21-7 Beaver-Induced Sedimentation in River Corridors of Eastern Connecticut

Session: Functions of River Corridors, Floodplains and Wetlands (Posters)

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Beaver dams are natural, semi-permeable features that modify streams by impacting how sediment is transported and stored along river valleys. These structures convert through-flowing channels into ponded, wetland-dominated reaches that can persist for decades. Previous studies in mountainous watersheds within western North America suggest that sedimentation rates decline with beaver pond age, but whether this pattern holds for the New England landscape is not yet known. This study combines sediment coring with historical aerial imagery interpretation to evaluate beaver-induced sedimentation across northeastern Connecticut watersheds. Imagery from 1934 to 2023 is used to identify beaver pond locations and determine the earliest visible appearance of beaver dams and ponded water. Pond locations identified from multi-decadal aerial imagery are analyzed to characterize metrics such as pond area, site permanence (permanent vs. intermittent), and geomorphic setting (main-stem vs. off-channel, drainage area). Three sites were selected for detailed sediment study through sediment coring at beaver ponds spanning ~5–40 years. Sediment cores are analyzed for grain size, loss-on-ignition, bulk Pb, and geochronology (¹³⁷Cs and ²¹⁰Pb), and age–depth models are used to reconstruct sediment accumulation through time. Results from these new sites will be combined with two previously studied sites in Connecticut (one of which is ~60 years old) to extend the temporal range of the dataset. Overall, sedimentological and geochemical analyses are used to distinguish beaver-induced deposits from other fluvial sediments in these river corridors. Results from this study will improve our understanding of how beaver ponds alter sediment accumulation and channel form in these river valleys over decadal timescales, with implications for river corridor morphology and wetland development.

Geological Society of America Abstracts with Programs. Vol. 58, No. 2, 2026

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