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Review of selected east coast Florida inlets
Boca Raton Inlet, Florida 
Evaluation of coastal processes and management practices and development of

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Review of selected east coast Florida inlets Boca Raton Inlet, Florida Evaluation of coastal processes and management practices and development of
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Review of selected east coast Florida inlets Boca Raton Inlet, Florida Evaluation of coastal processes and management practices and development of
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Dean, Robert G.
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Gainesville, Fla.
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Coastal & Oceanographic Engineering Dept. of Civil & Coastal Engineering, University of Florida
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English

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University of Florida
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TJFL/COEL -2004/007

REVIEW OF SELECTED EAST COAST FLORIDA INLETS BOCA RATON INLET, FLORIDA EVALUATION OF COASTAL PROCESSES AND MANAGEMENT PRACTICES AN]) DEVELOPMENT OF SEDIMENT BUDGETS
by
Robert Dean William McDougal and
Andrea Smith
June 28, 2004
Submitted to:
Bureau of Beaches and Coastal Systems Department of Environmental Protection Tallahassee, FL 32399
Coastal & Oceanographic Engineering Program
Department of Civil & Coastal Engineering 575 Weil Hall 9 P.O.Box 116580 e Gainesville, Florida 32611-6580
LTNIVERSIT OF FLOT7RIDT~A




UFL/COEL -2004/007

REVIEW OF SELECTED EAST COAST FLORIDA INLETS BOCA RATON INLET, FLORIDA EVALUATION OF COASTAL PROCESSES AND MANAGEMENT PRACTICES AND DEVELOPMENT OF SEDIMENT BUDGETS
by
Robert Dean William McDougal and
Andrea Smith

June 28, 2004
Submitted to: Bureau of Beaches and Coastal Systems Department of Environmental Protection Tallahassee, FL 32399




REVIEW OF SELECTED EAST COAST FLORIDA INLETS
BOCA RATON INLET, FLORIDA
EVALUATION OF COASTAL PROCESSES AND
MANAGEMENT PRACTICES AND
DEVELOPMENT OF SEDIMENT BUDGETS
June 28, 2004
Prepared by:
Robert Dean William McDougal Andrea Smith
Submitted to:
Bureau of Beaches and Coastal Systems Department of Environmental Protection
Tallahassee, FL 32399
Submitted by:
Department of Civil and Coastal Engineering
University of Florida
Gainesville, FL 32611-6590




TABLE OF CONTENTS
ADVANCE SUMMARY .............................................1I
1.0 INTRODUCTION ............................................... 2
2.0 THE SYSTEM OF INTEREST ...................................... 3
2.1 General .................................................. 3
2.2 Boca Raton Inlet............................................ 3
3.0 DATA USED IN ANALYSIS........................................ 7
3.1 Survey Data................................................... 7
3.2 Nourishments Conducted......................................... 7
3.3 Sand Bypassing at Boca Raton and Hillsboro Inlets ... ..................9
4.0 CORRECTIONSIMODIFICATIONS TO SURVEY DATA .................12
4.1 Attempts to Correct Survey Data for Non-Closure ...................... 12
4.2 Correction for Monument Relocation ............................... 13
5.0 UNCERTAINTIES IN DEVELOPING SEDIMENT BUDGETS .............15
5.1 General .................................................. 15
5.2 Volume Changes........................................... 15
5.3 Bypassing Quantities by Dredge................................ 16
5.4 Natural Bypassing Quantities ................................. 16
5.5 Nourishment Volumes...................................... 16
6.0 GRAP-HCAL PRESENTATION OF RESULTS......................... 17
6.1 Total Changes in Cumulative Volumes and Planform Areas
Within Segments........................................... 17
6.1.1 Changes in Cumulative Volumes ....................... 17
6.1.2 Changes in Total Cumulative Beach Area Within Segments ... 19
6.2 Longshore Distributions of Volume and Shoreline Change ............19
6.3 Sediment Budgets.......................................... 22
7.0 RESULTS AND INTERPRETATION ................................ 24
7.1 Cumulative Plan Area and Volume Changes With Time
for the Three Sections ....................................... 24
7.1.1 Segment 1........................................ 24
7.1.2 Segment 2........................................ 26
7.1.3 Segment 3........................................ 28




7.2 Distributions and Cumulative Distributions of Shoreline and Volume
Changes in Various Segments ................................. 31
7.2.1 G eneral .............................................. 31
7.2.2 Early Time Period: Mid 1970's to. Early 1990's .......... 31
7.2.2.1 Shoreline Changes, Early Time Period ........ 31
7.2.2.2 Volume Changes, Early Time Period ......... 33
7.2.3 Later Time Period ................................ 35
7.2.3.1 Shoreline Changes, Later Time Period ......... 35
7.2.3.2 Volume Changes, Later Time Period ......... 35
7.3 Sediment Budgets ............................................. 38
7.3.1 G eneral .............................................. 38
7.3.2 Sediment Budgets For Each of Three Segments ............... 38
7.3.3 Global Sediment Budgets ............................... 40
8.0 RECOMMENDED SEDIMENT BUDGET PROTOCOL FOR BOCA RATON
IN LET ............................................................ 41
8.1 G eneral ................. .................................... 41
8.2 Recommended Sediment Budget Protocol for Boca Raton Inlet .......... 42
9.0 POSSIBLE FUTURE EFFORTS ....................................... 42
9.1 Deerfield Beach Groin Field ..................................... 42
9.2 Bar Bypassing Around Boca Raton Inlet ........................... 43
10.0 SUMMARY AND CONCLUSIONS .................................... 44
10.1Sum m ary .................................................... 44
10.2 Conclusions ................................................ 45
11.0 ACKNOWLEDGEMENTS ........................................... 45
12.0 REFERENCES .................................................... 46
APPENDIX A: A SERIES OF 18 PHOTOGRAPHS OF
BOCA RATON INLET: 1936 TO 1995 ................................ 47
APPENDIX B: SEDIMENT BUDGET METHODOLOGY ..................... 67
APPENDIX C: PLOTS OF SELECTED PROFILES CORRESPONDING TO
LONG PROFILE MONUMENTS FOR EARLIEST SURVEY
FROM R- 189 IN PALM BEACH COUNTY TO
R-55 IN BROWARD COUNTY ............................... 71




LIST OF FIGURES
Figure Caption Page
I Aerial Photograph of Boca Raton Inlet. November 6, 1995 ......... 2
2 Representation of System of Interest as
Three Shoreline Segments ................................ 4
3 Modifications to Boca Raton Inlet System. (From CPE, 1992) ...... 6
4 Schematic of System Considered and Distances of Relevant Features
South of Monument R-189 in Palm Beach County ............. 8
5 Historical Bypassing Characteristics at Boca Raton Inlet ......... 10
6 Historical Bypassing Characteristics at Hillsboro Inlet ............ 11
7 Survey Procedure With Wading Profiles Conducted at Low Tide
and Boat Profiles Conducted at High Tide ............... 12
8 Four Profile Surveys at Monument R- 15 in Broward County ....... 14
9 Cumulative Differences in Elevation Beyond 20 foot Depth Distance.
M onument R-15 .................................... 14
10 Corrected Profiles at Monument R-15 in Broward County .......... 15
11 Total Volume Change With Time in Segment 2
and Cumulative Nourishment in Segment 2 ............... 18
12 Volume Change in Segment 2 Minus Nourishment ............... 18
13 Total Plan Area Change in Segment 2 ......................... 19
14 Distributions of Volume Change Rates and Cumulative
Change Rates For Period: Early 1990's to Early 2000's.
Calculations to 20 feet Depth Distance Offshore ................ 20
15 Volumetric Sediment Budgets For Early and Later Time Periods .... 23
16 Cumulative Plan Area Changes in Segment I ................. ;. 24
17 Cumulative Volume Changes in Segment 1
and Nourishment History ............................. 25
18 Cumulative Volume Changes Minus Nourishment in Segment 1 ..... 25
19 Cumulative Plan Area Changes in Segment 2 ................... 27
20 Cumulative Volume Changes in Segment 2
and Nourishment Hi story .............................. 27
21 Cumulative Volume Changes Minus Nourishment in Segment 2 ..... 28
22 Cumulative Plan Area Changes in Segment 3 ................... 29
23 Cumulative Volume Change in Segment 3
and Nourishment History ............................ 29
24 Cumulative Volume Change Minus Nourishment in Segment 3 ...... 30
24 Distributions of Shoreline Change Rates and Cumulative
Change Rates for Period: Mid 1970's to Early 1990's ............. 32




26 Distributions of Volume Changes and Cumulative Change Rates for
Period: Mid 1970's to Early 1990's.
Calculations to 20 feet Depth Distance Offshore ............34
27 Distributions of Shoreline Change Rates and Cumulative
Change Rates for Period: Early 1990's to Early 2000's ............ 36
28 Distributions of Volume Change Rates and Cumulative Change
Rates for Period: Early 1990's to Early 2000's.
Calculations to 20 feet Depth Distance Offshore ...........37
29 Volumetric Sediment Budgets For Early and Later Time Periods ..... 39
30 Typical King Pile Groin Installation.
Note: Rubble Mounds at Ends of Groins Not Shown ........43
LIST OF TABLES
Table Caption Page
1 Major Developments at Boca Raton Inlet
(From CPE, 1992) ................................. 5
2 Estimates of Net (Southward) Longshore Sediment Transport ........5
3 Survey Data Used in This Study ............................. 7
4 Nourishments of Influence to Segments and Time Periods Analyzed 9
5 Results of "Global Sediment Budget" Analysis ..................41




ADVANCE SUMMMARY

Available survey data were analyzed to determine the natural sand transport characteristics in the vicinity of Boca Raton Inlet for the purpose of developing a sediment budget for this inlet. This inlet has a weir section located in the updrift (north) jetty and a dedicated dredge which transfers sand to the downdrift beaches. This bypassing is supplemented by bypassing from the ebb tidal shoal on an infrequent basis (average of 8 years). The objective in the development of a recommended sediment budget leading to sediment management practices is to mimic, to the degree practical, the natural flows of sand past an inlet so that the natural processes are transparent to the presence of the inlet. In the development of sediment budgets it is necessary to recognize that the natural flows of sand can vary substantially from year to year. Thus a sediment budget should not incorporate a rigid requirement for an annual bypassing rate, but should provide a means to track and respond to the relative volumetric changes on the immediate updrift and downdrift beaches. The objective should be to achieve equity through balancing these volume changes.
The time period of interest encompassed in this effort was from the mid 1970's to the most recent surveys. During this period, a total of four nearly complete surveys were available in Palm Beach County and nine such surveys were available in Broward County. A total distance of approximately 18 miles was considered extending from approximately 7 miles north of Boca Raton Inlet to 5 miles south of Hillsboro Inlet. The encompassed system was considered as three segments with Segment 1 north of Boca Raton Inlet, Segment 2 the approximate 5 miles between Boca Raton Inlet and Hillsboro Inlet and Segment 3 south of Hillsboro Inlet. The nourishments both inside and adjacent to the system were accounted for as were the bypassing at the two inlets.
These survey and other data were analyzed and the results presented in several formats to aid interpretation. The formats which were most related to determination of a sediment budget considered two time periods: An "Early Period" from Mid 1970's to Early 1990's and a "Later Period" from Early 1990's to Early 2000's. During the Early period it was found that the volume in Segment 2 increased at a rate of 13,300 yd 3/year with no nourishment in this segment during this period. During the Later period when the survey data are expected to be more accurate, Segment 2 increased in volume at a rate of 77,600 yd 3/year above the average rate of nourishment and hydraulic bypassing additions. This could be due to either more natural bypassing via the ebb tidal shoal at Boca Raton Inlet and/or differences between the actual and reported hydraulic bypassing rates at the two inlets. The conclusion is that the volume in Segment 2 has been increasing over the total time period examined.
A sediment budget protocol for Boca Raton Inlet is recommended which includes: (1) Maintain a hydraulic bypassing capability of 100,000 yd 3/year which includes bypassing from the ebb tidal shoal as needed, (2) Conduct annual surveys to determine the volume change differences north and south of the inlet, and (3) During the following year, respond to these differences through bypassing modifications.




REVIEW OF SELECTED EAST COAST FLORIDA INLETS BOCA RATON INLET, FLORIDA
EVALUATION OF COASTAL PROCESSES AND MANAGEMENT PRACTICES AND
DEVELOPMENT OF SEDIMENT BUDGETS
1.0 INTRODUCTION
The primary objective of the project on which this report is based is to develop a recommended sediment budget protocol for Boca Raton Inlet, recognizing its inherent interannual variability. Although there are several approaches that could be utilized toward this objective, the generally extensive survey data along the Florida shoreline make the use of such data the most credible and appropriate approach. Although the focus is on Boca Raton Inlet, Hillsboro Inlet and beaches to the south of Hillsboro Inlet have been included to provide a broader base and a basis for checking the validity of some of the volume changes. Figure I presents a 1995 photograph of Boca Raton Inlet.

Figure 1. Aerial Photograph of Boca Raton Inlet. November 6, 1995.




2.0 THE SYSTEM OF INTEREST

2.1 General
The system of interest to this effort is defined as extending from Monument R- 189 in Palm Beach County to Monument R-55 in Broward County, a total distance of 93,810 feet, approximately 18 miles. As shown in Figure 2, this system is naturally represented as three segments with Segment I north of Boca Raton Inlet, Segment 2 between Boca Raton Inlet and Hillsboro Inlet and Segment 3 south of Hillsboro Inlet.
2.2 Boca Raton Inlet
Boca Raton Inlet is a natural inlet that is now stabilized by a north jetty of some 6 10 feet in length and a 490 feet long south jetty (both approximate and relative to the south shoreline). In its natural condition, this inlet was alternately open and closed. The inlet served to relieve elevated water levels in Boca Raton Lake following periods of high rainfall; however, during extended periods of low rainfall, the inlet was closed by natural sediment transport processes.
The major events leading to the modem day stabilized Boca Raton Inlet are summarized in Table 1 and Figure I has presented a reasonably recent photograph of Boca Raton Inlet. In its current form, Boca Raton Inlet is stabilized by north and south jetties with a weir of 65 feet in the north jetty and an 8 inch cutter head dredge which serves to transport sand to beaches south of the inlet. Figure 3, from Coastal Planning and Engineering (CPE, 1992) presents a summary of modifications made to Boca Raton Inlet and a recent configuration. This figure does not reflect a recent 50 feet seaward location of the weir section in the north jetty.
Various estimates exist of the net annual longshore sediment transport at Boca Raton Inlet. These estimates are summarized in Table 2. The Walton (1976) estimate is believed to be too large as a consequence of the effect of the Gulf Stream increasing the wave heights observed from ships which were used to calculate sediment transport.
Appendix A presents 18 historical aerial photographs extending from 1936 to 1995.




dV/dt QNOUP

dV/dt QnoIrOUR

dV/dt QNOUR

Segment 1

Segment 2 Segment 3

- OUT

Figure 2. Representation of System of Interest as Three Shoreline Segments.
Dates Shown are for "Early" Time Period.

Boca Raton Iv Hillsboro Inl

I




Table 1. Major Developments at Boca Raton Inlet
(From CPE, 1992)

Date(s) Development
1925 -1926 Inlet improvement by dredging. Inlet oriented to southeast
1930 -1931 Two jetties constructed approximately perpendicular to shoreline. Inlet
shoaling continued, requiring periodic dredging. 1940's Air Force provided funding to maintain inlet open, but was unsuccessful.
1952 Jetties repaired and inlet dredged.
1960 Report by Coastal Engineering Laboratory of the University of Florida
(CEIJ/UF) recommended jetty extension and dedicated dredge to maintain
__________inlet open and navigable.
1972 City of Boca Raton purchased small dredge and tug for purpose of bypassing
sand.
1975 City extended jetties and made repairs using CELIUF design for guidance.
North jetty extended 180 feet and included a section of concrete filled bags which could be removed to form a weir section. 1980 Concrete bags removed to form 65 feet weir section.
1980's Dredge capabilities increased to improve transfer from offshore shoal.
1985 Offshore shoal dredged: 221,000 yd' and placed on south beach.
R-223 to R-225.6
1996 Offshore shoal dredged: 220,000 yd' and placed on south beach.
R-223 to R-225.6
2002 Offshore shoal dredged: 343,000 yd' and placed on south beach.
R-223 to R-227.7
Table 2
Estimates of Net (Southward) Net Longshore, Sediment Transport
Source of Estimate Estimated Net Longshore Sediment Transport (yd /yr)
U. S. Army Corps of Engineers 150,000
(1955) ________________________Walton (1976) 280,000
Coastal Planning and 121,500
Engineering (1992) (This estimate is for the period: 1985 to 1991).




0 0
,. .
CD
('D
-t
0 CD0
0

&UGA tfAIUN INLL I 180 FT. NORTH JETTY
EXTENSION (1975)
SOUTH JETTY REINFORCED WITH BOULDERS AND CONCRETE BAGS ALONG 540 FT. LENGTH (1975)

DISCHARGE FOR DREDGE SAND
FROM INLET MAINTENANCE
SOUTH JETTY REINFORCED WITH BOULDERS ALONG 160 FT. LENGTH (1980)

ATLANTIC

OCEAN

.--*-APPROXIMATE MEAN HIGH
WATER SHORELINE

- APPROXIMATE MEAN HIGH
WATER SHORELINE
N
65 FT. WEIR 0 100 200
[SECTION (1980)
SCALE IN FEET




3.0 DATA USED IN ANALYSIS

3.1 Survey Data
The profile data analyzed in this study for Palm Beach and Broward Counties included four surveys for Palm Beach County and nine surveys for Broward County as summarized in Table 3.
Table 3
Survey Data Used in This Study
Palm Beach County Broward County
File Name Survey Date(s) File Name Survey Date(s)
PAL74AA.CCC Jan. 1975 BRO76AA.CON Dec. 1976
PAL90AA.CCC July to Oct. 1990 BRO93AA.FMN Oct. 1993
PALOOA.FCM July to Oct. 2000 2425-396.DEP Feb. & Mar. 1996
PAL01A.FCM June & July 2001 BRO97AA.FMN Aug. 1997
2592-998.DEP Aug. 1998
2657-999.DEP Aug. 1999
0901REV.DNR' Aug., Sept. 1991
1101REV.DNR' Dec. 2001, Jan. 2002
BRO02.NEW' Feb., Mar., & Aug. 2002
These files have been modified to remove obvious errors.
The data included in the analysis extended from Monument R-189 in Palm Beach County to Monument R-55 in Broward County, a distance of approximately 93,810 feet, about 18 miles. As shown in Figure 4, the north and south jetties of Boca Raton Inlet are located 36,179 feet and 36,494 feet south of Palm Beach County Monument R-189, respectively. The corresponding distances for the north and south jetties of Hillsboro Inlet are 64,518 feet and 65,237 feet south, respectively from Palm Beach Monument R-189.
3.2 Nourishments Conducted
The nourishments that were conducted within and adjacent to the area are summarized in Table 4. The first five entries in the table for Palm Beach County are for the Delray Beach nourishment project which is actually outside the limits of the area analyzed. However, as will be discussed later, this area is sufficiently close that it has affected the volume changes within Segment 1.




R-189 (0 feet)

k-~-R-22 (35,149 feet) North Jetty (36,179 feet) Boca Raton Inlet
South Jetty (36,494 feet) R-223 (36,654 feet)
--- -County Line (41,739 feet)
Hillsboro lne R-24 and North Jetty (64,518 feet)
South Jetty (65,237 feet) R-25 (65,397 feet)
R-55 (93,810 feet)
Figure 4. Schematic of System Considered and Distances of Relevant Features
South of Monument R- 189 in Palm Beach County.




Table 4

Nourishments of Influence to Segments and Time Periods Analyzed

Palm Beach County _____Broward County____Nourishment Alongshore Volume Nourishment Alongshore Volume
Date Ranges (yd') Date Ranges (yd')
July 1973 R-175.5 to R-188.5 1,635,000 1972 R-7 to R-12 360,000
May 1978 R-177.2 to R-182.7 701,000 1998 R-6 to R-12 555,000
Oct. 1984 R-175.5 to R-188.5 1,300,000 1970 R-32 to R-49 1,076,000
Dec. 1992 R-180 to R-188.5 1,198,000 1983 R-26 to R-53 1,900,000
Apr. 2002 R-180 to R-188.5 1,150,000 ___ ___Aug 1988 R-205 to R-212 1,100,000_____________Apr. 1998 R-205 to R-212 680,000 _______________3.3 Sand Bypassing at Boca Raton and Hillsboro Inlets
Sand bypassing operations are carried out at both Boca Raton Inlet and Hillsboro Inlet by relatively small dedicated dredges. The bypassing quantities are based on calibrations of the dredges and the time histories of these quantities were provided for purposes of this study. Figure 5 presents the annual and cumulative bypassing quantities for Boca Raton Inlet and Figure 6 presents the same type of information for Hillsboro Inlet. In addition to the more or less ongoing bypassing at Boca Raton Inlet, on three occasions a larger dredge has been utilized to dredge the ebb tidal shoal. Because this report reserves the term "nourishment" for sediment transported and placed on the beaches from outside the normally active littoral system, the removal of sand from the ebb tidal shoal and placement on the downdrift beaches is included here in the bypassing category. These ebb shoal bypassing events at Boca Raton Inlet are shown as the dotted lines in Figure 5a and are reflected in Figure 5b as the steeper portions of the cumulative curve.




An

0
)0
ii l i.i.....''..I.... ..J.........LS.......
1985 1995 20C

Year
a) Annual Bypassing Quantities

1985 1995

Year
b) Cumulative Bypassing Quantities
Figure 5. Historical Bypassing Characteristics at Boca Raton Inlet
10

05

0 cc)
0
M 2000
0
to 0) cc >.1000
E




Year

a) Annual Bypassing Quantities

1975 1985 1995
Year
b) Cumulative Bypassing Quantities

Figure 6. Historical Bypassing Characteristics at Hillsboro Inlet.
11

"Au

1401-

4VV

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4.0 CORRECTIONS/MODIFICATIONS TO SURVEY DATA
4.1 Attempts to Correct Survey Data for Non-Closure
The profile surveys analyzed here that extended a sufficient distance seaward to calculate volumes were always surveyed in two segments: (1) A so-called "wading survey" in which the person carrying the survey rod walks/wades along the profile and the elevation is determined, usually with a level, and (2) A "boat" portion of the survey in which the elevation of the sea floor relative to the water level is determined by a fathometer. Figure
7 shows these two operations schematically. The wading portion of the survey is much more accurate than the boat portion and is usually conducted at low tide. The reduced accuracy with the boat survey, which is usually more of a concern with the earlier (1970's) surveys, is that the water level from which the fathometer soundings were measured is known only approximately. A common approach to determining an estimate of the water level reference is by placing a tide gage on a support and the tide gage recording then serves to establish the vertical datum. In some cases, the tide gage was placed inside an interior water body or on a bridge pier; however, the water levels at neither of these locations is representative of the water level on the outer coast where the surveys are being conducted. An indication that the survey data are in need of correction is if the outer portions of the surveys do not "close", that is, they are at different elevations for the various surveys. A further indication of a datum problem is if the outer portions of the various surveys are more or less parallel. One can argue that if the profiles do not "close" at their outer extremities, either a correction is in order or the profiles did not extend a sufficient distance seaward to capture the entire volume change.
Land Survey
Off shore Survey
Figure 7. Survey Procedure With Wading Profiles Conducted at Low Tide and Boat Profiles Conducted at High Tide.
A method that was attempted to correct the outer portions of the profiles in this study is as follows. A depth of 20 feet was adopted as the depth seaward of which, there should be little or no actual profile elevation changes. Because the most recent profile was presumably surveyed with the most modern methods, this profile was adopted as the reference. Commencing at the distance associated with the 20 foot water depth on the most recent profile, the differences between the most recent profile and each of the other




profiles was integrated (actually summed) in the offshore direction. Ideally, this integral (sum) would be zero at all locations seaward of the starting location signifying that there was no offset in the two profiles under consideration. If this integral (sum) varies linearly from the starting location, this is an indication of a uniform offset. A least squares straight line was fit to this integral passing through the starting point (distance corresponding to 20 foot depth on the reference profile) with the slope of the line representing the vertical offset which could then be used to correct the profile seaward of the 5 foot water depth (which was assumed to be the seaward limit of the wading surveys). All profiles (except the most recent) would be corrected in this manner.
Figure 8 presents four surveys in Broward County at Monument R-15, a profile that showed a large intersurvey difference in the earliest profile. Is seen that the 1976 profile is generally at a considerably higher elevation than the other three surveys. Figure 9 presents the variation of the integral (sum) of the deviations from the starting location. It is seen that the differences between the 1976 survey and the reference profile (2002) are nearly linear. Also shown in this figure are the vertical corrections indicated by this method for all three surveys. At this monument, all indicated corrections except for the 1976 survey were small, ie 1976,- 2.57 ft, 1993, +0.13 ft, 1997: +0.11 ft. Figure 10 presents the corTected profiles where it is seen that all the outer portions of the profiles are now much more consistent. Also, the elevation reduction in the 1976 profile at the 5 feet water depth is evident.
Thorough inspection of the profiles during the latter portions of this study effort did not inspire confidence in the described method of correcting profiles and, although earlier versions of this report included results from this correction method, it was decided to not include results from this method, but rather to include only the volumes based on uncorrected profiles. The correction procedure described above is simply not consistent with the range of characteristics of obvious survey errors. Appendix C presents plots of all of the monuments from which long survey lines were conducted during the earliest (1970's) surveys and illustrates some of the potential pitfalls in applying the correction method. It appeared that to apply this correction method appropriately, each profile would require treatment individually without a consistent set of rules, thus injecting too much subjectivity into the analysis. Proceeding with the uncorrected surveys is at least unbiased and not subjective. In summary, all volumetric results presented in this report are based on the uncorrected profiles.
4.2 Correction for Monument Relocation
Where appropriate, the survey data were corrected for monument relocation. The locations of the monuments are presented in State Plane Coordinates in each survey data set. If the monument had been relocated, the measurements from the new monument were shifted an appropriate horizontal distance corresponding to the projection of the shift on the alignment (azimuth) of the profile line.




1 0 . . ......
..... ~. .... .. .. .. . .. .. .. .... ..... . .... .. i
0 0
z
- 1 0 . . . . .? . . . . .i. . . . .. . . . - - --- - - - - .
4) -20
l~lJ-- -40 ... ... .. ,++ \ ... ... ..! ... .. ..i ............. ............. I :+..-. ... -.... .. ....... ............
C
0
4= -30
-50
0 1000 2000 3000 400
Distance (ft)
Figure 8. Four Profile Surveys at Monument R- 15 in Broward County
1600
I 1976, m =-:.57 ... .......
, 1997, m=-0111
0
,I,,1200
4)
w 10 00 . .. . .. . ... . . . . . .. .
8800
400 .
Q . . ... +
.... .:+ ...... ... ... ..... ......... -: + : -' '++ -,-- : + .+. +.. >+. .. :..... ..
*200
0 100 200 300 400 500 600 700
Distance From 20 foot Contour (ft)
Figure 9. Cumulative Differences in Elevation Beyond 20 foot Depth Distance.
Monument R-15.




.10 ..19
2002
z
-0
20 -2
00
= -30
-50 0
0 1000 2000 3000 4000
Distance (ft)
Figure 10. Corrected Profiles at Monument R-15 in Broward County.
5.0 UNCERTAINTIES IN DEVELOPING THE SEDIMENT BUDGETS
5.1 General
It is useful in developing the sediment budgets to understand, to the degree possible, the uncertainties in the components forming the basis for the sediment budgets. These components include: volume changes, bypassing quantities by dredge, natural bypassing around the two inlets, and nourishment quantities. The estimated accuracies associated with each of these components are discussed below.
5.2 Volume Changes
The volume changes were calculated from the surveyed profiles. The numbers of profiles in the three segments were: Segment 1, 34 profiles; Segment 2, 29 profiles and Segment 3, 31 profiles. The first surveys (1974/1975 in Palm Beach County and 1976 in Broward County) extended beyond wading depth at only every third monument, so for the early surveys, volumes could be computed from only approximately one-third of the profiles. If errors in the individual profiles were randomly distributed, one would expect that with the numbers of profiles in a particular segment, the overall volumetric errors would be relatively small. However, if a bias in the survey data for one time period existed, this could contribute to a rather large overall volumetric error. As discussed previously, the




most likely cause of a survey bias would be the offsets due to an incorrect vertical datum. It is difficult to estimate the overall error in calculated volumes; however, the analysis results for the system of interest will assist later in this effort. The Reader is referred to the profile plots in Appendix C to develop a partial appreciation of the errors in the early surveys where a bias appears evident, especially in Segments 2 and 3 of the system under consideration.
5.3 Bypassing Quantities by Dredge
The reported bypassing rates are based on calibration of the dredge and development of average pumping rates based on intake pressures and other measurements. Although best efforts have led to these calibrations and the applications thereof, it is estimated that the overall bypassing quantities are accurate to within 30%.
5.4 Natural Bypassing Quantities
A natural inlet will establish an ebb tidal shoal which serves as a "sand bridge" for a portion of the net longshore sediment transport around the inlet. The weir sections present in the north jetties of the two inlets tend to reduce the quantities of sediment jetted to the ebb tidal shoal and thus the tendency for natural bypassing. However, the weir and deposition basin features for the two inlets differ in the degree to which they sequester sediment. Boca Raton Inlet can only store limited sediment volumes in the inlet channel whereas Hillsboro Inlet has a substantial deposition basin which has a greater tendency to prevent sand from being transported to the ebb tidal shoal. Thus, some of the sand that flows through the weir section in the north jetty of Boca Raton Inlet is accessed by the dredge and transported to the downdrift beaches and some is jetted to the ebb tidal shoal which can be fairly prominent. The centroid of the Boca Raton Inlet ebb tidal shoal is positioned to the south of the entrance channel, in part due to dredging and, possibly in part, due to the predominant direction of the longshore transport and longshore currents during ebb tidal flows. As the ebb tidal shoal grows, there is a greater tendency for natural transport to the south beaches. While it is likely that some sand has been bypassed naturally, it is not possible to make a quantitative estimate of the associated volumes. As in the case of volumetric errors, the analysis results presented later may contribute to a better understanding of natural bypassing quantities.
5.5 Nourishment Volumes
It is estimated that the errors in nourishment volumes are within approximately 20% of the reported volumes with the actual amount more likely to be greater than reported.




6.0 GRAPHICAL PRESENTATION OF RESULTS

Three graphical formnats are used herein to present different types of results as described below.
6.1 Total Changes in Cumulative Volumes and Planform Areas Within Segments
6.1.1 Changes in Cumulative Volumes
The three shoreline segments considered have been discussed earlier and presented in Figures 2 and 4. This first graphical format utilizes the four surveys in Palm Beach County and the nine surveys in Broward County combined with the nourishment information (Table 4) to determine the total volume and planform area changes in the three segments. Examples of these results are presented for the total volume changes and the changes accounting for the effects of beach nourishment.
The procedure described above is straightforward for Segments 1 and 3; however, because portions of Segment 2 are in the two different counties and were surveyed at different times, an approximation was necessary. Because approximately 8 1% of Segment 2 lies in Broward County, the Segment 2 volume and plan area changes in Palm Beach County corresponding to the Broward County survey dates were interpolated linearly from analyzed results from the four surveys in Palm Beach County and then added to the Broward County results.
Examples of this type of results are presented in Figures 11 and 12 for the volume changes in Segment 2. The solid line in Figure 11I represents the total volume change from 1976 and the dashed line is the cumulate nourishment volume in Segment 2 (only the 1998 nourishment for Segment 2). Figure 12 presents the volume change with the nourishment deducted. If all of the volume calculations and estimates of nourishment were exact, this latter quantity would be zero if the bypassing at Boca Raton Inlet and Hillsboro Inlet were equal. Later presentations of the sediment budget will include this type of information with the bypassing taken into consideration. Figure 12 indicates that during the period encompassed by this study, there has been a net increase in volume in Segment 2 of approximately 740,000 yd 3. Additionally, the effects of the 1998 nourishment are evident.




1980

1990 Year

2000

Figure 11. Total Volume Change With Time in Segment 2
and Cumulative Nourishment in Segment 2.

1980 1990 2000
Year

Figure 12. Volume Change in Segment 2 Minus Nourishment.

-a-- Tot

1.8
(I,
0 1.60 1.4 1.2
4) 1.oE
70.8 o 0.6
0) 0.4
C
*-- 0.2
C.

Ia Volume Change
urishrnent Volum e -------............. ... .. ... .. ... ... .. ... ..
. . . . . . . .... . . . ... . . . . . .. . . ... . . - - -
. . . . . . . . ... . . . . . . . . i 2 i 1 2 1 1
........... . . .
. . .. .... .. . 2. .. . ... .. .. . .. . .. ..... . .. . . t .. .. ... . .
.. . i .. ...... .. .... ..... .. -. ... .. .. ..... .. ... ... .. ..... . .

u.u
1970

2010

c,,
08
"0 0.8 ..
0 0.7 0.6 S0.5 S0.4 C 0.3
0)0.2
*- 0.1
0.0 L
1970

2010




6.1.2 Changes in Total Cumulative Beach Area Within Segments

The total cumulative beach area (area above the NGVD contour) within the three segments was calculated in a manner similar to that for volumes as just described. However, there is no basis for correcting total plan areas for nourishment. Figure 13 presents the total cumulative beach area changes for Segment 2 where it is seen that the shoreline area increased from 1976 to 1993, then decreased until the 1998 beach nourishment project followed by a general decrease. The results in Figures I11 and 13 for the total volume and planform area bear general similarities and both have increased over the period of record examined herein.
~1.5 __ _0 Total Volume Change
0----- Nourishment Volume
0
1 .0
19018 99 0021
Yea
Fiue1.Ttl lnAe hng nSget2
6. oghr itiuin f oueadSoeieCag
19 970 198 1990y 2000's Iti2010 egetIta hreaevlm nressa oto
6.2 monushors Ditsibu actions f a Volu e nSore ine ofchage o nltTi
sheneand volumeri icheane adte, cumlartivte doisibutn of these0 changes.rFigdu
in 1998 between R-205 and R-212 (Table 4). Additionally, the Delray Beach




20
.4
C
C) -10
E

.............. ....:
.... i ...;... .: ; ..i ... ... .i. ..? ... ......... ....... ... ..... .... !.. ...
....... ... . .. .
I..... . .
.. .. ... I ...... .. .. i i
. . i . i i i. . i

0 10000 20000 30000 40000 50000 60000 70000 80000 90000 100000
Longshore Distance (ft)
a) Longshore Distribution of Volume Change Rates,
Early 1990's to Early 2000s.

150000 0 130000 0 110000 ca
90000
01
r_ 70000
50000
E 30000 0 10000
-1000 .>
-30000 E -50000 U)

H'd OI i "' i : I : :9b Po.! I O9! I I
...... ..... ..... .. . . ... . . .. . . .. .. .- : . ....
. ........- ------- .I.. ..- .--. --.. ..........
. .. . .. . . .. . . . ........i.....i....i.....!........... !..... .... ...... .V . . . . . ... .. .
... ... ... i. ..... .. .. .....L .. ... ... ....... ...... ..... .. .. ......... ........ .
0 10000 20000 30000 40000 50000 60000 70000 80000 90000 100000 Longshore Distance (ft)

b) Cumulative Distribution of Volume Change Rates, Early 1990's to Early 2000's
Figure 14. Distributions of Volume Change Rates and
Cumulative Change Rates For Period: Early 1990's to Early 2000's.
Calculations to 20 feet Depth Distance Offshore.

0
0
0

8




nourishment project which commenced in 1973 and in which 4,834,000 yd 3 had been placed by 2001 has influenced the northern portion of this segment. In Segment 2, the volume changes are also dominantly increases, and again due in part to the 1998 nourishment of 555,000 yd 3 between monuments R-6 and R-12 in Broward County. In Segment 3, the changes are both accretion and erosion and there have been no large scale beach nourishment projects in this time period represented by the two surveys.
The lower panel in Figure 14 presents the cumulative volume changes within the three, segments. In Segment 1, the volumes are accumulated starting at the north jetty of Boca Raton Inlet toward the north. In Segment 2, two cumulative curves are presented with one curve commencing at the south jetty of Boca Raton Inlet and continuing south to the north jetty of Hillsboro Inlet and the second curve commencing at the north jetty of HiEllsboro Inlet and continuing north to the south jetty of Boca Raton Inlet. Of course, these two curves in Segment 2 are related as they are both based on the same volume change information (upper panel). In Segment 3, the volume changes are accumulated commencing at the south jetty of H-illsboro Inlet and continuing south to Monument R55. In Segment 1, the total volumetric accumulation rate from the north Boca Raton Inlet jetty north to Monument R-189 is 61,500 yd 3/year. This is compared to the average beach nourishment placement of 61,800 yd3/year. Additionally, it is estimated that a total of some 40,000 yd 3/year has entered the northern portion of Segment 1 as a result of the Delray Beach nourishment project. Segment 2 has experienced a volume increase of approximately 100,000 yd 3/year whereas the average nourishment rate is 61,700 yd 3/year. Segment 3 lost volume at an average rate of 11,500 yd 3/year during this period when no nourishment occurred in this segment.
The complete set of the graphs of this type will be presented later in the "Results and Interpretation" section including shoreline changes and cumulative shoreline changes (changes in plan area). It can be appreciated that the information available in plots of the types presented forms the basis of a sediment budget, a primary objective of this study.




6.3 Sediment Budgets

The third graphical format employed to present results is the sediment budget. The basis for the development of the volumetric sediment budgets is presented in Appendix B. An example of the format used to present the sediment budgets is shown in Figure 15. The information in this type figure is in average yd3/yr and accounts for all nourishment and bypassing. As will be discussed in greater detail later, this allows estimates to be developed of the net longshore sediment transport into the northern boundary of the system (R-189 in Palm Beach County) and out of the system (R-55 in Broward County). Additionally, the amount of information available allows a check of the results in Segment 2 where the net volume change based on nourishment and bypassing can be compared with that calculated from surveys providing an overall basis for evaluating accuracy of calculations, volumetric and nourishment estimates and bar bypassing with the caveat that bar bypassing may be reasonably large at Boca Raton Inlet. This type results and their interpretation will be discussed in greater detail later.




Second Period

S QN = 149,500 yd3/y
dV/dt = 169,900 yd3/yr
QNOUR 73,300 yd3/yr
Boca Raton Inlet) Boca Raton I
- = 53,000 yd3/yr
(1975 -1990)
= 47,000 yd3/yr (1976 to 1993)

IV/dt = 13,300 yd*/yr vs 26,500 yd3/yr (Calc) QNOUR = 0

Hillsboro Inlet Hillsboro In:
Bp = 73,500 yd3/yr
S dV/dt 66,800 yd3/yr
QNOUR = 111,760 yd3/yr
Qour = 118,460 yd3/y

QIN = 85,100 yd3/yr dV/dt = 61,500 yd-/yr
QNou = 61,800 yd3/yr
nlet BP = 86,400 yd3/yr
1990 to 2001)
= 88,900 yd'/yr
(1993 to 2002)
dV/dt 100,200 yd3/yr vs 22,600 yd3/yr (Calc) QNOURn = 61,700 yd3/yr
let Qn, = 128,000 yd3/yr
dV/dt = -11,500 yd3/yr QNOUR = 0
QouTr = 139,500 yd3/yr

Figure 15. Volumetric Sediment Budgets For Early and Later Time Periods.

First Period




7.0 RESULTS AND INTERPRETATION
Results are presented and interpreted in the three formats presented in earlier sections of this report.
7.1 Cumulative Plan Area and Volume Changes With Time for the Three Sections
7.1.1 Segment 1
Figures 16 through 18 present the results for cumulative plan area changes and volume changes for Segment 1. The cumulative plan area in Segment 1 (Figure 16) increases from 1974 to 1990, then decreases from 1990 to 2000 and increases from 2000 to 2001. Overall, there has been a total of approximately 1,590,000 square feet of dry beach area accumulation from 1975 to 2001. During the period represented in Figure 16, there has been a total of 1,780,000 yd3 of nourishment within Segment 1 and 4,834,000 yd3 of nourishment immediately north of Segment 1 (the Delray Beach Nourishment project). Both of these nourishments undoubtedly contributed to the positive cumulative plan area changes shown in Figure 16.

S2.0 01.8 .21.6
S1.4 01.2
~0.8
0
MC 0.6 .r- 0.4
0.0
197

1980 1990 2000
Year

Figure 16. Cumulative Plan Area Changes in Segment 1.




1990

2000

--- Total Volumne Change
~ ~ ~ ~ - - - - - N u i me tV lm .. ....... ............. .............. :...............
i i A'' i A

Year
Figure 17. Cumulative Volume Changes in Segment 1
and Nourishment History.

1980 1990 2000
Year

Figure 18. Cumulative Volume Changes Minus Nourishment in Segment 1.

0 1970

" 1.8 0 1.6 0 1.4 S1.2 4 1.0 S0.8 0.6 4)
IM 0.4 0.2
0.0
1970

2010

2010




Figure 17 presents the volume changes. The nourishment volume additions in Segment 1 are also presented in this figure. Figure 18 presents the volumes with the nourishments in Segment 1 subtracted. It is seen that the volume gain without nourishment is approximately 1.4 million yd It has been estimated previously (Dean, 2002) that at least
0.8 million yd 3of this increase is due to transport induced by the Delray Beach nourishment project located immediately to the north of Segment 1. This conclusion is reinforced by the study by Beachier (1993) which found that by 1990, the nourishment spreading effects of the Delray B each nourishment project extended at least two miles south of the Project limits and, based on his Figure 4, considering the 1974 to 1990 surveys, there was an average of 25,800 yd 3/year deposited within the first two miles south of the Project.
7.1.2 Segment 2
Figures 19 through 21 present cumulative plan area and volume change information for Segment 2. As for Segment 1, the plan area changes also increase with some oscillations. These oscillations may be due, in part, to the greater number of surveys providing greater detail in Broward County. It is seen from Figure 19 that over the total period represented, there has been an increase of approximately 750,000 square feet during which there has been nourishment of 555,000 yd 3 within Segment 2.




r-1.50 16.0 U) 4)
.0
197

1980

1990

2000

Year
Figure 20. Cumulative Volume Changes in Segment 2
and Nourishment History.

1980 1990 2000 2010
Year
Figure 19. Cumulative Plan Area Changes in Segment 2.

............ ...... ................. .............
0 Total Volume Change
------- Nourishm ent Volum e ... ........... ...... ............. .............. ...........
.......................... ..................................... -- ----------- ...... .......... .............
.......... ........ ..... ................... .......... ------------ .... .......... .............
.. .. .... .. ... ..... .. -- -- --- - ... ..... ..... ... ...... .... ..... . ...... ... ... ... ... .
--- --- -- --- ... ..... ...... .. .. ..... ... .. ..... .. ..... .. -- -- ... ... ... .. .. ...
.......... ........... ... -------- .... .. ... -------. ............. ...... .......... ........ ......
. . . . . . . . . . . .
. .. ........ ... ... ...... ... ..... --- --- --- ....... ........ ---- .............
.............. ............. ------------------ ...... ..... ............. ..... ........ .....................
.............. ............. ........... .. ......... .. ...... ............................
---- ---------------- ....... ...... ............ -- -- ---- .............. ..........
-- --------- ... .......... ........... ...
.. ..... .. ... ... .. .. .. .... .. .. .... -- ------ ---- ---- -- ---- --- --- ... .. .

1.8 0 1.6
o 1.4 ~1.2 4)1.0
E
7F 0.8 S0.6
MC 0.2 Q)

IJ.u 1970

2010




CO)
0 .9 ...... ------------ ------ ----- ---- ........... ...... ....... ............
.. ............... .... ----- -------- ......... .. .. .... .. .. .. .. ..... .. ..
.. .......... .... ............. ......... .... .. ..
0 0.8
........ ........... ----- ....... -- -------- ------------- ... .. .. .. ... .. ..... ... ...
------------- ---- -------- ......... ... .... .. .... ... ... ...
0 0 .7 --- ------ ----- -:" .... I'll, :
......... ..... ------------ --------- -- ---------- --- ------ ..... . ..... ....... -- -- --
.. .............. .. .. ... .... ...... ----- --- -- ----- ---- ...... . .. .. ... ..... .... .....
0.6
-------------- ---- ... ..... ..... ---- ---- ...... .. .......
4 ) 0 .5 ....... ........ ..... --- -- ------------------ ------ -0 .4 ------- .................. ............. ------------ --------- ......... ... 4
---- ---- .. ... .. .. .. .. .. ..... ................ .. ---- ---- ----....... .................. .... .........
r_ 0 .3 --------- ....... ....... --- -- ---- ---: ......... .. .. .. .. .........
.. .. .. ........ --- ---- ------- -------- --- --- ..... :
.. ............ .... ---------
IM 0 .2 -- --- --- ........ ... -- -' ---- :- --......... ....... ....... ....... .. .. .. -- -- --............ -- ------- -- -- .... ..... .. .. .. .....
0 .1 ------ ... .... ..... :-
.............
........ .. .... ....... ------------ ---------- -- ... .. .... ......... .. ..... >
0.0
1970 1980 1990 2000 2010
Year
Figure 21. Cumulative Volume Changes Nfinus Nourishment in Segment 2.
The volume changes and the nourishment in Segment 2 are presented in Figure 20. It is seen that there is a gradual increase to 1997, followed by an abrupt increase from 1997 to
3
1999, due to the 1998 nourishment of 555,000 yd followed by general stability. Figure 21 presents the volumes minus the 1998 nourishment. It is seen that there is a general stability in volumes following the 1998 nourishment. This is compared to the (anticipated) decrease in plan area subsequent to the 1998 nourishment (Figure 19).
7.1.3 Segment 3
The cumulative shoreline area and volume changes in Segment 3 are shown in Figures 22 through 24. As for the other two segments, these results show an overall increase in cumulative shoreline area. Referring to Figure 22, the total area increase over the period represented is approximately, 2,100,000 square feet. During the period represented, there has been nourishment of 1,900,000 yd 3 within Segment 3.




a Total Volume Change
A--- Nourishment Volume

.... ...... .. ... .. .. ......... .. ........ .. .. .... ........ .... .

3
2
0 L 1970

2010

1980 1990 2000
Year
Figure 22. Cumulative Plan Area Changes in Segment 3.

. ... ........ -- ------ --- ..... ...
.... .............
--- ------ -... ..... ...... -- -- -- --

....... .. .. .......
f
.. .. . . .. .. .. .. .. .

I 1970

2000

2010

1980

1990

Year
Figure 23. Cumulative Volume Change in Segment 3.




3
cr)
V .............. .............. ------ I ......... -- ----------- --------- ..............
4 0 2 .......... ........ .............. -------- ............
---- ------- ------ ....... ................ ------------ .......... ....
0
. ............. ----------- .................... --------- ------- -------------- ..............
0 ------E .............
.... ......... .............. ....... ...... .............. ..............
> ---- ---- ------ ..... ..... ........ -------------------- --- ----------- ------- ..............
r -2
ZI
..............
-3
1970 1980 1990 2000 2010
Year
Figure 24. Cumulative Volume Change Minus Nourishment in Segment 3.
The volume changes in Segment 3 and the nourishment volume placed directly within Segment 3 during the period represented are shown in Figure 23. It is seen that from 1976 to 1993, the volume increase is certainly related to, but less than, the nourishment. This may be due, in part, to a 1970 nourishment placed within Segment 3 (R-32 to R-49) of 1,076,000 yd 3 which was still inducing sediment transport from the Segment 3 system during the period examined here. Figure 24 presents the total volume changes minus the nourishment volumes placed in Segment 3.




7.2 Distributions and Cumulative Distributions of Shoreline and Volume Changes in Various Segments
7.2.1 General
This second presentation format has been explained earlier in this report and is one in which the distributions of shoreline and volume change rates are presented on a monument by monument basis and also the cumulative shoreline and volume change rates are presented in each of the three segments. These presentation formats provide a convenient basis for examining the rates of change at any location in the shoreline segment of interest.
These types of results are presented for two periods as discussed earlier. For Palm Beach County, the early period is from 1974/1975 to 1990 and the second period extends from 1990 to 2001. For Broward County, the time periods are from 1976 to 1993 and 1993 to 2002. As is evident, these periods are not the same for the two counties which complicates Segment 2 since it lies in both counties but predominantly (89%) in Broward County. These two periods will be referred to as the "Mid 1970's to Early 1990's" and "Early 1990's to Early 2000's", respectively. They will also be termed the "Early" and "Later" time periods for convenience. Finally, these results are presented as annual rates which facilitates the interpretation in sediment budget terms.
7.2.2 Early Time Period: Mid 1970's to Early 1990's
7.2.2.1 Shoreline Changes, Early Time Period
Figure 25a presents the longshore distribution of shoreline change rates on a monument by monument basis for this early time period. Several features are evident from this figure. First, it appears that there has been a net shoreline accumulation against the north Boca Raton jetty (recall that the weir section in the north jetty was opened in 1980). Also, the 1988 North Boca Raton Beach nourishment project of 1,100,000 yd 3 is evident. Relative to the longshore distance in Figure 25, this nourishment occurred from 16,700 feet to 24,700 feet south of Monument 189. The effect of the Delray Beach nourishment project is evident near the north end of Segment 1 and appears to extend southward to at least 9,000 feet.
In Segment 2, one monument shows large shoreline recession immediately south of Boca Raton Inlet and the effects of the 1985 ebb tidal shoal bypassing is evident (221,000 yd3 between Monuments R-223 and R-225.6). Finally, it appears that the shoreline has generally built out north of Hillsboro Inlet. In Segment 3, the 1983 nourishment project of 1,900,000 yd3 which extended from Monument R-26 to R-53 is evident.
Figure 25b presents the cumulative shoreline changes derived from the results in Figure 25a. These results are a different way of considering the results in Figure 25a and allow




20 b
0 .... ...... ....... .. ......... ..
1 1 H I1 aI M: IiNlltlIII 41111,,11111111,:
a)E

C
0 C
a)
C
I
0 o,

0 10000 20000 30000 40000 50000 60000 70000 80000 90000 100000
Longshore Distance (ft)

b) Cumulative Distribution of Shoreline Change Rates, Mid 1970's to Early 1990's. Figure 25. Distributions of Shoreline Change Rates and Cumulative Change Rates for Period: Mid 1970's to Early 1990's.
32

IA. I i
.10 ...-..
. ......... ... ......... ...........
-20
0 10000 20000 30000 40000 50000 60000 70000 80000 90000 100000
Longshore Distance (if)
a) Longshore Distribution of Shoreline Change Rates,
Mid 1970's to Early 1990s.
140000 : : : : : : : : !i : 1
140 ... ...........
120000 ....... .. .... .. )N;
100000 ..............'..."'.
...... ... ....."i " " .-." ..".-." ..' .......... . .'" .' .. ".". .. .... .
80000 ... .....
60000 .... ........... ......... ..... ....... ....... .. .. ...............
40000 ......... .......
20000 .. ...
o I
0

-20000




quantification of the total cumulative shoreline change rate at any shoreline location. At monuments where there is a large shoreline change rate, the cumulative curves in Figure 25b have steep slopes. It is seen that at the north end of Segment 1, the average annual platform area had increased by approximately 118,000 ft 2 per year over this 15 year period. In Segment 2, the value is approximately 37,000 ft per year. In Segment 3, the average is approximately 121,000 ft per year.
7.2.2.2 Volumes Changes, Early Time Period
The monument by monument volume changes and cumulative volume changes for this early period are presented in Figures 26a and 26b, respectively. For this period, the volumes increased in all three segments. Segment I volumes increased by approximately 170,000 yd 3 /year, in Segment 2, the increase was 13,300 yd 3 /year and in Segment 3, the increase was approximately 67,000 yd 3 /year.




20
CU
.. ........ ................ ........
..... Ti~iii iii............. i
0
0 10000 20000 30000 40000 5 60000 70000 8 90 100000
Longshore Distance (ft)
a) Longshore Distribution of Volume Change Rates,
Mid 1970's to Early 1900's.

200000
150000 100000

500
- -- - . ..
.. .i. .i. .i. .i. . ........ .. .i........ ... i. ;. . . . . .. ... .......... .. . .
E -5ooo I I
0 10000 20000 30000 40000 50000 60000 70000 80000 90000 100000 Longshore Distance (ft)
b) Cumulative Distribution of Volume Change Rates, Mid 1970's to Early 1990's. Figure 26. Distributions of Volume Changes and Cumulative Change Rates for Period:
Mid 1970's to Early 1990's. Calculations to 20 feet Depth Distance Offshore.
34

- - .... ....: ..... ....". ..... :..... .......... ... ....... "
:. ....:
h, d . A H:.fl.. ............ . ... .
i i i i i : il i l Ii




7.2.3 Later Time Period

7.2.3.1 Shoreline Changes, Later Time Period
The monument-by-monument shoreline change results are presented in Figure 27a and the cumulative results are presented in Figure 28b. In Segment 1, it is seen that there is a general shoreline recession for several thousands of feet north of Boca Raton Inlet, and generally mixed changes to the north within the limits of Segment 1. It may seem 3 surprising that there is not a greater signal from the 1998 nourishment of 680,000 yd3 in the same location as the earlier (1988) North Boca Project; however, this may be due to the larger 1988 project (1,100,000 yd 3) profiles continuing to equilibrate (shoreline recession) which had a greater effect than the shoreline advancement from the 1998 project. Overall, referring to the cumulative curves, Segment 1 lost area and Segments 2 and 3 both gained area at about the same rate. Most of the Segment 2 gain was in its northerly portion where the 1998 nourishment of 555,000 yd 3 occurred.
7.2.3.2 Volume Changes, Later Time Period
The corrected monument-by-monument and cumulative results are presented in Figures 28a and 28b, respectively. As expected, it is seen that the volume changes are more consistent with the nourishment carried out than the shoreline changes. Whereas the overall net shoreline area change in Segment 1 was negative, the cumulative volume change for Segment 1 is positive. As noted, this is consistent with profile equilibration that occurs after beach nourishment, particularly the relatively large 1988 North Boca Raton nourishment project. Of interest are the substantial differences between the early and later time periods as will be discussed in greater detail later. The net annual rates of volumetric change in Segments 1, 2 and 3 are + 61,500 yd 3/year, + 100,200 yd 3/year, and
- 11,500 yd 3/year, respectively.




2
0 4
0
02
o
-2

.0

0 10000 20000 30000 40000 50000 60000 70000 80000 90000 100000
Longshore Distance (ft)
a) Longshore Distribution of Shoreline Change Rates, Early 1990's to Early 2000's.

50000
40000 30000
20000 10000
0
-10000
-20000
-30000
-40000

-50000 . .. .
0 10000 20000 30000 40000 50000 60000 70000 80000 90000 100000 Longshore Distance (ft)

b) Cumulative Distribution of Shoreline Change Rates, Early 1990's to Early 2000's. Figure 27. Distributions of Shoreline Change Rates and Cumulative Change Rates for Period: Early 1990's to Early 2000's.

0 : : .: : : :: : : : :: : : I
....... i i i i i i T.... .. ..-- -.... ..... ...... ..... ....... ...... ...... ... ... .. ..... ..... ..... .
0 1 : : J .... ..... ...... i...... .....i ..... ...i i i i----.--i :I::. ..... .. .- . ... ..... ..... .....
..... .... ..... .... .... ~
0 T
10 ..... -- i ..... ... .......... i i....... ... ..... .... ..... ..... ...... ..... .....

. .i : :.. ... ..... .....! i i : ..., . ..... :..... ..... \ ..... . . .. ... .... .
..... ... .... .... .... ... ....
.......f ... I~o ..... .. . . .. . .I. . .
... ........ ..... ...... ... .. ..... ... ......... .. .. .... ..
.... ... ... .. . . .. .. ... ... .
.. . . ... .. .. .....: i i ; i




i i i...... i . . . ..........
1 0 ... ...................... ..... ..... .. ... ..... ..................... .. . . ... ..... ..... .
C ... ..... .. ... ....... .... ... .. .. .: .......... .. . . . . . . . .
c u t II , I f it Jl, i
- O . .. . .... ....... . . . . . . . . . ......... ..... ..... .....!..... .... ..... .
-20
0 10000 20000 30000 40000 50oo 60000 7ooo 80000 9oo 00000oo Longshore Distance (ft)
a) Longshore Distribution of Volume Change Rates, Early 1990's to Early 2000's.
6.
i i :......... .......i . . i
0it
0130000 20000 30000............. 400 5.0000 60000.70000. 8000 9
. . ...
50000 ........... ....... ...
.. ..... .. i .........: i: : i j : .
0, .. ...... ....................... ..............
a 130000 .. ...
.......... .... ............. ........ .. ......... ..
11...0. .. .... .. . . .
4)
. .. ..... .. . ... ) .......
,
1 0000
o 50000
E -50000
E .so0 10000 20000 30000 40000 50000 60000 70000 80000 90000 100000
Longshore Distance (ft)
b) Cumulative Distribution of Volume Change Rates, Early 1990's to Early 2000's.
Figure 28. Distributions of Volume Change Rates and Cumulative Change Rates for Period: Early 1990's to Early 2000's. Calculations to 20 feet Depth Distance Offshore.
37




7.3 Sediment Budgets

7.3.1 General
The basis for the development of the volumetric sediment budgets is presented in Appendix B. Of primary significance are the natural cycles that exist in wave and sediment transport characteristics, including the net longshore sediment transport which forms the primary basis for appropriate sediment bypassing characteristics. Thus, because the volumes of sediment transported along the shore can vary substantially from one year to the next, it is not appropriate to plan to bypass the same quantities of sediment on an annual basis. A more realistic approach is to plan on an average bypassing quantity and to adjust the annual bypassing quantities according to relative volume changes north and south of the inlet. Methods of quantifying these adjustments will be addressed in later sections of this report. Sediment budgets were developed for the two time periods represented by Figures 25 through 28 in the preceding section of this report. These sediment budgets account for the bypassing and nourishment.
The sediment budgets for the volume changes are presented in Figure 29 and are discussed in the following paragraphs.
7.3.2 Sediment Budgets For Each of Three Segments
Figure 29, shown earlier as Figure 15, presents the volumetric sediment budget for the Early and Later time periods. It is seen that the calculated sediment transports into Segment I differ substantially for the two time periods whereas the sediment flows out of Segment 3 are in better agreement. Although the distance encompassed was approximately 18 miles, one would not expect the net natural longshore sediment transport quantities to change greatly over this distance. It is somewhat surprising that the Early time period values of transport into Segment I and transport out of Segment 3 appear more consistent with expectations than the Later time period even thought the survey techniques are expected to be better during the Later time period. Also the volume changes calculated from surveys and based on nourishment and bypassing quantities are in better agreement during the Early than Later time period.
It is of interest (and perhaps relevant) that the reported bypassing quantities at Mllsboro Inlet are significantly greater than those at Boca Raton Inlet for both time periods: Early time period: approximately 20,000 yd 3 /year greater and Later time period: approximately 40,000 yd 3 /year greater. Also, because the Delray Beach nourishment project was in its earlier stages of evolution during the Early time period, there may have been more induced sediment flows into Segment 1 during the Early than Later time periods.
Focusing on the Later time period, it is noted that there was a volumetric rate of increase of 77,600 yd 3 /year more in Segment 2 as determined by surveys than can be accounted for by the reported bypassing and nourishment quantities. If, as an example, the sum of the natural and net hydraulic bypassing at Boca Raton Inlet during the second time period




Second Period

- QIN = 149,500 yd3/y dV/dt = 169,900 yd3/yr QNOUR 73,300 yd3/yr

Q- = 85,100 yd3/yr dV/dt = 61,500 yd3/yr QNOUR = 61,800 yd3/yr

W W
Boca Raton Inlet Boca Raton Inlet BP = 86,400 yd3/yr
BP = 53,000 yd3/yr 1990 to 2001)
(1975 -1990) = 88,900 yd3/yr
(1975 -1990)
= 47,000 yd3/yr (1993 to 2002)
(1976 to 1993)

IV/dt = 13,300 yd3/yr vs 26,500 yd3/yr (Calc QNOVR = 0

Hillsboro In] = 73,500 yd3'/yr

dV/dt 66,800 yd3/yr QNOuR = 111,760 yd3/yr
QouT = 118,460 yd 3y

dV/dt 100,200 yd3/yr vs 22,600 yd3/yr (Calc) QNOUR = 61,700 yd3/yr let QBr = 128,000 yd3/yr dV/dt -11,500 yd3/yr QNoun 0

4QouT = 139,500 yd3/yr

Figure 29. Volumetric Sediment Budgets For Early and Later Time Periods.

Hillsboro

First Period




was greater than reported by this 77,600 yd 3/year, the sediment budget in Segment 2 would be balanced and the sediment inflow to Segment 1 would be 162,700 yd 3/year versus 139,500 yd3/year transported out of Segment 3 as determined by survey and reported bypassing quantities. This discussion has focused on modifications of bypassing quantities at Boca Raton Inlet; however, it can be shown that in order to balance the volumes in Segment 2, it is only necessary that the difference between the sediment bypassing around Boca Raton Inlet minus that around Hillsboro Inlet be increased by 77,600 yd 3/year and this would automatically result in the net sediment transport into Segment 1 and out of Segment 3 to agreeing within 23,200 yd 3/year which is considered reasonable recognizing that some sediment transport is induced into Segment 1 as a result of the large Delray Beach nourishment project (Table 4). Therefore it is suggested that not too much concern be placed on differences less that 40,000 yd 3/year transported into and out of.Segments 1 and 3, respectively.
It is noted that for the Early time period, increasing the flows around Boca Raton Inlet relative to Hillsboro Inlet for the Earl Z time period would tend to balance the volume differences for Segment 2 (39,800 yd /year would be required); however, this would further increase the differences between the sediment transport into Segment 1 and out of Segment 3. Again, the Delray Beach nourishment project plays a definite but unquantified role here.
Finally, the effect of the offshore reef structures on sediment transport should be noted. It has been stated earlier that the net sediment transport into Segment 1 should be approximately equal to the transport out of Segment 3. This is expected to be the case for natural conditions. However, if nourishment covers portions of the reef structures within the active sediment transport zone, the transport on these portions of the active profile will be increased and the transport under the same wave conditions will increase thereby causing an imbalance between QIN and QouT.
7.3.4 Global Sediment Budgets
The above sediment budget calculations have focused on each of the three segments. As was evident, the bar bypassing was an unknown in the quantification of the budgets for each of these three segments. As shown in Appendix B, it is possible to consider a "Global Sediment Budget", ie one that combines all three segments. There are advantages and disadvantages to consideration of a global sediment budget. The main advantage is that bypassing at the two inlets does not appear in the budget since it is internal to the overall system. The main disadvantage is that it is only possible to determine the difference between the net sediment transport into the north end of the total system considered and the transport out at the south end of the system. That is, the method can only quantify the difference AQ where
AQ =QIN Q




Ideally, this transport difference should be small relative to the absolute values of the various components. It can be shown (Appendix B)
AQ=QJQoUT = N -( dV -I(QOuR)
which simply states that the difference in inflow and outflow of sediment is the difference between the volume stored in the system and the volume placed in the system through nourishment. The values in Figure 29 were substituted into the above equation and the results are shown in Table 5. It is seen that the differences are less for the Later intersurvey period than for the Early period. As noted previously, this could be due to the larger profile spacing for the long lines for the Early period. Additionally, it is known that there is a substantial amount of sediment inflow into the system considered as a result of the Delray Beach nourishment project. Considering that QN and Qoutr are on the order of 125,000 yd3, the percent transport differences in Table 5 range from 21% to 52%.
Table 5
Results of "Global Sediment Budget" Analysis
Time Period AQ (yd3/year)
Early 64,940
Later 25,700
8.0 RECOMMENDED SEDIMENT BUDGET PROTOCOL FOR BOCA RATON INLET
8.1 General
Previous discussions and the analysis results have emphasized that there may be substantial interannual differences in the appropriate sediment budget for Boca Raton Inlet. These differences are due primarily to the wave climate, particularly the wave directions and wave heights. Some years are more stormy than others and thus may cause more net longshore sediment transport. Additionally, in discussing the need for hydraulic (dredge) bypassing around Boca Raton Inlet, the natural bypassing component should be recognized.




8.2 Recommended Sediment Budget Protocol for Boca Raton Inlet

In view of the above discussion and the findings of this report, the recommended elements of a sediment budget protocol for Boca Raton Inlet include the following:
(1) Maintain a capability to bypass 100,000 yd3/year which includes bypassing from
the ebb tidal shoal as needed.
(2) Quantify the hydraulic bypassing need through an analysis of annual surveys
conducted north and south of the inlet. These surveys should extend 5,000 feet
north and 5,000 feet south of the inlet and the effects of beach nourishment should
be taken into consideration in the analysis using accepted coastal engineering procedures. The surveys should be conducted at approximately the same time
each year and should extend to at least the 30 foot depth contour. This
quantification should be based on a determination of required bypassing changes
in the year following the survey to balance differences in the volume changes
updrift and downdrift of Boca Raton Inlet occurring during the previous year. It is suggested that these results and their interpretations be shared with representatives
of the updrift and downdrift Stakeholders. The downdrift volumes should not
include those sequestered in the Boca Raton Inlet ebb tidal shoal.
9.0 POSSIBLE FUTURE EFFORTS
9.1 Deerfield Beach Groin Field
The Deerfield Beach groin field was installed subsequent to and partly as a result of the severe March 1962 storm. This field comprises 53 groins with the first groin at the north Broward County Line and the southern most groin at the Deerfield Beach/Hillsboro Beach City boundary. These groins are constructed of King Piles with rubble mounds at the seaward ends and are spaced at approximately 100 feet. King Pile groins are adjustable and consist of concrete piling in the planform of the letter "H" with panels (wooden or concrete) placed in the slots formed in the "H" section, see Figure 30. Additionally, there are several (four or more) less prominent groins along the northern portions of HiEllsboro Beach. The Deerfield Beach groin field occupies approximately 19% of the Segment 2 shoreline. However, in addition, the Deerfield groin field retains sand in the compartment to the north extending to the south jetty of Boca Raton Inlet. Thus, this groin field affects (stabilizes) to some degree approximately 40% of the total shoreline of Segment 2.




0 STABILIZED PROFILE

- ORIGINAL PROFILE-,"
CONCRETE BASE PANEL

. KING-PILE (PRESTRESSED) 12" WOODEN PANELS

-KING PILE

Figure 30. Typical King Pile Groin Installation. Note: Rubble Mounds at Ends of Groins Not Shown.
An effort to quantify the effect of the Deerfield Beach groin field would include an in depth analysis of survey-based shoreline and volume changes focused on the vicinity of the groin field and affected updrift and downdrift areas. Additionally, numerical modeling of shoreline and volume changes would be conducted to complement the survey-based analysis results. Emphasis would be directed to: (1) Volumetric retention within and north of the groin field, (2) Stabilization of offshore region seaward of the groins as they have filled, (3) Details of sand bypassing around the groin field (downdrift attachment locations), and (4) Downdrift effects of groin fields under various seasonal wave climate scenarios.
9.2 Bar Bypassing Around Boca Raton Inlet
An unquantified issue in this report is the quantity of sand bypassed around Boca Raton Inlet by natural transport on the ebb tidal shoal ("bar bypassing"). The ebb tidal shoal serves as a "sand bridge" with the shoal increasing in size until it can bypass the full net longshore sediment transport. However, the bar geometry (depth over the bar) for bypassing of the full net longshore sediment transport is not consistent with safe navigation, thus requiring dredging.
The most appropriate approach to investigating bar bypassing is through a focus on the available survey data in the immediate vicinity of the Boca Raton Inlet coupled with a sand tracer experiment and results of a literature review of similar cases. It is considered that there would be considerable uncertainty associated with results obtained from the sand tracer experiment. Therefore if a decision is reached to proceed with an investigation of bar bypassing, it is suggested that the study options and their prognoses for success be reviewed carefully.




10.0 SUMMARY AND CONCLUSIONS

10.1 Summary
This report has analyzed the shoreline and volume changes in the vicinity of Boca Raton Inlet. A total longshore distance of approximately 94,000 feet was included in the analysis extending from Monument R- 189 in Palm Beach County, some 36,200 feet north of Boca Raton Inlet to Monument R-55 in Broward County, approximately 28,600 feet south of Hillsboro Inlet. The survey data analyzed in Palm Beach County includes four separate surveys: 1974/1975, 1993, 2000 and 2001 whereas nine surveys were analyzed in Broward County: 1976, 1993, 1996, 1997, 1998, 1999, 2001 (two surveys in 200 1) and 2002.
This system is unique in terms of the amount of data available including the bypassing at the two inlets, each of which includes a weir in the updrift (north) jetty, and the various nourishment projects that have been conducted within and adjacent to the area analyzed. The survey and other data were combined to establish sediment budgets over two time periods for the system of interest with an emphasis on Boca Raton Inlet. The system was represented in three natural segments with Segment 1 approximately 36,200 feet long and located north of Boca Raton Inlet, Segment 2 between Boca Raton and Hillsboro Inlets and approximately 28,000 feet in length and Segment 3 south of Hillsboro Inlet and 28,600 feet long. Because nourishment in close proximity to the overall system boundaries (either inside or outside) will induce sediment transport out of or into the system over and above that which would naturally occur, these effects were taken into account both quantitatively and qualitatively.
Analysis results were presented in three formats. A complicating factor in all three formats was that Segment 2 lies in both counties (but predominantly in Broward County) and the survey dates for the two counties do not coincide. One format was the variation with time of the volume changes within each segment which included the effects of nourishment and with the nourishment deducted. This format shows the overall changes in the system segments and highlights the role of beach nourishment. The second formnat was to select three surveys in each segment and to develop distributions of shoreline and volume changes for the three segments and the two intersurvey periods. The intersurvey periods investigated for Palm Beach County are: 1975 to 1990 and 1990 to 2001. The corresponding periods for Broward County are: 1976 to 1993 and 1993 to 2002. These plots allow easy quantification and identification of the locations of shoreline and volume changes. The sediment budgets developed for the two time periods establish a natural net southerly flow of sediments across the northern boundary into Segment 1 ranging from approximately 85,100 yd 3/year to 149,500 yd 3/year and flows out of the southern boundary ranging from 118,460 yd 3/year to 139,500 yd 3/year. Finally, the third format presented the results in a sediment budget framework for the same time periods as for the second format. These results identified discrepancies in the volume changes in Segment 2 as determined from survey data and reported bypassing quantities and differences between calculated net transport into Segment 1 and out of Segment 3. The calculated




volumes during the Later time period were considered more accurate and it was found that if the relative bypassing at Boca Raton and Hillsboro Inlets were increased, both the discrepancies in Segment 2 and the differences in net transport at the two ends of the system considered could be reduced to reasonable values for the Later time period. A portion of this increase may be due to the natural bypassing along the Boca Raton Inlet ebb tidal shoal. Additionally, sand transport has been induced into the north end of Segment 1 by the Delray Beach nourishment project immediately to the north of this segment.
Available historical survey data have been analyzed to establish a recommended sediment budget for Boca Raton Inlet and the overall sediment budget for the encompassed area has been clarified. A sediment budget protocol for Boca Raton Inlet is recommended.
10.2 Conclusions
Although some uncertainties remain in the calculated volumetric changes and reported bypassing, a reasonably solid basis for a recommended sediment budget protocol for Boca Raton Inlet has been developed as follows:
(1) Maintain a capability to bypass 100,000 yd 3/year which includes bypassing from
the ebb tidal shoal as needed.
(2) Quantify the hydraulic bypassing need through an analysis of annual surveys
conducted north and south of the inlet. These surveys should extend 5,000 feet
north and 5,000 feet south of the inlet and the effects of beach nourishment should
be taken into consideration in the analysis using accepted coastal engineering procedures. The surveys should be conducted at approximately the same time
each year and should extend to at least the 30 foot depth contour. This
quantification should be based on a determination of required bypassing changes
in the year following the survey to balance differences in the volume changes
updrift and downdrift of Boca Raton Inlet occurring during the previous year. It is suggested that these results and their interpretations be shared with representatives
of the updrift and downdrift Stakeholders. The downdrift volumes should not
include those sequestered in the Boca Raton Inlet ebb tidal shoal.
11.0 ACKNOWLEDGEMENTS
This effort benefited considerably through meetings and discussions with and suggestions by the Technical Advisory Committee (TAG). The TAG consisted of Representatives of the Bureau of Beaches and Coastal Systems of the Florida Department of Environmental Protection, Palm Beach County, Broward County, City of Boca Raton, City of Deerfield Beach, and IMllsboro Inlet District.




12.0 REFERENCES

Beachler, K.E. (1993): The Positive Impacts to Neighboring Beaches From the Deiray Beach Nourishment Program, Proceedings, Sixth National Conference on Beach Preservation Technology: The State of the Art of Beach Nourishment, Vol. 6, 223-238.
Coastal Planning and Engineering, Inc. (2002) "Boca Raton Inlet Management Plan", Submitted to the City of Boca Raton.
Coastal Planning and Engineering, Inc. (2002) "2002 Post Construction Monitoring Report of the Boca Raton Inlet and Adjacent Beaches", Boca Raton, Florida.
Coastal Planning and Engineering, Inc. (1991) "Boca Raton Inlet and Adjacent Beaches Management Program, Status Report No. 9", Boca Raton, Florida.
Dean, R.G. (2002) "Beach Nourishment: Principles and Applications", World Scientific Press, 399 pages.
Strock, A.V. and Associates, Inc. (1979) "Preliminary Report: Boca Raton Inlet and Adjacent Beaches for the City of Boca Raton".
University of Florida Department of Coastal and Oceanographic Engineering Archives, Aerial Photographs for Boca Raton Inlet and Hillsboro Inlet.
U. S. Army Corps of Engineers (1985) "Beach Erosion Control Project for Palm Beach County, Florida General Design Memorandum. with Palm Beach Harbor Section 111 Report and Environmental Impact Statement", Jacksonville District, In Draft Form.
Walton, T. L. (1976) "Littoral Drift Estimates Along the Coastline of Florida", Florida
Sea Grant Program Report No. 13.




APPENDIX A
A SERIES OF 18 PHOTOGRAPHS OF BOCA RATON INLET
1936 TO 1995




APPENDIX A
A SERIES OF 18 PHOTOGRAPHS OF BOCA RATON INLET 1936 TO 1995
1 A.0 INTRODUCTION
This Appendix presents a series of 18 aerial photographs of Boca Raton Inlet extending from February 22, 1936 to February 6, 1995. The dates of the individual photographs are listed in Table A. 1. The photographs are from the Coastal Engineering Archives at the University of Florida.
Table A. I
Dates of Aerial Photographs Included in This Appendix
Figure Number Date of Photograph Figure Number Date of Photograph
A. I February 22, 1936 A.10 November 21, 1968
A.2 May 3, 1940 A.11 November 6, 1969
A.3 March 9, 1945 A. 12 August 17, 1970
A.4 November 22, 1945 A. 13 March 8, 1971
A.5 August 21, 1959 A.14 April 12, 1973
A.6 October 21, 1961 A.15 April 4, 1975
A.7 February 21, 1964 A.16 April 23, 1986
A.8 March 13, 1965 A.17 February 11, 1991
A.9 February 14, 1968 1 A.18 I February 6, 1995




Figure A. I Aerial Photograph of Boca Raton Inlet. February 22, 1936.




Figure A.2 Aerial Photograph of Boca Raton Inlet. May 3, 1940.
50




Figure A.3 Aerial Photograph of Boca Raton Inlet. March 9, 1945.
51




Figure A.4 Aerial Photograph of Boca Raton Inlet. November 22, 1945 52




Figure A.5 Aerial Photograph of Boca Raton Inlet. August 21, 1959.
53




Figure A.6 Aerial Photograph of Boca Raton Inlet. October 21, 1961.
54




Figure A.7 Aerial Photograph of Boca Raton Inlet. February 21, 1964.
55




Figure A.8 Aerial Photograph of Boca Raton Inlet. March 13, 1965.
56




Figure A.9 Aerial Photograph of Boca Raton Inlet. February 14, 1968.
57




Figure A. 10 Aerial Photograph of Boca Raton Inlet. November 21, 1968.
58




Figure A. I I Aerial Photograph of Boca Raton Inlet. November 6, 1969.
59




Figure A. 12 Aerial Photograph of Boca Raton Inlet. August 17, 1970.
60




Figure A. 13 Aerial Photograph of Boca Raton Inlet. March 8, 197 1.
61




Figure A.14 Aerial Photograph of Boca Raton Inlet. April 12, 1973.
62




Figure A. 15 Aerial Photograph of Boca Raton Inlet. April 4, 1975.
63




Figure A. 16 Aerial Photograph of Boca Raton Inlet. April 23, 1986.
64




Figure A.17 Aerial Photograph of Boca Raton Inlet. February 11, 1991.
65




Figure A. 18 Aerial Photograph of Boca Raton Inlet. February 6, 1995.
66




APPENDIX B
SEDIMENT BUDGET METHODOLOGY




APPENDIX B

SEDIMENT BUDGET METHODOLOGY
B.1.0 General
A sediment budget is simply a formal procedure to account for the sediment inflows into and outflows from and additions to a system to result in volume changes within the system. The degree to which the sediment budget can be developed and checked depends on the amount of data available. It will be shown that of the three segments considered (Figure B. 1), only Segment 2 has sufficient information to check against the documented volume changes based on survey data if the bar bypassing contributions are negligible. For Segments 1 and 3, there is only sufficient information to quantify the net annual sediment transport into and out of Segments 1 and 3, respectively.
B.1.1 Sediment Budget Relationships
Referring to Figure B. 1 for terminology, the equations for the sediment budgets for the three segments are:
Segment 1: For this case, all of the quantities are known to allow calculation of the net transport into the segment, QINI. The equation defining Q1.l is:
Q.JI = QBP,BR + (dVt) QNOuR, (B.1)
in which QBPBR is the average rate of bypassing at Boca Raton Inlet during the period of
(dV/t)I is the average rate of volumetric increase within Segment 1 and
QNOUR,1 is the average volumetric rate of nourishment in Segment 1 during the period of interest.
Segment 2: For Segment 2, all of the information is available to balance and check the budget assuming negligible bar bypassing. Thus, whether or not the sediment balances provide a measure of the confidence that should be placed in the data and assumptions. The sediment budget for this Segment 2 is:
9
(dV (B.2)
QBP,BR -QBP,HI dt 2 + Ql0UR,0'-O
and where the "?" signifies that if the equation doesn't balance, this is a measure of the uncertainty in the sediment budget.




dV/dt QNOUR

Boca Raton

QDP

Hillsboro Inlet
)- B

dV/dt QNOUR 4OUT

Segment 1 Segment 2 Segment 3

Figure B.1 Segments Used in Sediment Budget Analysis.
Note: Dates Shown are for "Early" Period Considered in Establishing Sediment Budgets.




Segment 3: For this case, all of the quantities are known to allow calculation of the net transport out of the segment, QoUT,3. The equation defining QOUT,3 is:
QOUT3 = + -(dV/)(B3
Qouvr3 ='_ QBP,H, + QNOUR.3 dt )3
A caveat to the discussion above is that if natural "bar" bypassing occurs around the two inlets, the quantities QBP,BR and QBP,HI are to be interpreted to include the bar bypassing.
B.1.2 Global Sediment Budget
The methodology presented to this point has concentrated on the sediment inflows and outflows of the individual segments considered. A so-called "global sediment budget" can also be developed which allows calculation of the difference between the net transport into and out of the entire system. It is anticipated that the volume of sediment entering and leaving the entire system considered here (Segments 1, 2 and 3) will be approximately equal under natural conditions. Combining Equations (B. 1), (B.2) and (B.3),
AQ = QN-Q =Xi I -(QNOUR (B4)
dt } =
The advantage of this global consideration is that bypassing (hydraulic and natural) at the two inlets do not appear in the formulation since they are internal to the entire system under consideration. The disadvantage is that only an estimate of the difference in transport in and out of the system is determined.
In the case under consideration, it is anticipated that AQ will be greater than zero since the Delray Beach nourishment project immediately to the north of the system under consideration will induce sediment transport into the system over and above the natural sediment transport.




APPENDIX C
PLOTS OF SELECTED PROFILES CORRESPONDING TO LONG PROFILE MONUMENTS FOR EARLIEST SURVEY
FROM R-189 IN PALM BEACH COUNTY TO
R-55 IN BROWARD COUNTY




R-1 89
20
200
r_ -30
0
0 .5... . . . .
-60
0 1000 2003000 400
Distance (ft) Figure C. 1. Plot of Profiles for Monument R- 189 in Palm Beach County.
R-1 92
20
10
0
z -2 0. . . . ... . . . . .. . . . .
0
S-30
0
-60
0 1000 2000 300 4000
Figure C.2. Plot of Profiles for Monument R-192 in Palm Beach County.




20 10
0 z-10 .0o
0
, -20 r -30
0
U
-50

R-195

0 1000 2000 3000 4000
Distance (ft)
Figure C.3. Plot of Profiles for Monument R-195 in Palm Beach County.

10 A----20
, o \ .... .. .. ..... .... .... .... .. ........... ........ ... .. ............... i .................
0
.. . .. . . . . . . . .......... .. . ......... -.... ........ . . . . . . . .
-1 0 .
4 2 0 ...... ... .. . . ...
............ ...... .. ...
-30
.2 -30-0
4-0
0 1002 "4
Distance (ft)
Figure CA. Plot of Profiles for Monument R-198 in Palm Beach County.




2020
-20
0
99
0
ZR-224
0
4) -0
0 5 .. . . . . .. . . .. . . . . .8
4-0
0 1002 "4
Distance (ft)
Figure C.6. Plot of Profiles for Monument R-201 in Palm Beach County.




R-207

Figure C.7. Plot of Profiles for Monument R-207 in Palm Beach County.

1000 2000 3000 4000
Distance (ft)

Figure C.8. Plot of Profiles for Monument R-210 in Palm Beach County.

0
z
-10
0
' -20
0
r -30
0
iU El

20 10
10 0.10
-40
-30
0 4) 4
U
-50 -60




R-213

Figure C.9. Plot of Profiles for Monument R-213 in Palm Beach County.

1000 2000 3000
Distance (ft)

4000

Figure C. 10. Plot of Profiles for Monument R-216 in Palm Beach County.

0
z-10 ON0
-30
0
040 'U

20 10 40
0 2z 10
0
-20
-30
0
-40 -50 -60




1 0 . - . .-
00
z 0
0 1. . . . . ..o. . . . .. . . . . .. . . . . .
.. .. . .. ..-. .. . .. .
E-30
0
4)- 4-- --- . .. .. ... .
-60
0 1000 200 3000 400
Distance (ft)
Figure C. 11. Plot of Profiles for Monument R-219 in Palm Beach County.

0
> . .. . .. . . . .. . . . . . . . .
S-20 C -30
0
4)-40
-60
Distance (ift) Figure C. 12. Plot of Profiles for Monument R-222 in Palm Beach County.




4000

1000 2000 3000

Distance (ft)
Figure C. 13. Plot of Profiles for Monument R-1 in Broward County.

1000 2000 3000

4000

Distance (ft)
Figure C. 14. Plot of Profiles for Monument R-3 in Broward County.




0 1000 2000 3000 4M0
Distance (ft)
Figure C. 15. Plot of Profiles for Monument R-6 in Broward County.

Iv1- 19971
---- 2002
>0
o -10 . . . .. ... .
P -20.. . . ... . .. .
o 8
I~ 50
-60
0 1000 2000 3000 4000
Distance (ft)
Figure C. 16. Plot of Profiles for Monument R-9 in Broward County.




R-1 2

-30 .......... .......!....... ..... ..............!....... .......: ......
>0
0 0 . . .. . . . .. . . . . . . . . . . . . .. . . . , . . . / . ... . . . .- .. . . . . . .
0o -10- - . .. .. . .
- 3 0 . . . . . . . . .... . . . . .... . . . . . . . . . .! . . . . . . . . . . . . . .
S-20 ii
-3023
0
- -- - - . . .
-60
0 1000 2000O 300 4000
Distance (ft)
Figure C. 17. Plot of Profiles for Monument R-1 2 in Broward County.

R-1 5

IV 1997
0
. . ..~..... ... .. ..... . .. .. ... ...... . : .... .. ......... ... .
0 ........: .......::....... :... ::,o .: -., *.. "........ .......... :.............. i
. . . . . . i. . .. . . .. : . . . . . : . . . . . . . . . . . . . . . . . . .. . . . . . . .. . . . . . ..
0-10
4-6
a)
-30
C
0-40 '
-5 0 . . . .- -- -- - .. . .. . . .
-60
0 1000 2000 300 400
Distance (ft) Figure C. 18. Plot of Profiles for Monument R-15 in Broward County.




10
> 0
z o -10 : -20
-30
0
(U-40
-50 -60

R-1 8

1000 2000 3000
Distance (ft)

Figure C. 19. Plot of Profiles for Monument R-18 in Broward County.

R-21

4000

0 1000 2000 3000
Distance (ft)

Figure C.20. Plot of Profiles for Monument R-21 in Broward County.




R-24
20
1f -0 ............ :....... ........ ...:.......... :..................... .............. ...............
.. .. . --5-- 2002 :i
> 0
0 .. .. .. . .. .. ... . .
S-01002030040
0
0
~-50
-60
0 1000 2000 300 400
Distance (ft)
Figure C.21. Plot of Profiles for Monument R-24 in Broward County.

I U > 0
0
z
o -10
-20
0 ~-30
0
-40
-50
-60

R-27

1000 2000 3000

Distance (ft)
Figure C.22. Plot of Profiles for Monument R-27 in Broward County.




R-30

20
10
>0
0
z
o -10
4-z ', -20
~-30
C
0 CO -40
0
-50
-60

Figure C.23. Plot of Profiles for Monument R-30 in Broward County.

R-33

,-. Iv 1 19971
.............. ....... ........ .............. -- 2 0 0 ......
> 0
0-10 .
. .. .. . .. .
,9 i . . . .!. . . . .. ,... . . . ... ... . . !.. . . .. . . . . . . . . . . . . . .
-3 0 - - . . . ... . . . .
0 .............. ........... ..... ........ ...... ...... ........... Ot.... ...... .. .' ......
-40 -- ...... -- ------ .... .............. ............. ............. i ........... ............ i..........
4 1 ............... .............. i. ........ ............... ............ ............ .. ........ .. .......... .
-5 0 .. ......... i. ............... . . .. ............. -- - ........... .. .............. ............... . .... --
.... ... .... ... ........... s.............. : .... ..................................... . ........ .............
-60
0 1000 2000 3000 4000
Distance (ft)
Figure C.24. Plot of Profiles for Monument R-33 in Broward County.

1000 2000 3000
Distance (ft)




R-36

4000

1000 2000 3000

Distance (ft)
Figure C.25. Plot of Profiles for Monument R-36 in Broward County.

R-39

0 1000 2000 3000

4000

Distance (ft)
Figure C.26. Plot of Profiles for Monument R-39 in Broward County.

a > 0
0
z
o -1o
,-20
-30
0 CC -40 a)




R-42

1)
0 1000 2000 3000 4000
Distance (ft)
Figure C.27. Plot of Profiles for Monument R-42 in Broward County.

R-45

0 1000 2000 3000 4000
Distance (ft)
Figure C.28. Plot of Profiles for Monument R-45 in Broward County.




R-48
20
____1976
10 1993
V,~----- 1997
---- 2002
0
-20 .....
-20 .. ..... ":........ ;...... .... .. ................................. ; ........
-30 .. --4 0 .. ... .. ... ... . ..i . .. .. . i ... ... .. .............. .... .. . ..... .... .... ...... ..::"
-40
. . . . .. . . . . .. . . . . . . . . .. . . . . ... . . . .. . . . . . . . : . . . . . . ,
-50... .
-60
0 1000 2000 3000 4000
Distance (ft)
Figure C.29. Plot of Profiles for Monument R-48 in Broward County.

R-51

0 1000 2000 3000 4000
Distance (ft)
Figure C.30. Plot of Profiles for Monument R-51 in Broward County.




R-54
20
1976
. .0. .............. .............. .1............... .... .993
1% .1997
10
- 0 - --
O -I 0 . . ... . . . . . . . - - - - --.. . . . . . . -- - - - --- - - - - -- --.. .. . . . . : . . .... . .
.. ... ... ~ -. ------... ......... ....... -------------........: ..... ...
-2 0- . . . . . . .. . . . . . . . .. . . . . . . . . . .. . . . . . . . .
0
(40 -z
----- -- ---- --...... ............- ............:.............. .......:.... ,.. ......
4)
0 .. . .. .. -- .. .... .. -- ------.. .. .. .. -- ------ ... .. .. . .. ... ... .. .. ... ... . .. ....... .. .
- . . . ..- . . ..- -. . . . . . . ... . . . . . . . . . . . . . ... I- . . . . . . .
- - - . . .... . .i . . . . .. . . . . . . . :: . . . . . . .- - ... . . . . . i . . . . . i .. . . . . . ..
" o .... .... ...... . ... i .... .. ... -- -- --- --- --- ....... -- -- ...... ....... i.... .. ......... ........ .. .. ... ....... .. >
: i
-60
0 1000 2000 3000 4000
Distance (ft)
Figure C.3 1. Plot of Profiles for Monument R-54 in Broward County.