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Intra-site differences in nearshore bar behavior on a nontidal beach (Sulina-Sf. Gheorghe, Danube Delta coast)

Domenii publicaţii > Ştiinţele pământului şi planetare + Tipuri publicaţii > Articol în volumul unei conferinţe

Autori: Tatui, F.; Vespremeanu-Stroe, A.; Ruessink, B.G.

Editorial: Journal of Coastal Research, SI64, p.840-844, 2011.

Rezumat:

Long-term, cyclic offshore migration is a common occurrence on many multiple-barred beaches. The inter-site
variability of this behavior was documented to be related to differences in certain key geometric parameters.
Besides the inter-site variability, there also appears to be considerable intra-site variability in sandbar behavior,
factors controlling these differences not being properly understood. A 6-year bathymetric dataset collected along
16 km of low-lying nontidal beach, located within the central and southern part of the interdistributary Sulina –
Sf. Gheorghe beach (Danube Delta coast – Black Sea) was analyzed with complex empirical orthogonal
functions to quantify intra-site differences and similarities in cyclic offshore progressive bar behavior. The study
area can be split into 3 longshore sectors with different cross-shore bar behavior characteristics: i) Km 0 – 1:
accretional sector – the lowest slopes, likely to be influenced by the mouth bar dynamics and presenting the
smallest offshore migration rates and the largest cycle return periods; ii) Km 1 – 6: stable sector – the largest
values for bar height and volume and median values for migration rates and cycle return periods; iii) Km 6 -16:
erosive sector – the steepest slopes, with a narrow bar zone and the smallest values in the bar morphometric
parameters, highest migration rates and smallest cycle return periods, including a transition area (Km 6 – 9)
characterized by bar switching. Our analysis clearly states the intra-site differences in spatial and temporal
sandbar behavior on a nontidal deltaic coast as a result of the medium and long-term evolution of the coast, with
substantially different bar behavior on the sediment-rich accretional sector than on the erosive sector.

Cuvinte cheie: Offshore migration, bar migration cycle, longshore sediment transport (LST)

URL: http://www.ics2011.pl/artic/SP64_840-844_F.Tatui.pdf