closer than 2 km from
the eastern end of Perdido Key.









INTRODUCTION


Perdido Key is the most western barrier island in Florida and extends from the east at
Pensacola Pass, FL to Perdido Pass, AL on the western end, a distance of 24 kilometers. Figure 1
provides a location map. Perdido Key was formerly connected to the mainland and became an island
between 1930 and 1934 with the excavation of the Intercoastal Waterway which severed the Island
at the location of the present bridge from Pensacola. The net longshore sediment transport in this area
is from east to west at a rate believed to be on the order of 100,000 m3 per year although as will be
discussed later, there is considerable uncertainty regarding this estimate. Pensacola Pass, located
updrift of Perdido Key has been deepened for navigation purposes since 1883 with a total in excess
of 28 million m3 of sand removed prior to the project of concern here. All but 7.2 million m3 of this
was disposed in deep waters of the Gulf. In its natural state, a relatively shallow ebb tidal shoal
associated with this channel formed a "bridge" for the net longshore sediment transport around the
entrance. With the deepened channel, this sediment transport pathway was rendered less effective and
the Perdido Key beaches to the West commenced to erode (Dean, 1988b). Indeed, in some locations,
Perdido Key had decreased to approximately one-half its original width.

The plans to establish a Home Port for the aircraft carrier Kitty Hawk in Pensacola Bay
required a deeper channel and provided an ideal and one-time opportunity to place substantial
quantities of predominantly good quality sand on the Perdido Key beaches. Placement of sand on the
beach was the most economical and environmentally beneficial disposal option associated with the
required dredging. The eastern 10.5 kilometers of Perdido Key is part of the GINS administered by
the National Park. Commencing in September 1989, a total of approximately 4.1 million m3 was
placed in an area extending from Pensacola Pass over a distance of 7.3 km to just west of the easterly
terminus of the National Park Service road. Commencing in 1990, an additional approximate 3
million m3 was placed offshore in water depths of 5.5 to 6.5 m over a longshore distance of
approximately 3 km. The locations of both the beach and "profile" (underwater) nourishment are
shown in Figure 2.

Associated with this sand placement was the potential for significant effects, both beneficial
and detrimental to the natural characteristics of the system. As a result of concerns of the effects of
this placement on the general characteristics of the GINS, a broadly based monitoring program was
undertaken that comprised physical and biological components. This report provides a synthesis of
the various study elements and recommendations for future nourishments.

THE NATURAL SETTING
General

Perdido Key is a relatively narrow, linear barrier island located in Escambia County in the
western "Panhandle" of Florida (Figure 1). It trends east-west with its southern shores facing the Gulf
of Mexico and is bordered by Big Lagoon and Old River on its northern shores. Perdido Pass (the
entrance to Perdido Bay) forms the western boundary of Perdido Key, and the island is bordered by
Pensacola Pass on its eastern end. As noted, the eastern 10.5 km of Perdido Key is within the GINS
administered by the National Park Service.


I








































0 5 km
6-s-=-- -- ........


Figure 1. Location map (Work et al., 1991c).





















METEOROLOGICAL
STATION '\ .


PROFILE NOURISHMENT


S 1 2 3 4 5 km
I II-


WAVE GAGE
NOTE:
R-40 is FLORIDA DEPARTMENT OFNATURAL
RESOURCES MONUMENTED "RANGE 40"


Figure 2. Components of beach nourishment project (Work et al., 1991b).









The climate in the area is usually mild with onshore sea breezes and temperatures that
generally range from 100 C in the winter to 250 C in the summer. Average wave heights in the area
are available from a number of sources. Hurricanes affect the area. In recent times, Hurricanes
Camille (1969), Eloise (1975), Frederic (1979), Elena (1985) and Andrew (1992) have passed
sufficiently close to cause significant storm erosion. Of these hurricanes, Frederic had the greatest
impact and it is still possible to find reasonably large pieces of debris from the macadam road in the
Project area that were transported northward by the waves and storm tide which overtopped the Key
in numerous locations.


Geology

Escambia County lies in the Gulf Coastal Plain physiographic province which extends along
the entire gulf coast of the United States. Coastal plain sediments, most of which were deposited
during higher stands of the sea, consist of unconsolidated sands, limestones, silts and clays of
Cretaceous, Tertiary, and Quaternary age. The coastal plain is approximately 300 km wide (in the N-
S direction) along the Florida panhandle. Cooke (1939) subdivides the coastal plain in this area into
two topographic regions: the Western Highlands, consisting of a southwestward sloping plateau
whose surface has been incised by numerous streams; and the Coastal Lowlands, consisting of
relatively undissected, nearly level plains lying less than 30 m above present sea level. The Coastal
Lowlands occupy a narrow strip 16 to 20 km wide along the coast and it is within this region that
Perdido Key lies.

The coastal plain is bounded to the north by the Piedmont Plateau physiographic province
where igneous and metamorphic rocks ranging in age from Precambrian to Paleozoic are exposed at
the surface. These ancient rocks extend to great but unknown depths beneath the coastal plain region
and are unconformably overlain by the unconsolidated coastal plain sediments which form a
southward thickening wedge.

The subsurface geology of Escambia County is more similar to that of the north-central Gulf
Coast comprised of Alabama, Mississippi, and Louisiana to the west rather than the geology of
peninsular Florida to the east. A detailed description of the geology is given by Marsh (1966) and Coe
(1979). The generalized stratigraphic column for the western Florida panhandle is shown in Figure 3.
Escambia County lies on the north flank of the Gulf Coast geosyncline (Barton et al., 1933; Howe,
1936) and the east flank of the Mississippi Embayment. These structures contribute to the
southwestward dip which is characteristic of all the formations in the area at least as far down as the
base of the Cretaceous deposits (Figure 4). Faulting has occurred to the northeast of Escambia
County where a west-northwestward-trending graben, the Pollard graben, extends southward from
Alabama. The major fault lines in this area are the Jay, Pollard, and Foshee faults which extend
downward through the Upper Cretaceous sediments.

The most distinctive feature of this coastal plain topography is the Pleistocene marine
"terraces" which have been traced by previous workers along the Gulf Coast and along much of the
Atlantic coast. For the state of Florida, the findings of these previous workers are summarized in map
form (see Florida Geological Survey map series no. 71, 1975). These terraces represent ancient














GENERALIZED GEOLOGIC COLUMN
OF FORMATIONS IN THE WESTERN FLORIDA PANHANDLE
GRAPHIC
SERIES SECTION FORMATION
PLEISTOCENE MARINE TERRACE DEPOSITS: Sand, light tan, fine to coarse

SCITRONELLE FORMATION: Sand with lenses of clay and gravel. Sand, light-
PLEISTOCENE (?) yellowish-brown to reddish-brown, very fine to very coarse and
poorly sorted. Hardpan layers in upper part. Logs and carbonace-
ous zones present In places. Fossils extremely scarce except near
the coast where shell beds may be the marine equivalent of the
fluvial faces of the Citronelle.


s' MIOCENE COARSE CLASTICS: Fossillferous sand with lenses of clay and
gravel. Sand is light-gray to light-brown, very fine to very coarse
and poorly sorted. Fossils abundant, mostly minute mollusks.
S Contains a few zones of carbonaceous material. Lower part of
coarse plastics present only in northern part of area, interfingering
UPPER MIOCENE with Pensacola Clay In the central part.

PENSACOLA CLAY: Formation consists of an Upper Member and Lower
Member of dark-to-light-gray, tough, sandy clay; separated by the
S Escambia Sand Member of gray, fine to coarse, quartz sand. Con-
.. tains carbonized plant fragments, and abundant mollusks and fora-
n minifers. Pensacola Clay Is present only In southern half of area,
UPPER MIDDLE TO Interfingering with the Miocene coarse plastics in the central part.
LOWER UPPER MIOCENE


LOWER MIOCENE AND CHCKASAWHAY LIMESTONE AND TAMPA FORMATION UNDIFFERENTIATED
lp : T Limestone, light-gray to grayish-white, hard, with several beds
UPPER OLIGOCENE
UPPER OLGOCENE of clay; Chickasawhav: Dolomitic limestone, gray, vesicular.
MIDDLE OLIGOCENE ---- BUCATUNNA CLAY MEMBER OF BYRAM FORMATION: Clay, dark-gray soft, silty
IDDE ,-_,- ---- to sandy, foraminiferal, carbonaceous
CALA GROUP: Limestone, light-gray to chalky-white foraminifers extremely
UPPER EOCENE abundant, esp. Lepidocvcllna: corals, echinolds, mollusks, bryozoans



S- LISBON EQUIVALENT: Shaly limestone, dark-gray to grayish cream; hard,
,-- compact; glauconitic; with thick Intervals of dense, light gray shale.
MIDDLE EOCENE -j-

T'iALLAHATTA FORMATION: Shale and siltstone, light-gray, hard, with numer-
j : ous Interbeds of gray limestone and very fine to very coarse, pebbly
sand. Foraminifers locally abundant

HATCHETIGBEE FORMATION: Clay, gray to dark-gray, micaceous, silty, with
LOWER EOCENE -- beds of glauconitic shale, siltstone, and shaly limestone. Mollusks,
foraminifers, corals echinolds. Bashi Marl Member (about 10 feet
-- thick) at base.


Geologic column of formations in western panhandle of Florida (Marsh, 1966)


Figure 3.


















o C
O -


Figure 4. Geologic cross-section through western Florida's Gulf coast (Marsh, 1966)


Mean Sea
Level
400
800
1200
1600


East
S I









shorelines, deposited during major stillstands or slight transgressions of the sea, during the
Pleistocene as sea level fluctuated with the glacial and interglacial periods which characterized this
epoch. During these major stillstands or slight transgressions of the sea and similar to the depositional
processes going on at present-day coastlines, formation of a barrier island chain occurred with
associated lagoonal/marsh sediments being deposited on the landward side of the barrier island
sequence. Inlet deposits, estuarine and channel sediments, and a seaward thinning wedge of offshore
sediments were also deposited and are therefore also associated with the terrace deposits. Thus, each
terrace is basically an ancient barrier island complex, preservation of which has occurred as a result
of each subsequent fluctuation in sea level being less than the previous sea level rise.

In Escambia County remnants of these terraces are preserved as upland plateaus, flat-topped
hills, low coastal plains, and benches along the rivers and bays. Three marine surfaces of Pleistocene
age may be recognized in topographic profiles across the area (Figure 5).

These surfaces may be associated with the Pamlico shoreline (8 m above present mean sea
level) which developed during the late Pleistocene, the Penholloway shoreline (21 m) which
developed during early Pleistocene, and a seaward-sloping upland surface whose elevation ranges
from approximately 30 to 800 m which is probably a composite of Cooke's Hazelhurst (formerly
Brandywine) terrace (Cooke, 1945) and MacNeil's "high terrace" (MacNeil, 1950).

Presently, the bulk of the northwest Florida coast is eroding with the eroded material being
deposited at spit termini rather than being lost offshore. The 48 km stretch of Santa Rosa Island
between Pensacola Beach and Fort Walton Beach is the only coastal stretch prograding seaward
along this area (between 1934 and 1965/69, seaward growth rate averaged 0.6 m/yr).

From his study of the beach ridge plains between Pensacola, FL and Mobile Point, AL, Stapor
(1973) concludes that there has been a complex history of interrupted deposition rather than constant,
continuous construction along this stretch of coastline. Stapor (1973) observes that in this area: (1)
net coastal erosion has replaced net seaward growth of beach ridge plains, (2) relatively young, high
coastal dunes presently migrate over older beach ridge plains, and (3) heavy mineral concentrations
found along present eroding beaches are absent in beach ridge plains. From these observations, Stapor
(1973) suggests there has been a shift from an economy of abundant sand (promoting beach ridge
construction) to one of a shortage of sand (net coastal erosion) where exact timing of this shift for
individual regions depends on the depletion of local sand supplies.

Stapor (1973) suggests that a series of longshore drift cells, rather than one well-integrated
longshore drift system, characterizes the northwest Florida coast, with some of these drift cells
appearing to be interconnected, but many apparently experiencing little net exchange of sand with
either adjacent cells or offshore regions. He proposes that shoreline changes from records going back
to 1871 indicate that Santa Rosa Island was probably composed of several longshore drift cells,
possibly experiencing net communication, but not a single, well integrated system, with Perdido Key
appearing to have also been characterized by cellular transport. Stone et al. (1992) reach similar
conclusions.
















V.,id a~~M 0 m


Figure 5. Geologic profiles through Pensacola Bay area (Marsh, 1966)









In the north-central Gulf coast, core data (Otvos, 1979) provide supporting evidence that
shoal-bar aggradation (Otvos, 1981), rather than spit segmentation (Gilbert, 1885) or mainland dune-
ridge engulfment (Hoyt, 1967), has been the predominant mechanism of barrier island formation. In
contrast with the transgressive Atlantic coast where barrier island evolution is typically associated
with landward migration (de Beaumont, 1845), the barrier islands of the Gulf coast between Gulfport
and Pensacola seem to have emerged from shoals practically "in place" and have shifted only laterally
to the west in the general direction of littoral drift (Otvos, 1979).

Another barrier island type also recognized along the north central gulf coast is the secondary
"composite" barrier island. This type of island is characterized by the presence of a shallow pre-
Holocene (usually Pleistocene) core extending near or above present sea level which is veneered by
Holocene shoreface, beach and dune deposits. During island formation the pre-Holocene core acts
as a stabilizer while further seaward and longshore progradation take place. This island development
pattern has been observed at eastern Dauphin Island (Otvos, 1976, 1979), central Santa Rosa Island
(Otvos, 1982), Deer and Round Islands, as well as at several South Carolina, Georgia, and northern
Florida islands (e.g., Hilton Head, Sapelo, Ossabaw, St. Catherines, and Wassaw Islands).


Sea Level Change

Tide gage data for Pensacola Harbor were obtained from the National Ocean Survey up
through 1990. This type of data had been analyzed earlier by Hicks et al. (1983) and indicate a long
term trend of gradual rise at a rate of approximately 2 mm per year. This rate is 70 % larger than the
world wide average of approximately 0.12 mm/year.

Sea level rise places erosional pressure on the shoreline and is thus relevant to its stability. The
presence of a slow subsidence component is common in the tide gage results from low latitude
regions due to the global adjustments occurring from melting of the glaciers at the higher latitudes.
This results in an augmented relative sea level rise. The results from the Pensacola tide gage are
presented in Figure 6.


Tides

The gulf tides at Perdido Key are predominantly diurnal. The mean tidal range is 0.4 m (National
Ocean Service, 1995). Based on tide data extracted from wave gages off Perdido Key, the tidal
ranges vary from nearly zero to approximately 1 m over a fortnightly period.

Waves

Based on the wave data collected in conjunction with this study, the waves in the area are
predominantly from the southeast with an average annual significant wave height of 0.45 m and the
monthly averages ranging from 0.27 to 0.68 m. The average annual wave period is 5.7 sec and the
range of monthly average periods is from 4.7 sec to 6.4 sec.









1-3.00










`2.75
I
ia)


2.50 'I I I I I I I
1920 1930 1940 1950 1960 1970 1980 1990
Year
Figure 6. Relative sea level elevations, Pensacola, FL gage. Arbitrary datum.









Longshore Sediment Transport


Longshore sediment transport is the result of waves approaching the shoreline at an angle with
waves from the east resulting in westerly transport and vice versa. There are two overall measures
of transport that are used in coastal engineering. Net transport is the difference between the longshore
transport in the two directions and has a direction itself. For example, we might say that the net
annual transport at Perdido Key is 100,000 m3 to the west. The direction of the net transport is
referred to as "the downdrift direction" and the opposite direction is referred to as "updrift". Gross
sediment transport is the sum of the absolute transports in the two directions and does not have an
associated sign. The net transport is important because if one considers a location sufficiently west
along Perdido Key, if the net transport is westerly as is believed, it represents the rate at which sand
is leaving the portion of the island which lies to the east. The gross transport can be relevant near an
inlet because if the transports flow into a channel unimpeded and are unable to be supplied to the
nearshore system during periods of transport reversal, then the inlet will accumulate sand at the rate
of the gross transport. Figure 7 presents examples of these concepts.

Several estimates of net longshore sediment transport have been developed in the Perdido Key
area, including Johnson (1956), Gorsline (1966), U. S. Army Corps of Engineers (1972), Walton
(1973), and Stone et al. (1992). These estimates are listed in Table 1 and are based on various
approaches and apply at different locations. Johnson (1956) based his estimate of 153,000 m3 per


Table 1. Estimates of Longshore Sediment Transport by Different Investigators
Reference Net Longshore Comments
Sediment Transport
(m3/yr) and Direction
Johnson (1956) 153,000, Westerly Estimates for Perdido Pass, Based on
Impoundment Records at Perdido Pass
Gorsline (1966) 75,000 Westerly Estimates for Gulf Beach, Based on
Monthly Wave Observations Over a One
Year (1962) Period

U. S. Army Corps of 50,000 Westerly Estimates for Perdido Pass Based on
Engineers (1972) Dredging Records at Perdido Pass and
at East Pass (Entrance to Choctawhatchee
Bay)
Walton (1973) 210,000 Westerly Estimates for Perdido Key, Based on Wave
Observations from Ships

Stone et al. (1992) Variable, Ranging From Estimates for Perdido Key, Based on Two
50,000 Westerly to Independent Estimates for Deep Water
20,000 Easterly Waves







































(Net


Figure 7. Hypothetical sediment transport quantities illustrating relevance of net and gross transport rates.


SPensacola Pass Will Accumulate
Sand at 200,000m3/yr
(Gross Rate) km
5 km









year on the accumulation of sediment within the weir jetty at Perdido Pass. It addition to this location
being some distance from the nourishment area of concern here, it is known that if a weir section is
too low, it will draw sand from the adjacent beach at a rate which exceeds the net longshore sediment
transport. Gorsline established his estimate of 75,000 m3 per year on the basis of monthly visits to
the central portion of Perdido Key in 1962 and the application of wave estimates through an empirical
method. The U.S. Army Corps of Engineers estimate of 50,000 m3 per year (Westerly) was
determined from examining dredging records at Perdido Pass and East Pass, the entrance to
Choctawhatchee Bay. Walton's estimate of 210,000 m3 per year (Westerly) is based on ship wave
data which are then transferred to shore using a simple refraction model accounting for wave damping
due to friction and percolation. The estimates of Stone et al. (1992) are the most comprehensive to
date and transfer two independent sets of wave data to shore through a ray tracing refraction model.
The results from both sets of wave data predict a reversal in sediment transport direction near the
eastern end of Perdido Key. The ranges of net eastward transport for the two data sets are from nil
to approximately 20,000 m3 per year whereas the net westward transport along the mid-length of
Perdido Key is approximately 50,000 m3 per year for both data sets. Fortunately for purposes of
comparing the beach nourishment evolution, the direction of transport is not of first order importance
as will be discussed later.


PERDIDO KEY NOURISHMENT PROJECTS

General

Upon placement of a beach nourishment project, the planform and profile of the project are
usually out of equilibrium, see Figure 8. In most cases, as for the nourishment at Perdido Key, the
profile: is over steepened and induces a seaward transport and due to the planform protuberance,
longshore transport occurs that tends to reduce the bulge in the shoreline. It is not possible to provide
general quantification of the time scales associated with these two equilibration processes. However,
if the project is reasonably long as it is here, the spreading out longshoree) time scale is on the order
of decades and the profile equilibration time scale is on the order of 2 to 5 years. The available data
have been applied below to examine these time scales.

To date Perdido Key has been nourished twice, in 1985 and the nourishment in 1989-1991.
Additionally, the 1989-1991 nourishment included a beach nourishment and a profile (underwater)
nourishment.


1985 Nourishment

The July 1985 nourishment comprised the placement of approximately 1.9 million m3 of sand
and extended from R-60 to R-64, a distance of approximately 1.2 km for a placement density of 1,550
m3 per m of shoreline. Hurricane Elena (September 1985) occurred two months after nourishment
and if the nourishment had not been in place, the nourishment area and adjacent areas of Perdido Key
would have surely been impacted to a greater degree than occurred. The placement profile was such
that the berm was high, approximately 3 m as contrasted to the natural berm elevation of less than











Original Shoreline


S"-"Spreading Out" Losses





Sand Moves Offshore to
._ Equilibrate Profile



Nourished Shoreline


"Spreading Out" Losses


a) Plan View Showing "Spreading Out" Losses
and Sand Moving Offshore to Equilibrate Profile


Dry Beach W
(Fine Sand)


Dry Beach Width (Coarse Sand)

SInitial Placed Profile


Sand)


Original Profile


Equilibrated Profile (Fine Sand)


Figure 8.


b) Elevation View Showing Original Profile, Initial Placed Profile,
and Adjusted Profiles That Would Result from Nourishment
Project with Coarse and Fine Sands
Sand transport losses and beach profiles associated with a beach nourishment
project (Dean and Abramian, 1993)









2 m. This high berm prevented the natural overwash processes which generally occur during moderate
storms and as a result, only wind acted on the berm of the nourished beach. The wind tended to
remove the fine material leaving a "lag" deposit of shell fragments. With time, the shell layer became
more and more evident and appeared unnatural. Although there was no concerted effort to monitor
the performance of this project, in conjunction with their National Park Service responsibilities,
investigators from Rutgers University carried out limited measurements (Rutgers University,
Undated). The shoreline changes from March 1977 to September 1985 and September 1985 to
October 1987 are presented in Figure 9. Based on aerial photographs, the change of average beach
width over the nourished area is shown in Figure 10 (Dean, 1988b).

Referring to Figure 9, and recalling that Hurricane Elena occurred in September 1985, it is
seen that the combination of the nourishment project and Hurricane Elena advanced the shoreline in
the area of nourishment by up to 120 m from March 1977 to September 1985. From September 1985
to October 1987, the shoreline decreased by a maximum of approximately 90 m. Prior to the more
recent beach nourishment, the high berm area was still present. In conjunction with preparations for
the 1989-1991 nourishment, the berm elevation was reduced to conform with more natural,
elevations.


1989-11991 Nourishment

The most recent nourishment comprised two components: a beach nourishment and a profile
(underwater) nourishment.

1989-1990 Beach Nourishment Approximately 4.1 million m3 was placed commencing in
the Fall of 1989 and ending in the Fall of 1990. Placement extended from R-40 to R-64, a distance
of approximately 7.3 km, for a placement density of approximately 560 m3 per m, approximately 36%
of the 1985 placement density. This nourishment advanced the shoreline Gulfward by an average of
approximately 140 m. A profile for Range R-58 is shown in Figure 11 (see Figure 2 for locations of
ranges). The design elevation of the profile at the Gulfward end of the berm was about 1.2 m, less
than the natural elevation of 2 m to allow the berm to build to a natural elevation through storm runup
and overtopping of the berm. Monitoring subsequent to Hurricane Andrew in August 1992
documented that the intended build up due to storms did indeed occur.

In preparation for this nourishment, 55 sediment cores representing material to be dredged
for the channel deepening project were available for evaluation. These cores were examined and
recommendations were made for material to be placed on the beach (Dean, 1988b). Although these
cores seemed adequate at the time and it is estimated that greater than 98% of the material placed was
of a quality comparable to the natural beach sediments, some fines (silts and clays) were encountered
in the dredging and formed a thin layer in the vicinity of DNR Monuments R-42 to R-58. This
material was substantially different than the native and was most prevalent in the 5 m sediment
samples and to a lesser extent in the 8 m samples. As shown in Figures 12 and 13 for the 5 m and 8 m
depths,, respectively, these fine sediments ranged up to almost 100% in some early samples. It was
found that the percentage of fines decreased with time and that in the 1993 sampling, the maximum
percentage was less than 10% as shown in Figure 12 and 13. This diminution in the fine sediment






























-500 i I I I I I I I I I I I i I I
55 60 65
DNR RANGE MONUMENT NUMBER

Figure 9. Shoreline changes associated with first (1985) nourishment (Rutgers,
Personal Communication).


.P


0
..I soo

E I,



X. 500

1 200



1 100


S100
100
i:


200 j F MAMJ J ASO ND J FMIA J J A SOND J FM AMJ J AS ONDJ FA MJ J AS
1964 4- e1s8- 1986 --4 -1997-





Figure 10. Average shoreline changes associated with and within first (1985) nourishment
project area (Dean, 1988b).


Hurriclne



I/ o
So
I /


al mam a ii 1 11 .1 11 11 11 1 I I 1I I II l Ii I I I I I I I I II I


I`


|











Perdido Key: Range 58 Azimuth 165 degrees


0 200 400 600 800 1000 1200 1400 1600
Distance from Monument [m]

Figure 11. Profiles collected during this study at Range R-58, showing beach and profile evolution.


C I
0
cs -2
iu
















100

, 80

i. 60
C
| 40

a- 20
n


5 m Sand Samples
Percentage Finer than 0.0097 mm


--------------- ------------ ------ -----------------

-------------- ------------ ---- -----------------




....... .k .. .. .
--------------... -- -- --- -- - -


30 34 38 42 44 46 50 54 58 61 63 65 67
Range Number increasing towards East

I Nov.'89 E Sep.'90 m Oct.'91 M Oct.'92 M Nov.'93

Figure 12. Percentage of fines for 5 m samples for all years of study (Otay and
Dean, 1994).


8 m Sand Samples
Percentage Finer than 0.0097 mm
100
o 80--- --------------------------------
i- 60 .----------------------- ----------------------------

^ 40--- -------------------------------
20
Q---------------------- ------- -------------------------

30 34 38 42 44 46 50 54 58 61 63 65 67
Range Number increasing towards East

3 INov.'89 I Sep.'90 Oct.'91 M Oct.'92 Nov.'93

Figure 13. Percentage of fines for 8 m samples for all years of study (Otay and
Dean, 1994).









concentration is believed to have been caused by the preferential suspension of these fine sediments
in the relatively energetic area in which the sediments were placed and the transport to areas more
conducive to their deposition and stability.

1990-1991 Profile Nourishment The 1990-1991 underwater nourishment comprised
approximately 3 million m3 and was placed in nominal water depths ranging from 4 to 6 m and
extended from R-49 to R-60, a distance of 3.4 km. A "gap" between the Gulfward end of the beach
nourishment and the landward limit of the profile nourishment was left intentionally with the hope that
the biota in this gap would survive and would serve as a source area for repopulation of the biota in
the adjacent regions of direct sand placement where survival was less probable. The beach and profile
nourishments for R-58, presented in Figure 11 show this gap which at this location exceeds a width
of 250 m.


SUMMARY OF MONITORING STUDY RESULTS

Monitoring to document the effects of and response to the 1989-1991 nourishment project
included the following: (1) a physical component, (2) a benthic component, (3) a vegetation
component, and (4) a component to examine the population of the endangered Perdido Key Beach
Mouse. The studies associated with each of these components and the major results are reviewed in
the following paragraphs.


Physical Monitoring

Prior to discussing the physical monitoring, it is worthwhile to describe the reference system
along Perdido Key which forms a common basis for all of the study components. The Florida
Department of Natural Resources (FDNR) has established a monumented baseline along its 24
predominantly sandy coastal counties. This baseline consists of concrete monuments imbedded into
the dune well back from normal shoreline fluctuations and spaced along the shoreline at nominal
distances of 305 m (1000 feet). A brass cap identifying the monument is imbedded in the top of each
monument. The elevation of the top of the brass cap on each monument has been established relative
to the National Geodetic Vertical Datum (NGVD) and the horizontal position of the monument has
been referenced to State Plane Coordinates. The monuments in each county are numbered
consecutively with the Gulf of Mexico counties commencing on the western or northerly end with
the first monument. These monuments are referred to, for example, as R-45 for "Range 45". In
Escambia County, the 211 monuments commence at the Alabama-Florida border and the last
monument on Perdido Key is Monument R-67 just west of Pensacola Pass. The State of Florida has
conducted previous surveys from these monuments along fixed azimuths. These monuments and the
previous surveys provide a valuable basis for this study. The base line for this study and all study
components were referenced to these monuments. Figure 2 has previously shown the monuments in
the study area which range from R-30 to R-67. It is seen that the beach nourishment extends from
R-40 through R-64, a distance of approximately 7.3 km.









The annual results of the physical studies have been presented previously in the following
reports: Work et al., 1990; Work et al., 1991a,b,c; Work and Dean, 1992 and Otay and Dean, 1993,
Otay and Dean, 1994. The monitoring program included beach and offshore profiling, sand sample
collection and analysis, measurement of waves by one gage initially and two gages during the last
three years of the project, and meteorological conditions. In addition to the normal beach profiling,
special measurements were carried out over the offshore nourishment area to determine whether this
deposit was migrating shoreward. The locations of the profile lines, the wave gages and the
meteorological station have been presented in Figure 2.

It was found that, with the exception of the fine sand discussed earlier, the sand was
compatible with the native, see Figure 14 which presents the variation of sand size with time. The
profiles equilibrated during the monitoring period, but had reached only about 50 % of the equilibrium
slope as of the last survey. Figures 15 and 16 present average profiles within and outside of the
nourished area and Table 2 summarizes the slopes of these average profiles. The planform resulting
from nourishment represents a protuberance relative to pre-nourishment and it is expected that this
will spread out with time. It was found that the system evolved consistent with present knowledge
of sediment transport processes along a nourished shoreline. The profile evolved toward the pre-
nourished form and the volume placed spread out gradually to the adjacent shores as expected (Work
and Dean, 1995). As of the last survey, 78% of the material placed within the project area remained
in the project area. It was also found that the material on the east end of the project area was lost
more rapidly than on the west end. This is interpreted as being due to the effect of the proximity of
Pensacola Pass as a sink which allows sand to move into, but once there, the sand cannot be moved
back to the beaches. In a sense, Pensacola Pass acts as a check valve allowing sand to move into the
Pass but when wave conditions are favorable for sand moving out of the Pass, this is prevented by
the deep channel. Of the volume of sand added on the eastern one-half of the project, 71% remained
whereas on the western half, 85% remained. Figure 17 presents the percentage remaining over time


Table 2. Characteristics of Averaged Profiles
Profile Group Slope of Portion of Profile
Portion ofProfile
Natural Initial After 4 Years

West of Upper 1.5 m 1:57 NA NA
Nourished
Area Upper 5.5 m 1:48 NA NA
Nourished Area Upper 1.5 m 1:44 1:17 1:27
Not Landward
ofBerm Upper 5.5 m 1:53 1:17 1:26
Nourished Area Upper 1.5 m 1:59 1:13 1:50
Landward
o:Berm Upper 5.5 m 1:51 1:18 1:31










Crosshore Distribution of D50
Longshore averaged for All Years


0.5

E 0.4
a)
N 0.3

-0.2
E
c-001
U)


dune berm -1 m -5 m
mid-beach beachface -2 m -8 m

O Nov.'890 Sep.'90 Oct.'91 M Oct.'92 Nov.'93


Figure 14. Longshore averaged cross-shore distribution
of D50. Temporal variation for all years of study (Otay and
Dean, 1994).

Average Profiles Within Protected Beach Nourishment


-100 0 100
Distance from Sep.90 Waterline [m]


Figure 15. Average of profiles within nourished area. Averages based on
profiles at R-45, R-46, R-48, R-50, R-52, R-54, R-56 and R-58 (Otay and
Dean, 1994).










Average Profiles West of Nourished Area


Figure 16. Average of profiles west of nourished area. Averages
based on profiles at R-30, R-32, R-36 and R-38 (Otay and Dean,
1994).


1.0 j it
.o
.: < West Half of Project
'Entire: Project

S o ...... i . .... .... i ...... ... ........ .. ... ..... ... .. .... ...
I ................... ...........
S o East Half if Project



0 .0





Years After Nourishment
Figure 17. Proportion of sand remaining in project area vs. time.









for the entire project and for the eastern and western one-half portions of the project. It is expected
that the relative amounts remaining in the two ends of the project would depend on the wave
directions where, with more waves propagating from the west, the losses on the eastern end of the
project into the channel would be greater. Based on the documented decrease in volume over the
monitoring period, a factor was determined which can be used with confidence to estimate the
evolution of future nourishment projects. This is the basis for the theoretical curve in Figure 17 which
is to be compared with the "entire project" curve. The effects of Hurricane Andrew which caused
maximum significant wave heights of 2.7 m, were documented, including the washover deposits on
the berm. These deposits raised the berm by approximately 35 cm over a width of approximately 30
m (Figure 11). The offshore deposit was surveyed over a three year period and it was established that
the mound was spreading out in both the seaward and landward directions. However, within the limits
of measurement accuracy, it was concluded that the centroid of the mound was not moving either
landward or seaward (Otay, 1994). It appears that the mound is exerting some stabilizing influence
on the beach landward of the mound.


Benthic Studies

Previous reports describing detailed results of the benthic project are presented in Rakocinski
et al., 1990, 1991a,b, 1992a,b, 1993a,b and 1994. The design of the benthic studies included
monitoring at nine stations along four lines approximately perpendicular to the shoreline. Three of
these stations were within the nourishment area ( Transect B at R-40, Transect C at R-50, and
Transect D at R-60) and one was a control (Transect A at R-32) located approximately 2400 m to
the west of the nourishment area. Figure 18 shows the locations of the four lines. The inner five
stations along each line were "floating" signifying that they were referenced to the mean high water
line at the time of the sampling. These were located at 0, 25 m, 50 m, 75 m, and 100 m from the
existing mean high water line. The remaining four stations were at fixed points located at 150 m, 300
m, 500 m, and 800 m from the pre-nourished Mean High Water shoreline, termed the Old Mean High
Water (OMHW). A total of 10 surveys was carried out including one pre-nourishment survey in
October 1989 and a post-nourishment sampling in September 1990. The last sampling was conducted
in September 1992.

The effects of the nourishment were documented by quantifying four biological indices: (a)
Species richness (the number of species in eight cores), (b) Total and species densities, (c) Estimated
diversity, and (d) Estimated evenness.

Two general approaches were applied to evaluate the impact and recovery characteristics of
beach nourishment. The first was to plot the four indices referenced above in various forms which
allowed intertransect comparisons as well as evaluation of the changes over time of the various
indices. The second approach was through principal component analysis (termed PCOR in the benthic
reports) which provides an objective basis for identifying the similarities of the nourishment affected
transects with those of the reference transect. These two approaches provide different approaches
of evaluating the same data and are partly complementary and in part yield similar information.












































Figure 18. Map of the study area at Perdido Key. Locations of transects: A at DNR R-32, B at
DNR R-40, C at DNR R-50, and D at DNR R-60 (adapted from Rakocinski et al., 1993b).













26









Example results from the direct method of analysis are presented in Figures 19 and 20 for stations
located at 300 m and 800 m from the OMHW. Station 800 on Transects C and D are in the area of
"profile nourishment" and were blanketed by up to 1 m of sand. Note the pre-dredging values in
Autumn 1989 and their generally higher values as compared to the post-dredging values. Following
nourishment, there was a clear reduction in two of the four indices at all but Transect A which is
located outside the nourishment area. Additionally, it is evident that at Transect C, the location of
greatest fine sediments, the numbers of species and estimated diversity were depressed. Finally,
although there is considerably variability in the data, there is a general trend toward recovery with
time.

The results of the PCOR analysis can be described generally as follows. The method allows
ranges of natural variability to be established and to be compared with the variability at the nourished
stations. The analysis was applied to quantify the biological assemblage structure separately for the
inner floating and outer fixed stations for only the fall surveys, thereby attempting to avoid the effects
of seasonality. It was found, consistent with the method of direct comparison, that the differences
between the nourished area characteristics and those at the reference transect tended to diminish with
time. For the inner floating stations, at the start of the post-nourishment study, six of 15 stations fell
outside the natural variability whereas for the last fall survey, only two of fifteen fell outside. For the
twelve outer fixed stations, seven fell outside the range of natural variability during the first post-
nourishment survey whereas during the last autumn survey, this number had decreased to two.
Examination of the raw data showed that some of the extreme variability was caused by changes in
taxa from shallow to deep water types in the nourished area.

The introduction of silts and clays as part of the nourishment project was found to cause the
greatest effect on the biota. The areas most affected were located on Transect C at locations from
150 to 500 m from the original MHW shoreline although there were some lesser effects at Transect
D. These effects at Transect D had been reduced substantially after approximately one year while
those at Transect C persisted at a reduced level to the last survey period (September 1992).

In summary of the benthic studies, the major lasting impact of the beach nourishment project
was due to the effects of the fine sediment that was placed predominantly in the vicinity of Transect
C. The shorter lived impacts were due to burial of organisms by the large amounts of material placed
in both the beach and profile nourishment. Over the post-nourishment period, both methods showed
substantial recovery although recovery was not complete at the time of the last survey (September
1992).


Vegetation Studies

Detailed results of the vegetation studies are available in Gibson and Looney 1992a,b, Gibson
et al., 1992, Gibson and Looney, 1993 and Gibson and Ely, 1994. Prior to commencement of the
nourishment, seven vegetation types were found to be present in the area of interest on Perdido Key.
These include, progressing from the Gulf to the Bay: strand, dunes, back slopes, wooded dunes, dry
swales, wet swales and marsh. These seven types are shown schematically in Figure 21. In the case
of the beach nourishment at Perdido Key, the "strand" corresponds to the wide nearly horizontal













SPECIES RICHNESS
STATION 7 300 METERS FROM OR!G!NAL BEACH
Inn,


A
0
o



0-0 TRANSECTA
*- *. TRANSECTB
A*.A TRAN.ECT C
A-**A TRANSECT D


AU89


0


\ /*\ o .,o' ...


S 9/ I
\. ,, .' .%I
""A" "A" A


AU90 SP91 AU'91 SP92 AU92
W190 SU91 W191 SU92


TOTAL DENSITY
STATION 7 300 METERS FROM ORIGINAL BEACH


AA o0



O/ /* /' 'A




o-0 SECTA \ I
03 ** TRA NSECTB A/ *
A) A TRANSECTC 8 **A' *
A...-A TANSECTD '


AU89


AU90 SP91 AU91 SP92 AU92
W190 SU91 W191 SU92


ESTIMATED DIVERSITY
STATION 7 300 METER~ FROM ORiGiNAL BEACH
4

o




-o m,..... .-*** v
S0. TRNSECTA
o a -A



*- *- TRANSECT C
A- A TRANSECT
A-**A INSECTD
0 I I -


1.2-


0.9-


= 0.6-


0.3-


AU89


AU90 SP91 AU91 SP92 AU92
W190 SU91 W191 SU92


ESTIMATED EVENNESS
STATION 7 300 METERS FROM ORIGINAL BEACH





A .** A
A. *.. \.*2 .

0 \,"

0-0 TRANECT A
*- TRANSECT B
A-:&A1 TRANSECT C
A- TRANSECT 0


AU9O SP91 AU91 SP92 AU92
W190 SU91 W191 SU92


Figure 19. Time-course variation in faunal indices at station 7 for transects A-D across ten completed sampling records (Rakocinski
et al., 1994).


I- 80.
UJ

w 60


o 40

S 20
S20
z


-


""'


AU89


X


0.i














SPECIES RICHNESS
STATION 9 800 METERS FROM ORIGINAL BEACH
120

"0 \ 0
00
90 A




.. .*

30- o-o RANsectr A
e- ** RANSECT B
A*..A TRANSECT C
A- *A WTRNSEC D
0


AUB9


AU90 SP91 AU91 SP92 AU92
W190 SU91 W191 SU92


TOTAL DENSITY
STATION 9 BO0 METERS FROM ORIGINAL BEACH


10.0.

E




I 1.0,


AU89


r7IsJAT n mLr.I&
ES IMATED DIVERSITY
STATION 9 800 METERS FROM ORIGINAL BEACH

A..
-.., .o .." .
2.




A


1 0-o0 TANSECTA
*- TRANSECTB
A****A TRANSECT C
A- -A RANSECT D
0*


1.2


0.9



- 0.6


0.3


n-f


AU90 SP91 AU91 SP92 AU92
W190 SU91 W191 SU92


AU89


AU90 SP91 AU91 SP92 AU92
W190 SU91 W191 SU92


ESTIMATED EVENNESS
STATION 9 800 METERS FROM ORIGINAL BEACH





....... "....

0 A Ar



0- 0 TRANSECT A
*- ** TRANSECrB
A****A TRANSECT C
A...A TRANSECr D
A-, .- "RANECr D


AUB9


AU90 SP91 AU91 SP92 AU92
W190 SU91 W191 SU92


Figure 20. Time-course variation in faunal indices at station 9 for transects A-D across ten completed sampling periods (Rakocinski
et al., 1994).


A





0-0 TRANSECTA
*- TRANSECTB
A...-A TRANSECT C
A- TRANSECTO


~_


. = I = m




















Low

Disturbed

Developing


I---- I


N


Dunes
I


Established
I I


Dry Swales --


I---!


Wooded
SDunes
Wet Swales

Marsh...


100


----
300


METERS


Figure 21. Schematic profile of Perdido Key showing the distribution of vegetation types (Gibson and Ely, 1994).


Strand


0 M
MHW


~Y'- Y-VI~
I


r--I
R~~a Sle 91 nq









section resulting from the placement of sand. This will be referred to herein as the bermm". It is this
area that is a primary focus of the vegetation studies.

The vegetation studies (or at least a portion thereof) were based on sampling and observations
in reference transects located in a cross-shore direction at twelve meter intervals with respect to the
OMHW. These plots were rectangular with a surface area of 10 m2 and a two meter dimension in the
cross-shore direction and a 5 m dimension in the longshore direction. The DNR ranges at which these
plots were located include all even numbered ranges between and including R-40 through R-64.
Various measures of the vegetative development on the beach established by nourishment were
employed to provide indices of recovery. Each of these is summarized below.

The colonization of the new beach was examined in Autumn 1993 and Spring 1994. It was
found that within this time period extending over a portion of the third and fourth years after
nourishment, one new species colonized the beach in Autumn 1993 and two new species colonized
the beach in Spring 1994. The density of seedlings was found to be low in Autumn 1993 and higher
in Spring 1994 with the dominant seedling in 1994 being a new species.

Successional trends were examined by surveying the 2 m by 5 m plots from Spring 1991 to
Spring 1994. Hurricane Andrew in August 1992 decreased the number of colonized plots. A
surprising result is that an unexpected large percentage (47%) of plots that were colonized in one
season were abandoned in the next season. This percentage depends in an unknown way on the size
of the plots (here 10 m2). This percentage was highest (78%) from Summer to Autumn and lowest
(16%) from Spring to Summer. Species turnover rates represent the frequency at which the individual
species in a plot appear or disappear from season to season. Initially, it was found that the turnover
rate was high above the OMHW and lower below OMHW. The turnover rates were approximately
the same for the last three intersurvey periods extending from Spring 1993 to Spring 1994. Figure 22
presents, in histogram form, the turnover results for the new beach for the period Spring 1990 to
Spring 1994.

The concept of a "seed bank" refers to the development and maintenance, through natural
processes, of a reservoir of seeds in the upper layers of sediment and is deemed important because,
in the event of a catastrophic storm damaging the standing vegetation crop, the seed bank would play
a vital role in the relatively rapid vegetation redevelopment. With a substantial nourishment such as
that under consideration here, there is the possibility of affecting the natural seed bank on the pre-
nourishment portions of the Key and, of course, there is no pre-existing seed bank on that portion of
the Key resulting from nourishment. The seed bank is quantified by sampling the upper layers of
sediment from a particular area and allowing the seeds in that sediment to germinate under controlled
conditions. It was found that the seed bank Gulfward of the OMHW developed very slowly, whereas
landward of the OMHW, the seed bank remained robust following nourishment. Hurricane Andrew
in August 1992 inundated the berm with salt water and adversely affected the development of a seed
bank on the new beach.

In addition to the sampling and analysis of the data, a Markov model of vegetative
development of the new beach was carried out. This type model assigns a percentage to each of the
possible outcomes of a particular event for a selected time step. For example, one outcome might be









80


70-


60-


4W 50-
050







20-


10-


0-
0 1 2 3 4 5 6 7 8 9

Seasons of continuous colonization

Figure 22. Frequency distribution of number of continuous seasons that a plot below old MHW
was colonized with vegetation (Gibson and Ely, 1994).









that for a state of a particular species at a certain density, there is a probability that the species will
either increase or decrease in density by particular amounts. By choices such as this, the vegetative
state at one time is advanced to a later time and evolution of the various species comprising the mix
of flora species can be simulated. In the application here, the probabilities were based on values
established through surveys of vegetation above OMHW. Application of the model predicted that
of the seven types of vegetation identified in the natural system, the dune and back slope types would
be established rapidly and would dominate, comprising 85% of the types present when the system
reached steady state. The time to reach equilibrium was predicted to be approximately 10 years for
these two types. The model also predicted that the proportion of "empty" plots would decrease
rapidly in the first few years to less than 10% to 15% within the first 2 to 3 years. The percentage of
empty plots based on field data was considerably higher than predicted. The results of this modeling
are illustrated in Figure 23.

Although not a focus of the vegetation studies, casual observation and photographs
documented the effectiveness of the sand fencing in accumulating sand and stabilizing vegetation.

In summary, the principal conclusions from the vegetation studies were: (1) The vegetation
developing on the nourished beach is representative of barrier island coastal systems, although the
rate of establishment is reasonably slow, (2) The development of a soil seed bank on the nourished
beach is relatively slow, (3) Any detrimental effects of the nourishment on vegetation above OMHW
are minimal, (4) The rates of succession are relatively low, and (5) Vegetation developed rapidly and
was maintained around the deposits resulting from eolian transport around the sand fences.


Perdido Key Beach Mouse

The Perdido Key Beach Mouse is an endangered species, thus the possible effects of the
nourishment project on this species were of special concern. Previous documentation has been
provided in Holler (1990) and Holler and Moyers (1994). Due to the extensive beach erosion and
overwash associated with Hurricane Frederic in 1979, the mouse population in the GINS was
completely annihilated and was reestablished through transplanting animals from Florida Point in Gulf
State Park, AL located some 22 km to the west of Pensacola Pass and mice trapped in Fort Pickens
Park on Santa Rosa Island. The basis of the study was quarterly trapping data commencing at the
eastern end of Perdido Key and extending 7 km to the west. Trapping was also carried out at Florida
Point to provide control. In GINS, 512 trapping stations were occupied whereas the trapping at
Florida Point extended only over 1.5 km which is the length of the mouse colony there. A computer
algorithm was used to estimate total mice population from the number of individuals caught in a
particular trapping. In addition to the trapping data, field collections and analysis included: vegetation
data in the vicinity of trap locations, habitat data analysis, fecal pellet analysis, and stomach contents
for mice collected at Fort Pickins on Santa Rosa Island. A population dynamics simulation model was
applied (Sankaran, 1993) based on information obtained in the trapping data to allow evaluation of
the effects of various factors on the population growth or decline. Variables examined included: initial
population size, the opportunity for an individual to mate, gene frequencies, survival rate, litter size,
gestation period, age to maturity and dispersal ability. Realistic ranges of each of the independent
variables were included in the simulations.











60 ,

Dune Strand ---
\ Wet Swales
50- Marsh v


40 -- --------------------------
40 .......... .... ......... .............................................. .
S Back slopes ......



0o
oo
cn 30 -
O


20 S Wooded dunes -*-

Empty -. .- -


Dry Swales -.-
10


--- ----------------------------
0 I I I I I
0 20 40 60 80 100

Time (years)

Figure 23. One-hundred year simulation of vegetation types above old MHW starting from
Autunm 1989 field values (Gibson and Ely, 1994).









It was found that the estimated mouse population, based on the trapping data, decreased
during the study. Overall, the numbers of mice in the eastern end of the trapping area increased
slightly whereas the populations in the central and western sections decreased. Figure 24 presents the
numbers of mice captured in the three sub sections of the GINS. As shown in Figure 25, the Florida
Point population was found to fluctuate, but did not demonstrate the overall decrease observed in the
GINS population.

The dynamics of a mouse population is complex and dependent on many parameters. A useful
feature of a population dynamics model is that it allows each of the independent variables to be
changed so that the sensitivity of the population (the dependent variable) at some time in the future
can be examined. Two general models were examined (Sankaran, 1993). In the first (termed the
panmictic model), all members of the mature population have an equal probability of mating with an
unpaired mature member of the population of opposite sex. In the second model, the population was
considered to be dispersed geographically and the probability of mating decreased for members of
the population depending on their separation distance.

A significant result from the panmictic population model was that there was a strong
correlation between the initial population size and the probability of population extinction. That is,
due to the various factors that may reduce populations over time, small initial populations face a
greater probability of extinction than larger initial populations. For the independent variables chosen
to best represent the dynamics of the mice colony, an initial population of 150 had an extinction
probability of approximately 0.3. For the Perdido Key mouse population of 15 in Autumn 1993, an
extinction probability of nearly unity was found. The greatest factor that was found to influence the
probability of extinction was litter size. For example, for an initial population that had a probability
of extinction of 0.8, increasing the litter size from 4 to 5 decreased the probability of extinction to 0.2.
For fixed litter sizes of 6 and 7, all populations grew over time, ie the probability of extinction
approached zero.

The second model considers a lesser overall probability of mating due to geographic dispersal
of members of the population and is considered to be more representative of the Perdido Key mouse
population. The results of this model can be interpreted as representing a smaller "effective" initial
population since for the same total population, there is a reduced probability of mating with a mature
member of the opposite sex. In general, the results of this model paralleled those of the panmictic
model with the exception that the probabilities of extinction were found to be higher due to the
smaller "effective" population, ie. For this case, a fixed litter size of 7 had an extinction probability
of 0.97 and a mean extinction time of 31 months.


SYNTHESIS OF STUDY COMPONENTS

Synthesis in the present context refers to the integration of existing knowledge and the findings
of the present study elements to address the concerns which formed the justification for the present
study. As noted previously, these concerns included: (1) the beneficial and adverse short and long
term effects of the Perdido Key nourishment projects, (2) the time scales of such effects, and (3) the
development of recommendations in case of future nourishments. Some synthesis has occurred in the









n1PERDDO KE BEACH M)IOUS IQiZ DfPLI iATIONi

GULF ISLANDS NATIONAL SEASHORE
50

LU ..
4 ........ .. ,, -..


Q 4 0 .............. ..............* ........................ .. ...... .................. .-.-, ,... ................ ...i.
4 4 *
4* *4 *.
3. .. \
3 0 ........... .......... .......... ....... .

S- ...... : ...... ........ ...... ........



SWIN1 SUM91 WIN2 AUT92 SP93 UT93


AUT88 AUT89


SP90 AUT90 SP91 AUT91 SP92 WIN93 SUM93


DISTRIBUTION ON TRAPPING TRANSECT


EAST


CENTRAL


WEST


Figure 24. Variation with time in mice captured in three segments of the GINS trapping area (Holler and Moyers, 1994).











PERDIDO KEY BEACH MOUSE POPULATION


Florida Point, Perdido Key


220
200
180
160
140
120
100
80


SP86 SP87 SP88 SP89 SP90 SP91 SP92 SP93
AUT86 AUT87 AUT88 AUT89 AUT90 AUT91 AUT92 AUT93
Indiv.Captured CAPTURE Estimate PERCENT SUBADULTS
V///;Z Z ******


40

Ct)

30 D



20



10



0


Figure 25. Results from trapping data at Florida Point (Holler and Moyers, 1994).


I









reviews of the various study components presented here. Additionally, earlier synthesis reports
include Work et al. (1991c) and Montague and Fonyo (1992). This section will focus on crystallizing
the main synthesis elements as they relate to nourishment on Perdido Key.

This synthesis attempts to relate the findings established from the various study elements to
these concerns summarized above in a constructive manner to ensure that future nourishments will
minimize future impacts. In this context, the major findings are: (1) With the possible exception of
the Perdido Key Beach Mouse, the overall system appears to be evolving toward pre-nourishment
conditions, (2) The major adverse impacts of the nourishment project were because of the fine
components of the material placed and the large size of the project, and (3) The rates of evolution
toward natural conditions were slower than anticipated.

It is significant to note that with the exception of the placement of approximately 7.5 km of
sand fence placed approximately 30 m Gulfward of the toe of the primary dune, there were no broad
scale measures to stabilize the beach fill nor to expedite the establishment of the vegetation.
Vegetation can be established on the wide berm by the following two modes: dispersal of seeds and
propagation by roots. The dispersal by seeds can occur by eolian transport, by birds or by other
pathways. In the case of sea oats, the seeds become mature in the Autumn after which they are more
readily separated from the stalk. Northeasters typically occur from September through April and are
generally accompanied by a one or more day period of winds out of the north which can transport
seeds southward over the broad Perdido Key berm. Conditions most conducive for these seeds to
germinate and take root include the presence of depressions which tend to trap the seeds, allow them
to become covered with sand and to collect water during periods of precipitation. This mode of sea
oats propagation was demonstrated by an experiment of opportunity in which ruts left by the tires of
a vehicle had been effective in causing sea oats to grow. These plants were present from at least the
second year of monitoring and persisted through the final year of monitoring. Additionally, the sand
accumulated by sand fences was effective in promoting the initiation of and sustaining vegetation.
Finally, during the first post-nourishment field surveys of beach profiles (Autumn, 1990), sea oat
seeds were stripped from plants and were buried approximately half-way across the unvegetated berm
in a small trench approximately one-half meter in length and 12 cm deep. This took place at the
following ranges: R-42 R-44, R-45 and R-48. One year later plants were present at all locations
where seeds were buried and persisted through the final survey. This experiment and the observations
at the sand fences and in the tire ruts indicate that vegetation would respond to efforts to expedite
its establishment. The second mode of Plant propagation is through root structures. In the case of sea
oats, the rhizomes are quite effective in extending the range locally. This mode acts on the
"perimeters" of the unvegetated area whereas the dispersal acts on an "area" basis. The rate at which
rhizomes are able to propagate sea oats is relatively small, on the order of one meter per year (Barnett
and Crewz, 1990). Salmon et al. (1982) provide guidelines for the establishment of dune vegetation.
Recommendations include the desirability of using seedlings rather than seeds due to the much greater
survival rate. Also, the effectiveness of sand fencing in promoting growth and survival is noted.

Similar to establishment of vegetation on the berm area, repopulation of the benthos can also
occur by areal or perimeter processes. The areal process is through larval stages that can rapidly
provide new stock to an area void of one or more species. The rate of perimeter repopulation varies
substantially depending on the location in which the species resides. On the beach face, longshore









currents can easily move 10 km per day. In deeper waters, the movement of benthic animals is slower,
but faster than revegetation through the perimeters of the affected area. The finer fractions of the
placed material suppressed the recovery of the benthos due to different species populating these areas
and the reduced richness and density.

In summary of the synthesis of study elements, smaller projects of uniformly good quality sand
would result in quite rapid recovery. Additionally, relatively simple and inexpensive methods exist to
expedite vegetative colonization. The results of this synthesis are implemented in recommendations
for future nourishment in the following section.


FUTURE NOURISHMENTS

One of the objectives of the present study was to develop guidelines for future nourishments
and to provide a methodology for predicting the physical evolution of beach nourishment projects.
In discussing future nourishment projects, it is useful to attempt to put them in perspective with the
beach and underwater nourishment projects monitored here which amounted to a total placement of
approximately 7.1 million m3, with 4.1 million m3 being placed as nourishment to the beach. Although
this amount of nourishment doubled the width of the island in some locations, this nourishment, in
effect, restored only a portion of the volume that had been removed from the nearshore natural
system by dredging of sand from the Pensacola Pass entrance channel and disposal at sea. Secondly,
the most probable amount of material to become available in any single future nourishments is more
on the order of 0.25 to 0.75 million m3, from 6% to 18% of the amount placed in the monitored
beach nourishment project. Finally, material available for beach nourishment will most likely be from
maintenance dredging and will be sand that has been transported from the adjacent beaches and thus
is expected to be of uniformly good quality. The monitored beach nourishment project amounted to
an average placement density of 560 m3 per m of shoreline over the approximately 7.3 km of
nourished beach.

If nourishment occurs over a short beach length, the longshore disturbance is minimized and
it is likely that as the sand spreads out slowly, most of the biota in adjacent areas will be able to cope
with the changes and the remainder will be able to depart the area. On the other hand, there are
limitations to the placement density of sand and there may be aesthetic reasons to avoid creating a
large gulfward anomaly of shoreline position. Considering 0.5 million m3 of dredged sand available,
for the same placement density as the monitored project, the shoreline segment to be nourished would
be approximately 1 km. However, this would result in an average shoreline advancement of
approximately 140 m, a substantial projection. It is thus recommended that the shoreline length to be
nourished in any future project be based on a placement density ranging from 200 to 250 m3 per m
and that the fill be tapered at the ends over lengths of 200 m or so. The associated initial shoreline
advancement ranges from approximately 50 to 60 m. Moreover, as the profile adjusts, the beach will
narrow by the gradual spreading of the placed material to the adjacent beaches. An example
placement for 500,000 m3 is presented in Figure 26. The calculated planform evolution of the project
is shown in Figure 27. The placement area relative to Pensacola Pass is also of importance. If too
close, there is a greater tendency for the material to be transported into and be deposited in the Pass
thereby increasing the frequency of required dredging and decreasing the longevity of the placed













/

/


0 1 2 3 4 5km


Approximate
Westerly Park
Boundary


NOTE:
R-40 Is Florida Department of Natural
Resources Monumented "Range 40"


Figure 26. Recommended location for future beach nourishment.









70 11 1

- -6 0 ......... -

50 -
Initial

..1 Year
30 *302 2Yearts

20 5 Years
..0 ----- --- ------- --- I--
\ " - I - -- -I I --- -- I - -.







S-....... ... .- a .... .. .. ...... ...... :. ........ ....... .......
1 -0 1 Ys.... :... .. ... ... --- -
- .. ,

-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1
Longshore Distance From Project Centerline (km)


2 3


Figure 27. Predicted planform evolution for project of 500,000 cubic meters.









material. However, the dredging costs are less for placement as close to the Pass as possible. Thus,
based in part on the calculated evolution in Figure 17, it is recommended that the material be placed
with its easterly extremity no closer than 2 km to Pensacola Pass, i.e. commencing at R-60 and
extending to R-54 with tapered ends east and west of these monuments. The placed underwater
profile will be dictated by the stability of the material during placement. For the initial above water
profile including the berm elevation and slope, the berm characteristics associated with the design of
the 1989-1990 project were found to be effective in allowing natural overwash to occur and to
maintain a natural appearance. The design characteristics are shown in Figure 28 for the
recommended future nourishment.


SUMMARY AND CONCLUSIONS

This suite of studies has documented the effects of major beach and profile nourishment
projects. The beach was nourished with 4.1 million m3 of sand in the period 1989-1990 and the
profile was nourished with 3 million m3 of sand from 1990-1991. The only extensive effort to stabilize
the sand or to promote vegetative redevelopment on the wide unvegetated berm was through
placement of approximately 7.5 km of sand fence extending from approximately R-40 to R-64.

Although the nourishment material was dominantly compatible with the native material, a
small percentage of the beach nourishment included silt and clay sized fractions. This material was
concentrated around the 5 m contour and extending from R-42 to R-58 but also was present to a
lesser degree at the 8 m contour in the vicinity of R-46. This fine material diminished with time due
to suspension and transport to areas of less energy where it was more stable.

The documented physical evolution of the beach is consistent with general knowledge of
sediment transport processes in the vicinity of a nourishment project. The nourishment sand spreads
out in a longshore direction, thereby reducing the planform anomaly and sand is also transported
seaward to approach the pre-nourished profile. The sand placed underwater to form the profile
nourishment was found to spread out on its northerly and southerly edges; however, within the limits
of measurement capabilities, the centroids of the north-south cross-sections have not moved
shoreward or Gulfward.

The main findings from the benthic study were that the presence of very fine material delayed
recovery from impacts due to the nourishment project; however, there was a consistent trend toward
pre-nourishment conditions. Opportunistic species rapidly populated the area affected by the fine
material.

The major findings from the vegetation study are: (1) the vegetation developing on the wide
berm is consistent with expectations for a barrier island coastal system, (2) The development of a seed
bank in the berm is proceeding at a slow rate, (3) The rate of plant succession on the berm is lower
than expected although this may have been affected by Hurricane Andrew (August, 1992) which
significantly overwashed and ponded salt water on the berm, (4) The sand fence and other
"experiments of opportunity" demonstrated the efficacy of artificial methods of expediting vegetation
development on the wide berm.


1














........................ ....... ..... ....... ..................................
I I I I I I - - - .


S. .--- .--- ------. ..... ........... .. i1.............. 1 2 i 1 1 2 i.. Iiii12il i ...i








Profile R-58, Nov 1993-;....
... .. .. ...- ... .. .. .. :.. .. :,. .. . .. .. -.. .. . .. .. .. .. . . .... ..







Distance From Monument (m)


Figure 28. Recommended characteristics of nourished profiles. Shown for R-58.


0

SS
13










The population of the Perdido Key Beach Mouse declined within the area monitored on
Perdido Key. However, because the population was fairly small at the time of nourishment, and
because the population had previously undergone extreme fluctuations, including complete
annihilation by Hurricane Frederic in 1979, and perhaps other factors, it is not possible to state that
the population decline is related to the nourishment projects.

Based on the results of the study components, recommendations are developed for future
nourishments. These include nourishment with compatible sand volumes of not greater than 500,000
m3 where practical, at a placement density of 200 to 250 m3/m with the eastern end not closer than
2 km to Pensacola Pass.


ACKNOWLEDGMENTS

Many individuals have contributed to this project. First, we wish to acknowledge the funding
support provided by the U. S. Navy and the guidance and interest of the Navy Project Monitor,
Mr. Laurens Pitts. The National Park Service has provided a great deal of cooperation and logistical
field support throughout the project. The Technical Review Group contributed constructive
suggestions and advice primarily through the annual meetings. Finally, we are very grateful to the
many University of Florida students and staff who participated in the field trips and other project
activities.


REFERENCES

Barnett, M.R. and Crewz, D.W. (1990) "An Introduction to Planting and Maintaining Selected
Common Coastal Plants in Florida", Florida Sea Grant Report No. 97, 108 pp.
Barton, D.C., Ritz, C.H., and Hicky, M. (1933). "Gulf Coast Geosyncline", Amer. Assoc. of
Petroleum Geol. Bull., v. 17, no. 12, pp. 1446-1450.
Coe, C.J. (1979). "Geology of the Plio-pleistocene Sediments in Escambia and Santa Rosa Counties,
Florida", M.S. thesis, Florida State University, Tallahassee, Florida, 113 pp.
Cooke, C.W. (1939). "Scenery of Florida Interpreted by a Geologist", Florida Geological Survey
Bulletin, no. 17, 118 pp.
Cooke, C.W. (1945). "Geology of Florida", Florida Geological Survey Bulletin, no. 29, 339 pp.
Dean, R.G. (1988a). "Review of Dredging Effects on Adjacent Park Systems", Coastal and
Oceanographic Engineering Department, University of Florida, Gainesville, Florida.
Dean, R.G. (1988b). "Recommendations for Placement of Dredged Sand on Perdido Key, Gulf
Islands National Seashore", Coastal and Oceanographic Engineering Department, University
of Florida, Gainesville, Florida.
Dean, R.G. and Abramian, J. (1993). "Rational Techniques for Evaluating Potential of Sands for
Beach Nourishment", Report DRP-93-2, Coastal Engineering Research Center, U.S. Army
Waterways Experiment Station, Vicksburg, MS.










Gibson D.J., Looney, P.B and Mixon, ,S.R. (1992). "Vegetation Monitoring After Beach
Renourishment on Perdido Key: 1992", Annual Report submitted to the National Park
Service. Institute of Coastal and Estuarine Research, I.C.E.R. Rept. 02:30-09-92, University
of West Florida, Pensacola, Florida, 47 pp.
Gibson, D.J. and Looney, P.B. (1992a). "Seasonal Variation in Vegetation Classification on Perdido
Key, a Barrier Island off the Coast of the Florida Panhandle", Journal of Coastal Research,
Vol 8, pp. 943-956. .
Gibson, D.J. and Looney, P.B. (1992b). "Vegetation Colonization of Dredge Spoil on Perdido
Key, Florida", Journal of Coastal Research, Vol 10, pp.133-134.
Gibson, D.J. and Looney, P.B. (1993). "Vegetation Monitoring After Beach Renourishment on
Perdido Key: 1993", Annual Report submitted to the National Park Service. Institute of
Coastal and Estuarine Research, I.C.E.R. Rept. 03:30-09-93, University of West Florida,
Pensacola, Florida, 58 pp.
Gibson, D.J. and Ely, J.S. (1994). "Vegetation Monitoring After Beach Renourishment on Perdido
Key: 1992", Final Report submitted to the National Park Service. Institute of Coastal and
Estuarine Research, I.C.E.R. Rept. 02:09-22-94, University of West Florida, Pensacola,
Florida, 76 pp.
Gorsline, D.S. (1966). "Dynamic Characteristics of West Florida Gulf Coast Beaches", Marine
Geology, Vol. 4, pp. 187-206.
Hicks, S.D., Debaugh, H.A. and Hickman, L.E. (1983). "Sea Level Variations for the United States,
1855-1980", National Ocean Service, Rockville, MD.
Holler, N.R. (1990). "Beach Mouse Research Program Gulf Islands National Seashore Beach
Renourishment Project", Report to Technical Review Committee, September.
Holler, N.R. and Moyers, J.E. (1994) "Beach Mouse Research Program Gulf Islands National
Seashore Beach Renourishment Project", Annual Report to Technical Review Committee,
March.
Howe, H.V. (1936). "Stratigraphic Evidence of Gulf Coast Geosyncline", Geol. Soc. of Amer.
Proceedings, 1935, pp. 82, (abs.).
Hoyt, J.H. (1967). "Barrier Island Formation", Geol. Soc. Am. Bull., 78: pp. 1125-1135.
Johnson, J.W. (1956). "Dynamics of Nearshore Movement", American Association of Petroleum
Geologists Bulletin, Vol. 40, pp. 2211-2232.
Marsl, O.T. (1966). "Geology of Escambia and Santa Rosa Counties, Western Florida Panhandle",
Florida Geological Survey Bulletin, no. 46, 140 pp.
MacNeil, F.S. (1950). "Pleistocene Shoreline in Florida and Georgia", U.S. Geological Survey, Prof.
Paper 221-F.
Montague, C.L. and Fonyo, C.M. (1992) "A Preliminary Ecosystem Synthesis for Beach
Management at Perdido Key, Florida", Department of Environmental Engineering Sciences,
University of Florida, Submitted to Naval Facilities Command, Charleston, SC. 65 pp.
National Ocean Service (1995). "Tide Tables, East Coast of North and South America", U.S.
Department of Commerce, Washington, D.C.
Otay, E.N. (1994). "Long-term Evolution of Nearshore Disposal Berms", Dissertation submitted to
the Department of Coastal and Oceanographic Engineering, University of Florida, Gainesville,
FL.









Otay, E.N. and Dean, R.G. (1993). "Perdido Key Beach Nourishment Project: Gulf Islands National
Seashore, 1992 Annual Report", Coastal and Oceanographic Engineering Department,
University of Florida, Gainesville, Florida.
Otay, E.N. and Dean, R.G. (1994). "Perdido Key Beach Nourishment Project: Gulf Islands National
Seashore, 1993 Annual Report", Coastal and Oceanographic Engineering Department,
University of Florida, Gainesville, Florida.
Otvos, E.G., Jr. (1976). "Holocene Barrier Island Development over Pre-existing Pleistocene High
Ground: Dauphin Island, Alabama", Geol. Soc. Amer., Southeastern section, 25th mtg.
Otvos;, E.G., Jr. (1979). "Barrier Island Evolution and History of Migration, North-Central Gulf
Coast", In: S.P. Leatherman (Editor), Barrier Islands. Academic Press, New York, N.Y., pp.
291-319.
Otvos, E.G., Jr. (1981). "Barrier Island Formation Through Nearshore Aggradation Stratigraphic
Field Evidence", Marine Geology, 43: 195-243.
Otvos, E.G., Jr. (1982). "Santa Rosa Island, Florida Panhandle, Origins of a Composite Barrier
Island", Southeastern Geology, Vol. 23, No. 1, pp. 15-23, Duke University Press, Durham,
N.C.
Rakocinski, C., LeCroy, S.E., McLelland, J.A. and Heard, R.W. (1990). "Response by
Macroinvertebrate Communities to Beach Renourishment at Perdido Key Florida", Annual
Report submitted to the National Park Service by the Gulf Coast Research Laboratory,
G.C.R.L. Rep.01:10-29-90, Ocean Springs, Mississippi 68 pp.
Rakocinski, C., LeCroy, S.E., McLelland, J.A. and Heard, R.W. (1991a). "Responses by
Macroinvertebrate Communities to Beach Renourishment at Perdido Key Florida II". Gulf
Coast Research Laboratory, Final Report to the National Park Service.
Rakocinski, C., LeCroy, S.E., McLelland, J.A., and Heard, R.W. (1991b). "Responses by
Macroinvertebrate Communities to Beach Renourishment at Perdido Key Florida: Initial
Faunal Impact", Gulf Coast Research Laboratory Semi-Annual Report to the National Park
Service.
Rakocinski, C., LeCroy, S.E., McLelland, J.A. and Heard, R.W. (1992a). "Responses by
Macroinvertebrate Communities to Beach Renourishment at Perdido Key Florida: Monitoring
Phase", Gulf Coast Research Laboratory Semi-Annual Report to the National Park Service.
Rakocinski, C., LeCroy, S.E., McLelland, J.A. and Heard, R.W. (1992b). "Responses by
Macroinvertebrate Communities to Beach Renourishment at Perdido Key Florida: Continued
Faunal Impact", Gulf Coast Research Laboratory Annual Report to the National Park Service.
Rakocinski, C., Heard, R.W., LeCroy, S.E., McLelland, J.A. and Simons, T. (1993a). "Seaward
Change and Zonation of the Sandy-Shore Macrofauna at Perdido Key, Florida, U. S. A",
Estuarine, Coastal and Shelf Science, Vol 36, pp. 81-104.
Rakocinski, C., LeCroy, S.E., McLelland, J.A. and Heard, R.W. (1993b). "Responses by
Macroinvertebrate Communities to Beach Renourishment at Perdido Key Florida: Monitoring
Phase II", Gulf Coast Research Laboratory Annual Report to the National Park Service.
Rakocinski, C., LeCroy, S.E., McLelland, J.A. and Heard, R.W. (1994). "Responses by
Macroinvertebrate Communities to Beach Renourishment at Perdido Key Florida: Benthic
Recovery", Gulf Coast Research Laboratory Final Report to the National Park Service. 132
pp.
Salmon, J., Henningsen, D. and McAlpin, T. (1982) Dune Restoration and Revegetation Manual",
Florida Sea Grant Report No. 48, 60 pp.









Sankaran, M. (1993). "Population Dynamics of the Beach Mouse (Peromyscus Polionotus
Trissyllepsis): a Simulation Study", M.S. Thesis, Auburn University, AL.
Stapor, F.W. (1973). "Coastal Sand Budgets and Holocene Beach Ridge Plain Development,
Northwest Florida", Ph.D. thesis, Florida State University, Talahassee, Florida, 219 pp.
Stone, G.W., Stapor, F.W., Jr., May, J.P. and Morgan, M.P. (1992). "Multiple Sediment Sources and
a Cellular, Non-integrated, Longshore Drift System: Northwest Florida and Southeast
Alabama Coast, U.S.A", Marine Geology, Vol. 105, pp. 141-154.
U.S. Army Corps of Engineers (1972). "Evaluation of Weir Jetty Systems at Perdido Pass, Alabama,
and East Pass, Florida", Mobile District, Mobile, Alabama.
Walton, T.L. (1973). "Littoral Drift Computations along the Gulf Coast of Florida by Means of Ship
Wave Observations", Department of Coastal and Oceanographic Engineering Report No. TR-
15, University of Florida, Gainesville, Florida.
Work, P.A., Lin, L.-H. and Dean, R.G. (1990). "Perdido Key Beach Nourishment Project: Gulf
Islands National Seashore. Pre-Nourishment Survey Conducted October 28-November 3,
1989", Coastal and Oceanographic Engineering Department, University of Florida,
Gainesville, Florida.
Work, P.A., Lin, L.-H., and Dean, R.G. (1991a). "Perdido Key Beach Nourishment Project: Gulf
Islands National Seashore. 1990 Annual Report", Coastal and Oceanographic Engineering
Department, University of Florida, Gainesville, Florida.
Work, P.A., Lin, L.-H., and Dean, R.G. (1991b). "Perdido Key Beach Nourishment Project: Gulf
Islands National Seashore. First Post-Nourishment Survey Conducted September 22-26,
1990", Coastal and Oceanographic Engineering Department, University of Florida,
Gainesville, Florida.
Work, P.A., Charles, L., and Dean, R.G. (1991c). "Perdido Key, Historical Summary and
Interpretation of Monitoring Programs", Coastal and Oceanographic Engineering
Department, University of Florida, Gainesville, Florida.
Work, P.A. and Dean, R.G. (1992). "Perdido Key Beach Nourishment Project: Gulf Islands National
Seashore, 1991 Annual Report", Coastal and Oceanographic Engineering Department,
University of Florida, Gainesville, Florida.
Work, P.A. and Dean, R.G. (1995). "Assessment and Prediction of Beach-Nourishment Evolution,"
American Society of Civil Engineers, Journal of Waterway, Port, Coastal and Ocean
Engineering, Vol. 121, No. 3, pp.182- 189.




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