Source, conveyance and fate of suspended sediments following Hurricane Irene. New England, USA

Geomorphology
By: , and 

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Abstract

Hurricane Irene passed directly over the Connecticut River valley in late August, 2011. Intense precipitation and high antecedent soil moisture resulted in record flooding, mass wasting and fluvial erosion, allowing for observations of how these rare but significant extreme events affect a landscape still responding to Pleistocene glaciation and associated sediment emplacement. Clays and silts from upland glacial deposits, once suspended in the stream network, were routed directly to the mouth of the Connecticut River, resulting in record-breaking sediment loads fifteen-times greater than predicted from the pre-existing rating curve. Denudation was particularly extensive in mountainous areas. We calculate that sediment yield during the event from the Deerfield River, a steep tributary comprising 5% of the entire Connecticut River watershed, exceeded at minimum 10–40 years of routine sediment discharge and accounted for approximately 40% of the total event sediment discharge from the Connecticut River. A series of surface sediment cores taken in floodplain ponds adjacent to the tidal section of the Connecticut River before and after the event provides insight into differences in sediment sourcing and routing for the Irene event compared to periods of more routine flooding. Relative to routine conditions, sedimentation from Irene was anomalously inorganic, fine grained, and enriched in elements commonly found in chemically immature glacial tills and glaciolacustrine material. These unique sedimentary characteristics document the crucial role played by extreme precipitation from tropical disturbances in denuding this landscape.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Source, conveyance and fate of suspended sediments following Hurricane Irene. New England, USA
Series title Geomorphology
DOI 10.1016/j.geomorph.2014.07.028
Volume 226
Year Published 2014
Language English
Publisher Elsevier
Contributing office(s) Connecticut Water Science Center
Description 11 p.
First page 124
Last page 134
Country United States
Other Geospatial New England