BEACHES as INFRASTRUCTURE

Broward County Climate Change Task Force Property and Infrastructure (Built Environment Adaptation) Subcommittee June 19, 2009 Stephen Higgins Beach Erosion Administrator Broward County Natural Resources Protection and Management Division Environmental Protection and Growth Management Department

Beaches: What Are They Good For? Protection Economic Engines Habitat

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The Beach as Economic Engine Broward Tourism 10.6 million visitors to Broward County in 2007 Total expenditures by visitors in 2006-2007: $8.9 billion Beaches ranked 2nd as reason to visit Broward County (visiting family/friends ranked 1st) Broward’s beaches create and sustain 18,000 jobs (1996)

The Beach as Economic Engine Broward Tourism: Foreign visitors spent >$1.8 billion in 2006-2007 Property values raised by $1.8 billion due to beaches (1996) Property taxes increased by $30 million due to beaches (1996)

Tourism tax revenues >$24.5 million in 2007

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The Beach as Protection Broward’s beaches protect >$4 billion in upland property and infrastructure from storm wave damage Beaches serve as sacrificial buffer, eroding while protecting

To succeed as protection, beaches need adequate sand supply Dunes Alongshore sand input from upstream Width: room for dynamic adjustment (landward movement)

Coastal Development 1955

2008 1,800,000 1,600,000 1,400,000

Broward County Resident Population

1,200,000 1,000,000 800,000 600,000 400,000 200,000 0 1920

1930

1940

1950

1960

1970

1980

1990

2000

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Development vs. The Beach  Elimination of dunes  Reduction of beach width  Disruption of alongshore movement of sand  Sand supply in system no longer adequate to naturally repair beach Hollywood Beach, 1962

Development vs. The Beach

Hollywood Beach, 2002

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Current and Traditional Responses to Erosion: Sand Replenishment or “Nourishment”

Replace sand lost via dredging offshore 1 to 2 million cubic yards per project Significant environmental issues w/reefs Costs have grown from $1M to $6M/mile Large projects becoming less feasible

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Responses to Erosion: Sand Bypassing at

Inlets

Sand Trap

Discharge

Breakwater

Weir

Existing Sand Bypassing at Hillsboro Inlet, FL

Responses to Erosion: Sand Bypassing at Inlets  Currently in planning stages  $20M initial construction cost, $0.5M/year avg operations  Will supplement/reduce beach nourishment needs by 50,000 to 80,000 cy/year  Controversial – opposed by interests north, supported by interests south

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Current Responses: Erosion Control Structures

Groins, breakwaters can slow the alongshore and offshore movement of sand Durable, low-maintenance High initial cost - $0.5M to $1M each Can transfer erosion problem to other locations In most applications, must be combined with nourishment

Sea Level Rise (SLR) and Beaches  SLR estimated at 3 to 9

inches by 2030 (Broward CCTF-Science and Technical Committee, May 2009)

 In nature, beaches

respond to SLR or still water lever rise by moving landward, elevating berm, and adjusting profile.

 Inundation maps not

representative of beach response to SLR

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SLR-Induced Beach Erosion Control Response Costs  Assume 3 to 9 inches of SLR by 2030 per Broward CCTF Scientific and Technical subcommittee  Current annual cost of nourishment program (12 miles of beach) = ~$8M  Current and proposed annual cost of sand bypassing = $2.4 million. Bypassing could reduce nourishment costs by up to 50%.  SLR of 3-9 inches by 2030 could result in the need to place an additional 367,200 cy to 1,108,900 cy by 2030 (12 miles of beach)

SLR-Induced Beach Erosion Control Response Costs 17,500 cy to 53,800 cy/year @ $40/cy = $700K to $2.2M/year, inclusive of soft costs Erosion control structures (not armoring) initial costs = $500K/structure x 200 structures for 12 miles of beach = $7.8M/year. High initial construction cost. EC Structures could reduce the short/mid-term need for beach nourishment by up to 75%

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Summary of SLR-Induced Beach Erosion Control Response Costs (amortized over 21 years, 2009-2030)

EXISTING EROSION CONTROL PROGRAM (12 miles)

Activity

Estimated Annual Costs

Beach Nourishment

$8,000,000

Beach Nourishment with Sand Bypassing

$6,400,000

SCENARIOS WITH +9" SLR BY 2030 (12 miles)

Activity Beach Nourishment only

Estimated Net Annual Cost $10,200,000

Beach Nourishment with Sand Bypassing

Beach Nourishment with Sand Bypassing and 200 Structures

$7,500,000

$11,475,000

Notes: 1. Initial construction cost for structures = ~$100M 2. Initial construction cost for PE bypassing = $20M 3. Beach nourishment presupposes available, suitable sand

Alternatives to Beach Erosion Control

Armoring (seawalls) ~$13.2M per mile of beach x 12 miles = $158.4M Decreased tourism revenues, lower property values, fewer taxes

Strategic/opportunistic retreat from beach/barrier island

Gradually reduce commercial and residential density

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Caveats and Disclaimers (of course)

 The foregoing are essentially educated WAG’s  Presupposes constant rate of SLR – not abrupt changes in rate

 Does not account for potential increases in

frequency/intensity of tropical or extra-tropical coastal storms

 Should rate of SLR increase abruptly or if frequency of storms increases, beach erosion control may become untenable

Recommendations  Beach nourishment using local offshore, non-local offshore, and/or nondomestic sand

 Beach nourishment using sands of opportunity (upland mines, imported bulk material, processed glass, construction excavations)  Sand Quality critical (environmental impacts)  Smaller, more frequent events  Upland sand storage, truck to beach

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Recommendations  Maximize sand bypassing @ Port Everglades & Hillsboro Inlet  Build erosion control structures where appropriate  Plan for/implement strategic opportunistic retreat using redevelopment as trigger

 Consider feasibility of armoring where retreat not possible or likely

Thank you

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