HOW UNIQUE WAS TROPICAL STORM IRENE? A COMPARISON OF DEPOSITS FROM HISTORICAL FLOODS ON THE LOWER CONNECTICUT RIVER

Here we present results from a 550 cm long sediment core from Keeney Cove, an abandoned cut-off meander of the Lower Connecticut River formed during a spring flood in 1692. The stratigraphic profile begins with varved sediments from Glacial Lake Hitchcock overlain by an unconformity formed when the river incised into these glacial deposits. Grain size decreases above this unconformity and marks the gradual closing of the upriver inlet into the lake. Inorganic and notably dense deposits interbed the upper mud facies and correlate to the timing of historical floods. The resultant sedimentation from Irene is apparent within cores collected immediately following the event. Typical flood deposits are coarse grained, however, Irene sediments are anomalously fine grained and similar in size and composition to underlying glaciolacustrine sediments. Flooding and landscape disturbance during Tropical Storm Irene was particularly extreme within the upper watershed, however, discharge was relatively moderate within the lower river near Keeney Cove. Irene’s unique deposit may reflect the sedimentary fingerprint of flooding on the new managed river system following widespread flood control upriver.