Sediment transport and deposition processes near ocean outfalls in southern California

ASTM Selected Technical Papers
By: , and 
Edited by: Locat J.Galvez-Cloutier R.Chaney R.Demars K.

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Abstract

An urbanized coastal ocean that has complex topography and large-scale atmospheric and oceanographic forcing can contain a variety of sediment and pollutant distribution patterns. For example, the central southern California Bight has two large embayments, Santa Monica and San Pedro Bays, that are connected by a short, very narrow shelf off the Palos Verdes peninsula. The complex topography causes quite different oceanographic and sediment distribution patterns in this fairly small region of the coastal ocean. In addition, three sewage outfalls discharge material over the outer shelf. A large suite of sediment cores was obtained and analyzed for contaminants, physical properties, accumulation rates, and grain sizes. Arrays of instrumented moorings that monitor currents, waves, water clarity, water density and collect resuspended materials were deployed. The data and models developed for the Palos Verdes margin suggest that a large reservoir of DDT and its byproducts exists in the coastal ocean sediment and will continue to be exhumed and transported along the shelf for a long time. On the Santa Monica shelf, very large internal waves, or bores, are generated at the shelf break. The near-bottom currents associated with these waves sweep sediment and the associated contaminants from the shelf onto the continental slope. On the San Pedro margin an initial examination of recent data collected in the coastal ocean does not suggest that bacterial contamination on local beaches is primarily caused by transport of material from the adjacent ocean outfall.

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Publication type Conference Paper
Publication Subtype Conference Paper
Title Sediment transport and deposition processes near ocean outfalls in southern California
Series title ASTM Selected Technical Papers
DOI 10.1520/STP11567S
Issue 1442
Year Published 2003
Language English
Description 13 p.
Larger Work Title ASTM Special Technical Publication
First page 253
Last page 265
Conference Title Contaminated Sediments: Characterization, Evaluation, Mitigation, Restoration, and Management Strategy Performance
Conference Location Quebec City, Quebec, Canada
Conference Date May 26-28, 2003
Country United States
State California
Other Geospatial southern California
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