Publications

Perspective vol. 1
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 region.

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 bypassing program.
  • 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 INLET
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 equilibration.
  • 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 CUT
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 the system.
  • 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 the north.

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 projects.

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 littoral system.
  • 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 project.
  • Pooling of resources through local, state and federal cooperation to cut costs during project implementation.

CONCLUSIONS
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 community efforts.

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 beach management.

References

Dade County Regional Sediment Budget, Coastal Systems International, Inc, 1997

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, Inc, 1995

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, 1994

Port Everglades Inlet Management Plan, Coastal Technology Corporation, 1994

Sunny Isles Beach Restoration Project, 18 Month Monitoring Study, Coastal Technology Corporation, 1993

Port Everglades Sand Bypassing Study, Coastal Technology Corporation, 1988

Dade County Beach Management Plan, Coastal Technology Corporation, 1987

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.

Download a printable PDF version of this newsletter
Beach Management: A Regional Approach.
Beach Management: A Regional Approach.
Hillsboro Inlet to Port Everglades
Hillsboro Inlet to Port Everglades
Port Everglades to Bakers Haulover Inlet
Port Everglades to Bakers Haulover Inlet
Bakers Bakers Haulover Inlet to Haulover to Government Cut

Bakers Bakers Haulover Inlet to Haulover
to Government Cut

Beach Management: A Regional Approach.
Beach Management: A Regional Approach.
Historic Beach Nourishment Projects in Broward
and Dade County

 

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