Suspended-sediment flux and retention in a backwater tidal slough complex near the landward boundary of an estuary

Estuaries and Coasts
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Abstract

Backwater tidal sloughs are commonly found at the landward boundary of estuaries. The Cache Slough complex is a backwater tidal region within the Upper Sacramento–San Joaquin Delta that includes two features that are relevant for resource managers: (1) relatively high abundance of the endangered fish, delta smelt (Hypomesus transpacificus), which prefers turbid water and (2) a recently flooded shallow island, Liberty Island, that is a prototype for habitat restoration. We characterized the turbidity around Liberty Island by measuring suspended-sediment flux at four locations from July 2008 through December 2010. An estuarine turbidity maximum in the backwater Cache Slough complex is created by tidal asymmetry, a limited tidal excursion, and wind-wave resuspension. During the study, there was a net export of sediment, though sediment accumulates within the region from landward tidal transport during the dry season. Sediment is continually resuspended by both wind waves and flood tide currents. The suspended-sediment mass oscillates within the region until winter freshwater flow pulses flush it seaward. The hydrodynamic characteristics within the backwater region such as low freshwater flow during the dry season, flood tide dominance, and a limited tidal excursion favor sediment retention.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Suspended-sediment flux and retention in a backwater tidal slough complex near the landward boundary of an estuary
Series title Estuaries and Coasts
DOI 10.1007/s12237-012-9574-z
Volume 36
Issue 2
Year Published 2013
Language English
Publisher Springer
Contributing office(s) California Water Science Center, San Francisco Bay-Delta
Description 19 p.
First page 300
Last page 318
Country United States
State California
Other Geospatial Sacramento-San Joaquin Delta, San Francisco Bay