Beach Management: A Regional Approach.
One community's erosion problems should not
be considered in isolation, as sediment movement along a shoreline
does not adhere to political boundaries dividing cities, counties
or other districts. Successful beach management involves the
coordination of several interrelated components including coastal
engineering, economics and funding, public law and policy, and
environmental issues. Although communities continue to separately
address each of these components, effective beach management
in the future will require a more regional approach with close
collaboration among local communities, state and federal governments.
This will enable more cost effective projects with improved
cost sharing resulting in increased benefits to the entire coastal
Beach Management is dependent upon a thorough understanding
of regional coastal dynamics and the causes of erosion. Coastal
Systems has conducted a number of coastal engineering studies
within the geographic region extending from Hillsboro Inlet
to Government Cut. This thirty-five mile stretch of shoreline
with four inlets encompasses two counties, one taxing district
and ten local municipalities. Available reports and recent hydrographic
survey data have been utilized to calculate volumetric and shoreline
changes within the region and to develop a sediment budget.
The results from these studies have been combined to achieve
a regional understanding of the coastal dynamics and to develop
a beach management plan having a regional perspective.
HILLSBORO INLET TO PORT EVERGLADES
Management practices at Hillsboro Inlet, together
with historical trends of erosion/accretion downdrift were evaluated
in order to understand the sand movement within this littoral
region. This analysis contributed to the development of procedures
to achieve maximum bypassing at Hillsboro Inlet.
A deeper exterior sand trap/channel was proposed
to improve bypassing at the inlet. An estimated 35,600 cubic
yards of sand per year are lost from the littoral system seaward
of the nearshore hardbottom south of the inlet. The proposed
improvements will eliminate this loss and result in the bypassing
of 97% of the estimated 120,000 cubic yards per year net longshore
transport currently arriving at the inlet from the north.
The following conclusions are derived from these studies:
- The 1983 Pompano/Lauderdale-by-the-Sea
(Segment II) Renourishment Project has remained stable
to accretional due to the effective bypassing practices
at Hillsboro Inlet. Recent trends of accretion of
approximately 20,000 cubic yards per year within the
project limits further confirm these findings.
- The five mile stretch of shoreline
south of Lauderdale-by-the-Sea has also remained stable.
This condition indicates that the proposed beach nourishment
necessary to achieve an optimum design width would
be sustained with limited renourishment requirements.
- Substantial accretion is occurring
within the two mile stretch north of Port Everglades
Inlet due to the configuration of the north jetty,
the nearshore spoil shoal, and the lack of a sand
- The proposed improvements to Hillsboro
Inlet will result in reduced offshore losses thereby
creating an increased sediment supply to the downdrift
region. The volume of sediment arriving at Port Everglades
will similarly increase further warranting the need
for a sand bypassing program at Port Everglades.
PORT EVERGLADES TO BAKERS HAULOVER
The 13½ mile segment of shoreline
extending from Port Everglades to Bakers Haulover Inlet is
one of the most unstable segments within all of Broward and
Dade Counties. Beach renourishment projects are required on
an ongoing basis at John U. Lloyd, Hollywood/Hallandale and
Sunny Isles in order to maintain an acceptable beach width.
The volumetric and shoreline changes within this region were
analyzed to evaluate the short-term performance of these projects
and to develop a long-term regional sediment budget. The following
conclusions are drawn:
- The John U. Lloyd segment eroded
at an average rate of 36,000 cubic yards per year
over the 16 year study period. These losses are due
to both the no-bypassing condition at Port Everglades
Inlet and losses into the non-nourished shoreline
segment of Dania.
- The Hollywood/Hallandale segment
is eroding at a unit rate comparable to John U. Lloyd
due to the limited volume of sand arriving at the
project limits and to end losses.
- Overall, the Sunny Isles segment
has not eroded as severely as the above reaches. However,
nearshore erosion rates (above -6.0 feet NGVD) were
in the order of 60,000 cubic yards per year indicating
a significant post-nourishment, cross-shore profile
- A cursory analysis utilizing limited
survey data at Bakers Haulover Inlet indicates an
ebb shoal accretion rate of 32,000 cubic yards per
year. This high accretion rate may be attributed to
recent modifications to the northern inlet jetty and
the substantial volume of sand placed along the beaches
to the north over the last 10 years.
- This segment is most unstable due
to the deficit of sand created by Port Everglades
and the end losses induced by the discontinuities
between renourishment projects.
BAKERS HAULOVER INLET TO GOVERNMENT
The littoral segment between Bakers Haulover
Inlet and Government Cut represents one of the largest beach
nourishment projects in the United States. Approximately 18
million cubic yards of sand have been placed along this shoreline
since the 1960’s. The size of this region and the renourishment
requirements warranted a regional approach to its management
through the development of a regional sediment budget.
Historic shoreline and volumetric changes were
examined in order to develop this budget and to identify existing
hotspot and coldspot areas. Several conclusions and recommendations
are drawn from this study:
- This segment receives a very limited
natural supply of sand from the north. Only 21,000
cubic yards per year bypass Bakers Haulover Inlet.
This results in a deficit within the system which
requires ongoing renourishment efforts. Increased
sand bypassing at the inlet would reduce the deficit
within Bal Harbour and Surfside.
- A large percentage of the observed
nearshore sand losses have accumulated below the 6
feet NGVD contour resulting in a small net loss from
- As much as 20,000 cubic yards per
year are lost from the system at Government Cut through
and around the north jetty.
- The significant hotspot at 32nd Street
may be attributable to changes in shoreline orientation.
The use of structures to correct this hotspot should
be considered. This would result in a better distribution
of the available sand supply.
- Alternatively, it may be feasible
to recycle the surplus sand being transported south
of 32nd Street (117,000 cubic yards per year) to offset
the gross erosion (96,000 cubic yards) occurring to
BENEFITS OF A REGIONAL APPROACH
A regional understanding of coastal dynamics
will enable better planning and coordination of beach management
programs. A more collaborative effort between adjoining communities
and State and Federal Governments would result in better use
of resources, increased funding opportunities and more cost-effective
Some specific benefits of the regional approach include:
- Increased public involvement and
understanding of beach management issues.
- Integration of inlet/port and beach
management plans toward maintaining an entire regional
- Potential for shoreline “smoothing”
by redirecting sediment from coldspots into hotspots.
- Better understanding of the large-scale
demand and availability of sand.
- Optimization of the mining or dredging
of available sand sources.
- Higher priority could be given to
the processing of permits for projects having an opportunity
to share resources.
- Coldspots and their negative effects
on the region could be taken into consideration during
both the permitting and funding allocation of projects.
- Recognition of benefits to adjacent
areas resulting in better cost/benefit ratios, increased
justification, and prioritization for project funding.
- Cost optimization through the consolidation
of smaller projects into a larger littoral regional
- Pooling of resources through local,
state and federal cooperation to cut costs during
Beach management practices may be made more efficient by recognizing
the differences between the natural coastal system and the
political framework. Whereas sand flows across political boundaries,
projects are largely being implemented according to the needs
and efforts of individual communities. Currently, design,
permitting, and funding procedures for implementing beach
projects are generally structured to accommodate these individual
Changes in public policy could provide for stronger
regional beach management planning with greater emphasis on
the benefits and detriments associated with activities in
adjacent communities. Specifically, projects with a larger
regional benefit may be given increased funding, a high prioritization
and/or qualify for accelerated regulatory approvals. Regions
inducing a sediment deficit or other system inefficiencies
should also be encouraged to implement improvements.
A continued evolution and adaptation of
laws, policies and procedures will be required to synchronize
the political and natural systems toward successful regional
Dade County Regional Sediment Budget, Coastal Systems International,
Combined Sand Bypassing and Navigation Improvements at Hillsboro
Inlet, Broward County, Florida, Lin, Paul C.-P, Hansen, Inger
E. and Sasso, R. Harvey, 1996
Hillsboro Inlet Management Plan, Coastal Systems International,
Regional Sand Movement and Performance of Successive Beach
Nourishment Projects, Lin, Paul C.-P, Hansen, Inger E. and
Sasso, R Harvey, 1994
Impact Evaluation of the Proposed Sunny Isles Beach Restoration
Project on the Town of Golden Beach, Coastal Technology Corporation,
Port Everglades Inlet Management Plan, Coastal Technology
Sunny Isles Beach Restoration Project, 18 Month Monitoring
Study, Coastal Technology Corporation, 1993
Port Everglades Sand Bypassing Study, Coastal Technology Corporation,
Dade County Beach Management Plan, Coastal Technology Corporation,
Disclaimer: The material presented in this perspective
is for general information only. The information should not
be used without first securing engineering advice from qualified
personnel with respect to its suitability for any application.
Utilization of this information assumes all liability arising
from such use.
By: Coastal Systems International, Inc.