5-3 Assessing Short-term Change in Beach Morphology and Sediment Transport at a Pocket Beach in Madison, Connecticut

Session: Nearshore and Estuarine Research: Dynamics and Future Resiliency in the Coastal Zone (Posters)

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Abstract:

Coastal systems in the northeastern United States are continuously reworked by seasonal wave action and have been widely impacted by global climate change. Due to the protected nature of the Connecticut coast, many coastal areas are not prioritized for coastal erosion research. This project examines seven months of beach profile and sediment change at a narrow pocket beach at Hammonasset Beach State Park in Madison, Connecticut. Four fixed RTK-GPS transects (0m-40m) spanning from the mean water line to the backbeach-marsh boundary were surveyed monthly from May to November 2025 to quantify topographic change. Standard sieving methods were used to analyze the dried sediment samples collected from each transect. Because abundant shell material complicated the grain size statistics, lithic-carbonate ratios were estimated visually. The greatest variability in topography was exhibited on the foreshore, transitioning from steep, coarse early-summer profiles to fully developed summer berms by late August, followed by a shift toward winter morphology in October and November. Abnormally high precipitation rates in June produced the most abrupt changes, including berm formation and localized erosion on the more exposed eastern transects. Sedimentological data support these patterns, with finer, better-sorted grains in summer and coarser, poorly sorted, shell-rich material during the transition to a winter profile. Analysis of historical aerial imagery from 2004 to 2023 indicated slight long-term shoreline movement, suggesting that while the foreshore adjusted rapidly to seasonal forcing, the backbeach and shoreline position remained somewhat stable long-term.

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