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Turbidity Hysteresis in an Estuary and Tidal River Following an Extreme Discharge Event

Authors:

David Ralston

Brian Yellen

Jonathan Woodruff

Sarah Fernald

Publication Type:
Journal Article
Year of Publication:
2020
Publisher:
American Geophysical Union (AGU)
Secondary Title:
Geophysical Research Letters
ISSN:
0094-8276, 1944-8007
DOI:
10.1029/2020gl088005
Issue:
15
Volume:
47
Year:
2020

Abstract

Nonlinear turbidity-discharge relationships are explored in the context of sediment sourcing and event-driven hysteresis using long-term (≥12-year) turbidity observations from the tidal freshwater and saline estuary of the Hudson River. At four locations spanning 175 km, turbidity generally increased with discharge but did not follow a constant log-log dependence, in part due to event-driven adjustments in sediment availability. Following major sediment inputs from extreme precipitation and discharge events in 2011, turbidity in the tidal river increased by 20–50% for a given discharge. The coherent shifts in the turbidity-discharge relationship along the tidal river over the subsequent 2 years suggest that the 2011 events increased sediment availability for resuspension. In the saline estuary, changes in the sediment-discharge relationship were less apparent after the high discharge events, indicating that greater background turbidity due to internal sources make event-driven inputs less important in the saline estuary at interannual time scales.