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UFL/COEL-99/023
MONITORING REPORT
MIDTOWN BEACH NOURISHMENT PROJECT IN
PALM BEACH, FLORIDA
October 1995 to September 1999
by
Robert G. Dean
December 6, 1999
Prepared for:
Town of Palm Beach
Post Office Box 2029
360 South County Road
Palm Beach, Florida 33480
MONITORING REPORT
MIDTOWN BEACH NOURISHMENT PROJECT
IN PALM BEACH, FLORIDA
October 1995 to September 1999
December 6, 1999
Prepared For:
Town of Palm Beach
Post Office Box 2029
360 South County Road
Palm Beach, Florida 33480
Prepared by:
Robert G. Dean
Department of Coastal and Oceanographic Engineering
University of Florida
Gainesville, Florida 32611
TABLE OF CONTENTS
LIST OF FIGURES ...................................... .................. iii
LIST OF TABLES ...................................................... iii
INTRODUCTION ..................................................... 1
R ESU LTS ............................................ .......................3
Beach Profiles ................................ .......................3
Longshore Distributions of Shoreline Change and Volume Density ................. 8
Changes in Total Volumes and Plan Areas ................................... 8
Changes in Volume and Average Shoreline Position Along the North Beach Area ..... 8
SUMMARY AND CONCLUSIONS ......................................... 12
REFERENCES ............................................................. 13
LIST OF FIGURES
FIGURE PAGE
1 Location Map of Project Area Showing Borrow and Nourishment Areas. (Adapted
from ATM Drawing) .................................... ............. 2
2 Profiles at DNR Monument R-96D Located Approximately One-Quarter of
Nourished Length From North End of Project .......... ............. ........ 4
3 Profiles at DNR Monument R-97C126 Located Approximately Midway Along
Nourished Project ............ .......................................... 5
4 Profiles at DNR Monument R-98G Located Approximately Three Quarters of
Nourished Length From North End of Project .............................. 6
5 Profiles at DNR Monument R-99D Located Approximately 400 feet South of Most
Southerly Groin ................................ .................. ......... 7
6 NGVD Shoreline Changes Due to Nourishment Project ......................... 9
7 Volume Changes Due to Nourishment Project ................................ 10
8 Percentage Total Volume and Plan Area Remaining in Placement Area ............ 11
LIST OF TABLES
TABLE PAGE
1 Dates of Monitoring Surveys .... .......................................... 3
2 Changes in Total Volumes and Plan Areas ................................. 12
MONITORING REPORT
MIDTOWN BEACH NOURISHMENT PROJECT
IN PALM BEACH, FLORIDA
October 1995 to September 1999
INTRODUCTION
During the period October 18, 1995 to December 10, 1995, approximately 880,000 cubic yards of
sand were dredged from a borrow area extending from approximately 2,000 feet south to 4,800 feet
south of the south jetty at Lake Worth Entrance and placed along portions of the Midtown Beach
section in the Town of Palm Beach, Florida. As shown in Figure 1, the cross-shore dimensions of
the borrow area varied from 1,600 feet at its northern end to 2,500 feet at its southern end. The
original depths at the borrow area site varied from 25 to 35 feet and the maximum dredged depths
were approximately 40 feet. The dredged sand was placed along the Midtown Beach as nourishment
extending from via Bethesda at the north end to via Marina at the south end, a distance of
approximately 5,400 feet. To stabilize the nourishment project, eleven groins were constructed. The
locations of these groins are shown in Figure 1 along with the borrow area and the approximate
planform of the nourished beach. Sea Systems, Inc has conducted a pre-nourishment survey and
eight post-nourishment surveys to document the performance of this project. The purpose of this
report is to present the results of an analysis of these nine surveys.
The dates of the surveys are presented in Table 1. Although the placement of material was completed
in December 1995, as can be seen from Table 1, the first post-nourishment survey was not completed
until April 9, 1996 due to activities related to construction of the eleven groins. During the period
between completion of nourishment and the first post-nourishment survey, a significant northeaster
occurred (March 8-10, 1996) which undoubtedly caused loss of some sand from the Project beach.
Thus, since the first post-nourishment survey post-dated the March storm, the first post-nourishment
survey does not reflect the total amount of sand placed. It is noteworthy that the September 1999
survey was conducted over a period 4 to 7 days prior to Hurricane Floyd's passing the east coast of
Florida.
This report updates the monitoring results through the September 1999 survey. Previous monitoring
results, presented in Dean (1997a, 1997b, 1997c, 1998a and 1998b, 1999), provide details on
aspects of the nourishment project not addressed in the present report.
Borrow Area
R-87 OCEAN I I
-ea 0 1.0
-89 Scale (Miles)
-90
-91
-92
S-93 Typical Groin, One of Eleven
S-9 Numbered From S at the North to
S 11 at the Southern End
R- --Project Site
-97
S 98
-100
Figure 1. Location Map of Project Area Showing Borrow and Nourishment Areas.
(Adapted from ATM Drawing).
Table 1
Dates of Monitoring Surveys
Survey Number Type of Survey Dates
1 Pre-Nourishment October 13-21, 1995
2 Post-Nourishment April 1-9, 1996
3 Post-Nourishment August 12-25, 1996
4 Post-Nourishment March 31 to April 8, 1997
5 Post-Nourishment August 27-30, 1997
6 Post-Nourishment April 22-27, 1998
7 Post-Nourishment August 17-31, 1998
8 Post-Nourishment April 6 12, 1999
9 Post-Nourishment September 7 14, 1999
RESULTS
The results are presented in various forms, including samples of beach profiles, longshore
distribution of additional beach width for several surveys, longshore distribution of additional
volume for several surveys, and total additional areas and volumes as functions of time. Since the
most recent survey did not encompass the North Beach area, the present report does not address this
area.
Beach Profiles
Figures 2, 3, 4 and 5 present examples of beach profiles in the nourishment area. Figures 2, 3 and
4 are located at approximately one-quarter, one-half and three quarters of the distance from the
northerly to the southerly limits of the beach nourishment project, respectively. The profile shown
in Figure 5 is approximately 400 feet south of the southern most groin and in an area where the beach
has receded substantially during the last intersurvey period. In order to maintain the number of
surveys presented reasonable, only the pre-nourishment survey (October 1995), the first post-
nourishment survey (April 1996), the second post-nourishment survey (August 1996), the fourth
post-nourishment survey (August 1997), the sixth post-nourishment survey (August 1998) and the
most recent survey (September 1999) are presented on these plots. It is seen from inspection of these
figures that the NGVD shorelines at the two northern profiles shown (Figures 2 and 3) had advanced
slightly since the August 1998 survey, whereas at the profile located at the three-quarters distance
(D
O
0
4-a
0
4-1
O
c)
W:
10
0
-10
-20
-30
-40
0
Figure 2. Profiles at DNR Monument R-96D Located Approximately
One-Quarter of Nourished Length From North End of Project
20
3000
1000 2000
Seaward Distance from Monument (ft)
October 1995
......... April 1996
-------- August 1996
------- August 1997
--- August 1998
September 1999
.. -
I
- - - - - -
20
October 1995
0 ......... April 1996
> 10 ---- ._.-.- August 1996
------- August 1997
Z \. --- August 1998
O -- .-... September 1999
0 --- -30
>- 0 ..*
S 1 0 ... .. ............................. ............................... -
W -30
0 1000 2000 3000
Seaward Distance from Monument (ft)
Figure 3. Profiles at DNR Monument R-97C126 Located
Approximately Midway Along Nourished Project
20
O October 1995
> 10 ........ April1996
S.-------- August 1996
S------- August 1997
O \- August 1998
0 .. -. September 1999
4 -10
1 0" : ......... ........
S- 2 0 . . .. . . . . .. . . . . .. . . . ... ..... . .. . . . . . . : . . . . . . . . . . . . . . . . .
0 -20 ...........
2j -30
-40
0 1000 2000 3000
Seaward Distance from Monument (ft)
Figure 4. Profiles at DNR Monument R-98G Located Approximately
Three Quarters of Nourished Length From North End of Project
20
October 1995
S 10 . ..... ............................ ........ April 1996
>. .-------.- August 1996
\------- August 1997
Z 0 ,,-\\"--- ... .... ......August 1998
o. ........ September 1999
-4-0
S -2 0 ............. .... .. ..:.................. .... ...
0 -40
-20
Wu -40 leatMnmnR9 LotdA rx tl
0 1000 2000 3000
Seaward Distance from Monument (ft)
Figure 5. Profiles at DNR Monument R-99D Located Approximately
400 feet South of Most Southerly Groin.
I I
from the north Project limits (Figure 4), the NGVD shoreline was approximately stationary over the
past year. At the southern most profile shown (Figure 5), the shoreline had retreated back to its pre-
nourishment position. The three southerly profiles shown all show recession of the upper contours
over the past year.
Longshore Distributions of Shoreline Change and Volume Density
Figure 6 presents the longshore distribution of NGVD shoreline change within the nourishment area
for the first post-nourishment survey (April 1996) and for all subsequent Fall surveys. There was an
increase in width in the northern portion of the Project and a decrease in width in the southern
portion of the project, especially south of the most southerly groin. On average, there is still
approximately 96 feet of additional beach width within the Project area as a result of the beach
nourishment project. During the last intersurvey period, the average beach width within the Project
area increased by 12.7 feet. As noted previously, the shoreline changes were quite irregular during
the past year. Part of this average increase in beach width at the NGVD elevation is due to sand
being transported both onshore and offshore (from higher contours) to this elevation. Figure 7
presents the additional volume density along the Project area. There is a very small loss in volume
during the most recent intersurvey period (5,000 cubic yards) which is less than 1% of the total
volume placed.. There is still an average of approximately 113 cubic yards per foot of beach of
additional sand volume within the Project area as a result of the nourishment project.
Changes in Total Volumes and Plan Areas
Table 2 presents the total changes in volumes and plan areas from the pre-nourishment survey to the
eight post-nourishment surveys. The above statement regarding the gain in beach width is evident
as an increase in total plan area. Additionally, the small loss in sediment volume during the last
intersurvey period is also evident.
Figure 8 presents the history of percentage change in total volume and plan area. It is seen that as of
September 1999, there is approximately 58% of the placed plan area remaining and 70% of the
placed volume remaining in the Project. Although the placed plan area was not determined prior to
the March 1996 storm it was estimated to be 20.5 acres. As noted from Figure 8 and discussed
previously, there was a small decrease in the volume and a moderate increase in the plan area
between April 1999 and September 1999.
Changes in Volume and Average Position Along the North Beach Area
As noted previously, because the September 1999 survey did not include profiles from the North
Beach area, the most recent available results are summarized in the October 1995 to April 1999
Monitoring Report (Dean, 1999).
300
I I
2000
3000
,)
L-
0
-C
CO
I
4000
-, -~.
I I I
5000
6000
7000
Distance South of Monument R-94E (ft)
Figure 6. NGVD Shoreline Changes Due to Nourishment Project
i,
K~i
200
Project Limits
F/i
1996
st 1996
st 1997
st 1998
amber1999
100
0
V7
-100
1000
8000
April
-------- Augu
------- Augu
.. .- Augu
S..--** Septe
^.<--^ M //^-.-
i I "--'V I .
C") v- LO ,, ..- 00 :)
rr 10(, \, O,
C) 0 ) 00l) 0 ) 0 ) ) \ ,
V) / '
300
------- August 1997
2CO00 ........ - August 1998
C~200 ----------- ----------------- --~j~ ~~--- --
*...... September 1999
\,4 -----," -- .--- ---- .--------,-----
ci))
c^l 100 ::
C / C I- LO C I,- CO --
S 0 Project Limits
-100'
0 1000 2000 3000 4000 5000 6000 7000 8000
Distance South of Monument R-94E (ft)
Figure 7. Volume Changes Due to Nourishment Project
I- 100
--. Volumes
9 0 ...................... ................... ... Plan A areas I
80 -- -
E 70
- 60
5 0 .. .... ... ... ... . .... .... .. . ..... . ........... ..... .. ... ....... . .
50
0 4 0 ....... .......... .............. A ......
30 --
` .. .. ...... .... .... .-
1 0 . . . . . . . . . .. . . . . . . . . . . . .... . ... . . . . .. ..... . . . . ... . . .
(.< N0- 0 ) I
C- 4 a
S< <
0..
30 7.....---.........-T------- -------.........----.....-T.
U)) 0F
0 1 2 3 4
Years After Completion of Nourishment
Figure 8. Percentage Total Volume and Plan Area
Remaining in Placement Area
Table 2
Changes in Total Volumes and Plan Areas
Period Change in Volume (yd3) Change in Plan Area (Acres)
October 1995 to April 1996 +794,900* (+759,900) +18.4* (+17.9)
October 1995 to August 1996 +790,400* (+754,800) +18.4* (+17.7)
October 1995 to April 1997 +684,100* (+648,200) +14.4* (+14.0)
October 1995 to August 1997 +672,400* (+640,100) +14.4* (+14.0)
October 1995 to April 1998 +657,800* (+620,500) +11.1* (+10.6)
October 1995 to August 1998 +628,600' (+593,300) +11.8* (+11.2)
August 1998 to April 1999 +650,488* (+616,800) + 10.6* (+10.3)
April 1999 to September 1999 + 640,852* (+ 611,800) + 11.9*+ 11.9)
*Notes: These changes are from Monument R-94I to R-100C, a longshore distance of 6,100 feet.
The numbers in parentheses represent the changes over the 5,400 feet constructed
Project length.
SUMMARY AND CONCLUSIONS
This report has presented an analysis of the changes occurring in the Project area associated with the
Midtown Beach Nourishment Project. Nourishment of this project commenced 3.9 years prior to the
most recent monitoring and was completed 3.7 years prior to the most recent survey in September
1999.
Based on the eight post-nourishment surveys representing approximately 3.9 years since
commencement of nourishment, the Midtown Beach project has performed quite well. Of the
880,000 cubic yards placed, there are some 611,800 cubic yards remaining in the placement area.
As shown in Figure 8, the volume has decreased slightly during the last intersurvey period and the
additional plan area has increased moderately during the last intersurvey period, from 10.3 acres to
11.9 acres. This area is relative to the pre-nourishment condition when there was almost no beach.
As of the September 1999 survey, approximately 70% of the volume placed remained in the
placement area and 58% of the dry beach plan area was present. It is evident that the groins are
functioning to stabilize the sand placed in the 1995 Midtown Beach Nourishment Project.
REFERENCES
Dean, R. G. (1997a) "Midtown Beach Nourishment Project in Palm Beach, Florida: October 1995
to August 1996", University of Florida, Department of Coastal and Oceanographic Engineering
Department, Report No. UFL/COEL-97/001.
Dean, R. G. (1997b) "Midtown Beach Nourishment Project in Palm Beach, Florida: October 1995
to April 1997", University of Florida, Department of Coastal and Oceanographic Engineering
Department, Report No. UFL/COEL-97/013.
Dean, R. G. (1997c) "Midtown Beach Nourishment Project in Palm Beach, Florida: October 1995
to August 1997", University of Florida, Department of Coastal and Oceanographic Engineering
Department, Report No. UFL/COEL-97/015.
Dean, R. G. (1998a) "Midtown Beach Nourishment Project in Palm Beach, Florida: October 1995
to April 1998", University of Florida, Department of Coastal and Oceanographic Engineering
Department, Report No. UFL/COEL-98/012.
Dean, R. G. (1998b) "Midtown Beach Nourishment Project in Palm Beach, Florida: October 1995
to August 1998", University of Florida, Department of Coastal and Oceanographic Engineering
Department, Report No. UFL/COEL-98/019.
Dean, R. G. (1999) "Midtown Beach Nourishment Project in Palm Beach, Florida: October 1995
to April 1999", University of Florida, Department of Coastal and Oceanographic Engineering
Department, Report No. UFL/COEL-99/018.
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