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dc.contributor.authorFerré, Benedicte
dc.contributor.authorSherwood, Christopher R.
dc.contributor.authorWiberg, Patricia L.
dc.date.accessioned2018-07-25T12:57:12Z
dc.date.available2018-07-25T12:57:12Z
dc.date.issued2010-02-01
dc.description.abstractSediment transport and the potential for erosion or deposition have been investigated on the Palos Verdes (PV) and San Pedro shelves in southern California to help assess the fate of an effluent-affected deposit contaminated with DDT and PCBs. Bottom boundary layer measurements at two 60-m sites in spring 2004 were used to set model parameters and evaluate a one-dimensional (vertical) model of local, steady-state resuspension, and suspended-sediment transport. The model demonstrated skill (Brier scores up to 0.75) reproducing the magnitudes of bottom shear stress, current speeds, and suspended-sediment concentrations measured during an April transport event, but the model tended to underpredict observed rotation in the bottom-boundary layer, possibly because the model did not account for the effects of temperature–salinity stratification. The model was run with wave input estimated from a nearby buoy and current input from four to six years of measurements at thirteen sites on the 35- and 65-m isobaths on the PV and San Pedro shelves. Sediment characteristics and erodibility were based on gentle wet-sieve analysis and erosion-chamber measurements. Modeled flow and sediment transport were mostly alongshelf toward the northwest on the PV shelf with a significant offshore component. The 95th percentile of bottom shear stresses ranged from 0.09 to 0.16 Pa at the 65-m sites, and the lowest values were in the middle of the PV shelf, near the Whites Point sewage outfalls where the effluent-affected layer is thickest. Long-term mean transport rates varied from 0.9 to 4.8 metric tons m−1 yr−1 along the 65-m isobaths on the PV shelf, and were much higher at the 35-m sites. Gradients in modeled alongshore transport rates suggest that, in the absence of a supply of sediment from the outfalls or PV coast, erosion at rates of ∼0.2 mm yr−1 might occur in the region southeast of the outfalls. These rates are small compared to some estimates of background natural sedimentation rates (∼5 mm yr−1), but do not preclude higher localized rates near abrupt transitions in sediment characteristics. However, low particle settling velocities and strong currents result in transport length-scales that are long relative to the narrow width of the PV shelf, which combined with the significant offshore component in transport, means that transport of resuspended sediment towards deep water is as likely as transport along the axis of the effluent-affected deposit.en_US
dc.description.sponsorshipUS Environmental Protection Agency Palos Verdes Superfunden_US
dc.descriptionAccepted manuscript version. Published version available at <a href=https://doi.org/10.1016/j.csr.2010.01.011> https://doi.org/10.1016/j.csr.2010.01.011</a>. Accepted manuscript version, licensed <a href=http://creativecommons.org/licenses/by-nc-nd/4.0/> CC BY-NC-ND 4.0.</a>en_US
dc.identifier.citationFerré, B., Sherwood, C.R. & Wiberg, P.L. (2010). Sediment transport on the Palos Verdes shelf, California. Continental Shelf Research, 30(7), 761-780. https://doi.org/10.1016/j.csr.2010.01.011en_US
dc.identifier.cristinIDFRIDAID 348299
dc.identifier.doi10.1016/j.csr.2010.01.011
dc.identifier.issn0278-4343
dc.identifier.issn1873-6955
dc.identifier.urihttps://hdl.handle.net/10037/13266
dc.language.isoengen_US
dc.publisherElsevieren_US
dc.relation.journalContinental Shelf Research
dc.rights.accessRightsopenAccessen_US
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Geofag: 450en_US
dc.subjectVDP::Mathematics and natural science: 400::Geosciences: 450en_US
dc.subjectSediment transporten_US
dc.subjectErodibilityen_US
dc.subjectDDTen_US
dc.subjectPCBsen_US
dc.subjectNumerical modelen_US
dc.subjectUSAen_US
dc.subjectCaliforniaen_US
dc.subjectPalos Verdesen_US
dc.titleSediment transport on the Palos Verdes shelf, Californiaen_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US
dc.typePeer revieweden_US


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