Southwest Florida Assesses Salt Marsh Vulnerability to Sea Level Rise

^epa.gov/arc-x/southwest-florida-assesses-salt-marsh-vulnerability-sea-level-rise

Salt marshes are vitally important to Southwest Florida.

They serve as storm surge buffers, shoreline stabilizers and
breeding grounds for wildlife. The 2014 National Climate
Assessment projects that salt marshes are at risk both in
Florida and around the country from anticipated climate
impacts including relative sea level rise, coastal erosion,
and more intense storms. The Charlotte Harbor National
Estuary Program and Southwest Florida Regional Planning
Commission, supported by an EPA assistance grant,
collaborated to assess the historic and current range of salt
marshes in this region, and identify their vulnerability to
changing climate conditions.

The Climate Change Vulnerability Assessment and
Adaptation Opportunities for Salt Marsh Types in Southwest
Florida study determined that the current pace of sea level
rise appears to allow some locations for marsh migration on
mainland shores, however "in other locations salt marshes
are drowning where there is no location to move to." The study further mapped these areas to better determine the barriers to
movement and understand where salt marshes are able to, and in the future expected to, move as they adapt to higher sea
levels. By providing information on expected migration and isolation areas, the report helps local governments identify priority
conservation areas to preserve salt marshes and their associated benefits under current and future conditions. The study
included recommendations that governments, stakeholder groups or the public could take as part of their adaptation
strategies (e.g., protecting or armoring of shorelines).

•	Salt marshes

•	2014 National Climate Assessment

How Did They Do It?

Identified climate vulnerability to salt marsh wetlands

•	Identified key climate risks to marshes including sea level
rise, more intense hurricane and storm surges, saltwater
intrusion, and greater levels of sedimentation or erosion.

•	Identified the most at-risk marsh land using a sea level
response map scenario that considered the likelihood of
land use protections (e.g. conservation designation) and
residential adaptation responses (e.g., protecting

or armoring shorelines).

Applicable EPA Tools

Being Prepared For Climate Change Workbook helps
develop a risk-based climate change adaptation plan
consisting of a vulnerability assessment and an action
plan to reduce the most pressing coastal risks.

Being Prepared For Climate Change Workbook

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How Did They Do It?

Developed actionable adaptation recommendations

• Specific recommended actions for municipalities were to:

o Identify existing marsh migration corridors for
maintenance and conduct further research to
identify the highest priority corridors to protect from
future development.

° Support restoration of existing salt marshes by
removal of exotic vegetation, removal of barriers to
tidal connection, and degradation of exotic
dominated adjacent uplands.

° Discourage or stop shoreline hardening including
seawalls, bulkheads, rip-rap, and "living shorelines"
backed by rip-rap.

° Restore impaired water flows to enhance sediment
supply for marsh deposition.

° Back-fill mosquito control ditches, borrow pits, and
agricultural pits to reduce depth and sediment loss
and facilitate salt marsh establishment and
migration.

Applicable EPA Tools

Synthesis of Adaptation Options for Coastal Areas
Guidebook helps identify climate risks to coastal
ecosystems and review adaptation options available
to coastal managers.

The Rolling Easements Primer provides a more in-
depth review of a adaptation option applicable to
protecting coastal marshes.

Similar Cases and More Information

To see another example of how a coastal community assessed their vulnerability view the San Juan Estuary Programs
Vulnerability Assessment Case or the Southeast Florida Climate Compact. Many coastal communities in the southeast may
have to account for other climate vulnerabilities, such as threats to drinking and wastewater services. Saltwater intrusion, sea
level rise and more intense hurricanes can threaten coastal infrastructure. To learn more about how another southeastern
community adapted to saltwater intrusion and potential water quantity considerations see how Tampa Bay Water diversified
their source water to promote resiliency to current and future conditions.

References

• Climate Change Vulnerability Assessment and Adaptation Opportunities for Salt Marsh Types in Southwest Florida

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