Breaking the Disaster Cycle: Future Directions in Natural Hazard Mitigation
Coastal Erosion Issues; Shifting Hazardous Development Costs to Users
Author: David Salvesen University of North Carolina Chapel Hill Coastal Erosion Issues; Shifting Hazardous Development Costs to Users
¾ Objectives:
10.1 Understand the nature of coastal erosion processes.
10.2 Discuss the political, social, and economic issues raised by erosion impacts.
10.3 Describe the proposed structural and regulatory solutions to coastal erosion.
Future Directions in 2 9/17/2004 Natural Hazard Mitigation Coastal Erosion Issues; Shifting Hazardous Development Costs to Users
¾ Objectives:
10.4 Review the costs of coastal hazards and how they are paid.
10.5 Discuss issues of who should pay for protection of property in hazardous areas.
10.6 Discuss proposed approaches to shifting the costs of hazardous development to property owners, such as risk based taxation.
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¾ Objective 10.1
– Understand the nature of coastal erosion processes:
• Natural processes 9 wind 9 waves 9 current (longshore) 9 sea level rise • Human intervention 9 construction of jetties and groins 9 construction of dams 9 dredging channels or inlets
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Severe beach erosion in Studio City, CA. (Source: FEMA) Future Directions in 5 9/17/2004 Natural Hazard Mitigation Coastal Erosion Issues; Shifting Hazardous Development Costs to Users
¾ Objective 10.2
– Discuss the political, social, and economic issues raised by erosion impacts:
• Rights and responsibilities of beach front property owners • Who should bear the costs? • Disclosure requirements • Permitting processes • Federal policies regarding building in hazard areas
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¾ Objective 10.3
– Describe structural and nonstructural approaches to coastal erosion:
• Structural 9 Hard stabilization 9 Soft stabilization • Non-structural 9 Relocation 9 Land use controls 9 Land acquisition 9 Expenditure limitation 9 Public Notification Future Directions in 7 9/17/2004 Natural Hazard Mitigation Coastal Erosion Issues; Shifting Hazardous Development Costs to Users ¾ Figure 10.2 Mitigating Coastal Erosion: Structural Measures
Hard ¾Seawalls - Vertical walls built on land and parallel to the beach to absorb wave energy. ¾Bulkheads - Similar to seawalls, but are generally smaller. Usually used to protect headland areas and inlet channels. ¾Breakwaters - Fixed or floating structures that are built just offshore, parallel the coast. They serve to reduce the energy of waves before they hit the shoreline. ¾Revetments - Riprap or interconnecting concrete blocks used to protect dunes and beaches from erosion. ¾Jetties - Rock walls or piles built perpendicular to the beach. Generally used to block flow of sand and prevent ship channels from filling in. ¾Groins - Similar to jetties. Usually built to capture migrating sand and increase the width of beaches. Soft ¾Beach nourishment – placing sand on an eroding beach.
Future Directions in 8 9/17/2004 Natural Hazard Mitigation Coastal Erosion Issues; Shifting Hazardous Development Costs to Users ¾ Figure 10.3 Saga of a Seawall
1) An eroding shoreline threatens buildings. 2) In response, homeowners build seawall. 3) Overtime, the wall’s size is increased, and the beach has disappeared. 4) Fifty years later, the seawall is huge, the beach is gone, the shore face has steepened, and the house is gone. Condominiums replace beach cottages, but no beach remains for visitors to enjoy.
Source: Adapted from Pilkey and Dixon, 1996:42
Future Directions in 9 9/17/2004 Natural Hazard Mitigation Coastal Erosion Issues; Shifting Hazardous Development Costs to Users ¾ Figure 10.4 Mitigation Coastal Erosion: Non-Structural Approaches
Relocation – Removing or relocating structures away from eroding areas
Land Use Controls – Zoning - divides land into separate land-use districts or zones and establishes the uses and density of development allowed in each zone. – Subdivision ordinances - governs the division of land into smaller parcels for development or sale. – Building setbacks – establishes minimum distance that new construction must be set back from the ocean’s edge Acquisition – Public purchase of property prone to erosion Expenditure Limitation – Limits public expenditures for infrastructure that supports development in erosion- prone coastal areas Public Notification – Notifies potential purchasers of potential threats from erosion
Future Directions in 10 9/17/2004 Natural Hazard Mitigation Coastal Erosion Issues; Shifting Hazardous Development Costs to Users ¾ Figure 10.5 Relocation of Cape Hatteras Lighthouse (Source: North Carolina Department of Transportation)
Future Directions in 11 9/17/2004 Natural Hazard Mitigation Coastal Erosion Issues; Shifting Hazardous Development Costs to Users
¾ Figure 10.6 States with Setback Controls
¾ Alabama yes ¾ Alaska no ¾ California yes ¾ Connecticut no ¾ Delaware yes ¾ Florida yes ¾ Georgia no ¾ Hawaii yes ¾ Louisiana no ¾ Maine yes ¾ Maryland yes
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¾ Figure 10.6 States with Setback Controls
¾ Massachusetts no ¾ Michigan yes ¾ Minnesota yes ¾ Mississippi no ¾ New Hampshire yes ¾ New Jersey yes ¾ New York yes ¾ North Carolina yes ¾ Ohio no ¾ Oregon yes ¾ Pennsylvania yes ¾ Rhode Island yes
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¾ Figure 10.6 States with Setback Controls
¾ South Carolina yes ¾ Texas no ¾ Virginia yes ¾ Washington yes ¾ Wisconsin yes ¾ American Samoa yes ¾ Guam yes ¾ Northern Marianas yes ¾ Puerto Rico yes ¾ Virgin Islands yes
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¾ Objective 10.4
– Review the costs of coastal hazards and how they are paid:
• Costs to coastal property owners will average a total of $530 million per year • Economic and non-economic costs to public • Federal government role 9 National Flood Insurance Program
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Flooded coastal development in Wrightsville Beach, NC (Source: FEMA) Future Directions in 16 9/17/2004 Natural Hazard Mitigation Coastal Erosion Issues; Shifting Hazardous Development Costs to Users
¾ Objective 10.5
– Discuss issues of who should pay for protection of property in hazardous areas:
• Until 1950s cost borne locally • Disaster Relief Act of 1970 expands federal role • Who benefits from hazard mitigation? • Who pays for hazard mitigation? • Incentives and disincentives for building in hazardous areas
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Cliffside erosion in Pacifica CA. (Source: FEMA) Future Directions in 18 9/17/2004 Natural Hazard Mitigation Coastal Erosion Issues; Shifting Hazardous Development Costs to Users
¾ Objective 10.6
– Discuss proposed approaches to shifting the costs of hazardous development to property owners, such as risk based taxation:
• Risk-based taxation 9 How it works 9 Advantages 9 Disadvantages
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