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-99/023

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 O F TA BLES ........................................................... iii
INTRO DUCTIO N ............................................................ 1
R E SU L T S ................................................................... 3
B each 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
REFEREN CES .............................................................. 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-97C 126 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
I 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 I along with the borrow area and the approximate platform 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-7 ULI AN I I
-ea 0 1.0
-89 Scale (Miles)
R-90
~-91
-93 Typical Groin, One of Eleven
Numbered From S I at the North to S II at the Southern End R-1--Project Site
- 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 I Type of Survey [Dates
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
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 Proiles
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 postnourishment 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




0
z
0
4-a
0 4
Wi
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 ........ ........ A pril 1996
.......- August 1996
August 1997 ....... August 1998
September 1999
. . . . . . . .. -

- -----------------------




__20
October 1995
o .... April 1996
> 10------ August 1996
---- August 1997
Z '.A'.August 1998
o r September 1999
> A ...
0w.-10......... ............. .....................
WU 30
0 1000 2000 3000
Seaward Distance from Monument (ft)
Figure 3. Profiles at DNR Monument R-970126 Located
Approximately Midway Along Nourished Project




20
O) October 1995
> 1 0--- --- --- -- --- ... .... .. ... .... ... ... ... A pril 1996
------- August 1996
Z August 1997
O August 1998
0 September 1999
4-20
U30 10 0030
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
O 10.......................................... ........ April 1996
> %N------- August 1996
---- August 1997
o September 1999
-4-0
> -10 ------0
W -40
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.




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 prenourishment 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

a)
-.
0

0
Ul)

I I

4000

-, -

I I I

5000

6000

7000

Distance South of Monument R-94E (ft)
Figure 6. NGVD Shoreline Changes Due to Nourishment Project

K

200

Project Limits

F/7i

1996 st 1996 st 1997 st 1998 ember 1999

100
0

V7

-100

1000

8000

April
-------- Augu
------- Augu
- .Augu
- -.. SeptE
- - -,- A
C") ..(0- 00:O)
C/) Cl) U) U) U) CI) U)
. .. .. . .. . ., .. ,, ,, . ..




300

-August 1997
2 0 0 . . . .... .... . . . . A u g u s t 1 9 9 8
"( ......... September 1999
ai)X U 1 0O 0 .............. . 4;. 1 ." j ........ ..... .......... .... .........
0'-')' .-" -- .A.,i '-W
(/) CO C O C) :) l) (D ,.) ) CO.. ).'.2
E
0 0 Project Limits
-100' J
0 1000 2000 3000 4000 5000 6000 7000 8000
Distance South of Monument R-94E (ft)

Figure 7. Volume Changes Due to Nourishment Project




- 100 '_______,___'
.E--- Volumes "U 7 ............................ ...... ........ ....A, P lan A reas
E
. ...... . . . . . . . . . . . . . . .... . . . . . . .
80
U,)
. . . . .. . . . . .... . . .. . . ... .... . . . . . . .
E 70
0-... .. . . .. .. .. . .. .. .. .. ...... ..
0 .... .... A,- ,- ................
1 . ... . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . .. . ... . . . . . . . .
0o 0)
I.-(1 C F )p
n)) 0)
0. ..... .-LU
Yer Afe Copeio fNursmn
oj10
0
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-941 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. UFLJCOEL-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.