9 D7. Marine and Coastal Geoscience (Posters)

Monday, 15 April 2024
8:00 AM - 12:00 PM
Grand Ballroom

VULNERABILITY AND RESILIENCE: ASSESSING TIDAL FLOODING AND SEA-LEVEL RISE IMPACTS ON LITTLE CUMBERLAND ISLAND, GEORGIA

Paper number: 9-6
Program: Technical Sessions
Time: 8:00 AM – 12:00 PM

Authors

Abstract

Small island communities are disproportionately affected by sea-level rise, yet prevailing climate initiatives typically prioritize heavily populated coastal cities. Additionally, climate-impact studies, predominantly conducted at regional scales, often overlook the nuanced morphodynamics of small islands. Little Cumberland Island, Georgia, typifies this oversight. The island has minimal development with ~40 homes accessible only by a single dock and dirt roads. Residents report an escalating frequency and magnitude of tidal flooding on low-elevation roads, posing a critical threat to the island's infrastructure longevity. The absence of site-specific flooding predictions leaves residents uncertain about the appropriate timing and approach for road development. This study addresses these challenges through three primary objectives: 1) quantifying the impact of wind velocity on tidal flooding, 2) predicting future flooding events considering sea-level rise, and 3) furnishing actionable results and guidance for island residents. Six strategically positioned pressure sensors were deployed along low-elevation roads to monitor inundation. Recorded tidal elevations, which include impacts from wind setup and local tidal amplification, were then compared to NOAA predictions for an offshore buoy, which do not consider wind effects. The results indicate that northeasterly winds at >15 mph can amplify tidal elevations by up to 50 cm. Extrapolating predicted sea-level rise onto observed tidal elevations suggests a potential doubling in the frequency of high-tide flood events inundating roads by at least 15 cm by 2030 and a nearly tripling by 2040. Consequently, we strongly advocate for the proactive development of flood-resilient elevated roads within the next 5-10 years, offering a pivotal strategy to mitigate the escalating impacts of tidal flooding and ensure the resilience of Little Cumberland Island's vital infrastructure.

Geological Society of America Abstracts with Programs. Vol. 56, No. 2

doi: 10.1130/abs/2024SE-398549

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