WHAT THE EVIDENCE SAYS
Coupled ADCIRC–SWAN simulations of Mobile Bay compared vegetated and unvegetated marsh scenarios under Hurricane Isaac and a reduced-atmospheric-forcing scenario. Marsh vegetation represented through increased bottom roughness produced minimal average reductions in adjacent-buffer hydrodynamic energy under the baseline extreme event, while the reduced-forcing scenario produced about a 21% average reduction. Compound river and coastal forcing also substantially increased modeled extreme flooding relative to coastal forcing alone.
WHY IT MATTERS / OUR READ
Nature-based infrastructure has a performance envelope. The useful design question is not whether marshes ‘protect’ a coast in the abstract, but under which storm intensity, geometry and compound-forcing conditions their attenuation remains consequential—and what gray or operational measures carry the residual risk.
CAVEATS / UNCERTAINTY
This is scenario-based hydrodynamic modeling, not measured avoided damage. Vegetation was represented through roughness rather than explicit stems and wave attenuation, flow velocity lacked observational validation, and the reduced-forcing case is not a flood-frequency or return-period analysis.
SOURCE
Frontiers in Marine Science
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