County presents vulnerability assessment outlining 25 resiliency "hot spots," seeks grants for adaptation

Amy Eason, environmental resource engineer for Martin County and the county's Resilient Martin lead, presented the countyvulnerability assessment to the CRA on July 28, describing exposure, sensitivity and adaptive capacity for county assets and identifying priority areas for work.

"A vulnerability assessment looks at exposure are you wet? sensitivity how wet are you? and adaptive capacity are you sinking, swimming or drowning?" Eason said, summarizing the framework required under Florida law. She said the assessment evaluates transportation, critical infrastructure, community and emergency facilities, and natural, cultural and historical resources against tidal flooding, storm surge and rainfall, using present-day and future projections (NOAA intermediate low and intermediate high scenarios).

Eason said the countywide analysis produced 25 "hot spots" that concentrate assets and climate risk and that planners will use those areas to prioritize adaptation funding. She described modeled combinations of sea-level rise, a 100-year storm surge and a 25-year rainfall event, which in some scenarios raise exposure to an elevation near 15.5 feet.

The assessment also included an urban-heat analysis to guide tree planting and green infrastructure, a land-use transition model that projects conversion of freshwater swamps to saltwater marsh and open water, and a sensitivity analysis that includes social vulnerability.

Eason outlined adaptation approaches the county will consider: protection (for example seawalls), accommodation (raising buildings and roads), retreat and avoidance. She said local, building-scale adaptations can show a 4:1 cost-benefit ratio, while community-scale measures may show a 2:1 ratio.

Eason described recent resiliency work and funding: she said Martin County has received about $625,000 in state planning funds and "several funds, about $11,000,000" aggregated for planning and infrastructure projects, typically requiring a 50/50 match and often combined with federal funding. She cited completed and ongoing projects such as MacArthur Boulevard (raised about 2.5 feet), dune and seawall work at Bathtub Beach and other coastal protections as examples of resilience measures already built.

Eason said the vulnerability assessment will be followed by an adaptation plan that will include targeted resilience planning, shoreline protections (including living shorelines and living seawalls), infrastructure fortification, land-use planning and regional coordination with agencies such as South Florida Water Management District. She said the county will continue public engagement and submit the assessment to the Florida Department of Environmental Protection as part of required deliverables.

"We want to make sure the public is aware of the situation because we could be in a situation where the public may not like the policies we come up with," Eason said, adding that outreach includes flood-insurance information and revisions to the countys local mitigation strategy.