• TABLE OF CONTENTS
HIDE
 Front Cover
 Title Page
 Table of Contents
 List of Figures
 List of Tables
 Main
 Description of methodology used...
 Plots of shoreline and volume...














Group Title: UFLCOEL-98020
Title: Hurricane Opal
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00091072/00001
 Material Information
Title: Hurricane Opal results from repeated surveys in selected developed and undeveloped areas
Series Title: UFLCOEL-98020
Physical Description: 1 v. (various foliations) : ill. ; 28 cm.
Language: English
Creator: Dean, Robert G ( Robert George ), 1930-
Suter, Carrie L
University of Florida -- Coastal and Oceanographic Engineering Dept
Florida -- Office of Beaches and Coastal Systems
Publisher: Coastal & Oceanographic Engineering Program, Dept. of Civil & Coastal Engineering, University of Florida
Place of Publication: Gainesville Fla
Publication Date: 1998
 Subjects
Subject: Hurricane Opal, 1995   ( lcsh )
Coast changes -- Florida -- Florida Panhandle   ( lcsh )
Hurricanes -- Environmental aspects -- Florida -- Florida Panhandle   ( lcsh )
Storm surges -- Environmental aspects -- Florida -- Florida Panhandle   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references.
Statement of Responsibility: prepared by Robert G. Dean and Carrie L. Suter.
General Note: "December 28, 1998."
General Note: "Project sponsor: Bureau of Beaches and Coastal Systems, Department of Environmental Protection."
 Record Information
Bibliographic ID: UF00091072
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 43794608

Table of Contents
    Front Cover
        Front Cover
    Title Page
        Page i
    Table of Contents
        Page ii
    List of Figures
        Page iii
        Page iv
        Page v
    List of Tables
        Page vi
    Main
        Page 1
        Page 2
        Page 3
        Page 4
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        Page 6
        Page 7
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        Page 14
        Page 15
        Page 16
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        Page 19
        Page 20
    Description of methodology used for computations of averages
        Page A-0
        Page A-1
        Page A-2
        Page A-3
        Page A-4
    Plots of shoreline and volume changes
        Page B-0
        Page B-1
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Full Text



UFL/COEL-98/020


HURRICANE OPAL
RESULTS FROM REPEATED SURVEYS IN SELECTED
DEVELOPED AND UNDEVELOPED AREAS




by


Robert G. Dean
and
Carrie L. Suter


December 28, 1998




Project Sponsor:

Bureau of Beaches and Coastal Systems
Department of Environmental Protection
Tallahassee, Florida 32399-3000












HURRICANE OPAL


RESULTS FROM REPEATED SURVEYS IN SELECTED


DEVELOPED AND UNDEVELOPED AREAS



December 28, 1998





Prepared by:

Robert G. Dean
and
Carrie L. Suter



Project Sponsor:

Bureau of Beaches and Coastal Systems
Department of Environmental Protection
Tallahassee, Florida 32399-3000







Submitted by:

Department of Coastal and Oceanographic Engineering
University of Florida
Gainesville, Florida 32611








TABLE OF CONTENTS


LIST OF FIGURES ....................................................... ... iii

LIST OF TABLES ............................................................ vi

1. INTRODUCTION ............................ . ...................... 1

1.1 Purpose .. .............................. ............... ........... 1
1.2 Background ................................ . ................. 2

2. MONITORING EFFORTS BY THE UNIVERSITY OF FLORIDA ................ 3

3. RESU LTS ...................... ................................. 3

3.1 Beach Profiles .................................................... .3
3.2 Beach Volumes and Widths .......................................... 5
3.3 Dune Recovery ....................... .......................... 11

4. D ISCU SSION ......................................................... 11

5. EFFECT OF FEBRUARY 1998 SURVEY .................................. 19

6. CONCLUSIONS ....................................................... 20

7. REFERENCES ........................................................ 20

APPENDICES

A DESCRIPTION OF METHODOLOGY USED FOR COMPUTATIONS OF
AVERAGES ..................................................... A-1

B PLOTS OF SHORELINE AND VOLUME CHANGES ....................... B-1













ii








LIST OF FIGURES


FIGURE PAGE

1. Location Map of Four Study Sites .......................................... 1

2. Beach Profile in Natural Area of Santa Rosa County, Monument Number R-188 ...... 4

3. Cumulative Change in Average Volume for All Escambia County Profiles ........... 7

4. Beach Profile R-194.5 in Developed Area of Santa Rosa County Showing
Artificially Placed Berm ...................................................9

5. Cumulative Change in Average Volume for All Counties ...................... 13

6, Cumulative Change in Average Volume for All Developed Profiles ............... 14

7. Cumulative Change in Average Volume for All Natural Profiles .................. 15

8. Cumulative Change in Average Shoreline Position for All Counties. Pre-Opal
and October 1995 Positions Based on Aerial Photography ....................... 16

9. Cumulative Change in Average Shoreline Position Line for All Developed
Profiles. Pre-Opal and Oct 1995 Positions Based on Aerial Photographs ............ 17

10. Cumulative Change in Average Shoreline Position for All Natural Profiles. Pre-
Opal and Oct 1995 Positions Based on Aerial Photographs ...................... 18

B-1. Cumulative Change in Average Volume for All Counties ...................... B-2

B-2. Cumulative Change in Average Volume for All Developed Profiles .............. B-3

B-3. Cumulative Change in Average Volume for All Natural Profiles ................. B-4

B-4. Cumulative Change in Average Shoreline Position for All Counties. Pre-Opal and
October 1995 Positions Based on Aerial Photography ......................... B-5

B-5. Cumulative Change in Average Shoreline Position for All Developed Profiles.
Pre-Opal and Oct 1995 Positions Based on Aerial Photographs .................. B-6

B-6. Cumulative Change in Average Shoreline Position for All Natural Profiles. Pre-
Opal and Oct 1995 Positions Based on Aerial Photographs ..................... B-7







B-7. Cumulative Change in Average Volume for All Escambia County Profiles ......... B-8

B-8. Cumulative Change in Average Volume for Developed Profiles in Escambia
County ..........................................................B-9

B-9. Cumulative Change in Average Volume for Natural Profiles in Escambia County .. B-10

B-10. Cumulative Change in Average Shoreline Position for All Escambia County
Profiles. March '84 and Oct '95 Positions Based on Aerial Photographs .......... B-11

B-1 1. Cumulative Change in Average Shoreline Position for Developed Profiles.
Escambia County. Mar '84 and Oct '95 Positions Based on Aerial Photographs .... B-12

B-12. Cumulative Change in Average Shoreline Position for Natural Profiles. Escambia
County. Mar '84 and Oct '95 Positions Based on Aerial Photographs ............. B-13

B-13. Cumulative Change in Average Volume for All Santa Rosa County Profiles ...... B-14

B-14. Cumulative Change in Average Volume for Developed Profiles in Santa Rosa
County ....................................................... B-15

B-15. Cumulative Change in Average Volume for Natural Profiles in Santa Rosa
County ....................................................... B-16

B-16. Cumulative Change in Average Shoreline Position for All Santa Rosa County
Profiles. March '84 and Oct '95 Positions Based on Aerial Photographs .......... B-17

B-17. Cumulative Change in Average Shoreline Position for Developed Profiles in
Santa Rosa County. Mar'84 and Oct '95 Positions Based on Aerial Photographs ... B-18

B-18. Cumulative Change in Average Shoreline Position for Natural Profiles in Santa
Rosa County. Mar '84 and Oct '95 Positions Based on Aerial Photographs ........ B-19

B-19. Cumulative Change in Average Volume for All Walton County Profiles ......... B-20

B-20. Cumulative Change in Average Volume for Developed Profiles in Walton County B-21

B-21 Cumulative Change in Average Volume for Natural Profiles in Walton County .... B-22

B-22. Cumulative Change in Shoreline Position for All Walton County Profiles. Oct
1995 Positions Based on Aerial Photographs ............................... B-23

B-23. Cumulative Change in Shoreline Position for Developed Profiles in Walton
County. Oct '95 Positions Based on Aerial Photographs ....................... B-24







B-24. Cumulative Change in Shoreline Positions for Natural Profiles in Walton County.
Oct '95 Positions Based on Aerial Photographs ........................... .B-25

B-25. Cumulative Change in Average Volume for All Bay County Profiles ............ B-26

B-26. Cumulative Change in Average Volume for Developed Profiles in Bay County .... B-27

B-27. Cumulative Change in Average Volume for Natural Profiles in Bay County ....... B-28

B-28. Cumulative Change in Average Shoreline Position for All Bay County Profiles.
Oct 1995 Positions Based on Aerial Photography ............................. B-29

B-29. Cumulative Change in Shoreline Position for Developed Shorelines in Bay
County. Oct 1995 Positions Based on Aerial Photography ..................... B-30

B-30. Cumulative Change in Average Shoreline Position for Natural Profiles for Bay
County........................ ...................................... B-31








LIST OF TABLES


TABLE PAGE

1. DNR Monument Numbers for "Developed" and "Natural Areas Monitored by
C O E ............................................ ...................... 3

2. Average Shoreline Changes: Pre-Opal to Immediately Post-Opal and Post-Opal to
First COE Survey in May 1996 ........................................... 10

3. Beach Volume and Width Trends as Determined by the Least Squares Method ...... 12

A-1 Original Shoreline Positions ................ .......................... A-1

A-2 Shoreline Changes from Original Positions ................................. A-2

A-3 Shoreline Changes from Original Positions, with Average Shoreline Change ...... A-2

A-4 Complete Data Set for Shoreline Changes with Average Shoreline Change Filled
in all Empty Data Sets ............................................. A-2

A-5 Complete Data Set for Original Shoreline Positions .......................... A-3

A-6 Shoreline Position Changes ................ ........................... A-4









HURRICANE OPAL
RESULTS FROM REPEATED SURVEYS IN SELECTED
DEVELOPED AND UNDEVELOPED AREAS



1. INTRODUCTION

1.1 Purpose

This report presents the results of an intensive two year monitoring study conducted in the
wake of Hurricanes Erin and Opal by the University of Florida's Department of Coastal and
Oceanographic Engineering (COE). Four specific shorelines sites, each including both developed
and natural areas in the Panhandle of Florida, were surveyed from May 1996 to February 1998. In
total, five surveys from the COE and several surveys and aerial photographs available from the
Florida Bureau of Beaches and Coastal Systems (BBCS) of the Florida Department of Environmental
Protection (DEP) provide the basis for both volumetric and beach width changes in the following
counties from west to east: Escambia, Santa Rosa, Walton and Bay, see Figure 1.


3390000


3370000


3350000


3330000


3310000


3290000


3270000 I I|
450000 470000 490000


510000 530000 550000 570000 590000 610000 630000 650000
EASTING (m, UTM Zone 16, NAD 1983)


Figure 1. Location Map of Four Study Sites.








1.2 Background


On October 4, 1995 at approximately 6:00 p.m. Central Daylight Time, Hurricane Opal made
landfall near Navarre Beach, which is located on Santa Rosa Island in Santa Rosa County. Prior to
Hurricane Opal, Hurricane Erin had impacted the Florida Panhandle on August 3, 1995. In the most
active storm season since 1933, Hurricane Opal was the 15th named storm out of 21 total tropical
storms or hurricanes. At landfall, the winds decreased to 110 mph from the maximum sustained
surface winds of 150 mph, which had placed the hurricane at a Category 4 status on the Saffir-
Simpson scale. As determined by the Beaches and Shores Resource Center of Florida State
University, the hurricane had a central pressure deficit of 2.16 in. mercury, a radius of maximum
winds estimated at approximately 30 miles and a forward speed of 23 knots in a north-northeast
direction (Leadon, 1996).

Storm surge data obtained from a National Oceanic and Atmospheric Agency (NOAA) tide
gauge located on the Panama City Beach pier showed a peak water level of 8.3 feet above National
Geodetic Vertical Datum (NGVD), which was nearly 8 feet above the normal predicted astronomical
tide. High water mark surveys conducted by DEP staff documented a storm surge ranging from 8-11
feet above NGVD between Pensacola Beach and Fort Walton Beach and approximately 12-20 feet
above NGVD between Destin and Seagrove Beach (FEMA, 1996). In Panama City Beach, evidence
of wave impacts and sand deposition were found in first-floors of structures up to 17-18 feet above
NGVD during post-storm inspections conducted by the DEP (Leadon, 1996).

Hurricane Opal caused extensive damage to the beach and dune system. Eight million cubic
yards of sand were lost from above sea level due to breaking waves, extensive flooding, a substantial
storm surge and extensive overwash in lower dune areas. East of Fort Walton Beach, portions of
Highway 98 were washed away, and many of the survey control monuments maintained by the
BBCS were destroyed (Leadon, 1996). The approximately $2 billion damage to structures during
Hurricane Opal rank it as one of the most costly natural disasters to affect the United States (FEMA,
1996). It caused more structural damage along the Florida coast than all of the hurricanes and
tropical storms combined in the last 20 years (Leadon, 1996).

Immediate post storm response consisted mainly of debris removal and beach scraping, the
bulldozing of sand from the lower portions of the subaerial profile and moving this sand landward
to the base of an eroded dune. Because the navigational entrance to St. Andrews Bay at the eastern
limit of Panama City Beach places erosional pressure on the shoreline of Panama City Beach, re-
nourishment of this beach is in progress and improved management of the sand resources in the
vicinity of the entrance is being investigated.








2. MONITORING EFFORTS BY THE UNIVERSITY OF FLORIDA


The five monitoring surveys conducted by the COE took place in: May 1996, October 1996,
March 1997, July 1997 and February 1998. The four areas surveyed in Escambia, Santa Rosa,
Walton and Bay Counties each contained approximately 20 survey monuments and each county area
contained approximately equal lengths of "developed" and "natural" shorelines. The monuments
were located approximately 500 feet apart, and the surveys were carried out with standard land-based
rod and level survey techniques with the surveying planned to extend from the monuments out to
wading depth limits. An area was deemed "natural" if there were no structures located in the
immediate vicinity of the monument and "developed" if there were. Walton County was the one
exception to this definition, as the entire study area was situated in a local city. Therefore, Henderson
State Park and four other monuments in Walton County were included in the "natural" category,
even though they would not normally be considered "natural", due to a parking lot adjacent to the
beach. This segment was considered natural due to the protection and vegetation of the dunes from
the parking lot down to the beach berm.

Table 1 presents the locations of the "developed" and "natural" areas, identified by their
corresponding BBCS monument numbers.


Table 1

DNR Monument Numbers for "Developed" and "Natural" Areas
Monitored by COE

County "Developed" "Natural"
Escambia R133 to R138.5 R139 to R144
Santa Rosa R192.5 to R197 R187 to R192

Walton R1 to R2, R4.5 to R6A.5 R2.5 to R4, R7 to R8.5

Bay R85 to R91. R93 R91.5 to R97 (except R93)


3. RESULTS

3.1 Beach Profiles

The survey data were plotted for each monument and computer programs were developed
and applied to extract shoreline and volumetric changes from the data. A typical profile for the
natural areas of Santa Rosa County is plotted in Figure 2 for Monument Number R-188. By plotting
several surveys on the same graph, erosional or accretional trends are evident. To better illustrate














20 ............... March 1997
------- July 1997
..... .. February 1998

15

0

" _ .__ _












0 100 200 300 400 500
Distance Seaward of Monument (ft)



Figure 2. Beach Profile in Natural Area of Santa Rosa County, Monument Number R-188.
0 100 200 300 400 500
Distance Seaward of Monument (ft)

Figure 2. Beach Profile in Natural Area of Santa Rosa County, Monument Number R-188.








these trends, the profile at Santa Rosa County Monument R-188 will be discussed in detail.

The monument location is plotted as zero on the horizontal axis, and all subsequent
horizontal positions are relative to the monument position. At this particular location in Santa Rosa
County, the dune system is extensive, as indicated by the 17 foot height of the primary dunes. The
dune heights in this area decrease with increasing proximity to the developed areas, which are
located 5,000 feet farther east. The solid line plotted on the graph represents the only DEP survey
(February 1996) used in the Santa Rosa County analysis. The survey was conducted 4 months after
Hurricane Opal and illustrates several storm effects. The very steep dune scarp with the distinct cut
at the base is a result of hurricane waves impacting this dune. Each subsequent survey shows an
increasingly milder slope of the dune scarp, probably due to sloughing of the sediments to approach
a more natural angle of repose, i.e. the steepest angle that a loose sediment of a given size can remain
stable.

The seasonal fluctuations are most evident in the vicinity of the beach face, which is located
approximately 180-260 feet from Monument R-188 at the gulfward limit of the berm. For those
surveys that would typically be considered "summer" profiles, the October 1996 and July 1997
surveys, the beachface locations are more landward than for the other surveys, thus resulting in a
narrower beach for the summer surveys. Two of the winter profiles, (May 1996 and March 1997)
consist of somewhat wider beaches with larger volumes. This is contrary to the normal definition
of "summer" and "winter" profiles normally associated with sandy beaches.

The February 1998 survey was conducted immediately after two storms impacted the area.
The narrowed beach width, a steep scarp in the vicinity of the high water lines of the storms (located
at approximately 220 feet) and an offshore bar are all signs of a post-storm beach. The sand in the
offshore bar was eroded from the beach face during the storm, but will most likely be redeposited
back on the beach during periods of milder wave activity.

Due to the different tide and wave conditions during the various surveys, each survey ends
at a different distance from the monument. For example, the DEP survey was conducted farther
offshore than any of the COE surveys which were planned to extend to wading depth only. The
volumetric computations were extended out to the seawardmost common surveyed point at the
monument location for all surveys. For Monument Number R-188 in Santa Rosa County, the last
data point for the July 1997 survey establishes the limiting distance for volumetric computations and
is approximately 250 feet from the monument.

3.2 Beach Volumes and Widths

The data for each survey were analyzed to quantify changes in beach volume and shoreline
position defined as the distance from the monument to the NGVD water line. These changes were
compared throughout the entire survey period. The changes were averaged for each county and for
each "developed" and "natural" segments within each county area, as will be apparent from the
figure title of each graph. Finally, the average changes that occurred between each survey were








combined to obtain a cumulative response throughout the entire survey period. For illustrative
purposes, the graph for the average change in volume for all Escambia County profiles will be
discussed in the following paragraphs, see Figure 3.

Analysis of the data concentrated on the changes that occurred between each successive
survey. However, the numbers of monuments surveyed for each time period were sometimes
different from one monitoring survey to the next. Some monuments were lost due to construction
or damaged due to other causes, and only half of the monuments had been established prior to the
COE October 1996 surveys. In the graphs, the numbers in parentheses beside each date signify the
number of monuments that the previous survey and the survey in question have in common. In
Figure 3, there were twenty common surveyed profiles between the October 1996 survey and the
March 1997 survey. However, three monuments were not located during the July 1997 survey, so
there are only seventeen common profiles between the March 1997 and the July 1997 surveys. The
number of common profiles can also be considered as an approximate measure of the confidence
level, as an increase in the number of common data points yields a higher confidence in the results.

For each monument, the changes were calculated by subtracting the values (shoreline
positions or volumes) of the previous survey from those of the present survey. Missing data sets
occur when a particular location was not surveyed on one trip, but was surveyed on a later trip. The
following example will illustrate this method: a monument is surveyed in May 1996 and October
1996, not surveyed in March 1997, but is surveyed again in July 1997 and February 1998. The
difference between the October 1996 and the May 1996 surveys is calculated. Because there is no
March 1997 data available for comparisons, both the October 1996-March 1997 comparison and the
March 1997-July 1997 comparison are missing data sets for this particular monument. The
difference in the February 1998 and the July 1997 surveys is determined and recorded. For this
particular example, there are two missing data sets and two data entries. A different method of
comparing the data is required when the data set is not complete; this technique is described and
discussed in detail in Appendix A.

All of the differences for a particular time interval are averaged based on the total number
of data sets available. The number of data sets used is noted in the graphs, as previously discussed.
For each graph in which the data represents an average of several values, the standard deviation of
the values entering into the average is shown as vertical bars, see Figure 3. The results for developed
or natural segments are obtained by averaging the appropriately designated monuments (Table 1)
according to the total number of data sets available for each respective classification.

Additional surveys and/or aerial photographs available through the DEP were used in some
instances to supplement the COE data set. The following DEP surveys and aerial photography were
used: for Escambia and Santa Rosa Counties, February 1996 (survey data), March 1984 (aerial
photography) and October 1995 (aerial photography); for Walton County, May 1995 (survey data),
March 1996 (survey data) and October 1995 (aerial photography); and for Bay County, March 1995
(survey data), February 1996 (survey data), October 1996 (survey data) and October 1995 (aerial
photography). In the graphs, the asterisk next to a date indicates that the data were obtained from












30-
Co N -_
C )

30 0) 0) -- 0. 0
o0) LL -

20
cc
m 10
-,



1 -10
c-



O -20
Best Fit Trend Line
o -30
S-40 -1
- -1 0 1 2 3
| Time (years)
0

Figure 3. Cumulative Change in Average Volume for All Escambia County Profiles.








DEP surveys, instead of COE surveys. Dates in parentheses indicate that these shoreline data were
obtained from aerial photography. The February 1996 survey in Figure 3 was conducted by the DEP,
and the remaining five surveys were conducted by COE.

The May 1996 survey is the earliest survey conducted by COE that is common for all of the
profiles. Thus, for consistency purposes, all of the changes are referenced to May 1996 for plotting
purposes, and the best fit trend lines of the data begin with May 1996, see Figure 3. In addition to
presenting data associated with our surveys, results are presented representing changes from pre-
Opal conditions to immediately post-Opal and immediately post-Opal to May 1996. Specifically,
shoreline position data were obtained from a time prior to the hurricanes and immediately after
Hurricane Opal. The additional data sources are: Escambia and Santa Rosa Counties, aerial
photographs from August 1984; Walton County, February 1995 survey data were used and; Bay
County, a DEP March 1995 survey was used. The October 6, 1995 aerial photographs (two days after
Hurricane Opal) were used for all counties. The pre-Opal conditions are always plotted at time zero.
All other values are plotted at their actual times. For plotting purposes, May 1996 is arbitrarily
selected at Year 1.0. Finally, the scale of the vertical axis for the volumetric and beach width changes
are the same for all counties to allow easy visual comparison.

Between the March 1997 and the July 1997 surveys, a berm with a nominal volume of 6
yd3/ft was added to the beach in Santa Rosa County in the "developed" locations, from R-193
through R-197. This berm was constructed through an emergency program of the Federal
Emergency Management Agency (FEMA). A typical profile which experienced this berm placement,
R-194.5, is shown in Figure 4. The addition of the FEMA berm is evident by reference to the
preceding surveys. Because this berm nourishment would have been the primary volumetric
component of change instead of natural recovery, no volumetric comparisons were made for those
monuments between those two survey dates. The post-nourishment surveys, July 1997 and February
1998, were compared as usual. After the placement, the volume of sand in the vicinity of the berm
placement should remain reasonably constant, even though there was some redistribution of the sand
from the initial shape, see Figure 4. There is no volumetric data set listed for the developed sites for
the July 1997 survey, since the beach at every developed monument was manipulated. No placement
of sand occurred in the natural areas in Santa Rosa County, so the associated data are unaffected.
Finally, all of the data points are used for the beach width comparisons for Santa Rosa County
because the artificial nourishment was considered to have a minimal effect on the beach width.

Table 2 presents the average county shoreline positions for the pre-Erin and pre-Opal dates
to immediately Post-Opal and for the period from immediately post-Opal to the May 1996 COE post-
Opal survey. It is seen that on average, the shoreline retreat from pre-Erin and pre-Opal to
immediately post-Opal is 63.2 feet and the average shoreline advancement from immediately post-
Opal to the COE May 1996 survey is 58.0 feet resulting in a net retreat of 5.2 feet. Thus at the time
of the first COE post-Opal survey, most of the shoreline recovery from the erosion due to the
hurricanes had occurred. This small net retreat is substantially less that the approximate 20 to 30 feet
of average seasonal shoreline change along the Panhandle beaches. It will be seen that the shoreline
changes over the period of COE monitoring were substantially less than from October 1995 (Post-
Opal) to May 1996.














20 -- February 1998


Artificial Berm
15


o Equilibrating Berm Equilibrating Berm
z 10
S---------------- ---




0
Figure 4. Beach Profile R-14.5 in Developed Area of Santa Rosa County.
SShowg A. Gulfly Pofld exicoay P d



-5
0 100 200 300 400 500
Distance Seaward of Monument (ft)

Figure 4. Beach Profile R-194.5 in Developed Area of Santa Rosa County.
Showing Artificially Placed Berm.







Table 2

Average Shoreline Changes: Pre-Opal to Immediately Post-Opal
and Post-Opal to First COE Survey in May 1996


County Segment Date of Photography (P) Average Shoreline Date of Photography (P) Average
Type or Survey (S) Change (ft) or Survey (S) Shoreline
(Pre-Opal to Post-Opal) (Post-Opal to May 1996) Change (ft)
Average -63.2 +58.0
Average of Composite Composite
All Four Developed -60.0 +54.3
Counties Natural -67.6 +63.3

Average March 1984 (P) -46.9 October 6, 1995 (P) +78.4
Escambia to to
Developed October 6, 1995 (P) -43May 1996 (S) +76.0
Natural -50.9 +81.2
Average March 1984 (P) -81.2 October 6, 1995 (P) +72.9
Santa Rosa to to
Developed October 6, 1995 (P) 80.5 May 1996 (S) +69.8
Natural -81.7 +75.5
Average May 1995 (S) -64.7 October 6, 1995 (P) +23.0
Walton to to
Developed October 6, 1995(P) -63.2 May 1996 (S) +20.7
Natural -67.1 +27.0
Average March 1995 (S) Insufficient Data October 6, 1995 (P) Insufficient Data
Bay to to
Developed October 6, 1995 (P) -53.3 May 1996 (S) +44.2
Natural Insufficient Data Insufficient Data








3.3 Dune Recovery


Individual beach and dune profiles were examined to determine the extent of dune recovery over the
1.75 year monitoring period. Although dunes on a few profiles showed a limited degree of recovery,
the numbers of such profiles and the amount of recovery were not considered sufficient to conduct
a detailed analysis of dune recovery. It is concluded that general dune recovery in the study area
occurs on a significantly longer time scale than that of the monitoring period.


4. DISCUSSION

The averages of all of the data were plotted for each location to provide a general overview
of the results. The averages for each time were plotted as well as error bars representing one
standard deviation of the spread of the averaged data. For the data points that have a lower number
of surveys included in the data analysis, the error bars presented are somewhat artificially reduced.
A linear "best fit" straight line was plotted for the data sets so that the slope of the line represents
the prevailing trend from May 1996 to February 1998, thereby encompassing the period of the COE
surveys. Because of the large number of figures in this report, all of the county plots are presented
in Appendix B. The composite results for the four counties are included in the main body of this
report as well as in Appendix B. The summary trend values for volumetric and shoreline changes
are presented in Table 3.

As Table 3 and Figure 5 show, the average overall rate of volume loss for all four counties
including the February 1998 data is 2.5 yd3/ft/yr. The difference between the trends in the developed
areas (-2.4 yd/ft/yr, Figure 6) and the natural areas (-2.6 yd/ft/yr, Figure 7) is not considered
significant. The overall rate of beach retreat for all of the counties is 10.6 ft/yr (Figure 8) with the
developed areas retreating at a rate of 9.8 ft/yr (Figure 9) and the natural areas retreating at 11.4 ft/yr
(Figure 10). If the effects of the erosive February 1998 storm are not included in the analysis, the
rates of erosion are reduced substantially or change to accretion in both the volumetric and shoreline
trends.

In Escambia County, the beach width and volume changes in the developed and undeveloped
areas are approximately the same, see Table 3 and Figures B-7 through B-12. Although natural areas
are slightly more erosive volumetrically and show greater shoreline recession than the developed
areas, the differences are not considered significant. The removal of the effects of the February 1998
storm from the analysis results in less erosion in all categories.

Santa Rosa County has an overall negative trend for both volume and beach changes, see
Table 3 and Figures B-13 through B-18. Although the exclusion of the February 1998 data reduces
the erosional trends, all trend values remain negative.

Overall, Walton County has the lowest erosion/greatest accretion rate of any county studied,
Table 3 and Figures B-19 through B-24. All of the rates are positive with removal of the February
1998 data.









Table 3


Beach Volume and Width Trends as Determined by the Least Squares Method

County Volume Trend (yd3/ft/yr) Shoreline Trend (ft/yr)
and

Shoreline Segment February 1998 included February 1998 included
Type

Yes No Yes No

All Counties- Average -2.5 0.1 -10.6 2.7

Developed -2.4 0.1 -9.8 -0.9

Natural -2.6 0.2 -11.4 5.8

Escambia- Average -2.5 -0.2 -16.7 -12.0

Developed -2.5 0.0 -15.8 -8.2

Natural -2.6 -0.3 -17.6 -13.1

Santa Rosa- Average -2.3 -0.6 -11.6 -4.9

Developed -1.7 -4.2 -6.7 -6.7

Natural -5.2 -0.7 -15.7 -4.2

Walton- Average -1.4 3.7 4.8 34.7

Developed -1.7 4.3 1.1 30.7

Natural -1.1 3.1 8.6 36.5

Bay- Average -4.0 -3.0 -17.8 -9.7

Developed -4.2 -3.7 -16.8 -12.7

Natural -3.4 -1.4 -20.6 3.1

(Note: there are varying amounts of natural and developed areas in each of the four counties.
Thus, a straight averaging method for these two shoreline types cannot be used).











2 40 ,
" 0) -co


( 10 M


I -2o10
20




E
o -30-

u -40'
| 0 1 2 3
E Time (years)
O


Figure 5. Cumulative Change in Average Volume for All Counties.











40 r- O0





10
0) 2








" -10
o Best Fit Trend
()
E -20

S-30

|- -40
-1 0 1
O Time (years)


Line


2 3


Figure 6. Cumulative Change in Average Volume for All Developed Profiles.










o I-
0- (o 0 0

- LL L O LL
a "un )*
cu 20
: :
10
a)


0





S-20
--1
0



> -30 -
(-40
| 40 -- I---- I-------
E 0 1 2 3
0 Time (years)

Figure 7. Cumulative Change in Average Volume for All Natural Profiles










o 80-
S 80 I
CL LO (


S 60 o)
0)) 00
nCD







.o 20 t

0 . \. ." ^....
-20


\ / Best Fit Trend Lin -
o -40 -


S-80
o
-100
-1 0 1 2
Time (years)

Figure 8. Cumulative Change in Average Shoreline Position for All Counties.
Pre-Opal and October 1995 Positions Based on Aerial Photography.


3








oQ

060 0 0


-40
100 r a) ) -
S80 U
o o





a -20 2
--est Fit Trend Line
-40
0^ 20i



-60 -

0 0 -
-80
-100 '
-1 0 1 2
Time (years)
Figure 9. Cumulative Change in Average Shoreline Position for All Developed Profiles.
Pre-Opal and Oct 1995 Positions Based on Aerial Photographs.


3














0


a)
CL
0
-c


U')
00

0
ca
(-
0
r
O


100

80

60

40

20

0

-20

-40

-60

-80

-100
-1.0


Best Fit Trend Line


1.0
Time (years)


2.0


3.0


Figure 10. Cumulative Change in Average Shoreline Position for All Natural Profiles.
Pre-Opal and Oct 1995 Positions Based on Aerial Photographs.


0.0








Bay County is generally characterized by negative volumetric and shoreline trends, Table 3
and Figures B-25 through B-30. This site is downdrift (west) of the entrance to St. Andrews Bay
which may play a role in these predominantly erosive trends.

Overall, although quantitative differences in volumetric and shoreline trends exist between
the developed and natural areas, they are not considered significant in light of the natural variability
of the beach and dune system.

5. EFFECT OF FEBRUARY 1998 SURVEY

The discussions of the trends in volumetric and shoreline changes have emphasized the role
of the erosive conditions documented in the February 1998 survey. In order to quantify the effect
of this storm on the overall results, the data for all of the counties were reanalyzed excluding the
February 1998 survey data set. The results are presented in Table 3, where it is seen that the
February 1998 data represent a significant component to the overall erosive trends documented in
this study.

Referring to Table 3 and Figures 5-10 for the four county composite results, it is reasonably
clear that the storms which occurred between the July 1997 and February 1998 surveys caused a
beach response that is as great or greater than the recovery effects of the beach system during the
preceding COE period of monitoring. Figures B-7 through B-30 will document that these discussions
and results are generally applicable individually to each of the four counties studied.








6. CONCLUSIONS


Changes in beach volumes and shoreline positions consist of trends due to longer term
"forces" and superimposed "noise" which can vary substantially seasonally and due to individual
storms and the causes of which are poorly understood quantitatively. In the present case, Hurricanes
Erin and Opal caused substantial shoreline and dune erosion along the Panhandle area of Florida.
The time scales of the beach and dune equilibration processes are of interest as are the degrees of
recovery in areas designated as "developed" and "natural". The surveys associated with this study
commenced in May 1996, some seven months after the passage of Hurricane Opal. Data obtained
from pre-Opal surveys and pre- and post-Opal aerial photographs have established that the shoreline
recovery was fairly rapid. The dune recovery occurs on a much longer time scale which depends on
the strength of the wind, the size of the sediment and the width of the berm.

The conclusions determined from this study are:

(1) The beach width recovers on reasonably short time scales, on the order of several months,

(2) The dune recovers on time scales on the order of years to decades, depending on several factors,

(3) The beach recession due to Hurricanes Erin and Opal was on the order of 60 to 70 feet,

(4) No clear evidence of differences between beach or dune recovery in "developed" and "natural"
areas could be identified,

(5) Any dune recovery over the 1.75 years on monitoring associated with this study was small, a
result of the relatively long time associated with dune recovery for the conditions (coarse sand and
narrow berms) in the study area, and

(6) The natural beach and dune system is characterized by substantial natural fluctuations, for which
the full causal relationships are not known, thereby complicating the interpretation of measured
changes. Two individual storms before the last COE survey (February 1998) affected the overall
trend rates of beach and dune change substantially.


7. REFERENCES

Federal Emergency Management Agency, 1996. Hurricane Opal in Florida: a Building
Performance Assessment, FEMA 281. August 1996.

Leadon, Mark E., 1996. "Hurricane Opal: Damage to Florida's Beaches, Dunes and Coastal
Structures", Proceedings, Ninth National Conference on Beach preservation Technology: The Furure
of Beach Nourishment, Edited by D. Tait, pp. 313-328.



















APPENDIX A



DESCRIPTION OF METHODOLOGY USED

FOR COMPUTATIONS OF AVERAGES








APPENDIX A


DESCRIPTION OF METHODOLOGY USED

FOR COMPUTATIONS OF AVERAGES

One of the difficulties encountered in calculating average shoreline positions and volume
changes for a number of monuments was related to the incomplete data for every time at a particular
monument location. Resolution of that problem under the constraint that all available data are to be
used is described below.

Table A-i is a hypothetical example of a spreadsheet denoting the original shoreline positions
of various monument locations for several surveys. Monuments R-l, R-3 and R-6 are the only
monuments with complete data sets. Monuments R-2, R-4 and R-5 all contain partially missing data
sets. This appendix provides a detailed description of the processes used to analyze "empty" data
sets.

Table A-1

Original Shoreline Positions

Time R-1 R-2 R-3 R-4 R-5 R-6
(years)

0 100 150 225 125 175 200

0.25 75 175 150 150

0.5 50 200 175

0.75 100 225 100 200 150

1 150 100 250 175 225 200

Table A-2 lists the changes that occurred in the original shoreline positions between surveys.
Only the changes between two consecutive data sets can be obtained for reasons listed in the main
body of text.

Table A-3 lists the data from Table A-2 (the changes in shoreline position) in addition to the average
shoreline change for each time interval.

Table A-4 lists the shoreline changes from Table A-3, and the missing data are filled with the
average shoreline change values.








Table A-2
Shoreline Changes from Original Positions


Change Between Time R-1 R-2 R-3 R-4 R-5 R-6
(years)

0.25-0.00 -25 -50 25 -50

0.5-0.25 -25 25 25

0.75-0.5 50 25 -25

1-0.75 50 25 75 25 50



Table A-3
Shoreline Changes from Original Positions, with Average Shoreline Change

Change Between Time R-1 R-2 R-3 R-4 R-5 R-6 Average Shoreline
(years) Change
0.25-0.00 -25 -50 25 -50 -25

0.5-0.25 -25 25 25 8.3

0.75-0.5 50 25 -25 16.7
1-0.75 50 25 75 25 50 45


Table A-4

Complete Data Set for Shoreline Changes with Average Shoreline Change
Filled in all Empty Data Sets

Change Between Time R-1 R-2 R-3 R-4 R-5 R-6 Average Shoreline
(years) Change
0.25-0.00 -25 -25 -50 25 -25 -50 -25

0.5-0.25 -25 8.3 25 8.3 8.3 25 8.3
0.75-0.5 50 16.7 25 16.7 16.7 -25 16.7
1-0.75 50 45 25 75 25 50 45








Table A-5 lists the original shoreline positions for each of the monuments, with the missing data
filled in. Working backward using the changes listed in Table 4A, the shoreline positions can be
reasonably estimated.

For consistency, three rules are followed when working backward. The first rule is if
there is only one missing data set from the original shoreline position spreadsheet, the value of
the missing number is obtained by adding the shoreline change to the number listed above the
missing value. For example, for Monument R-4, the shoreline position for time 0.5 is missing.
From Table A-4, the average change between time 0.5 and 0.25 is 8.3, and the number listed
above the missing data is 150 for time 0.25. Therefore, 8.3 is added to 150, and the value for the
previously missing data, at time 0.5, is 158.3.

For instances where there are two consecutively missing data sets from the original
shoreline position spreadsheet, the missing data are filled in using the adjacent cell values. For
example, for Monument R-5, the shoreline position for times 0.25 and 0.5 are missing. The
average change between time 0.25 and 0 from Table A-4 is -25, and the number listed adjacent to
the cell, the above value, is 175. Therefore, -25 is added to 175, and the value for the first
missing data, at time 0.25, is 150.

The second missing data value for Monument R-5 is located at time 0.5. The adjacent
cell with an original value is 200 for time 0.75. The average change between time 0.75 and 0.5,
from Table A-4, is 16.7. Therefore, the average change is added to the value of the adjacent cell,
and the missing data is filled with the value of 216.7.

In cases where there are three consecutively missing data sets in the original shoreline
position, a combination of the first two rules are used. The top and bottom missing data value
are filled in from adjacent cells, via rule two, and the middle missing data value is filled in from
the number listed above. See Monument R-2 for an example of this type.

Table A-5

Complete Data Set for Original Shoreline Positions

Time R-1 R-2 R-3 R-4 R-5 R-6
0 100 150 225 125 175 200
0.25 75 125 175 150 150 150
0.5 50 133.3 200 158.3 216.7 175
0.75 100 145 225 100 200 150
1 150 100 250 175 225 200








Table A-6 contains the final shoreline position change data that would be plotted in a
graph. The mean of the data and the standard deviation that are plotted are all obtained from a
spreadsheet of this type.

Table A-6
Shoreline Position Changes

Change Between Time R-1 R-2 R-3 R-4 R-5 R-6

0.25-0.00 -25 -25 -50 25 -25 -50

0.5-0.25 -25 8.3 25 8.3 66.7 25

0.75-0.5 50 11.7 25 -58.3 -16.7 -25

1-0.75 50 -45 25 75 25 50


A-4
















APPENDIX B

PLOTS OF SHORELINE AND VOLUME CHANGES








APPENDIX B


PLOTS OF SHORELINE AND VOLUME CHANGES

The thirty plots on the following pages are presented in five groups of six plots for each group. The
first group represents the composite changes for all four counties and the next four groups are for
the four individual counties in the following order: Escambia, Santa Rosa, Walton and Bay. The six
plots within each group are, in the following order: volume changes for all profiles in the group,
volume changes for "developed" profiles in the group, volume changes for "natural" profiles in the
group, shoreline changes for all profiles in the group, shoreline changes for "developed" profiles in
the group, and shoreline changes for "natural" profiles in the group.










C) 0 CT) C) C
30 -

20 1

10 **
0


-10 -1
Best Fit Trend Line
-20

-30
-40 I
-1 0 1 2 3
Time (years)

Figure B-1. Cumulative Change in Average Volume for All Counties.










400


r 30 >U

I 20-

I 10-
0
4 (0--------, --





co -10
o Best Fit Trend
E -20-
"3
2
S-30

7 -40
S -1 0 1
O Time (years)


Line


2 3


Figure B-2. Cumulative Change in Average Volume for All Developed Profiles.











a"


),
(0
co
),
m
a-



o,
0)


C
1-
0
U)
E



)
.-,



E
0


Time (years)


Figure B-3. Cumulative Change in Average Volume for All Natural Profiles


40

30

20

10

0

-10

-20

-30

-40


r o- 0 -
( 0 ) 0) 0)
T. 0) 0) L. 0) 0)
2

:L O lL LL






Be~-t Fi-Te...

Best Fit Trend Line /




------------- \ _______














0
-o
0
-c


2C

0)
w .
E
t-
c-a
.r




O


100

80

60

40

20

0

-20

-40

-60

-80

-100


Figure B-4.


0) 0C)


a) LL 0)
U U
0) )L 0) 0 ( 3


o I 1 o I |


Best Fit Trend Lint


0 1 2 3
Time (years)

Cumulative Change in Average Shoreline Position for All Counties.
Pre-Opal and October 1995 Positions Based on Aerial Photography.










0a )C)
O o

100 -

Sf o 0
60 L-
040


o 80 0
$ 60
I 40





-80
3-60-
-80
-100 '
-1 0 1 2 3
Time (years)
Figure B-5. Cumulative Change in Average Shoreline Position for All Developed Profiles.
Pre-Opal and Oct 1995 Positions Based on Aerial Photographs.











100
80
60
40
20
0 -

-20
-40
-60
-80
-100
-1.0


0.0


Best Fit Trend Line


1.0
Time (years)


Figure B-6. Cumulative Change in Average Shoreline Position for All Natural Profiles.
Pre-Opal and Oct 1995 Positions Based on Aerial Photographs.


2.0


3.0


'''











CD
>oC
0)
a )
LL >


0)
cv


CD
.c




cu
a,






Cu
rc


-5
a>
E
0


40

30

20

10

0

-10

-20

-30

-40
-1


Figure B-7. Cumulative Change in Average Volume for All Escambia County Profiles.


Best Fit Trend


1 2 3
Time (years)










S30 o-
40 C. 4- a
- LL "-' LL
20



C.
-) 1=30 *
// ----i *' ^ -* *--- .

S-10
r-
o -20 Best Fit Trend Line

S-30-

-40 '
S -1 0 1 2 3
E Time (years)
O
Figure B-8. Cumulative Change in Average Volume for Developed Profiles in Escambia County.










3 ca 75 0
I40 I



S20 0



S-10-
C D 0





-20 est Fit Trend Line
O 00
-. 30 -





E -40
0 -30



-1 0 1 2 3
Time (years)
Figure B-9. Cumulative Change in Average Volume for Natural Profiles in Escambia County









CN
00 O
0)100- -
100 --
0 O CD "
o) VI) 0-) (0) 00
80 -- aC o> 0
o 60 a L -0
60 -U -
S 40 -T
2
0 20

0
a)

C- -20
0 -40
a)
-60 Best Fit Trend Line
JU -60 -
-5
S-80
o
-100
-1 0 1 2 3
Time (years)

Figure B-10. Cumulative Change in Average Shoreline Position for All Escambia County Profiles.
March '84 and Oct '95 Positions Based on Aerial Photographs.










100 o

Z1 80- M F T i n
o -LL >
0 L L i LL
a 60 )
40- -6
o 80
-10 0 1 2





Time (years) -
Figure B-11. Cumulative Change in Average Shoreline Position for Developed Profiles.
ounty. Mar '84 and Oct '95 Positions Based on Aerial P-20hotographs.
-60
M -20 -



-100-
-1 0 1 2 3
Time (years)
Figure B-I1. Cumulative Change in Average Shoreline Position for Developed Profiles.
Escambia County. Mar'84 and Oct'95 Positions Based on Aerial Photographs.









00

100r 0) M I|
o j cn o, s
0 040 I% o
o 0
: t! a) LL >% CY0
0 I

| 40



-20

-c
a -40 -

-60 -6
60 \ /Best Fit Trend Line

S-80-
o
-100 -
-1 0 1 2 3
Time (years)
Figure B-12. Cumulative Change in Average Shoreline Position For Natural Profiles.
Escambia County. Mar '84 and Oct '95 Positions Based on Aerial Photographs.









o 00 0
.C C
00 0
...o. ...
030 Ia


-40 I o 0
5 10-
20


-10
m 10

.-2




S-30-



i. -1 0 1 2 3
|E Time (years)
0 F
Figure B-13. Cumulative Change in Average Volume for All Santa Rosa County Profiles.












(o
0)
.0 -0

LL C


S0) LO

(0 ) 0

0
-I-a n


cf)
-C

0,
a)
-

C.


c-
I-l



0)
-,

O

a.>




0
0I


0 1 2 3
Time (years)


Figure B-14. Cumulative Change in Average Volume for Developed Profiles
in Santa Rosa County.


40

30

20

10

0

-10

-20

-30

-40


Best Fit Trend Line 1












c 40 o- o o| o> o o,
-1 co

S 20 M
a)
-j
20

S10-





FD 0 .- 5 -R
-10-
C
c -20
a) Best Fit Trend Line

| -30
ca
^ -40-------------------
1 -1 0 1 2 3
E Time (years)
U
Figure B-15. Cumulative Change in Average Volume for Natural Profiles in Santa Rosa County.








00 -O



O 40,
1 20
8 0 -
0 0




8 -0 -
-100
L.-
S 20-



S 0 01 2
0)
-20
o -40




-100
-1 0 1 2 3
Time (years)
Figure B-16. Cumulative Change in Average Shoreline Position for All Santa Rosa County Profiles.
March'84 and Oct'95 Positions Based on Aerial Photographs.









U) -

100 0 M.0 M -
80 1
0 60 0 8

40
0 20
oo Ln

00 CD
-20
-c
o -40-
a)
u -60 -
_5 60 Best Fit Trend Line
E
S-80 -
-0 0 _---I------I------------I
-100
-1 0 1 2 3
Time (years)

Figure B-17. Cumulative Change in Average Shoreline Position for Developed Profiles
in Santa Rosa County. Mar '84 and Oct '95 Positions Based on Aerial Photographs.









,-, -
x-- 140 4 v (3 03
O (D CD 0) 00
100 CD 0m 0 0M CM ) 0)
S10 0) 0 M M
S80 ,
0 60 a 0


-n
I 40


= ._ 0 ----\ ---'-^Z _^ -- -

-" -20


n R-M n O Best Fit Trend Line
cu -60
75
-80
o
-100 '
-1 0 1 2 3
Time (years)
Figure B-18. Cumulative Change in Average Shoreline Position for Natural Profiles in
Santa Rosa County. Mar '84 and Oct '95 Positions Based on Aerial Photographs.










40 gD (,) 0)) 1


CD 30 a
S200 U

0--
I -10




o -20
(Best Fit-Trend Line


a)
S-40
- -1 0 1 2 3
E Time (years)
Figure B-19. Cumulative Change in Average Volume for All Walton County Profiles.
Figure B-1 9. Cumulative Change in Average Volume for All Walton County Profiles.











LO
0)LC) 0O I,*


10. 1
-10 -
ca -)



.1 200


I 10 -
o -




a-40
g Best Fit Trend Line
S-20


| -30
a)

-5 -1 0 1 2 3
= Time (years)
0
Figure B-20. Cumulative Change in Average Volume for Developed Profiles in Walton County.


h
C\1 O O
v
r


io











V
-'
CD
0)
-j
0
(u
a0
c:
CD

a,

a,
CD
"c

:3
-c
0

0)
E

a,

E
0


*4


40

30

20

10

0

-10

-20

-30

-40


Time (years)


Figure B-21. Cumulative Change in Average Volume for Natural Profiles in Walton County.


SBest Fit Trend Lne


V


#4










100- 0
LO CO
M M .- C.
0) N

0 0 06) 0)







S-60 0
o
V, 2 LL .

100 CD







-1 0 1 2 3
60
01 420 .......Q-

. 20... ..
20





IFigure B-22. Cumulative Change in Average Shoreline Position for A Walton County
P -40 Ot Best Fit Trend Line

| -60
E -80

100
-100 -----------------------
-1 0 1 2 3
Time (years)
Figure B-22. Cumulative Change in Average Shoreline Position for All Walton County
Profiles. Oct 1995 Positions Based on Aerial Photographs.






CD
VO 0)g
0) LO (3
0)C.
G) cu
cu 0)

0)
0 -,
CI O I


C g**
'44J-


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


0 1 2 3
Time (years)


Figure B-23. Cumulative Change
in Walton County.


in Average Shoreline Position for Developed Profiles
Oct '95 Positions Based on Aerial Photographs.


Best Fit Trend Line





LO

0)4
0) C0) !'0 N



100 / "- .- T -- "-
C8) 000
LO CL o) cu
o -0 0 E
M 60- 7
0 80a)
cl. 0
S60 60
1 40

S20 ..
ST 0 /
-0










Time (years)
-40

>in WaltBest Fit Trend Line
c-u-60

S-80

-100 I
-1 0 1 2 3
Time (years)
Figure B-24. Cumulative Change in Average Shoreline Position for Natural Profiles
in Walton County. Oct'95 Positions Based on Aerial Photographs.













S 30 u
O.
) -20 T
20 1
a)
mo 10

0 3




S30 -I Best Fit Trend L

r5
- 0 -1 0 1 2 3

| Time (years)
0
0


Figure B-25. Cumulative Change in Average Volume for All Bay County Profiles.


ine










SCD-
S 400
0) -I


S 20-
O l


00 . ...




S-20 Best Fit Trend Line
(D
E -
1 -30- 0
|-403

- -1 0 1 2
E Time (years)
0


Figure B-26. Cumulative Change in Average Volume for Developed Profiles in Bay County.


3


"'"










40 o co 0o




S00
4 0- 0
- 30- 3






-40
20

| 210 I

0D ."T..

-10-

0 -20 -D
E 0\
S-30 _Best Fit Trend LinE

> -40
- -1 0 1 2 3
E Time (years)
0
Figure B-27. Cumulative Change in Average Volume for Natural Profiles in Bay County.
Figure B-27. Cumulative Change in Average Volume for Natural Profiles in Bay County.


e








LO L0
0) LC)3 00
-c







80 4 a,
o -40
- 60





- -80Best Fit Trend Line "
40-





o 20

-100
-c
O -40
a)
-60
7 Best Fit Trend Line
o -80

-100
-1 0 1 2
Time (years)

Figure B-28. Cumulative Change in Average Shoreline Position for All Bay County
Profiles. Oct 1995 Positions Based on Aerial Photography.


3









(0
a0)


0)N
0 ?'-


100 r 0. U
SLL
0 u 0

o 40 -
0 60-








S-40
a)




| -60 Best Fit Trend Line/
5 -00


-100----
-1 0 1 2 3
Time (years)

Figure B-29. Cumulative Change in Average Shoreline Position for Developed Shorelines
in Bay County. Oct 1995 Positions Based on Aerial Photography.









o 0)
10003 c



M 0
680- a 0 a
, -.- I,.- T

.0 60

0 40
0 40

- 20









-80 -\Best Fit Tre
00

-100
U -20

S-401

e -60(year

-80 Best Fit Tre
O
-800
-100 10----
-1 0 1 2
Time (years)

Figure B-30. Cumulative Change in Average Shoreline Position for Natural Profiles
in Bay County.


I)


nd Line


3


(DO
(D3




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