Citation
Midtown beach nourishment project in Palm Beach, Florida

Material Information

Title:
Midtown beach nourishment project in Palm Beach, Florida October 1995 to August 1996
Series Title:
UFLCOEL-97001
Alternate title:
Monitoring report
Creator:
Dean, Robert G ( Robert George ), 1930-
University of Florida -- Coastal and Oceanographic Engineering Dept
Place of Publication:
Gainesville Fla
Publisher:
Coastal & Oceanographic Engineering Dept., University of Florida
Publication Date:
Language:
English
Physical Description:
v, 8, 48 leaves : ill. ; 28 cm.

Subjects

Subjects / Keywords:
Beach nourishment -- Florida -- Palm Beach ( lcsh )
Shore protection -- Florida -- Palm Beach ( lcsh )
Genre:
non-fiction ( marcgt )

Notes

General Note:
"February 24, 1997."
Statement of Responsibility:
prepared for town of Palm Beach ; prepared by Robert G. Dean.

Record Information

Source Institution:
University of Florida
Holding Location:
University of Florida
Rights Management:
The University of Florida George A. Smathers Libraries respect the intellectual property rights of others and do not claim any copyright interest in this item. This item may be protected by copyright but is made available here under a claim of fair use (17 U.S.C. §107) for non-profit research and educational purposes. Users of this work have responsibility for determining copyright status prior to reusing, publishing or reproducing this item for purposes other than what is allowed by fair use or other copyright exemptions. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder. The Smathers Libraries would like to learn more about this item and invite individuals or organizations to contact Digital Services (UFDC@uflib.ufl.edu) with any additional information they can provide.
Resource Identifier:
36846219 ( OCLC )

Full Text
UFL/COEL-99/013

MONITORING REPORT MIDTOWN BEACH NOURISHMENT PROJECT IN PALM BEACH, FLORIDA October 1995 to April 1999 by
Robert G. Dean

July 28, 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 April 1999
July 28, 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 O F TABLES ........................................................... iii
INTRODUCTIO N ............................................................ I
R E SU L T S ................................................................... 3
B each Profiles .......................................................... 3
Longshore Distributions of Shoreline Change and Volume Density ................ 7
Changes in Total Volumes and Plan Areas ................................... 7
Changes in Volume and Average Shoreline Position Along the North Beach Area .... 7 SUMMARY AND CONCLUSIONS ............................................ 10
REFE REN CES .............................................................. 12




LIST OF FIGURES
FIGURE PAGE
I 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-97CI26 Located Approximately Midway Along
N ourished Project ......................................................... 5
4 Profiles at DNR Monument R-98G Located Approximately Three Quarters of
Nourished Length From North End of Project ................................. 6
5 NGVD Shoreline Changes Due to Nourishment Project .......................... 8
6 Volume Changes Due to Nourishment Project ................................. 9
7 Percentage Total Volume and Plan Area Remaining in Placement Area ............ 11
LIST OF TABLES
TABLE PAGE
1 Dates of M onitoring Surveys ............................................... 3
2 Changes in Total Volumes and Plan Areas ................................... 10




MONITORING REPORT

MIDTOWN BEACH NOURISHMENT PROJECT IN PALM BEACH, FLORIDA
October 1995 to April 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 provide stability to the nourishment project, eleven groins were constructed. The locations of these groins are shown in Figure I along with the borrow area and the approximate platform of the nourished beach. Sea Systems, Inc has conducted a pre-nourishment survey and seven post-nourishment surveys to document the performance of the project. The purpose of this report is to present the results of an analysis of these eight 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 groin construction. During the period between completion of nourishment and the first post-nourishment survey, a significant northeaster occurred (March 8-10, 1996) which undoubtedly caused the transport of some sand from the nourished 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.
This report updates the monitoring results through the April 1999 survey. Previous monitoring results, presented in Dean (1997a, 1997b, 1997c, 1998a and 1998b), provide details on aspects of the nourishment project not addressed in the present report.




Borrow Area

R-87 OCEAN I I
R-88 0 1.0
R-89 Scale (Miles)
1-90
-92
1-93 Typical Groin, One of Eleven
-94 Numbered From S I at the North to
S1I at the Southern End
~-Project Site
., .o- m-97
F- 7 -InI
Figure 1. Location Map of Project Area Showing Borrow and Nourishment Areas.
(Adapted from ATM Drawing).




Table 1
Dates of Monitoring Surveys

Survey Number j Type of Survey JDates
1 Pre-Nourishment October 13-2 1, 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
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. In addition, the volume change and average shoreline change over the latest intersurvey period in the north beach monitored area are reported.
Beach Profiles
Figures 2, 3 and 4 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. 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 third post-nourishment survey (April 1997), the fifth postnourishment survey (April 1998), and the most recent survey (April 1999) are presented on these plots. It is seen from inspection of these figures that the northern most profile has been eroded the most, whereas the profiles located midway and near the southern end of the Project have experienced less erosion. This is consistent with the southerly direction of net longshore sediment transport in a sediment deficient coastal system.




20
October 1995
..... April 1996
10 April 1997
(D ---- April 1998
z ~April 1999
-4-1
40
00
LJ -30 IN~).
0 1000 2000 3000
Seaward Distance from Monument (ift)
Figure 2. Profiles at DNR Monument R-96D Located Approximately
One-Quarter of Nourished Length From North End of Project




20 October 1995
..... April 1996
>10 ---------------- - April 1997
CD April 1998
Z ~ April 1999
3 -10 ---- ----....................................................
Ca
a)
WJ 30
0 1000 2000 3000
Seaward Distance from Monument (ift)
Figure 3. Profiles at DNR Monument R-97C126 Located
Approximately Midway Along Nourished Project




20 10

z
0
0
0
0
-
0
0 wi

. . . . . . . . . .

1000 2000
Seaward Distance from Monument (ft)

3000

Figure 4. Profiles at DNR Monument R-98G Located Approximately
Three Quarters of Nourished Length From North End of Project

0 -

October 1995 ......... April 1996
........ April 1997
April 1998 April 1999

-10
-20
-30

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

..i;
',t ,'-.
II ,'m %
I!, '- "-: ,' ,




Longshore Distributions of Shoreline Change and Volume Density

Figure 5 presents the longshore distribution of shoreline change within the nourishment area for the first post-nourishment survey (April 1996) and for all subsequent April surveys. There was a moderate decrease in beach width during the last intersurvey period, although, on average, there is still approximately 83 feet of additional beach width in the Project area as a result of the beach nourishment project. During the last intersurvey period, the average beach width decreased by 7.3 feet. Part of this decrease in beach width is due to sand being transported offshore rather than due to a volume loss. Figure 6 presents the additional volume density along the Project area. There is actually a volume gain during the most recent intersurvey period of approximately 4.4 cubic yards per foot of beach which is considered a relatively small amount. There is still an average of approximately 115 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 seven post-nourishment surveys. The above statement regarding the loss in beach width is evident in the reduction in total plan area. Additionally, the small gain in sediment volume during the last intersurvey period is also evident. The additional volume remaining in April 1999 was almost identical to that remaining in April 1998.
Figure 7 presents the history of percentage change in total volume and plan area. It is seen that as of April 1999, there is approximately 50% of the placed plan area remaining and 70% of the placed volume remaining in the placement area. 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 7, there was a small increase in the volume and a small decrease in the plan area between August 1998 and April 1999.
Changes in Volume and Average Shoreline Position Along the North Beach Area
Since initiation of the Midtown Beach Nourishment Project, sand has been deposited by the sand transfer plant located on the north jetty of Lake Worth Entrance from the north to the south side of the Entrance. Sand transfer recommenced in May 1996 with the refurbished transfer plant and discharge line. As of April 1999, approximately 411,000 cubic yards of sand had been transferred. Of this amount, approximately 227,400 cubic yards is documented to remain within the 4,376 feet north beach monitoring segment. The volume change within this segment over the August 1998 to April 1999 monitoring period is +31,700 cubic yards compared to a placement volume during this same time period of 4 1,300 cubic yards. Stated differently, only 9,600 cubic yards was transported from the 4,376 feet monitored region. The amount transported out of the monitored area is considered very small for the winter period represented in the monitoring period. The average shoreline retreated by less than 1 foot over the north beach monitored shoreline segment during the last intersurvey period.




300

3000

4000

5000

6000

Distance South of Monument R-94E (ft)
Figure 5. NGVD Shoreline Changes Due to Nourishment Project

ai) c
C L
0 Cl)

200 100
0

1000

-100

2000

7000

8000

II
- - - - - - - - -
- - - - - - -

-' April 1996
......... April 1997
------- April 1998
--- --- ------ -- --- -- --- -- -- --- ---A p ril 1 9 9 9 - -
M10 1,-- 00 0
, ,Project Limits
I I I I I I I

i

I I I




300

April 1998
2 0 -- - - -- - - - .. .........-- -- -- - -- -- A pril 1999 -
C.o 2 00 ...............
>1
1 0 0 - .. . - -. ... ... .. . . ..... .. .. .. ........... I ......... .
M I! LO) (0 N- 0)M
-O .U)-, CO. C ) c )C /:U
E -------Project Limits
-10 0 1 I i
0 1000 2000 3000 4000 5000 6000 7000 8000
Distance South of Monument R-94E (ft)

Figure 6. Volume Changes Due to Nourishment Project




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)
*Notes: These changes are from Monument R-941 to R-1OOC, 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 3.5 years prior to the most recent monitoring and was completed 3.3 years prior to the most recent survey in April 1999.
Based on the seven post-nourishment surveys representing approximately 3.5 years since nourishment, the Midtown Beach project has performed quite well. Of the 880,000 cubic yards placed, there are some 616,800 cubic yards remaining in the placement area. As shown from Figure 7, the volume has increased slightly during the last intersurvey period and the additional plan area has decreased slightly during the last intersurvey period, from 11.2 acres to 10.3 acres. This area is relative to the pre-nourishment condition when there was almost no beach. As of the April 1999 survey, approximately 70% of the volume placed remained in the placement area and 50% of the dry beach plan area was present. It is evident that the groins are functioning to stabilize the sand placed in the 1995 beach nourishment project.
The monitored north beach area accumulated approximately 31,700 yd3 during the most recent intersurvey period and the average shoreline receded less than 1 foot in this region.




c 100
- - - - - . . . . . . . . . . v o ,
...* Pla
.... ... ... .................. ..............
ry 80----A
E 0 ........... ....... . . .* A . .. ,--- - - .. . -
.70
0 . . .. . .. . ............ ...-- -... . ..... .. ........... .... ... ..06 0 -- - - - - -
o. . . . . . . . . .... . . .. . ... . . .. 1 .1 . . .
4 0 . .. ..... .......... -- M
U) a: (30)
30 ..... S'
n 20 ~........... "< ..........=UL 20 ------- <
< <
C:, 1 . . . .......... ..........---0
Q-D I I I I t
0 1 2 3
Years After Completion of Nourishment
Figure 7. Percentage Total Volume and Plan Area
Remaining in Placement Area




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.