Citation
Continued development of program to quantify shoreline changes, Lee County, Florida

Material Information

Title:
Continued development of program to quantify shoreline changes, Lee County, Florida
Series Title:
UFLCOEL-2000001
Creator:
Malakar, Subarna B
Dean, Robert G ( Robert George ), 1930-
Lee County (Fla.) -- Board of County Commissioners
Place of Publication:
Gainesville Fla
Publisher:
Dept. of Civil and Coastal Engineering, University of Florida
Publication Date:
Language:
English
Physical Description:
iv, 16, A-24, B-21, C-36 : ill., maps ; 28 cm.

Subjects

Subjects / Keywords:
Shorelines -- Monitoring -- Florida -- Lee County ( lcsh )
Coast changes -- Florida -- Lee County ( lcsh )
Genre:
bibliography ( marcgt )
non-fiction ( marcgt )

Notes

Bibliography:
Includes bibliographical references (leaf 16).
General Note:
"January, 2000."
Statement of Responsibility:
Subarna B. Malakar, Robert G. Dean ; sponsored by Board of County Commissioners, Lee County, Florida.

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University of Florida
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University of Florida
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The University of Florida George A. Smathers Libraries respect the intellectual property rights of others and do not claim any copyright interest in this item. This item may be protected by copyright but is made available here under a claim of fair use (17 U.S.C. §107) for non-profit research and educational purposes. Users of this work have responsibility for determining copyright status prior to reusing, publishing or reproducing this item for purposes other than what is allowed by fair use or other copyright exemptions. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder. The Smathers Libraries would like to learn more about this item and invite individuals or organizations to contact Digital Services (UFDC@uflib.ufl.edu) with any additional information they can provide.
Resource Identifier:
49506073 ( OCLC )

Full Text
UFL/COEL-2000/001

CONTINUED DEVELOPMENT OF PROGRAM
TO QUANTIFY SHORELINE CHANGES,
LEE COUNTY, FLORIDA
January, 2000
Subarna B. Malakar
Robert G. Dean
Sponsored by:
Board of County Commissioners
Lee County, Florida
Department of Civil and Coastal Engineering
University of Florida
Gainesville, Florida 32611




TABLE OF CONTENTS
I INTRODUCTION ................................................................. 1
II BRIEF REVIEW OF PREVIOUS WORK .................................. 2
III FIELD PROGRAM ................................................................ 2
IV IMAGE PROCESSING......................................................... 5
V RESULTS............................................................................. 9
VI COSTS OF APPLYING THE METHODOLOGY........................ 15
VII SUMMARY AND CONCLUSIONS.......................................... 15
VIII ACKNOW LEGEMENTS ....................................................... 16
IX REFERENCES ...................................................................... 16

ii




FIGURE
1 Location Map of Study Area, Lee County, Florida .............................. 1
2 Location of MHWL on a Beach Profile and Plan View of the Monuments
and the Shoreline Location ....................................................... 4
3 Example of an Aerial Photograph................................................... 5
4 The Same Aerial Photograph of Figure 3 With Gulfside
of the Shore Blackened ........................................................... 6
5 Intensity Profile at DEP Monument R-98 in Captiva Island,
Lee C ounty .......................................................................... 7
6 Scanning Path of the Intensity Profiles Between the 2 Monuments ........... 8
7 Example of a Beach Profile Survey ............................................... 9
8 MHW Distances From 1998 Photograph Versus 1998 Surveys
for Lovers Key, Lee County ..................................................... 10
9 MHW Distances From 1998 Photograph Versus 1998 Surveys
for Captiva Island, Lee County .................................................. 10
10 MHW Distances From 1999 Photograph Versus 1999 Surveys
for Lovers Key, Lee County ....................................................... 11
11 MHW Distances From 1999 Photograph Versus 1999 Surveys
for Captiva Island, Lee County .................................................. 11
12 Long Term Standard Deviations Along the Coastline of Captiva Island,
Lee County (1858-1989) ........................................................... 13
13 Short Term Standard Deviations Along the Coastline of Captiva Island,
Lee County (1972-1989) ........................................................... 13
14 Long Term Standard Deviations Along the Coastline of Lovers Key,
Lee County (1858-1989) ....................................................... 13
15 Short Term Standard Deviations Along the Coastline of Lovers Key,
Lee County (1972-1989) ....................................... ................... 14
16 Example of Continuous MHW Shoreline Determined From Photograph.. 14

iii




TABLES

1 The DEP and Other Monument Identifications Located on Captiva Island
and Lovers Key, Lee County Florida ................................................... 2
2 Summary of Analyzed Results ......................................................... 12
APPENDICES
A Plots of May 5, 1998 and August 25, 1999 Surveys With Shoreline Locations
Determined From Photographs for Captiva Island and Lovers Key, Lee County,
Florida.
B Plots of Continuous Shorelines From August, 1999 Photographs for Captiva
Island and Lovers Key, Lee County, Florida.
C Plots of Continuous Shorelines From May, 1998 Photographs for Captiva Island
and Lovers Key, Lee County, Florida.

iv




CONTINUED DEVELOPMENT OF PROGRAM
TO QUANTIFY SHORELINE CHANGES, LEE COUNTY, FLORIDA
I. INTRODUCTION
This report presents a method for determining shoreline positions from aerial photographs that can then be used to quantify shoreline changes. The beaches of Captiva Island and Lovers Key, Lee County, Florida were selected for this study. See Figure 1 for the study site location. The objective of this study is to develop a semi-automatic method to determine the Mean High Water (MHW) distances with respect to Department of
LEE COUNTY(x
Figure 1. Location Map of Study Area, Lee County, Florida.

I




Environment Protection (DEP) monument locations on the aerial photographs and to evaluate the method through comparison against the MHW distances determined from conventional surveys. Thus following major storm events, aerial photography could be obtained and the methodology applied to rapidly determine the severity of erosion. The tasks comprising this study include: field work, aerial photography, image processing, data processing and analysis. This economical method of determining shoreline positions can be applied to any other beaches to quantify shoreline changes for beach erosion analysis and study.
II. BRIEF REVIEW OF PREVIOUS WORK
A previous phase of this study established that aerial photography combined with several ground truth surveys could result in determination of the MHWL locations within approximately 11 feet to 20 feet for the two surveys conducted (Kreuzkamp and Dean, 1997). Other investigators employing aerial photography for determination of MHWL positions had determined that the accuracies were on the order of 21 feet (Dolan, et al (1980) and 50 feet (Fisher and Overton, 1994). These previous studies were conducted in areas of higher wave action and thus greater wave run-up which contributes to the uncertainties.
The purpose of the present study was to automate, to the degree possible, the methodology such that less training, experience and judgement were required and thus subjectivity introduced by the analyst would be minimized.
III. FIELD PROGRAM
The first of the 2 field programs was carried out during the week of May 5h, 1998;
6 monuments were located on Lovers Key and 14 monuments were located on Captiva Island, see Table 1.
Captiva Island, Lee County Lovers Key, Lee County
CPE-84 #CPE-98 R-212 R-88 CPE-99 R-213 R-90 *R-100 R-214 R-91 *R- 102 *A-42
*R-92 R-103 R-220 R-93 CPE-104 R-221 R-94 R-108 R-222 CPE-96 R-109
R-97 II
Note. Indicates profiles surveyed on Aug. 25th, '99 only; # Indicate profiles surveyed on May 5th, '98 only
Table 1. The DEP and Other Monument Identifications Located on Captiva Island
and Lovers Key, Lee County Florida.

2




th
The second field program was carried out during the week of August 25 1999; 7 monuments were located on Lovers Key and 16 monuments were located on Captiva Island. For each of these monuments a large marker was placed centered on the monument so that these monument locations could be identified on the aerial photographs. A beach profile was surveyed along the DEP survey bearing to wading depth for each monument. Field beach profile survey notes were reduced to compute the MHW distance from each monument for the purpose of "ground-truthing" the MHW distances determined from aerial photographs; the beach survey profiles are also plotted and included in this report in Appendix A.
It is very important that a large clearly visible marker be placed securely at each monument location until the aerial photographs are taken; detailed field notes of the surrounding landmarks should also be taken for each monument location that could aid later in locating the monument position on the aerial photograph. This practice also applies to surveying beach profiles.
Following the ground field work, aerial photographs of the beaches on Lovers Key and Captiva Island in Lee County were promptly flown on May 12'h, 1998 and on August 27 1999 and 9x9 inch prints were produced at a scale of approximately 1:3000. From the May 12th, 1998 flight, 11 aerial photographs were selected for Lovers Key and 25 for Captiva Island. From the August 27th, 1999 flight, 8 aerial photographs were selected for Lovers Key and 14 for Captiva Island. Aerial photography should be avoided during early mornings and late afternoons when longer shadows may be cast along the beaches thus complicating the location of the monument markers on the ground. Also, recent weather conditions that may affect the normal position of the shoreline should be noted during timing of the flight when the aerial photographs were taken. An alternative to placing markers on the monuments would be to identify several permanent and easily identified positions on each area to be included in an aerial photograph and to establish the State Plane Coordinates of these positions. These positions could include intersections of lines on tennis courts, corners of swimming pools, street intersections, etc.
Unfortunately the August 1999 photographic flight was conducted early in the morning such that long shadows extended across the beach thus making it difficult to locate the monuments.

3




Figure 2 presents a sketch of a beach profile with the monument location and the MHW location on the profile which will be determined with respect to the 1928 National Geodetic Vertical Datum (NVGD). Figure 2 also shows an aerial plan view for each photograph where at least 2 monuments are located with the shoreline to be determined. The MHW elevations are 1.66 feet on Lovers Key and 1.49 feet on Captiva Island, both relative to NGVD.
Cross-Section of a Beach Profile
-Towards Land Monument
-..'.:9E.,' ..Towards Gulf -..MHWL
---Shoreline Distance Profile
Monument
Location A Survey Line
Monument
Location B Survey Line
Plan
Figure 2. Location of MHWL on a Beach Profile and Plan View of the
Monuments and the Shoreline Location.

4




Most DEP survey lines are approximately normal to the shoreline. The area in the photograph landward of the monuments and the area in the photograph seaward of the shoreline are not used, so except for small margins in these areas, they should be cut and removed to conserve disk storage and unnecessary processing time. It is also useful to place a label over each monument location. Some of the top and bottom portions of each photograph should also be cut to minimize unnecessary overlapping between adjacent photographs.
Using the image editing tools of the Adobe Photoshop software, shade the area seaward of the shoreline black. Familiarity with Adobe Photoshop software and practice in locating the shoreline in different photographic lighting conditions will be necessary to enable consistent location of the shoreline on the photographs and blacken the area seaward of the shoreline.
Figure 3 shows an example of a cropped photograph with DEP monuments R-98 and th
R-99 in Captiva Island taken on May 12 1998 and Figure 4 shows the same photograph with the area gulfward of the shoreline blackened. The final edited photographs are saved as jpg-files.
R-98
' IC
Figure 4. The Same Aerial Photograph of Figure 3 With Gulfside of the Shore
Blacken.

6




IV. IMAGE PROCESSING

Before the aerial photographs or images can be processed, they are prepared as follows:
1. The first step is to select the aerial photographs to use for the study that will
provide a continuous coverage of the shoreline in the study areas and such that
two monuments can be located on each selected photograph, see Figure 3.
2. Next, two end-monuments are located and marked on each selected photograph
with the aid of all available resources such as DEP aerial photographs, field notes, etc. For the image in Figure 3, DEP monuments R-98 and R-99 have been
selected.
3. After setting the resolution to "300 dpi, sharp black and white photograph" on the
scanner, each selected photo is scanned, for example on a HP Scanner 4c and
using HP scanning software, the scanned images are saved as tif-files.
tit
Figure 3. Example of a Scanned Aerial Photograph.
Next, using an image editor such as Adobe Photoshop, the shoreline in each photograph is adjusted such that it is approximately parallel with the left edge of the photograph. The reason for this is that it will save time and a later step from not having to compute the shoreline distance from the monument normal to the shoreline.

5




In the next step, a Matlab image processing program developed inhouse is run for each jpg-file, in which, interactively on the displayed image (photograph), with the use of the mouse, the pixel coordinates of the two monument locations are determined including the range of pixel coordinate values for the image. The origin of the pixel coordinates are located on the top and left corner of the photograph with the x axis positive direction from left to right and with the y axis positive direction from top to bottom. The physical width of the pixel varies with the size of the photograph and thus the conversion scale from pixel to the State Plane Coordinates may vary from one photograph to another, thus each image is processed independent of the other photographs and nonuniform pixel size will not affect the analysis results.
Given an image jpg-file and the data collected for each image from above, another Matlab image processing program developed inhouse is run. This program generates a continuous intensity profile for the specified connected line segments, see Figure 5 for an example of the intensity profile generated through DEP monument R-98. These intensity profiles through DEP monuments R-98 and R-99 are also plotted on Figure 4.
R-98
Intensity
MHWL Road
GULF 0
Figure 5. Intensity Profile at DEP Monument R-98 in Captiva Island, Lee County.
Figure 6 presents an illustration depicting the scanning by the MATLAB software program. The length of the line segments, for instance for AB, CD, EF, etc. is fixed for each image and the spacing between these line segments is at a fixed interval, which for this study is set at 200 pixels apart to generate about 5 intensity profiles between monuments. The number of intensity profiles generated depends on the maximum yrange (parallel to shore) value specified for the image. The output of this program is an ASCII file containing (x,y,z) values for intensity profiles for each photograph, where x and y are the pixel coordinates (horizontal coordinates) for each intensity value z. As noted, Figure 5 provides an example of an intensity profile passing through DEP monument R-98; also see Figure 4 where the intensity profiles passing through the monuments are plotted on the photograph.

7




Figure 6. Scanning Path of the Intensity Profiles Between the 2 Monuments.
Notice in Figure 5 that the intensity values change sharply from 0 to some high value indicating a tonal (color) change and a probable change from wet to dry area. The sharp change in intensity values is used as the criterion to identify the location of the MHW that is consistent from one intensity profile to the next. Care is required to not interpret breaking waves, white caps and other conditions that might indicate sharp changes in the intensity values as false location of the MHW locations. Usually, once the MHW line is located it should not fluctuate too much from monument to monument, thus assisting in avoiding spurious high intensity values.
Fortran programs developed for this project are applied to read the ASCII output files to filter, to determine the shoreline, to compute and to plot the shoreline data and other results. The intensity profile that almost coincides with the beach survey line for a monument is used for comparison of the MHW distances determined from the photograph and the survey profile.

8

Direction of Intensity Profiling
A B Monument
C D
E F
-.
Monument
M G -n
C/0
I --




Knowing the 2 monument location coordinates in both the pixel and the State Plane Coordinate Systems on the photograph allows conversion from one system of coordinates to the other. Considering Figure 2, let monument locations A and B have State Plane Coordinates Northing and Easting as (NA, EA), (NB, EB) respectively, and in the local pixel coordinate system for each photograph, as (XA, YA), (XB, YB), the factorf to convert from the pixel coordinate system to the State Plane Coordinates can be computed as:
f = ( NBNA)2 + ( EB- E)2112 / [(XB -X)2 + (yB- yA)2)2.
Knowing the coordinates of a monument in both systems and the conversion scale factor f, the State Plane Coordinates of the origin of the pixel coordinate system can be determined for each photograph. For the study here however, since the x-axis in the Pixel Coordinate System is parallel to the profile line or almost normal to the shoreline, we merely need to convert the pixel x distance to the shoreline with respect to the monument to give us the photograph shoreline distance in feet from the monument.
V. RESULTS
In the following, results illustrating the data collected and the effectiveness of the method will be presented as follows: (1) Profile surveys, (2) Comparison between surveyed profiles and uncalibrated and calibrated aerial photograph results, and (3) Plots of the Mean High Water Lines (MHWLs) along Lover's Key and Captiva Island. As discussed in Section II, a total of 20 wading profiles were surveyed in the first survey in May 1998 and 23 wading profiles were surveyed in August 1999. All of these profiles are presented in Appendices A, B and C. An example is presented as Figure 7.

10
0
0 >~ 10

0 0 50 100 150 200 250 300 350 Distance in Feet
Figure 7. Example of a Beach Profile Survey for Monument R-97.

9

August 25, 1999 Survey Captiva Island, Lee County
MHW From Photograph MHW Elevation=1.49 ft MHW From Survey




The uncalibrated MHW positions determined from the aerial photographs at the surveyed monument locations were first compared with the surveyed positions at the same monument locations. These results for 1998 are shown in Figures 8 and 9 for Lover's Key and Captiva Island, respectively. Corresponding results for 1999 are presented in Figures 10 and 11.

- D. Calibrated
o Uncalibrated
ThL11Thli1I Ii I ff I I I Ifi I I

200

400

Measured Shoreline Distance (ft)

Figure 8. MHW Distances
Key, Lee County.
VLI0

0
0
0
0.
a)

400

200

0
0

From 1998 Photograph Versus 1998 Surveys for Lovers

200

400

6

00

Measured Shoreline Distance (ft)

MHW Distances From 1998 Photograph Versus Island, Lee County.

1998 Surveys for Captiva

10

600
400 200

0
0
0
E
Id)

(1

0

6

00

D Calibrated
-) Uncalibrated
I I 1 1 1 *

Figure 9.

0

0




200

600

400

Measured Shoreline Distance (ft)

Figure 10. MHW Distances From 1999 Photograph Versus
Key, Lee County.

600

0
0
.
0
0

400
200

0

200

400

Measured Shoreline Distance (ft)

Figure 11. MHW Distances From 1999 Photograph Versus
Island, Lee County.

1999 Surveys for Captiva

These results are presented in terms of distances from the monuments to the respective MHW locations. If the results were in exact agreement, all points would lie on the "line of equivalency" shown in these diagrams.
11

Calibrated
- o Uncalibrated
- -

0
0
.
0
0 .Z
En"

400

200 1

00

(9

0

1999 Surveys for Lovers

Calibrated
a Uncalibrated
* 0

00

6

I I I t I I I I I I I I I I I t I I I I I I I

i i t i i i i i !

6

0




Table 2

Summary of Analyzed Results
Survey Island Average Shoreline Differences (ft)t Standard Deviations (ft)t Uncalibrated Calibrated Uncalibrated Calibrated May 1998 Lovers Key 25.6 (9.1) 0.0 46.7 (11.1) 37.0 (3.6) Captiva -1.1 0.0 9.0 8.9
August 1999 Lovers Key -0.7 (9.2) 0.0 28.5 (19.6) 28.5 (16.7) Captiva 1.1 0.0 17.7 17.7
? Based on differences between shorelines established by photography and survey,
i.e. (MHWLphto MHWLsuvey).
A summary of results is presented in Table 2 where the differences between the MHW positions determined by the two methods are tabulated and the average differences are also presented. It is seen that for the 1998 program, the average uncalibrated difference is 25.6 feet for Lover's Key and -1.1 feet for Captiva Island. A positive difference indicates that the MHW shoreline determined from the photography analysis is located gulfward of the MHWL determined by survey. The associated standard deviations in differences between shoreline positions is 46.7 feet for Lover's Key and 9.0 feet for Captiva Island. For Lovers Key, it was noted that the differences for the survey and photographic results for line (R-213) were quite large and contributed unduly to the standard deviations. The shoreline in this location is on the northwest corner of Lovers Key and varies substantially with azimuth heading. For that reason, the results were calculated. excluding the results for this line and these results are presented in parenthesis and are considered more representative. The standard deviation decreased from 46.7 feet to 11.1 feet when results from R-213 are excluded.
For the 1999 program, the uncalibrated average differences were -0.7 feet and 1.1 feet for Lovers Key and Captiva Island respectively. The associated standard deviations are 28.5 feet and 17.7 feet for Lovers Key and Captiva Island, respectively.
Calibration of the aerial photograph results was carried out, by subtracting from each of the aerial photograph results for a particular island, the average difference between the aerial and surveyed positions. It is seen from Table 2 that this reduces the average difference to zero (it must!) and reduces the standard deviations for the differences only slightly for three of the four cases.
The interpretation of the above results (excluding those from profile R-213) is that, without calibration, the MHW shorelines can be established from aerial photography to within an approximate average of 2 feet and, on average, a standard deviation of approximately 15 feet. The effect of calibration is to reduce the standard deviations only slightly for three of the four cases.

12




To place these values in perspective, Figures 12, 13, 14 and 15 present the standard deviations in the historical data base (Dean, et al, 1998) for short and long periods for the two islands and the short- and long-term considerations. These results for Captiva Island include some contribution from beach nourishment activities.

'U0.

2501

C, 0 4) N 4) 4) 0 (V C, V' 0 4) N 4) 4) 0 CQ C, ~ CO 4) N 4) 4) 4)4)4)4)4)4)4)4)OC4)0000000000
I F I I I F F I F I I
~ I I I F F F F F F I
DEP Monument Locations Along the Shoreline

Long Term Standard Deviations Along the Coastline of Captiva Island, Lee County (1858-1989).

0
0
DEP Monument Locations Along the Shoreline

Short Term Standard Deviations Along the Coastline of Captiva Island, Lee County (1972-1989).

100
4)500 "I-

CV 0 N 4) CC 0 CV
CC CV (C CCC CCC CV eq (C (C eq CV
F F I F I F I F C 4) 4) 4) 4) 4) 4) 4) 4) 4) 4) 4)
DEP Monument Locations on Lovers Key, Lee County

4

Long Term Standard Deviations Along the Coastline of Lovers Key, Lee County (1858-1989).

13

0 CO 4)
CO
~0 CO

I F F F I F F F F F F F F F F F FFFFFF[L[ F F

Figure 12.

20
10 S5

Figure 13.

Figure 14.




loo0
0
s~50
0
V)0

N N ~ N N C- N N 0 N N N N N N N N N N N N I I I I I I
N N N N N N N N N N N
DEP Monument Locations Along the Shoreline

Short Term Standard Deviations Along the Coastline of Lovers Key, Lee County (1972-1989).

It is seen that the standard deviations associated with photographic methods (approximately 15 feet on average) is considerably less than that determined from the historical data (approximately 50 feet). It is believed that the larger standard deviations from the analysis for 1999 are primarily due to the aforementioned early morning flight which cast shadows causing difficulty in locating the monuments. In general it is expected that the availability of easily located landmarks will contribute to the accuracy of the photographic method of MHW determination.
With the MHW shorelines determined, they can be plotted continuously by drawing a straight line from one transect (Figure 6) to the next. Figure 16 presents an example of this type of results and Appendices B and C presents all results of this type.

a a.
c
c
C,

Figure 16.

900 600 300

0 300 600 900 1200 1500 1800 2100 Distance in Feet
Example of Continuous MHW Shoreline Determined From Photograph.

14

-~ I --- I

Figure 15.

+ Monument Location
Y MHW Location From Survey
-__Shoreline From Photo
August 1999 Data
R-102 R-103

I 4UU ,




VI. COSTS OF APPLYING THE METHODOLOGY

Two types of costs associated with the application of the methodology will be discussed:
(1) The start-up costs, and (2) Costs of applying the methodology for the full 40+ mile shoreline length of Lee County for each application. Some of these costs will be presented in terms of person-days or person weeks.
Start-up Costs
The start-up costs include purchasing two programs (Matlab and Photoshop) if these are not already owned by the County. This total cost is approximately $700. The training costs would require approximately two person weeks of an individual reasonably capable with computers. Additionally, it is recommended that in order to decrease costs for each application, a basis be developed to obviate the need to place targets at the monuments for each flight. It is estimated that this would require a one time effort of approximately three person weeks. As discussed previously, this would entail the establishment of the State Plane Coordinates of easily identifiable positions ( tennis court corners, swimming pool corners, street intersections etc), for each area to be included in one image.
Costs for a One-time Application for the Full 40+ Mile Lee County Shoreline
The costs would consist of aerial photography, approximately $4,000, and analysis time of approximately one person week. This assumes that the basis discussed above was available such that it would not be necessary to target the monuments for each application. If this is not the case, it would be necessary to include the costs (and time) required for targeting those monuments at which the previously placed targets had been disturbed. At some monuments the targets may remain in place for years and may require no effort or at most, the removal of a thin layer of wind-blown sand.
VII. SUMMARY AND CONCLUSIONS
This study has developed methodology for rapid and relatively inexpensive establishment of MHW shoreline positions. This methodology would find greatest application after severe storms to rapidly document changes or could possibly serve to quantify shoreline changes at intermediate times between full surveys to document the performance of a beach nourishment project.
With the availability of a trained individual, it is estimated that this methodology could yield shoreline positions along the full 40+ mile Lee County shoreline length within several days to a week after the photographs were available for analysis. The associated costs would be approximately $4,000 for the aerial photography and up to one person week time. Experience with the method could reduce the processing time further.

15




The accuracy of the uncalibrated methodology is approximately 2 foot for average island shoreline positions in developed areas with average standard deviations on the order of 15 feet, compared to the historical short-term variability in shoreline changes of approximately 50 feet. The relative accuracy is probably better. That is, the comparative accuracy between the results of two successive shoreline surveys is probably better than comparing photographic results to survey results.
Although the cost of the aerial photographs for the full Lee County shoreline is approximately $4,000, many counties fly their shorelines routinely, possibly for tax assessment purposes. If this is the case, it would be possible to develop a routine assessment of the condition of the shoreline and to identify at an early stage, areas that may be experiencing erosional stress.
Cost of applying this method to each county could be reduced by flying several counties simultaneously, thereby requiring only one aircraft mobilization.
VIII. ACKNOWLEDGEMENTS
The authors wish to express their appreciation for the assistance of Al Browder, Jamie McMahan, Roberto Liotta and David Altman in conducting the surveys.
IX. REFERENCES
Dean, R.G. J. Cheng and S. Malakar (1998) "Characteristics of Shoreline Change Along the Sandy Beaches of the State of Florida : An Atlas", University of Florida, Department of Coastal and Oceanographic Engineering Report No. UFL/COEL-98/015.
Dolan, R., B. P. Hayden, P. May and S May (1980) "The Reliability of Shoreline Change Measurements From Aerial photographs", Shore and Beach, Vol. 48, pp. 22-29.
Fisher, J. S. and M. F. Overton (1994) "Interpretation of Shoreline Position from Aerial Photographs", Proceedings, 24h International Conference on Coastal Engineering, Vol. 2, pp. 1998-2003.
Kruezkamp, A. J. and R. G. Dean (1997) "Pilot Program t6 Quantify Shoreline Changes in Lee County", University of Florida, Department of Coastal and Oceanographic Engineering Report No. UFL/COEL-97/002.
Kruezkamp, A. J. "Analysis of Conventional Aerial Photography to Determine Shoreline Position", University of Florida, Department of Coastal and Oceanographic Engineering Report No. UFL/COEL-97/007.

16




APPENDIX A
Plots of May 5, 1998 and August 25, 1999 Surveys With Shoreline Locations Determined From Photographs for Captiva Island and Lovers Key, Lee County, Florida.




May 5, 1998 Survey Aug 25, 1999 Survey -

-

MHW-Line

Vertical bars indicate MHW positions determined from photograph
'F ''''F I I F F I I 1 1 1 F I F F I I F FI F I I F l i i F l

50

100

150

200

250

300

350

Distance in Feet

-t
CO

20

Q)
0 CO r)

-10
C

)0

4

10




20

-1 1 1 I 1 1 1 1 1 1 1 1 1 111 1 11 111 1 1 1ii 111 1 1 1 1I 1l ~ l~ ~ 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1I 1 III 1 1 1 1 1 1 I I I .

May 5, 1998 Survey
Aug 25, 1999 Survey
) 10 -- -0
-__ MHW-Line
Vertical bars indicate MHW positions determined from photograph 10 50 100 1' 200 250 300 350 '''
0 50 100 150 200 256 300 350 400

Distance in Feet




May 5, 1998 Survey Aug 25, 1999 Survey Q)
- 0
0
4_________________ MHW-Line
Vertical bars indicate MHW positions determined from photograph
0 50 100 150 200 250 300 350 400
Distance in Feet
CQ




May 5, 1998 Survey Aug 25, 1999 Survey
Q) 10
10
____ ___ ____ ___ ____ ___ ___MHW-Line
>V0
Vertical bars indicate MHW positions determined from photograph 1 0 ' ' ' ' ' '. ''' ' ' i'' '
0 50 100 150 200 250 300 350 400
Distance in Feet rU




- I I I I I I I I I I III I I I i I I I I I I I I I I I I I I I I I I I I II I I I I I I I I II I I I I I I I I I II I I I I I I II

-- Aug 25, 1999 Survey

-____MHW-Line -

Vertical bars indicate
' I ' '11 1 1 '1 1 1 '1

50

100

150

200

MHW positions determined from photograph

250

300

350

Distance in Feet

C\2
0

20

10

0
0
0)

-10
C

V
00F/

4




May 5, 1998 Survey Aug 25, 1999 Survey -

MHW-Line -

Vertical bars indicate MHW positions determined from photograph

200

250

300

350

4

U0
00

Distance in Feet

20

10

Q) Q)
0

10 1
C

50

cv1 Un

100

150

I I

-




May 5, 1998 Survey
Aug 25, 1999 Survey
10
0
4--)__ _ __ _ __ _ __ _ MHW-Line
Vertical bars indicate MHW positions determined from photograph 11150 '' 400
0 50 100 150 200 250 300 350 400

Distance in Feet




May 5, 1998 Survey Aug 25, 1999 Survey w 10
MHW-Line0
Vertical bars indicate MHW positions determined from photograph
0 50 100 150 200 250 300 350 400

Distance in Feet




May 5, 1998 Survey
-__----_ Aug 25, 1999 Survey -

MHW-Line

Vertical bars indicate MHW positions determined from photograph
' ' ' ' ' ' ' ' ' ' ' ' ' ' ', 1 1 1 ' 'II 1 1 1

200

250

300

350

00

Distance in Feet

20

10

4)
Q)
0 4
CO

(0

-10
C

50

C'-

100

150

-- ---- -

4




I I III I LIII 111111111 II I liIj I I I I II III 11111111111 liii I I II III 1111

May 5, 1998 Survey 10
MHW-Line

Vertical bars indicate MHW positions determined from photograph

' 'l 'I '1 1 1 ' '' ' ' ' ' ' '1 '

50

100

150

200

250

300

350

4

:J
00

Distance in Feet

20

0

CD

-10

0




20 -11
May 5, 1998 Survey Aug 25, 1999 Survey
Q>
10
0
- _ _ _ __ _ _ _ _MHW-Line
Vertical bars indicate MHW positions determined from photograph
- 1 0 '' ' ' ' ' ' '
0 50 100 150 200 250 300 350 400
Distance in Feet




Aug 25, 1999 Survey
- -

MHW-Line -

I I I F I I I I I I

50

100

150

Vertical bars indicate MHW positions determined from photograph
I I ii IIIII IIIII I

200

250

300

Distance in Feet

20

-0.>
Q)
0

101

-10
C

350

:5 0,
)o

.0

4




111 1 I I I 11 11 , ,I .I. . .II I I I I. .II I I I .I I I I

Aug 25, 1999 Survey

-
~ -

MHW-Line

K

Vertical bars indicate MHW positions determined from photograph II I I I I I II I I I I I I I I I I I I II I I I'I I I I I II ITI I

50

100

150

200

250

300

350

a
0

Distance in Feet

0q

20

10

Q)
0

-10'
C

4




May 5, 1998 Survey Aug 25, 1999 Survey
MHW-Line

Vertical bars indicate MHW positions determined from photograph
i~ 1 1 . 1 1 1 1 1 1 1 1 .

50

100

150

200

250

300

350

4

00

Distance in Feet

20

10

Q)
0

10,
0

0

t t I I I I I I I I j i i I I I .




May 5, 1998 Survey Aug 25, 1999 Survey
MHW-Line

Vertical bars indicate MHW positions determined from photograph
' ' ' ' ' ' ' ' ' 1 1 1 1 1 1 1 11'' ' ' ' 'I I i i i I 'I ' 'I'' ' 'I'' ' ' 'I 'l 1

50

100

150

200

250

300

350

Distance in Feet

20

10

-4-,)
Q~)
Q.)

10 0
0

0
U

00

4




20 -11
May 5, 1998 Survey Aug 25, 1999 Survey
Q) 10
0
____ ___ ___ ____ ___ ___ ____ ___ ___MHW-Line
Vertical bars indicate MHW positions determined from photograph
- 1 0 ' ' 'I ' ' ' ' ' ' I ' ' 'I ' 'I'' ' '
0 50 100 150 200 250 300 350 400 Distance in Feet
0




20 -11
May 5, 1998 Survey Aug 25, 1999 Survey
10
-'2 MHW-Line
0
10 '
0 100 200 300 400 500 600 700 800

Distance in Feet




20

May 5, 1998 Survey Aug 25, 1999 Survey -

101-

MHW-Line

Vertical bars indicate MHW positions determined from photograph
' 'F1 'II F F I 'I 'F 'F '11 'il 'I '1 F IF ' ' 1'

100

150

200

250

300

350

4

1
00

Distance in Feet

4~)
Q.)
0
C.)

101
0

50

I I

0




2 0 1 1 1 1 1 1 May 5, 1998 Survey Aug 25, 1999 Survey
10
MHW-Line
CO
Vertical bars indicate MHW positions determined from photograph
0 100 200 300 400 500 600 700 800

Distance in Feet




20

May 5, 1998 Survey Aug 25, 1999 Survey -

10 -

MHW-Line

Vertical bars indicate MHW positions determined from photograph . . . I I I I I I I II . I . . I I I I I I I I I' ''I I I I I I I I I II 11 1I'

100

150

200

250

300

350

W
)o

Distance in Feet

0)
0 4-)
Q
4

Q

10
C

50


-

4




F F F I F F F I F I F I I IF I FFFj FF11111 FIll IF Fl FIll F IF F F Fill III FilFj IFIFIFIFI1FFIFFFFFF -

Aug 25, 1999 Survey

10

-10
C

MHW-Line

N

Vertical bars indicate MHW positions determined from photograph
' ' ' '1 'I I ' ' ' ' ' ''F F' ' ' ' ' F F F F' ' ' ' ' F I ' ' ' ''1 1 I ' ' ' ''F 1 I ' ' ' I

50

100

150

200

250

300

350

Distance in Feet

CK2

20

a) a)
C a)

4

J
w
la
)0




LIII l~j ~ II I II 111 11 LII ..111 1 ,1 , , Ii I III . I . . .i

May 5, 1998 Survey Aug 25, 1999 Survey -

MHW-Line

~7I

Vertical bars indicate MHW positions determined from photograph
I I 11 11 11 11 li i 11 11 11 1 1 11 11 II 11 1111 1 ''1 11 'i '

100

150

200

250

300

350

4

:5

Distance in Feet

20

10 -

Q)
0 Q*)

-10
0

50

0
C\2 C\2




I II li i I' 1 111 I 11111 IIJ I III I, I, ,11111 r riiiii iii i r

May 5, 1998 Survey Aug 25, 1999 Survey -

MHW-Line

-~ --~ -~ I

I 1' ' ''I I I I 'I 1 1 1

50

100

150

200

bars indicate MHW positions determined from photograph
II I I II 1 ''1 'I 'I 'I ''11 ''

250

300

350

- Distance in Feet C\2 C\2

20

101-

0
r-r)

10
C

00

4




20

liii IlIlIj III I 11111111

May 5, 1998 Survey -

101-

MHW-Line

-101
0

'I I I I 11 1111111111 '

50

100

150

200

250

Distance in Feet C\2

Q) C)
0 ~4-) CO

Co

300

350

:J
30

4

I I I I I I

- 1~~ ~~ ~ ~ 1 1 1 1 1 1 I I I I I I I I I I I . I . . J I I I 1 1 1

' '




APPENDIX B
Plots of Continuous Shoreline From August, 1999 Photographs for Captiva Island and Lovers Key, Lee County, Florida.




+ Monument Location Y MHW Location From Survey Shoreline From Photo August 1999 Data

1000

1200

Distance in Feet

800

600 k

R-85

8 400
200
0

CPE-84

Y

200

400

600

800

0

1400




+ Monument Location Y MHW Location From Survey Shoreline From Photo August 1999 Data

R-86

+

R-87

1600

2000

2400

Distance in Feet

1600

1200 F

800
400

0

400

800

1200

0

2800




+ Monument Location Y MHW Location From Survey Shoreline From Photo August 1999 Data
R-87
+ R-88
F+

800

1200

1600

2000

2400

2800

Distance in Feet

1600

1200

Q)
S800
C)

400

0

400

0




1600

+ Monument Location Y MHW Location From Survey Shoreline From Photo August 1999 Data 1200
T.
, 800
CO,
4p
-) R-88
+ R-90
400 +
Y Y
0 400 800 1200 1600 2000 2400 2800

Distance in Feet




+ Monument Location Y MHW Location From Survey Shoreline From Photo August 1999 Data

2000

2400

2800

Distance in Feet

1600

1200 F

800

400 F

R-91

+

R-92

0

+

400

800

1200

1600

0




+ Monument Location Y MHW Location From Survey Shoreline From Photo August 1999 Data

R-93

+

1500

1800

Distance in Feet

1200

900 k

Q.) Q) 600 CI)

300 -

0

R-92

+

300

600

900

1200

0
E

2100




+ Monument Location Y MHW Location From Survey Shoreline From Photo August 1999 Data
R-97

1500

1800

2100

Distance in Feet

1200

900 F

600

300 1-

CPE-96

+

0

300

600

900

1200

Iz




1200

+ Monument Location Y MHW Location From Survey Shoreline From Photo August 1999 Data 900
600
4-j
R-98 CPE-99 300 +
0 300 600 900 1200 1500 1800 2100

Distance in Feet




+ Monument Location Y MHW Location From Survey Shoreline From Photo August 1999 Data

400 CPE-99

1600

2000

2400

Distance in Feet

1600

1200

wz
C6

0
0
0 C-)
CI)
0

800 V

R-100

+

0

400

800

1200

0

2800




+ Monument Location
Y MHW Location From Survey
Shoreline From Photo
August 1999 Data
R- 103
R-102

1200

1500

1800

2100

Distance in Feet

1200

900 -

Q) 4j)

600

C

300 -

+

0

300

600

900




+ Monument Location Y MHW Location From Survey Shoreline From Photo August 1999 Data
R-105

2000

2400

2800

Distance in Feet

1600

1200 k

C)
C) C-)
~4~)
C,)

800 F

400

CPE- 104

+

0

400

800

1200

1600

0




+ Monument Location Y MHW Location From Survey Shoreline From Photo August 1999 Data
R-107

2000

2400

2800

Distance in Feet

1600

1200 k

Q)
Qj)

cc~

800 I

400

R-106

+

0

400

800

1200

1600

0




+ Monument Location Y MHW Location From Survey Shoreline From Photo August 1999 Data

R- 107

+4

R-109

+

1500

1800

2100

Distance in Feet

1200

900 k

Q4)
S600
CO,

300 -

0

300

600

900

1200

01
0 01

-- Y




1200
+ Monument Location Y MHW Location From Survey Shoreline From Photo August 1999 Data 900
900 R-212
R-213
600
300
Y
0 300 600 900 1200 1500 1800 2100

Distance in Feet




R-213
800 +
+ Monument Location Y MHW Location From Survey Shoreline From Photo August 1999 Data 600
Q)
400 R-214
+
4-)
.10 Y
200
0 200 400 600 800 1000 1200 1400

Distance in Feet




+ Monument Location Y MHW Location From Survey Shoreline From Photo August 1999 Data

R-214

R-215

1500

1800

2100

Distance in Feet

1200

900 k

t:1

4-) 0)
4-) CI)

600 F

+

300 k

0

+

300

600

900

1200

0




+ Monument Location Y MHW Location From Survey Shoreline From Photo August 1999 Data
R-217

1000

1200

1400

Distance in Feet

800

600 I-

400 L

-'2

C)
Q)

200

T-216

+

0

200

400

600

800

0




+ Monument Location
Y MHW Location From Survey
Shoreline From Photo
August 1999 Data
R-218

1000

1200

1400

Distance in Feet

800

600 F

Q) 400
C CI)

200 F

0

R-217

+

200

400

600

800

0




+ Monument Location Y MHW Location From Survey Shoreline From Photo August 1999 Data
R-220

Y
Y

1000

1200

N
0

1400

Distance in Feet

800

600 F

Q.)
a)
a)
0

400

200 k

A-42

+

0

200

400

600

800




+ Monument Location Y MHW Location From Survey Shoreline From Photo August 1999 Data

R-220

+

R-221

Y +
YF

1000

1200

1400

Distance in Feet

800

600 k

w

400

200

0

200

400

600

800




800

+ Monument Location Y MHW Location From Survey Shoreline From Photo August 4gqq2Data 600
400
CO)
-p R-221
200
Y
0 200 400 600 800 1000 1200 1400

Distance in Feet




APPENDIX C
Plots of Continuous Shoreline From May, 1998 Photographs for Captiva Island and Lovers Key, Lee County, Florida.




CPE-84
400
+ Monument Location Y MHW Location From Survey Shoreline From Photo May 1998 Data 300
R-83
200 +
100
0 100 200 300 400 500 600 700 Pixels




R-85

+

+ Monument Location Y MHW Location From Survey Shoreline From Photo May 1998 Data
CPE-84

-

200

400

600

800
Pixels

1000

1200

1400

800

600

C-)

400

200

0

U)




+ Monument Location Y MHW Location From Survey Shoreline From Photo May 1998 Data

1000

1200

1400

R-85

+

800

600 -

R-86

+

C-)

M)

400

200 F

0

200

400

600

800
Pixels




+ Monument Location
Y MHW Location From Survey
_ Shoreline From Photo R-87 May 1998 Data

+

1000

1200

1400

800

R-86

+

600 k

C-)

400

200 k

0

200

400

600

800
Pixels

,0




+ Monument Location R-87 Y MHW Location From Survey Shoreline From Photo May 1998 Data
R-88

200

400

600

800
Pixels

1000

1200

1400

800

+

600 F

U1

400

200 F

0




+ Monument Location Y MHW Location From Survey Shoreline From Photo May 1998 Data

1000

1200

1400

800

600 k

C)

R-88

+

WI

400 F

R-89

200 -

Y

0

200

400

600

800
Pixels




800

+ Monument Location R-89 Y MHW Location From Survey Shoreline From Photo May 1998 Data 600
R-90
400 -+
200 Y
0 200 400 600 800 1000 1200 1400 Pixels




+ Monument Location Y MHW Location From Survey Shoreline From Photo May 1998 Data

+

1000

1200

1400

800

600 F

C-)

U)
C)400

R-90

+

CPE-91

Y

200 F

0

200

400

600

800
Pixels




+ Monument Location Y MHW Location From Survey Shoreline From Photo May 1998 Data
R-92
CPE-91
+
-Y

0

200

400

600

800
Pixels

1000

1200

1400

800

600

In
400

(0

200

.0




+ Monument Location Y MHW Location From Survey Shoreline From Photo May 1998 Data
CPE-93
R-92 +

200

400

600

800
Pixels

1000

1200

1400

800

600 I-

)
S400

0

200 I

0

.0




+ Monument Location Y MHW Location From Survey Shoreline From Photo May 1998 Data
R-94
CPE-93
Y

200

400

600

800
Pixels

1000

1200

1400

800

600 F

0

400

200 I

0

.0




+ Monument Location Y MHW Location From Survey
- Shoreline From Photo
May 1998 Data

R-94

OL-95

1200

1400

800

600 |-

400

+

200 F

Y

+

0

200

400

600

800
Pixels

1000




+ Monument Location Y MHW Location From Survey Shoreline From Photo May 1998 Data

CPE-96

+

I I I I

1500

1800

2100

1200

900 F

600

300 F

OL-95

0

300

600

900

1200 Pixels




+ Monument Location Y MHW Location From Survey Shoreline From Photo May 1998 Data

1000

1200

1400

800

600 F

0

400

CPE-96

- +

R-97

200 I-

+

0

200

400

600

800
Pixels




+ Monument Location Y MHW Location From Survey Shoreline From Photo May 1998 Data

R-97

CPE-98

+ Y-

400

600

800
Pixels

1000

1200

1400

800

600 H

C) c-fl

400

+

200

0

200

.0




+ Monument Location Y MHW Location From Survey Shoreline From Photo May 1998 Data
CPE-99
CPE-98

200

400

600

800
Pixels

1000

1200

1400

800

600 F

C-)

0)

400

200 F

0




+ Monument Location
Y MHW Location From Survey
Shoreline From Photo
May 1998 Data
R-100

1000

1200

1400

800

600 F

C)
-'2

400

CPE-99

+

200 [ Y

0

200

400

600

800
Pixels




+ Monument Location Y MHW Location From Survey Shoreline From Photo May 1998 Data
R-101
+ R-102

200

400

600

800
Pixels

1000

1200

1400

800

600 F

CO)

Q) 400

200 -

0




800
+ Monument Location Y MHW Location From Survey Shoreline From Photo May 1998 Data 600
R-102
+ R-103
400
200
0 200 400 600 800 1000 1200 1400 Pixels




+ Monument Location Y MHW Location From Survey Shoreline From Photo May 1998 Data
R-103 CPE-104 ++

200

400

600

800
Pixels

1000

1200

1400

800

600 k

CD

Q) 400

200 [

0




+ Monument Location Y MHW Location From Survey Shoreline From Photo May 1998 Data
CPE-104 R-105

200

400

600

800
Pixels

1000

1200

1400

800

600 -

+

Y)

C-)

400 -

200 Ky

0




+ Monument Location
Y MHW Location From Survey
Shoreline From Photo
May 1998 Data R-106

R-105

800
Pixels

1000

1200

1400

800

600 k

a\

U)
Q)

400 I

200 k

0

200

400

600

.0




800
+ Monument Location Y MHW Location From Survey Shoreline From Photo R-106 May 1998 Data 600 + R-107 +
400
200
0 200 400 600 800 1000 1200 1400 Pixels




+ Monument Location Y MHW Location From Survey Shoreline From Photo May 1998 Data

R-108

1000

1200

1400

800

R-107

+

600 I

a

S4
a>400

200 [-

0

200

400

600

800
Pixels




+ Monument Location Y MHW Location From Survey Shoreline From Photo May 1998 Data

1000

1200

1400

800

600 F

C-)
Co

400

R-108

+-1

R-109

200 -

+

0

200

400

600

800
Pixels

Y

Y-




400

+ Monument Location Y MHW Location From Survey Shoreline From Photo May 1998 Data 300
R-212 R-211
200
100
0 100 200 300 400 500 600 700
Pixels




800

R-212

+

R-213

+

+ Monument Location Y MHW Location From Survey Shoreline From Photo May 1998 Data

600 I

Q) 400
X

200 F

0

Y

200

400

600

800
Pixels

1000

1200

1400

Z\)




800
+ Monument Location Y MHW Location From Survey R-213 Shoreline From Photo + May 1998 Data 600
400
200 R-214
Y
0 200 400 600 800 1000 1200 1400
Pixels




+ Monument Location Y MHW Location From Survey Shoreline From Photo May 1998 Data

+

1000

1200

1400

800

600 I

C-) Co Co

G)

400 k

R-214

+

200 F

0

R-215

200

400

600

800
Pixels




800
+ Monument Location Y MHW Location From Survey Shoreline From Photo May 1998 Data 600
Q) 400
200 T-216
R-215
0 200 400 600 800 1000 1200 1400 Pixels




800

600 F

+ Monument Location Y MHW Location From Survey Shoreline From Photo May 1998 Data
R-217
T-216 +

+

200

400

600

800
Pixels

1000

1200

.0

1400

a,

U)
Q) 400

200 -

0




+ Monument Location Y MHW Location From Survey Shoreline From Photo May 1998 Data
R-218
R-217 +

200

400

600

800
Pixels

1000

1200

1400

800

600

C-)

U)

400 k

200 F

0

.0