Waveland, Mississippi Local Hazard Mitigation Plan Update – Critical Evacuation Routes

The City of Waveland, Mississippi developed its Local Hazard Mitigation Plan (LHMP) in 2013 to update its 2007 plan, document the city’s hazard mitigation planning process, and identify relevant vulnerabilities and strategies to increase resiliency. The 2013 LHMP added climate change as a new hazard not previously addressed, as well as several other climate-related hazards such as coastal erosion, drought, extreme heat, and flooding. The LHMP assesses Waveland’s vulnerability to the hazards identified, as well as its hazard mitigation capabilities, and identifies evacuation planning as a high priority action item in light of the vulnerabilities identified.

The LHMP contains a Risk Assessment presented as four components: Hazard Identification, Hazard Profiles, Vulnerability Assessment, and a Capability Assessment. The Risk Assessment is followed by a Mitigation Strategy, identifying goals and objectives for addressing the identified risks. In the Hazard Identification, nine new hazards were added to this current plan that were not addressed in Waveland’s 2007 plan: climate change (storm surge, sea level rise); coastal/canal bank erosion; dam/levee failure; drought; earthquake; extreme heat; extreme winter weather; flood: stormwater/ localized flooding; and wildfire.

In addition to reviewing the other significant hazards affecting the region, the Hazard Profile describes the current and projected impacts of climate change and sea-level rise (SLR). The climate change Hazard Profile includes an extensive review of a variety of global and local climate and SLR projections. Waveland’s mitigation planners selected three scenarios predicting SLR by 2100, based on a combination of the SLR data in the Mississippi Department of Marine Resources report Assessment of Sea Level Rise in Coastal Mississippi and available inundation data from NOAA. These scenarios - 1 foot SLR in the best case scenario, 3 feet SLR in the average case, and 6 feet in the worst case scenario - were used in further mapping and vulnerability analysis in the LHMP.

The Hazard Profile also includes NOAA SLOSH model storm surge estimates of 22 to 24 foot potential surge across the Gulf Coast from a major hurricane, without accounting for future SLR. Projections indicate that a category 5 hurricane on a westerly track could threaten transportation assets at or below 30 feet above mean sea level; the entire community of Waveland is less than 28 feet above mean sea level.

The Hazard Profile indicates that more frequent flooding, including tidal, rain event, and storm surge flooding, will impact transportation infrastructure by disrupting travel and causing damage to roads, highways, bridges, and other structures. The LHMP includes a map of Waveland’s key evacuation routes, noting where these routes intersect low lying areas of four feet elevation or less. The LHMP recommends further evaluation of road elevations for key routes. The LHMP also maps critical facilities and evacuation routes against Federal Emergency Management Agency (FEMA) DFIRM flood zones. The Hazard Profile notes that Highway 603, one of two primary evacuation routes, was inundated during Hurricanes Isaac and Katrina and not usable to evacuate Waveland.  

As part of the LHMP update process, a comprehensive review and update of the Mitigation Strategy portion of the plan was conducted. The updated 2013 LHMP adds evacuation planning as a new, high priority action item, because some evacuation routes may be blocked by flooding during severe storm events. The Waveland Community Rating System Coordinator is responsible for reviewing the current evacuation plan in light of the vulnerabilities identified in the LHMP. The City of Waveland developed this LHMP update pursuant to the requirements of the Disaster Mitigation Act of 2000 so that Waveland would be eligible for the FEMA Pre-Disaster Mitigation and Hazard Mitigation Grant programs.

 Waveland completed this planning process with a grant from FEMA.

This Adaptation Clearinghouse entry was prepared with support from the Federal Highway Administration. This entry was last updated on January 29, 2015.

 

 

Publication Date: March 2013

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  • City of Waveland, Mississippi

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