Assessment of Sea Level Rise in Coastal Mississippi
Produced by the Mississippi Department of Marine Resources, this report includes a risk assessment and a detailed vulnerability assessment addressing sea level rise impacts to both natural and man-made systems on the Gulf Coast of Mississippi. The report also contains a number of sea level rise resiliency strategies categorized into three primary response pathways of armoring, retreating, and adapting.
The study area includes cities and counties in coastal Mississippi with the highest probability of being impacted by sea level rise - including Hancock, Harrison, and Jackson Counties - also representing one of the more densely populated regions of the State.
The assessment includes a summary of sea level rise projections from eleven different reports and published research papers. The results indicate that coastal Mississippi could experience sea level increases of 16.6 inches in twenty years, 41.5 inches in fifty years, and 74.7 inches by the year 2100.
Along with sea level rise, other concurrent vulnerabilities are assessed such as impacts to flood zones and elevations, erosion potential, ground water level increases, and salinity. The assessment of the coast’s vulnerability to these impacts considered multiple variables including geomorphology, coastal slope, sea level rise, shoreline erosion or accretion, mean tide range, and mean wave height.
The vulnerability assessment finds that natural ecosystems within the Mississippi Sound are at risk to both direct and indirect impacts of sea level rise. Direct impacts include deterioration of wetlands and other estuarine environments that have the potential to affect these systems’ ability to migrate as sea levels increase or decrease. Indirect impacts include changes in salinity, impacts to emergent vegetation, and the ability of sediments to migrate and settle in areas of potential land loss.
For example, Jackson County, Mississippi is home to two substantial National Wildlife Refuges (NWR), including the Mississippi Sandhill Crane NWR and the Grand Bay NWR. Both contain abundant wildlife and unique plant habitats that may be affected by increased water levels, salt intrusion, higher tide levels, and other effects of sea level rise.
The vulnerability assessment also studied man-made systems including residential and commercial land use areas, critical facilities and infrastructure, and potentially vulnerable populations. With high population densities and relatively high development densities in the near-shore areas of the Mississippi Gulf Coast, these man-made systems on the coast are all found to be vulnerable to direct and indirect impacts of sea level rise.
The plan provides an assortment of potential mitigation, planning, and policy options to local and regional entities. Recommended strategies in the categories of armoring, retreat, and adaptation are provided in tables along with respective benefits and constraints.
Table 6.3 provides detail on more than 30 sea level rise adaptation strategies such as to:
- Remove existing hard protection or other barriers to tidal and riverine flow (e.g. riverine and tidal dike removal.
- Integrate climate change scenarios into water supply system.
- Preserve and restore the structural complexity and biodiversity of vegetation in tidal marshes, and seagrass meadows.
Concluding the report, additional recommendations are given as supplementary actions designed to mitigate data gaps and other research deficiencies specific to Mississippi.
Publication Date: July 2011
- Mississippi Department of Marine Resources
- Policy analysis/recommendations