Coastal Hazards, Risk Assessment, and Property Damage Mitigation David M. Bush University of West Georgia Components of Risk Hazards Vulnerability Hazards are the Physical Processes Storms Earthquakes Floods High winds Vulnerability Fixed habitations and related structures: Docks Wharfs Buildings Pipelines Utilities Roads Damage PotentialPrimary Factors Elevation Forest Cover Elevation Elevation is a primary factor in determining flood zones Areas above A-zones are at lower risk Areas in V-zones (exposed to wind and waves) are at highest risk Vegetation Vegetation (especially maritime forest and dense shrub thicket) protects structures from wind damage Vegetation can offer a barrier against storm surge and waves Vegetation anchors sediment, stabilizes landforms, and preserves elevation Preliminary Risk Assessment FLOOD ZONEVEGETATIONRATING V---Extreme ANone or sparseHigh A Dense shrub or forest Moderate Above ANone or sparseModerate Above A Dense shrub or forest Low Responses to an Eroding Shoreline Hard Stabilization Seawalls, groins, breakwaters, etc. Soft Stabilization Beach replenishment, dune building Relocation or retreat Move back from eroding shoreline Hard Stabilization (Seawalls, etc.) Advantages Most dependable way to save beachfront property Disadvantages Degrades the recreational beach Reduces beach access Costly unsightly Modes of Beach Destruction by Seawalls Placement Loss Seawall is built on the recreational beach Passive Loss Beach continues to retreat and narrows in front of the seawall Active Loss Seawall directly causes erosion Soft Stabilization (Beach Nourishment) Advantages Widens the beach Protects buildings while beach is in place Disadvantages Temporary Costly Unknown environmental effects Relocation or Retreat Advantages Responds to sea-level rise Preserves the beach Saves shoreline stabilization costs Preserves builidings Disadvantages Politically difficult Potentially costly Loss of land Mitigation Options Hard Stabilization Soft Stabilization Vegetation Development and infrastructure Zoning and land use planning Mitigation Engineering Strengthen or move buildings Armor the coast Land Use Planning Limit or reduce development density Can help implement new techniques such as clustered housing Easiest with new developments Our Approach to Mitigation Coastal landform protection, restoration, augmentation Mostly low cost Many things individuals can do Environmentally sensitive Considers geologic/oceanographic processes PAR For the Shore Preserve, Augment, Restore Dunes (frontal and interior) Coastal barriers of all types Mangroves Shoals River mouth bars Maritime forest Add new sand to island